Document yb4p09rg5y0JgXEnLgvvXGKw4

FILE NAME: Ford (FD) DATE: 1973 Sept 20 DOC#: FD124 DOCUMENT DESCRIPTION: Letter to Ford Marketing from Doyle Vacuum Cleaner Co. with Attached Report - Analysis of Dust Control in Servicing Drum Brakes The sticky note shown below was written by Barry Castleman and attached to the page immediately following this one along the right margin at the spot marked on the next page with an -9 /2o/7 ^ O' "=N -- Septem ber 2 0 , 1973 H r . Dann Lem erand Ford M arketing Corporation Rotunda S e rv ic e R esearch P . 0 . Box 4577 D earb o rn , M ich ig a n 48121 , Dear Dann: ' E n c lo s e d a r e f i v e c o p ie s o f my a n a l y s i s o f th e b r a k e s mechanism c le a n in g i n v e s t i g a t io n f o r your use and. in fo r m a tio n . P le a s e under sta n d th a t in no way do I cla im any e x p e r tis e in e it h e r brake service or in parts clean in g. How ever, I do f e e l t h a t the p resen t- methods o f a i r b la s t in g "d ry" brake system s and "w et" s o lv e n t c le a n in g o f o ily mechanisms are both i n e f f ic ie n t and p resu m p tively hazardous to p e rso n n el. I do n o t see a p r a c t ic a l approach to "d ry " c le a n in g w ith a i r and a c o lle c t io n system even though i t i s p o s s ib le . The c o s t , m aintenance and d is p o s a l a sp e cts presen t p r o h ib itiv e co m p lica tio n s fo r use by autom otive se rv ice personnel in ty p ic a l se rv ice o p e ratio n s. The p re se n t "w et" wash-down o f o i l y mechanisms i s a b e tte r approach, b u t I f e e l t h a t i t can be v a s t l y im proved by r e l a t i v e l y new e q u ip ment th a t would be easy to m a in ta in , w ith sim ple d isp o sa l in cans. The wet m ethod can be made v e r y s a f e , s im p le , e f f i c i e n t and a t reaso n ab le equipm ent c o s t. I f I can be of fu rth e r a ssistan ce p lease a d v ise . S in cerely , ' DOYLE VACUUM CLEANER COMPANY 007398 DOYLE VACUUM CLEANER COMPANY stevens street, grand rapids, mlchlgam 4 9 50 2, area code 615, phone 2 4 5 -0 4 5 6 produced by fopd ANALYSIS OF DUST .CONTROL IN SERVICIN G DRUM BRAKES PROBLEM: The e s s e n tia l''p r o b le m i s the a ccu m u latio n o f a s b e s to s fib r e d u st r e s u ltin g from wear o f the brake shoe fr ic t io n m a te r ia ls . This a sb e sto s d u st is mixed w ith ordinary- road d u s t, iron d u st and the resid u es o f the b in d er (o ften epoxy m a te r ia ls ) used in the fr ic t io n m a te r ia l. T h is d u s t co v e rs the b rak e s h o e s , c y li n d e r , s p r in g s and o th e r b r a k e m echanism s m ounted on .th e b a c k in g p l a t e in a p p recia b le co n ce n tra tio n s and is g e n e ra lly d ry, except fo r those cases where le a k in g c y lin d e rs or a xle s e a ls cre a te an o ily r e s id u e . ' The r e s u lt a n t problem a r is e s from the custom ary h a b it o f th e m e ch an ics xn u s in g com pressed a i r to blow down the brake assem bly, thus c re a tin g f a i r l y heavy accumu la t io n s o f th is d u s t in the a i r around the v e h ic le and throughout the se rv ic e shop. T his d u s t has a r e l a t i v e l y h ig h t o x i c i t y , due to the number o f a sb e sto s f ib r e s th a t are l e f t suspended in _ the atm osphere; w hich, i f inha-led, can d ep lete re sp ira tio n c a p a b i l i t y o f th e human l u n g s . Under OSHA S ta n d a r d s f o r h a n d lin g asb esto s f ib r e s , the a llo w a b le 8 hour tim e average exposure s h a ll not exceed fiv e fib re s lo n ger than 5 m icrom eters per cu bic centim eter of a ir , and t h i s w