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Certified Training nVi Program i Or gr PL MASTER CYLINDER 'il VI t*l ~4 FRONT iiZ IAGNOSIS OF HYDRAULIC BRAKES INCLUDES: C Master Cylinder Brake Valve Disc/Drum Brakes Hydro-Boost Diagnosis Guide Reference Information Ford Parts and Service Division . Training ~and Publications Department, REAR - XJj ^ 5r CTP-1978-4 % ~ rt T r- - / ,, ~ -5--,~ r`r TABLE OF CONTENTS - TABLE OF CONTENTS : J "INTRODUCTION , fV ^ 1 tfDUAL MASTER CYLINDER OPERATION^ - " " : ~ ^ 5 " ' ~~V T ~ - BRAKE VALVE OPERATION % ' '' - ~' K~:'lr ' ~ ~~ 2" ~ DISC BRAKE OPERATION ; ^ -- 8: REAR DISC BRAKE SERVICE' : DRUM BRAKE OPERATION ' ~ ` -* ' - - - -- - ,, " _'' _ . ^7 " "12 v 16 X HYDRO-BOOST OPERATION "7 _ " -* J7 - - HYDRO-BOOST DIAGNOSIS-. _. JO .'NORMAL BRAKE OPERATION ---Pedal '--7 I Warning Light " ~ _ "" ' :" '- " __ I J -- ~ -- ' 24. ~'24 ~ 25 " DIAGNOSTIC-TEST. _ ~1 " " :** 'I* Air Entrapment Tesf ^ * ` ,, 2 Master Cylinder By-Pass Test 5 ~ - 3 Master Cylinder Non-Pressure Leak-Test - ' ' 4 External LeakTest _ ~ ~ " .. . "5 Master Cylinder Compensator Port Test ' ' 6' Power Brake Function Test - - * .... .... . DIAGNOSIS OF PROBLEM CONDITIONS - .. . Low Pedal, Brake Light On ~ Low_PedaL Brake Light Off . - - x - ' Erratic Pedal, Brake Light Oft " * - Excessive Pedal, Brake Light Off ' Spongy Pedal ~ ~~" 7" * * Brakes'Pull ** "" -- ' BrakeFluid Low " ' A* * _. " " .. "; - -27 ' - -- - -- .28 29 ` ~ ------ 30 . "~ - * _ '* 31 x"~" ~ ~^ ~32 _ - 34 - ' - - 34' ... - 35 ' '^ " ' *" --36' 36 "36 37 38 . ' BLEEDING BRAKE SYSTEM " "' - '' 7 ' :39 TECHNICAL SERVICE INFORMATION ' % ^SPECIFICATIONS AND TOOL LIST ' - " . ,, ' '' ` ' "43 ^ /44 : ANSWERS TO SELF CHECKS 2 : 'v ' 45 . . r NOTE. The recommendations and suggestions contained in this publication are made lo assist the dealer in improving his ' " - dealership parts and/or service department operations These recommendations and suggestions do not supersede or. override the provisions ofthe Warranty and Policy Manual and in any cases where (here may be a conflict, the provisions of the Warranty and Policy Manual shall govern - 5 ~"x - = " The descnpuons;testing procedures and specifications in this handbook were m affect at the time the handbook was approved for printing Ford Motor Company reserves the right to discontinue models at any time or change ~ 'specifications design or testing procedures without notice and without incurring obligations * - INTRODUCTION - ABOUT THIS BOOKLET-^ , ^ ^ V'" - \\_I " " * " This booklet contains information for understanding brake hydraulic system operation, testing in case of * j " _ " malfunction and accurate diagnosis based on test results " , " I- 2.- DIRECTION ^ - I ' _ ' " 7- \ 7 : ' / To complete this program booklet ` r _ r.K ' : -` , / ' - _t 1 ' Studyjhe brake system operation *7 _ '. "~ . T. j1 _ ~ ^- Study the diagnostic tests v - - -- ' ' - ~' _,, Study the procedures for specific problem conditions : ' . ~- - Study the brake bleeding procedures _ _ - - " \ z. " =" - .. *- - Perform the self-instruction exercises on vehicles - - " - " - " SELF CHECK QUESTIONS . 7 7- - . ' --I The booklet contains self check questions Check your answers at the back of the booklet Review the -1 materia) for any questions answered incorrectly * " ' t t _ I '"> ' ~ FINAL TEST - r_' A : : ^ ~ ` .. 1 ._ This course wfll be completed when you show your service'manager that you can perform the following - , Identify components of brake hydraulic ^systems and expiam what each does^ \ ~ V. l' Identify norroaJor correct brake operation' " " . ' - -;r ' _ - " ~ . Perform the following diagnosic tests and interpret results .. ' : _ - . ` -' - _ s 1 Air Entrapment Test . " ~4 *_ _ ' ' \ - _* r * ' ,, _* ~ 2 Master Cylinder By-Pass Test ~ ~ ~r - ' ,, I: : -c.;- . - - - " " - ' 3 Master'Cylinder-Non-Pressure Leak Test ^ `: ~ .1 4 External Leak Test - - ^ ~,,I ~ , - -__ I `~ : Z =- ' 5 Master Cylinder Compensator Port Test -- . ' _~ ,,* " 6 Vacuum Power Brake Function Te'st " - ^: ^ -* `- 7 Hydro-Boost Function Test - - c~v ' * "- 8 Accumulator or Brake'Reserve System Test (Hydro-Boost) ., ^ ; 8- Choose appropriate tests from these for specific problem conditions \ ~" Bleed a brake hydraulic systemv '~ = - Rebuild a caliper v. ,, ~ '' ~ 1 DUAL MASTER CYLINDER OPERATION DESCRIPTION OF DUAL MASTER CYLINDER _ ` Separate reservoirs, cylinders and pistons for front and rear systems i COMPENSATING PORTS This RESERVOIR supplies the FRONT brake system GASKET (diaphragm) in cover seals out dirt and moisture PUSH ROD applies brake pedal force to primary (front brake) piston REAR BRAKE PRESSURE OUTLET 0 SECONDARY PISTON pumps fluid to rear brakes SEALS separate front ' and rear system _ " pressures in cylinder PRIMARY