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-   -   OVR/brake boost failure (http://www.peachparts.com/shopforum/diesel-discussion/319653-ovr-brake-boost-failure.html)

ZRatedDog 06-10-2012 04:37 PM

OVR/brake boost failure
 
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haven't drove the car in few months, last week I tried to get it around block just to get things lubed up. Well...

Idles like crap, ABS + ASR lights on, no tach. Hmm... Drives ok, like it was before until Holy @rap, no power boost for brakes! Luckily no one at the intersection, glided through, no casualties ;)

Started to pour (like it would here in Fl) so no trouble shooting possible.

Last night after only 15 minutes on the forum decided to look at OVR. When I bought the car it had no cover on it, so I suspected some issues. Bingo! After wiggling it in its place a bit, it started to buzz. So just for the testing purposes, I jammed piece of cardboard to hold the contacts apart...Success! Idles normally, tacho works, no lights on the dash.

Still troubleshooting the brakes...too hot to work on the car now :rolleyes:

sixto 06-10-2012 04:57 PM

Would be nice to know what car you're talking about. Guessing '90s 126 from the picture.

You're not complaining about AC function, tranny shifting or shutting off the engine so it appears there is some vacuum from the engine vacuum pump. Is it an original or updated vacuum pump? Can you cap the brake booster line fitting at the vacuum pump and draw a vacuum at the engine shut-off fitting by the check valve? It'll take a lot of MityVac strokes to evacuate the brake booster.

Sixto
87 300D^2

ZRatedDog 06-10-2012 06:37 PM

Ups, my bad, you are totally right, Sixto :rolleyes:

its 87 300 DT, 167K, bought ~ 1 yr ago, vacuum pump seems original. I did cleaned up some of the vacuum lines (blue saucer) due to shifting issues ~ 8 months ago. In february bought a Acura TL, parked the 300 as a spare. Drove it 1-2 a month around the block, did not had any issues until this occurred.

It shifts as before, engine shut-off is w/out hesitation. A/C works.

I will head out to trouble shoot booster vacuum line, than I'll post my findings ;)

ZRatedDog 06-10-2012 07:09 PM

Yup, booster seems kaputt. :( Drove it around the block - If light throttle is applied, brakes works just fine.

Pulled the vacuum line from the booster fitting - engine idling - nice suction, enough to make mark on the finger (best I can explain w/out gauge). No loss of fluid in the master cylinder, I dont think that is the culprit.

How hard is to replace the freaking thing?

maska 06-10-2012 07:35 PM

Quote:

Originally Posted by ZRatedDog (Post 2953239)
haven't drove the car in few months, last week I tried to get it around block just to get things lubed up. Well...

Idles like crap, ABS + ASR lights on, no tach. Hmm... Drives ok, like it was before until Holy @rap, no power boost for brakes! Luckily no one at the intersection, glided through, no casualties ;)

Started to pour (like it would here in Fl) so no trouble shooting possible.

Last night after only 15 minutes on the forum decided to look at OVR. When I bought the car it had no cover on it, so I suspected some issues. Bingo! After wiggling it in its place a bit, it started to buzz. So just for the testing purposes, I jammed piece of cardboard to hold the contacts apart...Success! Idles normally, tacho works, no lights on the dash.

Still troubleshooting the brakes...too hot to work on the car now :rolleyes:


The OVP protects the ABS, and many other delicate parts !
So REPLACE it, [jamming a piece of plastic ! wont fix it !!] :eek:

ZRatedDog 06-10-2012 08:55 PM

Quote:

Originally Posted by maska (Post 2953319)
The OVP protects the ABS, and many other delicate parts !
So REPLACE it, [jamming a piece of plastic ! wont fix it !!] :eek:

oh I will, that was just for testing purpose ;)

maska 06-11-2012 08:20 PM


Thats good! When people make statments like that; They Frighten the S***t out of Me :(


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