i l l b e r e d u c e d to two su ch f i b r e s by J u l y 1, 1976. The c e il in g co n centra-tion fo r exposure s h a ll not exceed 10 f ib r e s lo n g e r than 5 m icrom eters per c u b ic centim eter of a ir a t any tim e. SITUATION: Sin ce sample a n a ly s is o f the dry d u st encountered in a t y p i c a l b ra k e s e r v i c e jo b has shown a t l e a s t 15% o f the t o t a l d u s t volum e i s composed- o f a sb e sto s f i b r e s , tne a i r d u s tin g o f brake mechanisms can be con sid ered h az ard o u s under OSHA s t a n d a r d s . The common use o f a i r d u s t in g guns h a s been found to be in o p e r a tio n a t f u l l l i n e p r e s s u r e , u s u a l l y f r o r a 90 p s i to 120 p s i . U nder o t h e r OSHA s t a n d a r d s , t h is i s n o t p e rm issib le and such a i r guns w il l have to be rep laced 007399 PRODUCED BY FORD w it h s u i t a b l e ty p e s w h ich l i m i t the o u tp u t to 35 p s i . In p r a c tic a l a n a ly sis o f a ty p ic a l brake serv ice jo b , i t w a s-fo u n d t h a t the 35 p s i " s a f e t y " a i r gun d id n ot e f f e c t i v e l y rem ove more than a b o u t 50`S to 50% o f the , lo o se d ry d u s t in the b rake mechanism. Thus, the use of sa fe ty regu lated a ir pressure is not p ra c tic a lly a cce p ta b le to acco m p lish the d u s t rem oval assuming t h a t th e r'c o n t r o l o f th e r s u l t t t a i r bourne d u s t i s p ra ctica l. ' . * DRY DUST REMOVAL METHOD : T h is m ethod in v o lv e s th e fo llo w in g e le m e n ts : 1 . A ir rem oval o f d u s t from the mechanism. ' ` 2. A ir bourne d ust c o lle c tio n . ' 3 . Sep aration o f d u st from the a ir . k . D isp o sitio n of separated d u st. 5 . Contam ination c o n tr o l o f c o lle c to r equipm ent. The approach e n v is io n s a se a le d c o lle c t o r hood around ' the rim o f the b ack in g p la t e , s a fe ty locked and sea le d to p e r m it u se o f h ig h p r e s s u r e a i r j e t s , co n n ecte d to an a i r mover and f i l t r a t i o n system w hich can be s a fe ly d isp o se d o f when the f i l t e r i n g c a p a c it y i s a t t a in e d . I t sh ou ld be noted t h a t su ch a system would r e q u ir e a s a f e t y i n t e r l o c k on th e h ig h p r e s s u r e a i r gun to p r e v e n t use e x c e p t in p rop er o p e ra tin g p o s itio n and s a fe c o n d it io n . A d d it io n a lly , i t would be n ece ssary to p rovid e means to . s e a l the equipm ent between uses to prevent contam ination spread s in c e the e n t ir e system would be coated w ith p o t e n t i a l l y h a z a rd o u s d u s t s on i n t e r i o r s u r f a c e s o f th e c o l l e c t o r and f i l t e r . A f a i r l y s u b s t a n t ia l a i r movement i s r e q u ir e d ( in the o rd e r o f 100 cfm or more) to e f f e c t i v e l y c o l l e c t a l l d u s t g e n e ra te d . This would re q u ire a s a fe ty v e n t to p rovid e "makeup" a ir sin ce the high pressu re a i r gun co u ld n o t e f f i c i e n t l y d e liv e r th is volume from the commonly a v a ila b le a i r s u p p ly . S e p a ra te or a d ju s ta b le c o lle c t o r hoods would be req u ire d fo r dvf-Ferert size d brakes. ' F i n a l l y , th e d i s p o s it i o n o f ..the c o lle c t e d d u s t , in c lu d in g d eco n tam in atio n o f th e c o lle c t o r and f i l t e r sy stem , would have to be p ro vid ed w ith an im perm eable d is p o s a l c o n ta in e r . T h is d r y m ethod w i l l o n ly be e f f e c t i v e on a " d r y " m echan- _ ism and those s e r v ic e jo b s in v o lv in g a leak o f the h y d ra u lic flu id or in tro d u ctio n o f d iffe r e n t ia l lu b rica n t through f a u l t y a x le se k !4 w i l l r e q u ir e a w et method o f c le a n in g s i n c e an a i r b l a s t i s i n e f f e c t i v e in such c a s e s . 