PISTON pumps' fluid to apply FRONT brakes BORE END SEAL prevents fluid from leaking out of bore - PISTON CUPS seal fluid from reservoir after passing compensating port _ HOW DUAL CYLINDER APPLIES BRAKES - ~ O Fluid m PRIMARY cylinder is pressurized to apply front brakes Pressure in primary cylinder pushes - SECONDARY PISTON forward I O SECONDARY CYLINDER " - is pressurized to - " apply rear brakes' f BRAKE VALVE is used to - (a) Delay (meter) front brake application on some models (b) Proportion rear pressure to front pressure on some models (c) Trigger warning system _ in case of failure on all ' models 2 PUSH ROD forces primary ' piston forward BOOSTER or HYDRO-BOOST (if used) increases force into master cylinder PEDAL is depressed DRUM-SHOE brakes are used on most rear wheels (and some front wheels) CAUPER-DISC type brakes are used on most front wheels (and some rear wheels)________ DUAL MASTER CYLINDER OPERATION o DUAL MASTER CYLINDER OPERATION TYPICAL MASTER CYLINDER COMPONENTS Disc brakes require larger reservoirs _ RETAINER SECONDARY SYSTEM ^ _ BRAKE OUTLET o rf USE seat/ I ON stop RIMARY SYSTEM B0LT BRAKE OUTLET /1 SECONDARY pTMhy ^ON ASs!mBLY aRSPMRI y MASTER CYLINDER BODY BLEEDER SCREW SHIPPING PLUG PRIMARY PISTON ASSEMBLY TUBE SEAT SECONDARY PISTON ASSEMBLY 4 BRAKE VALVE OPERATION ; GENERAL DISCRETION OF BRAKE VALVE ,, :~ ' 3 valvescontained m one body for front disc /rear drum operation .Metering valve not used in all systems - ~ ` I Pressure outlet hues from master cylinder go to BRAKE VALVE f Front brakepressure : is applied to metering - ~ vaJve and differential valve WARNING SWITCH is closed if differential valve shifts - DIFFERENTIAL VALVE shifts if pressure is lost to one ~_ system ^ ) METERING VALVE ' delays fuU appbcatioo front disc brake ~' operation untQ rear - < brake shoes are applied | PROPORTIONING VALVE . reduces pressure to -- Rear brake pressure is rear brakes during applied to differential ' hard application ' - -- valve and proportioning valve . ~ - TYPICAL BRAKE VALVES _*^ _ WITH METERING-VALVE _" WAGNER ELECTRIC DESIGN' " * ' KELSEY-HAYES DESIGN - : COMPACT AND SUBCOMPACT - VALVE: ` Metering valve not used on 4-wheel disc brakes BRAKE VALVE OPERATION PRESSURE DIFFERENTIAL VALVE " NORMAL" OPERATION ~ - ' I " * Rear brake pressure * is applied here - - - . Front brake pressure : ~ "~ is apphed here -- ' - ' = j~J \ PISTON is normally held centered by equal pressure ' at both ends ~ . , Switch trigger extends into groove" and switch is open BRAKE MALFUNCTION A leak m citherL\ system drops pressure to that systera - = I The piston moves toward the"reduced pressure side : 5 i Trigger is pushed in to close switch and ,, illuminate brake warning ' "light on instrument panel PROPORTIONING VALVE __ ; ~" : " ,,, ^ "- _ Used on front disc rear drum brake and 4-wheel disc In heavy application, reduces pressure to rear brakes~ ~~ ' ' -; ~ I ~ if" --~ - "Reduces possibility of early rear lockup, proportions less braking effectiveness to rear brakes "' Pressure is equal m both fanes from master cylinder to brake vaive PROPORTIONING VALVE begins to restrict flow to rear brakes . Pressure to rear brakes is reduced * 6 0 BRAKE VALVE OPERATION METERING VALVE~ V , " Delays full effectiveness of front disc brakes until rear brakes'are applied As (he master " cylinder pressure builds up ': ; ) METERING VALVE moves to a boId-ofT _ position. _ Pressure increase is sensed at the metering valve -- ' Full pressure ts " -- applied to _ i frontbrakes -- - FULL APPLICATION '- , -SELF-INSTRUCTION I" ',, _ > '_ -_ ' ' I Disassemble a dual master cylinder and ' familiarize yourself with its parts and how ~ ' they go together ; " -- - . r. ~ " - ',, - 2 Locate a brake' valve on a vehicle and' ,,trace the pressure lines from the master - cylinder and to the front and rear brakes 3 Identify the brake warning switch and electrical wiring to the warning light .-- - - ; " . SELF CHECKS '' ~- ' - Answer the following and check your . : = : - _* ' 1 What is'a master cylinder compensating * . ' port'' - -~ - =A - -. _ - _~ _ ' -- -' '-' ,- 2 How does the primary piston in the master cylinder actuate the secondary piston m ' * normal operation7 - ' - r,-_- Q - '- -- -`r - .. ~ 3 If the brake system leaks, what happens7 * (Give two occurrences) " - ' ' '- '~ ~ - 7 DISC BRAKE OPERATION FRONT DISC BRAKE OPERATION SLIDING CALIPER DESCRIPTION -- (Applies to Ford, Mercury, Granada, Monarch,-Lincoln Continental, Continental Mark IV and Versailles) - ......... SECTIONAL VIEW . PISTON is applied by hydraulic O OUTBOARD PAD AND LINING j pressure to apply brake pads - - presses against _, ~ outer braking'surface . ' - of rotor' _ [ CALIPER HOUSING 'is anchored but . can slide against ~ " anchor plate -INBOARD PAD AND LINING