ABS parts crossreference

["Michael Conrey" <michael_conrey@domain.elided>]

Carson,

Here is an old post from Scott Shadle that I dug out of the Digest Archives for you to add to your part crossovers database.

Michael Conrey
Smithsburg, MD

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From: Shadle, Scott
Date: 25 Aug 1997 17:54:16 -0400

I'd like to pass on some addnl. info that I received from my source at Teves.
Milano owners will note that the service manual shows how to disassemble the A
BS hydraulic unit, but the parts microfiche does not show the parts as being a
vailable separately. Well, it turns out that if the "valve body" (the hydraul
ic part of the ABS control system) fails on your Milano, it can be replaced by
the valve body from a '88-'90 Buick Reatta. (there may also be other US cars
for which the valve body would work on a Milano, but this was the one that se
emed to be the most obvious substitution), but there may be one minor modific
ation necessary - that is the studs that screw into the master cylinder unit o
nto which the valve body mounts may need to be replaced with longer studs, but
you won't know until you get the new valve body (the guy at Teves said that h
e does not know when and for what model that used the Mark II ABS the "upgrade
" to the thicker cover plate on the valve body was implemented. I also spoke
to him about the recent AD posting about someone in Texas rebuilding the MC po
rtion of the ABS. I asked whether or not it is advisable to try to rebuild th
em (he and I have spoken about this in the past and he said that Teves does no
t rebuild Mark II systems for any of the applications - including the much lar
ger volume applications on GM and Ford cars, because it is not an easy job).
He answer was that It can be done, but ONLY for the "regular master cylinder p
art" NOT the booster portion of the unit. He said that he has tried to rebuil
d these himself (just for "fun?" and edification) and has not succeeded - he a
lways broke or bent something. The problem is that you must remove and discon
nect the booster portion of the unit to get at the MC pistons/seals. The "sci
ssors" mechanism and other control linkages of the booster portion are somewha
t delicate and if bent may be nearly impossible to repair. Also, regarding re
building the booster section - DON'T - DON'T - DON"T!!!!!!!!!
This section is a very delicate force balance mechanism and the spool valve in
this section has a tolerance of +-0.00010 to +-0.000.15!! A SINGLE FIBER OF
COTTON FROM A SHOP TOWEL OR A "THIN" HUMAN HAIR COULD LEAD TO A FAILURE, AND
EVEN THOUGH THE VALVE PISTON IS MADE OF HARDENED STEEL, DROPPING IT ONTO A RUB
BER OR VINYL TILED FLOOR FROM WORKBENCH HEIGHT ONTO THE EDGE OF ONE OF ITS END
S COULD DEFORM IT ENOUGH TO CAUSE A FAILURE. THESE ARE ORIGINALLY ASSEMBLED
IN A "CLEAN ROOM" ENVIRONMENT. Luckily, they very rarely fail. The most comm
on failures of these ABS systems as they age (8 years or more/over 100K miles
or lots of urban stop and go driving) are the high pressure pump/motors, accum
ulators and the MC seals. He said that he does know where the Texas people a
re getting the rebuild parts, but he almost sure that there was no agreement b
etween the German company from whom Teves originally bought the pistons and se
als that prevents them from selling service parts. I also mentioned the 400
rebuild price. He said that that sounded a little high to him, but after refl
ection, he said that given his 0 for 2 record trying the rebuild them himself
(and he has any technical info that exists available to him) they may be recou
ping their "development" costs for unit that they broke until they got the pro
cedure right. So far I've only had to replace an accumulator on one of my Mil
ano, but knowing that at least for some failures there is an alternative to a
2000 new replacement unit is somewhat comforting. Good luck!!

scott shadle
National Highway Traffic Safety Administration
Office of Defect Investigation
Automotive Safety Engineer - Vehicle Dynamics (tires, wheels,
suspensions, and steering) & Braking Systems
(202) 366-2583; FAX (202) 366-1767; E-mail sshadle@domain.elided

1958 Alfa Romeo Guilietta Spider Veloce
1969 Alfa Romeo 1750 Spider Veloce
2 - 1987 Alfa Romeo Millano Platinums

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