007400 PRODUCED B Y FORD VET DUST REMOVAL METHOD: T h is method c o n s id e r s the f o llo w in g e le m e n ts : 1 . V e ry low p r e s s u r e , w et m is tin g . 2 . Low p r e s s u r e , h ig h f l u i d volum e w a sh in g . 3 . Liquid c o lle c tio n . - _ k. S e p a ra tio n o f re s id u e and l i q u i d ._ _ _ 5 . D is p o s itio n o f r e s id u e and. contam inated liq u id . The ap p ro ach 'in v o lv e s an open fu n n e l c o l le c t o r p la c e d below th e brake mechanism to c a tc h a " flu s h in g " or ''w ashing" f lu i d as i t d r a in s o f f the brake mechanism. This c o lle c to r i s connected to a sedim entation c o n ta in e r, a l i q u i d f i l t e r , a " c le a n " liq u id r e s e r v o ir and a low .p r e s s u r e , h ig h volum e pumping means w ith d e liv e r y ,n o z z le (s). The a s p e c t o f u l t r a low p r e s s u r e , low volume m is tin g i s _ gfl e f f e c t i v e means o f p r e w e t tin g the d u s t w ithouu d i s p l a c i n g same fro m th e m echanism s u r f a c e s . The m is t l i q u i d sh o u ld , be a "s a fe " m a te ria l. T h is m ethod w i l l be e f f e c t i v e on a l l typ es .o f bra^ce m echan ism s under a l l c o n d it io n s . The use o f a wet method o b v ia te s a l l n e c e s s it y o f a s e a le d sy ste m ^ sin ce a t no tim e w ould th e r e be any a ir b o u r n e d u s t c o n d it i o n . The w et method equipm ent is s e l f c le a n in g to elim in a te contam ination problem s and d is p o s a l can be e a s ily accom plished so long as the recovered d u st d e b ris is m aintained in a w et or m o ist c o n d it io n . The f i l t e r means can be e a s ily b a ck washed fo r rep eated use and the liq u id lo s s should be m inim al over a lo n g p erio d o f u se. The l i q u i d used sh o u ld be a s a fe s o lv e n t or em ulsion _ type t h a t has h ig h 'V e t t in g " power and adequate d e te rg in g or s o lv e n t e f f e c t to remove- the bond between the d u s t and th e b r a k e m ech an ism . The l i q u i d sh o u ld le a v e no " o i l y _ film th a t would i n h ib it the f r i c t io n a l e ff o r t o f the lin in g "m aterial. ' ~~ , NOTE; Means c o u ld be p ro v id e d to f lu s h the brake, drum d u rin g the mechaqism w ashing p ro ce ss. CONCLUSION: The w et method i s recommended s in c e i t p ro v id e c o s t co n tro l o f the d u st by im m ediately reco n d itio n in g the d u s t to a w et c o n d itio n w hich can be s a fe ly handled bv a r e l a t i v e l y s im p le p r o c e s s . The w et system i s s e l l c l e L " e S d d L n o .i l i . s im p lifie d . There does n ot appear 007401 PRODUCED BY FORD to be any need fo r com plicated s a fe r/ in te rlo ck s to in s u r e s a fe o p e r a tio n . The fix e d o p e ra tin g c o s t appears low in term s o f w ashable f i l t e r s and reu sab le f l u i d s . P ro b ab ly , one c o lle c to r fu n n e l could se rv ice a l l sizes o f brakes. " ` I t would appear th a t the wet system could be d evised by such firm s as m anufacture p atts w ashers. I f f in a l d r y in g o f d e co n tam in ated brake mechanisms was r e q u ir e d , a w et d ry vacuum c o u ld 'th e n be used sin ce there would not be any to x ic dust m a terials rem aining. Dewey I . ( Ja c k ) D o yle, J r . D o yle Vacuum C lea n er C o . Septem ber 1 0 , 1973 V 007402 PRODUCED B Y FORD