presses against ,, inner braking' surface of rotor ROTOR is anached at hub's to wheel and turns with wheel ~ ,, r_ DUST BOOT keeps contamination out of piston cylinder " ~ ANCHOR PLATE provides mounting for caliper and _ sliding Efface ~ 8 DISC BRAKE OPERATION FRONT DISC BRAKE OPERATION SLIDING CALIPER OPERATION DISC BRAKE OPERATION FRONT DISC BRAKE OPERATION PIN SLIDER CALIPER OPERATION -- (Applies to Fairmont and Zephyr) HOW THE PISTON SEAL ADJUSTS BRAKES PISTON SEAL HAS 3 FUNCTIONS I 1 - Seal pressure in the - cylinder - -- 2 Return "spring" for the piston - ' i 3 Automatic adjustment for lining wear on front caliper brake system ~"- - Q When linings wear Return distance is equal to relaxing - travel of seal - less than apply distance - if Unings are worn 9 10 DISC BRAKE OPERATION ` REAR DISC BRAKE OPERATION -- (Applies to Continental Mark IV and Versailles, optional on , Lincoln Continental, Ford, Mercury, Granada'and Monarch); r ~ _," : - "- Brakes are applied same as front disc brakes- ~ `J" - ' _ ^ ~y_ ~ x Rear'parking brakes are adjusted automatically by an adjuster within the piston - _ .y REAR DISC BRAKE SERVICE . ; PISTON REMOVAL The rear'disc brake piston is removed differently than'the front disc brake piston' ~- ' ,,v With the caliper assembly removed,'remove the parking brake lever end retainer,operating shaft - and balls Remove the anti-rotation pm with a magnet Remove the thrust screw with an alien-head ' - c ` - EXPLODED VIEW" s`"' The caliper consists of three (3) major groups PARKING BRAKE " - MECHANISM GROUP HOUSING AND " . Q - INLET PORT (MONARCH GRANADA" LINCOLN MERCURY - VERSAILLE AND FORD) . END RETAINER II REAR DISC BRAKE SERVICE O ADJUSTER INSPECTION Inspect can for ` ` Loose ~ ^ ,, ' Visible damage /SCREW ORIVERSv f Insert thrust screw in adjuster until it ' bottoms ' ~ ' | Insert two screwdrivers - . under thrust screw and pry '"up under the thrust screw The nut should rotate in ~ one direction and the thrust screw move outward * - - RESULTS REQUIRED - * . ' 'NUT TURNS - . -L - ' ' THRUST SCREW MOVES OUTWARD - NOTE _- Adjuster is not serviced separately Replace piston assembly if , - Adjuster is loose'or high in piston (not bottomed) ' -- ~ "Adjuster is damaged " ^~ rFails test - Brake adjustment is regularly too aght, loose or doesn t work ^ Thrua screw is markedRICHT orLEFT The piston and thrust screws are not interchangeable ~ ,, Sv . _* ' PARKING BRAKE MECHANISM INSPECTION Replace if damaged or bent - ''Check bearing surface for wear bnnnelhng ~ (polished OK if no wear) Check for corrosion, ,, pitting wear Replace if necessary Check ball pockets for wear (polished OK if not worn) ' Use new seal REAR DISC BRAKE SERVICE INSTALLING BOOT ON PISTON _ An easy way to install the boot on the piston is with low pressure compressed air (5 lbs ) Lubncate the . boot and seal with brake fluid Install the end retainer shaft actuator and parking brake lever bolt in the - empty caliper bore Gnp the piston by the ndge at the top Place the piston on the boot With an air nozzle shoot low pressure compressed air (5 lbs ) in the brake line inlet (a pressure gauge can be placed on the bleeder screw to safely regulate the air) The boot will balloon out on the piston Move the piston until the boot seats on the piston Stop the air flow DO NOT ATTEMPT TO PUSH THE PISTON IN THE BORE REMEMBER TO USE ONLY LOW PRESSURE AIR (5 LBS ) .- BOTTOMING PISTON IN CALIPER BORE _ Bottom the piston in the caliper bore assembly with special tool T75P-Z58S-B This will install the piston smoothly and evenly without damage ~ -- 14 BEAR DISC BRAKE SERVICE PARKING BRAKE ADJUSTMENT Back off the parking brake cable adjusting nut until the cables are loose f Adjustment is correct when _ a V* inch diameter pin will fit into both calipers parking brake alignment holes without contacting the parking brake levers and applying a force of 10 pounds to the parking brake levers produces no- rearward movement of the lever Tighten lhe parking brake cable adjusting nut until one or both of the parking brakes actuating levers just begin to move | Remove the pin from the alignment hole PARKING BRAKE ACTUATING LEVER (R H SHOWN L H TYPICAL) Apply and release the parking brake control Check the parking brake levers on the calipers to determine if they are fully returned to the stop position by attempting to pull them rearward NOTE If the lever _ moves rearward the table adjustment is too tight Repeat adjustment ' procedure NOTE If levers do not return to stop position, parking and service brake function will be affected as mileage is accumulated 15 DRUM BRAKE OPERATION WHEEL; CYLINDER OPERATION . c APPLICATION RELEASE Hydraulic pressure " from master cylinder _ pushes both pistons out ~ Fluid pressure CUPS are forced ' >- is released ' against cylinder wall to seal pressure ACTUATING PIN - - Shoe return springs push actuating pins ' back and force pistons m . BOOTS keep out . dust and dirt " ^7 PISTONS push actuating pms'against shoes : - BLEEDER BOOT CUP CYL"?DER SCREW PISTON CUP EXPANDERS - (part of spring) hold cups _ against cylinder wall . _ for a tight seal _- " "PISTON RETURN PISTON SPRING AND CUP CUP ' ' EXPANDER ASS Y BOOT I SPRING holds cups against piston . - ------SELF INSTRUCTION ` ' _ - - . - V SELF CHECKS `' "7 I1 i Locate caliper brakes and familiarize ~ ~ .yourself with their components -' 4 When pressure is released from a caliper, - 2 ' * - piston, how is the piston returned? __i- j 2 'Observes on-car operation of the rear ; " . parking brake linkage to the caliper - 3 Familiarize yourself with the wheel . " ,, ' cylinder and related components of a ; drum brake system : - _- 5 Which part of the disc brake assembly is ` attached to the wheel? "" ~a - I 4 rDisassemble and assemble a rear disc _ ' brake caliper " ' '~ ` -,, ^___ ! :-=- _ -- -. . --- - ._ , C_ " ~ ~ ;- " 16 I ~c. .'T,:1 HYDRO-BOOST OPERATION o DESCRIPTION ~~ 5. " - _ ` ~ x - : ` The Hydro-Boost brake booster replaces the brake.vacuum booster for brake assist on some vehicles The power steering pump provides the fluid pressure to operate both the Hydro-Boost unit and the power steering gear The Hydro-Boost assembly contains an open center spoof valve which controls.punip' pressure'magnitude dunng braking7, a lever mechanism to control the position of the valve, and a boost piston to provide the force necessary to operate a conventional master cylinder which is attached to the frontofthe booster The HydrorBoost also has a reserve system which is designed to store sufficient fluid under pressure to provide a brake application m the event that fluidJlow from the power steering pump is not available The brakes'can also be appliedjnanually if the reserve system is depleted The Hydro- - ' Boost unit is hot repairable and is replaced as a unit " -. HYDRO-BOOST OPERATION .'RELEASED POSITION-NO BRAKING . = When the brake pedal is m'released position (no braking) the spool valve return spring holds the spool ` - valve open In the open position, the sfx>ol valve provides an unrestricted fluid flow between the power ' . steering pump and the power steering gear Fluid pressure is blocked from entering the boost pressure "~ chamber by lands on the spool valve Therefore as fluid pressure increases with steering demand it has -- .no efTecfon the_boost pressure chamber The boost pressure chamber is vented through the spool valve ' * to the pump return port and back to the power steering pump _~ _ - ,, -- _ BRAKING POSITION _ "I _ ; - ' : = "> tZ ' " " " / - As the brake pedal is depressed it moves the pedaj rod and initiates movement of the spool valve This = preliminary movement of the valve closes the fluid return port to the pump from the boost chamber'and s : admits fluid into the boost chamber from the pressure port' Additional valve.move.ment restricts fluid I I 1 flow between the pump and steering gear causing the power steenng pump to increase fluid pressure to ' - maintain essentially the same flow" rate to'the power steenng gear As the fluid pressure increases in the ~ HYDRO-BOOST OPERATION ACCUMULATOR OR BRAKING RESERVE SYSTEM -POWER STEERING ' The Hydro-Boost also has a reserve system (com-^ L^GEAR' , accumulator pressed gas accumulator) which is'designed tostore _' ^ sufficient fluid under pressure for one or more brake " applications in the event that the fluid flow from the . "power steering pump is not available The brakes can ~ also be "applied manually if the reserve system is , depleted A typical Hydro-Boost power section is . ' shown below ~ DO NOT ATTEMPT TO CUT INTO ,, OR DISASSEMBLE THE ACCUMULATOR _ RESERVE SYSTEM PRESSURE - ' , - SELF CHECKS - ' _6"How is the Hydro-Boost system serviced? ~ " -' - - - `- - ." - - ** - - = * * 'j* '- - SELF INSTRUCTION - -r 1 Locate a vehicle equipped with ' . Hydro-Boost and familiarize yourself-1 - with the components - ' x ~ ~ : "2 Trace the path of fluid flow m the . Hydro-Boost system ' :." `i ~ -- : -- HYDRO-BOOST DIAGNOSIS Before beginning any Hydro-Boost diagnostic tests _- - Note the condjtion and compare it to a known good system " _ '" Normal Hydro-Boost brake units will produce certain characteristic booster noises that current technology cannot correct These noises occur, for the most part, when the brake pedal is manipulated in a manner not associated with everyday braking or driving habits The general category of normal operating noises are (1) hissing noises and (2) clunk, click or chatter noises The Hydro-Boost will emit normal hissing noises when above normal brake pedal efforts are applied. (40lbs pedal effort and up) The hiss sounds are particularly noticeable with the vehicle motionless and will increase in intensity as pedal pressures increase above 40 lbs and system operating temperature increases Loud hissing sounds at or below normal (20-25 lbs ) pedal effort warrants . investigation and possible correction _ ~" _ Clunk, clatter or clicking noises will be heard when the brake pedal is quickly released from hard ' (45-80lbs ) pedal efforts The noise is sinuharlo the linkage noises on manual brakes under the same circumstances, only more pronounced A combination of Hydro-Boost and Sure-Track brake systems will produce more obvious clunks or clicks including a possible double clunk under extreme pedal action Due to the ` quick release for hard application requirement for the noises, they will most likely be heard with the vehicle motionless or during a fast stop-start condition _ Verify that the proper power steenng hose connections exist as per the Shop Manual - _ 1 ERRATIC OPERATION, STICKING, BINDING OR GRABBING CONDITION OF HYDRO-BOOST - ." MEASURE DISTANCE HERE Run engine at fast idle Pull brake pedal rearward with approximately 10 lbs force Release the pedal and measure the distance to the floor board o Make a heavy brake application release the brake pedal and again measure the distance between pedal and floor board The pedal should .return to the normal position -~ IF PEDAL DOES NOT RETURN FREELY _- "- Check for binding conditions in pedal linkage - . Check for obstruction in return line and connections between Hydro-Boost and power steenng pump reservoir FLUID MOVEMENT OR SPOUT Remove master cylinder cover Observe fluid m reservoir while depressing pedal one inch In the forward reservoir, there should be some fluid movement or spout, and in the rear reservoir, there should be some minor movement . If no spouting or fluid movement occurs, Hydro-Boost unit is defective and must be replaced 20 HYDRO-BOOST DIAGNOSIS 2 EXCESSIVE BRAKE PEDAL EFFORT, BRAKE PEDAL CHATTER AND PULSATION - AND/OR LEAKS -_ BASIC TEST Engine off Depress and release brake pedal five limes to deplete all hydraulic pressure from Hydro-Boost - Depress pedal and hold with light pressure Start the engine - KB If system is operating correctly pedal will fall ^^'slightly and hold Less pressure will be needed to hold pedal down PEDAL SHOULD FALL SLIGHTLY AND HOLD WITH ENGINE ON IF NOT OPERATING CORRECTLY, CHECK POWER STEERING PUMP RESERVOIR FLUID - LEVEL - "_ IF FLUID LEVEL OK _ Check power steering belt tension and condition - Check idle speed and engine timing Check power steering pump flow and relief pressure test If all checks are good, the Hydro-Boost unit must be replaced 21 HYDRO-BOOST DIAGNOSIS 2 EXCESSIVE BRAKE PEDAL EFFORT BRAKE PEDAL CHATTER AND PULSATION AND/OR LEAKS (CONTINUED) - IF FLUID LEVEL NOT OK- _ Fill reservoir to specifications and perform Hydraulic Steering Leak Test HYDRAULIC STEERING LEAK TEST Stan the engine and run at medium speed Turn steering wheel (full nght or left) against slop - and hold while checking Hydro-Boost and hose connections for leaks DO NOT HOLD THE STEERING WHEEL AGAINST - THE STOP FOR MORE THAN FIVE SECONDS AT A TIME Repair all leaks - -_ ~ IF HOSE FITTINGS DO NOT LEAK, CHECK HYDRO-BOOST UNIT FOR LEAKS POWER STEERING POWER STEERING PUMP * ' CYLINDER Apply brake pedal with approximately 70 lbs effort and bold while checking Hydro-Boost unit for leaks DO NOT HOLD FOR MORE THAN FIVE SECONDS AT 70 LBS OR MORE BRAKE PEDAL EFFORT - IfHydro-Boost leaks, it is defective and must be replaced ~ 22 HYDRO-BOOST DIAGNOSIS 2 EXCESSIVE BRAKE PEDAL EFFORT,- BRAKE PEDAL CHATTER AND PULSATION - - AND/OR LEAKS (CONTINUED) ~~ ~ - - - "~ : IF BASIC TEST IS~ OK PERFORM ACCUMULATOR PRESSURE RETENTION TEST - '5 ^ - "ACCUMULATOR PRESSURE RETENTION TEST "` " =- ~ Run engine to medium speed Turn steering wheel (full right or full left) against stop and hold for - : ~ NOT MORE THAN FIVE SECONDS I " - I , I. Stop engine . y Wait 90 seconds and apply brakes Two or more brake applications should be power assisted if applications are not power assisted, Hydro~ -Boost unit is defective and must be replaced - NORMAL BRAKE OPERATION Changes in brake pedal feel or travel are usually the first indicators that somethingcould be wrong in the brake system " The following diagnostic procedures are based on L Pedal feel "- Pedal travel Warning light illumination ~ Master cylinder fluid level - "- ,,_ _- ' - - f_ - Before going into diagnosis, be sure you can identify normal conditions as follows _ NORMAL PEDAL ACTION SHOULO BE POWER ASSISTED IF APPLICATIONS ARE POWER ASSISTED, PERFORM HYDRAULIC STEERING LEAK TEST , ~ (REFER TO PAGE 22) - ' _ -" -- _ ' 5' ~ IF SYSTEM PASES HYDRAULIC STEERING LEAK TEST, PERFORM BRAKE SYSTEM EX TERNAL LEAK TESt(REFER TO PAGE'30) ~ -- ` ` .,, " _ ` ~ SELF-INSTRUCTION ~ - On a vehicle equipped with Hydro-Boost, perform all the Hydro-Boost Diagnostic Tests IF AN ABNORMAL CONDITION EXISTS, PERFORM THE APPROPRIATE DIAGNOSTIC TEST (S) IN THE NEXT SECTION '' 24 NORMAL BRAKE ACTION WARNING LIGHT OPERATION NORMAL BRAKE ACTION , CONDITIONS THAT DO NOT REQUIRE CORRECTION UNEQUAL FLUID LEVELS ~ ON DISC BRAKE VEHICLES - BRAKE FLUID LEVEL Wipe off top erf cylinder before removing cap NORMAL IF Va INCH FROM TOP -ON HORIZONTAL MASTER CYLINDERS OR IF M INCH FROM' TOP ON INCLINED MASTER CYLINDERS MEASURED AT THE REAR OF EACH RESERVOIR System is probably leak-free _ Perform leak - test procedures if fluid is low - ' CALIPER SYSTEM (LARGE RESERVOIR) Lowers as piston adjusts to lining wear Add fluid to Va inch from top on horizontal master cylinders or to Vfe inch from top on inclined master cylinders IF AN ABNORMAL CONDITION EXISTS, PERFORM THE APPROPRIATE DIAGNOSTIC TEST(S) IN THE NEXT SECTION 25 `Fluid in large reservoirs -displaced into caliper cylinder " with brake shoe wear - Add fluid to proper level -= TURBULENCE WHEN - -PEDAL IS RELEASED AFTER BEING PUMPED SEVERAL TIMES FLUID MAKES WAVES oo - Caused by fluid returning to' reservoir THESE NORMAL CONDITIONS REQUIRE NO CORRECTION 26 DIAGNOSTIC TESTS ABOUT DIAGNOSTIC TESTS I; ;.. . ' _ Leamhow to perform and interpret the tests on the next few pages - -" _ " *-- z_ Usually the abnormal condition will indicate which test(s) to perform '= If in doubt, refer to die diagnosis sequences m the'following section, with reference to the specific * DIAGNOSTIC TESTS 2 MASTER CYLINDER BY-PASS TEST -Check for internal leakage in master cylinder While pressing lightly pedal goes down slowly and warning light comes on, but no indication ofloss of reservoir fluid -- 28 DIAGNOSTIC TESTS 3 MASTER CYLINDER NON-PRESSURE EXTERNAL LEAK TEST - oo DIAGNOSTIC TESTS 4 EXTERNAL LEAK TEST ' Pedal low, warning light on / - I" I : - ` * . - Fluid level low or reservoir empty ~ .. ", _ : " Evidence of leak'may be washed away, fluid is soluble in water Check ail possible leak points -Repair where leakage is noted Bleed system^ DIAGNOSTIC TESTS 5 MASTER CYLINDER COMPENSATOR PORT TEST Check for open compensator ports in master cylinder DIAGNOSTIC TESTS 6 POWER BRAKE FUNCTION TEST - * _ _ Vacuum booster only ~ - - RESULTS - *- _ No Squirt or Gejser from Reser>oir -- Loosen master cylinder attaching nuts V4 inch, hold master cylinder away from booster and repeat steps 2 through 4 above If a squirt or geyser appears from reservoir adjust booster pushrod per Shop Manual procedure If squirt or geyser still does not appear replace master cylinder 31 Check pedal feel .- Idle engine one minute then 1 1. shut off for 5 minutes -* rf '' =- '- \ "APPLY AFTER 5 MINUTES WTTH ENGINE OFF. ~ X\ - ~ s \- - - \ - - X. - / \/ Rard-to-pusb -- check \ vacuum systems and supplyx-- especially vacuum check valves y s - -.r .. - * Same effort as with engine ' running -- power assist is okay 7,, ~- _ *~ ' '- . -- DIAGNOSTIC TESTS O; : '; "' * SELF INSTRUCTION. - - . ": / ~- . " r- SELF CHECKS - - . - _ Check several brake pedals on vehicles for ' - , 7To check the brakevvanung light, it should " feel and travel Note the difference - ' go on when ' -' between power and non-power.brakes " - - Check the brake warning light operation on - ' several vehicles ~ 3 " - ' - Check the brake fluid level on at least one -1 vehicle '.- - - Perform the diagnostic tests 1 through 6 as* time and vehicles are available ' I - _ __ ,, * __ - _ 8 .When is a reduced amount of fluid normal - - in a disc brake master cylinder' - . ~ _ *- . ~* -. - . ,,,, ^9' When is a geyser okay from the brake -- . reservoir9 ' ~~ `- : ~ " - _ -: . ' - _ -" - 0 :: '. ~ _ ` Not okay9~ ' "i .. -: 10 Fluid moves up and down within ' - a reservoir when you operate the brake * pedal,-but none is lost What is the condition9 - ' -- ~ *" DIAGNOSIS OF PROBLEM CONDITIONS ' The following pages give you testing procedures for specific problems, and refer to the tests you havejust ~ ' "studied / _ ~~ * '-_ - : * . * - ... ' - ~ ' * _ " i jBe sure you understand and can perform and interpret the tests - " . ` ~~ " Pay special attention to the significance ofpedal feel and whether or not the brake warning light is on _ - Be sure the brake warning light is operative before you use it as a diagnosis indicator DIAGNOSIS OF PROBLEM CONDITIONS LOW PEDAL -- BRAKE LIGHT ON INDICATES PRESSURE UNBALANCE BETWEEN SYSTEM ALSO PARKING' I BRAKE ON OR * ' INOPERATIVE SKID - _ CONTROL-SYSTEM ` 1 PEDAL FALLS FAST v ~ - ; -= -_ - V ii - - PUMP RAPIDLY " \ \\ SEVERAL TIMES - \\\ W. ~ \\\ - Mi \ - vKvWvS\ RESULTS WITH FOOT PRESSURE ' . APPLIED - - Pedal Dumos ud and holds -- Derform Air 5 ' - .; - Entrapment Test ! ` . -" "' ^ Pumps up and sinks -- perform Master _ - * * ^ ^Cylinder By-pass Test 2 and External Leak _ v . ' Test 4~ . * _- " - Fails to pump up -- check fluid level *- - ~~--Empty--fill bleed and Leak Tests 3 and 4 - . --Full -- Master Cylinder By-pass Test 2 : ' r Manual Brakes, first application after lonp ' '' , shutdown -- check for short m stonhphr * " = switch \ .* 33 34 - DIAGNOSIS OF PROBLEM CONDITIONS LOW PEDAL -- BRAKE LIGHT OFF INDICATES MISADJUSTEO DRUM BRAKES AIR BEING COMPRESSED OR LOOSE FRONT WHEEL BEARINGS (WITH DISC BRAKES) PEDAL FALLS SLOWLY LIGHT OFF- PRESSURE IS STAYING BALANCED BETWEEN SYSTEMS IMPORTANT PERFORM WARNING LIGHT CHECK BEFORE PROCEEDING' RESULTS _. . Empty or low -- fill, bleed and perform External Leak Tests 3 and 4 "- Full -- check for air entrapment, Test 1, especially if pedal is spongy as well as low - IMPORTANT Loose drum brake ' adjustment also causes geyser on brake release during Test 1 See Step 2 below - Wm Remove drum and check drum brake adjustmenfwith Rotunda Tool >1 001 Inspect adjuster mechanism for proper function Check front wheel beating on front-disc brake cars * Loose rotor may force caliper " piston back and cause excess - lining clearance _ Replace bearing if noisy SET TO ORUM DIAMETER HERE FIND CORRECT BRAKE SHOE DIAMETER HERE PERFORM ADJUSTMENT DIAGNOSIS OF PROBLEM CONDITIONS - LOW PEDAL -- BRAKE LIGHT OFF (CONTINUED) 5 PEDAL-FALLS FAST ~ Doesn't pump up -- continue to Step 2 - ; Empjy -- add fluid, bleed,"perform External - Leak Tests 3 and 4 - Full -- perform Air Entrapment Test landPower Brake Function Test 6- ~ ERRATIC PEDAL -- BRAKE LIGHT.OFF ~ EXCESSIVE PEDAL EFFORT-- - -- CONDITION MAY BE VERIFY BY - . BRAKE LIGHT OFF. ` ~ CAUSED BY CONDITION MAY BE VERIFY BY ' - Incomplete brake . Checking wheel' CAUSED BY : release ; ' rotation , ' Bind or obstruction in Detach master Loose wheel bearings Check bearing end '2 play - - .- Incorrect parking Check parking brake * pedal linkage - cylinder from dash.of booster and stroke - pedal carefully I brake'adjustment - ~ tension ~ - ~ ' ~ * Insufficient booster Blocked master - - Check for blocked -- cylinder compensator ~ master cylinder- i.. _ holes _" - ' compensator holes by vacuum or . Check Hydro-Boost _ Hydro-Boost pressure pressures or vacuum .. by performing Test 6 performing Test 5 * SPONGY PEDAL ' ". MAY BE NORMAL MODERN BRAKES ARE COMPARE WITH ANOTHER LIKE . ...VEHICLE - . -' - -- - Same -- probably okay ' - . = _ Spongy -- perform air Entrapment Test I - DIAGNOSIS OF PROBLEM CONDITIONS CHECK PEDAL HEIGHT Low -- perform External Leak Test 4 and inspect linings and drums _ -Normal -- Road test vehicle PULLS WHEN BRAKING CAN BE CAUSED BY . 1 Brakes Tires Suspension _ Alignment "' ROAD TEST CHECK FOR RESULTS Pull when brakes are applied Pull in normal driving on level road Erratic pull m braking -- check alignment, suspension insulators, steenng gear adjustment " Pull to same side in brakmg -- check strut insulators, tire pressure, brake drum, rotor, lining brake fluid line restriction (step 3) No pull with brakes off-- probably a brake problem, but may be strut insulator Pull with brakes off-- check alignment, tire pressure radial tire pull, dragging brake shoe "- " 37 BLEEDING BRAKE SYSTEM 0 EQUIPMENT FOR BLEEDING.. METERING VALVE - BLEEDER TOOL ' _ - _ ' - -Valve must be held ' Open.while bleeding' front brakes ' PENETRATING OIL- - . , - . : Saturate bleeder screws ~ before attempting to open ." - - to'avoid breaking " APPROXIMATELY 45! ...,, O Compress -V tool by ` MANUAL BLEEDING '2 Man operation - RUBBER HOSE BLEEDING BRAKE SYSTEM PRESSURE BLEEDING- . :. : "Diaphragm r type bleeder holds constant pressure ~ - * Replenishes master cylinder reservoirs automatically Bleeding is a one-man operation ' _ - . _ ; FOLLOW INSTRUCTIONS THAT ACCOMPANY BLEEDER ' o 39 .40 SHOP AIR CONNECTION Q BLEEDING BRAKE SYSTEM 6 BLEEDING MASTER CYLINDER * - If equipped with bleederlscrew : BLEEDER SCREW BLEEDING WHEEL CYLINDER .. ' OPEN % TURN w^ MANUAL BLEEDING ONLY-f CLOSE BEFORE PEDAL' x-- IS RETURNED TO _ RELEASE POSITION - BLEEDING BRAKE SYSTEM HYDRO-BOOST ,, ~ ` r; . . , I " ='2 ' I ; BLEEDING PROCEDURE ,, ~ "I" ~ ,, "i I Whenever Hydro-Boost- power,steenng pump or power steenng'gear is removed, serviced, and -installed the following bleeding procedure should be used _ -- ,, *_ - _ Fill power steering pump'with approved fluid only . - - CAUTION DO NOT CYCLE STEERING WHEEL TO BLEED SYSTEM AT THIS TIME - IMPORTANT Do NOT re-use fluid that is bled from system - ~- _ ~ BLEED UNTIL'ALL BUBBLES ARE GONE' ORDER FOR BLEEDING. ' Farthest from master,,cyhnder, next farthest, and so on - Front or rear system can be bled independently if both systems aren't affected 41 ' - - ^ SELF INSTRUCTION -X -" - - ' Familiarize yourself with brake bleeding equipment in your shop ,, - Ifa pressure bleeder is available perform a complete brake bleeding operation on your - _ own car ,, ' - ~ ? _' : _ - - -" < - ' ; - " 1 . -, - 1" SELF CHECKS " ; 13 If both brake systems must be bledr which system should be'bled first7 ^__ -_ _ -- " 14 If only one system is to be bled,"which wheel is firsts , - 42 TECHNICAL SERVICE INFORMATION TECHNICAL SERVICE BULLETINS (TSB) - _ Description Brake Asbestos Fiber Oust Removal Brake Fluid Discoloration Communication of Cerlain 1976 Rear Disc Brake Components Disc Brake Cabpcr Slide Grease - Drift Left on Brake Application ~ - New Design Rear Wheel Bolls Axle Shafts and Brake Drums ~ - ~ New Modified Design Hub and -' - Rotor Assembly and Wheel Stud _ Design for 1976 Front Disc Brakes " ; - _ " Power Brake Booster Diagnosis -- Vacuum and Hydro-Boost Rear Disc Brake Procedural Clarification -- Shop Manual Revision Replacement Hydro-Boost Brake _ Boosters " Rear Drum Brake Assemblies Backing Hate Ledge Wear and/or Slow Release of Brakes - Drifts Left on Brake Application -- Rear Disc Brake Procedural Clarification -- Shop Manual Revision Replacement Hydro-Boost Brake Boosters - Brake Caliper Attaching Bolls Front Disc Brakes Protective Covers - Rear Disc Brake Procedural Clarification -- Shop Manual Revision - ` Year and Modd ~ All Years -- AH Car Lines 1976 All Car Lines " ~ 1976 Vehicles Equipped with Rear Disc Brakes " 1976 All Vehicles So Equipped _ 1976 Granada Monarch ' 1976 Torino Ranchero Montego and Cougar _ 1976 Ford Torino Elite_Mereury Mark IV Lincoln Montego and Cougar 1976 Passenger Cars 1976 AH Vehicles So Equipped 1976 Vehicles So Equipped 1976 AH Models with Drum Brakes 1977 Ford LTD Station Wagons and LTD II Police or Taxi Vehicles 1977 Granada Monarch " - 1977 AH Vehicles So Equipped 1977 Vehicles So Equipped 1978 Fiesta " 1978 Fiestu 1978 All Vehicles So Equipped ~ Bulletin 104 116 Date Article 1/23/76 7/19/76 1269-S 1345 101 " 11/21/73 104 1/23/76 134 - 5/9/77 _ 144 JO/6/77 no* 1351 1832 1832 S 103 12/19/75 1337 121 10/6/76 1620 104 1/23/76 1352 146 11/4/77 2016 138 7/6/77 1896 104 1/23/76 1354 - 146 11/4/77 134 - _ 5/9/77 144 JtV6/77 2015 1832 1832 S 146 ` 138 149 140 lt/4/77 2016 7/6/77 12/23/77 mm 1896 2087 1940 146 11/4/77 2016 "- TRAINING BOOKLETS _- CTP-1974-6 Drum and Disc Brakes (Diagnosis and Repair) 1201-106 Evolution of Brakes - -O 43 TECHNICAL SERVICE INFORMATION ' SPECIFICATIONS " ; - - - ': = :APPLICATION .. Residual (outlet)check valxc'spring pressure - - > SPECIBCATION _ - ,6-25 psi ' Air pressure for installing hoof on piston ~ - - r" .Not more than A lbs Pm size for rear disc pai king brake alignment hole during adjustment ~ - ' - _ _ ~ _ ''I : ' I ~ - ,, `<4 inch -Bnik'c'pcilal pressure forIndrmal hissing'of _ .Hydro-Boost at normal brake ped tl application .... ' - _" . j --40 lbs and up . Brake pedal pressure for loud hissing of - _ Hydro Boost below normal brake pedal application -_ - - ~ -- - ~ ' 20-25 lbs ' ' Brake pedal pressure for clunk clatter or clicking * * noises of Hvdro-Boqst at hard brake pedal - " application s" -- . - - -- I' " 45-80 lbs - ~ Master cylinder fluid level' v` ` - Va inch from - ~ ` top -- honzonal _ .,, master cylinders V6 inch from top -- inclined master ~ * -cylinders ~ ~* . Pressure required on piessure bleeder during .. brake bleeding - .= _ . -" ~ ~ '* . -r = . I0-T0 lbs SPECIAL TOOLS _- ` '; 7 .NAME * Rear Djsc Brake Cdiper Piston Removal Tool _____' " -~ . . * _NUMBER . - T7SP-2588-A Rear Disc Brake Piston Turning Tool ~ * -- : ~ ' " T7^P-2^88-B - Drum Bntke Adjuster.ToolOne-Man Diaphragm-Type Bleeder ' . _ -v - ; - * .. Rotunda Tool 11-0001 Rotunda Tool 10-0011 44 = '"Tr?- ANSWERS TO SELF CHECKS Compare your answers with those below If they do not agree study the material again until you understand the answers given - " 1 A port in the bottom of the reservoir that allows fluid to flow in and out (to and from the brake lines) 2 -Through pressure on !he fluid in the primary cylinder " - -3 (1) Front piston mechanically operates the rear piston so the rear system still operates (2) Brake warning light switch is closed by the pressure differential valve 4 By distorting and then relaxing the piston seal _ 5 The rotor -~ 6 The unit is not servicabie It is replaced as a unit - - 7 The ignition is in START position with the engine cranking " 8 " When the disc brake linings are worn _ - 9 When pedal is first applied Not okay when pedal is pumped rapidly and released - 10 Master cylinder is by-passing internally 11 (I) External leak ~~ _ - (2) Master cylinder by-passing _ (3) Air entrapment _ "_ - " 12 Brakes will pull - " H Rear - _ _ __ 14 Farthest from master cylinder -' ~ - 45