Dreaded ABS topic

ValR

Registered User
Hi all!

All right ... so much said about it already but I`ve got few questions to SC`ers
About a week ago my breaks suddenly went out: usual symptoms - ABS+Brake lights on and hard pedal
I figured out that it was accumulator .. finallly went out after 11 years of service. I`ve ordered new one from Prior, but in a meantime decided to replace both relays.
When I did that and started the car - I heard buzzing sound. It was ABS pump motor. For some reason it was working non-stop. After about 10-15 mins of driving around it turned off and brakes were hard and lights went on too ... i guess thermal protection
worked and shut it off.

It acts really weird now, because sometimes it works but only with ABS light on a dash. And most of the time it doesn`t work at all.
I went through that little troubleshouting manual on Teves II ABS system. But ... no result.
Unplugged pressure switch connector from unit and grounded pin 4 like it was saying in that manual ... - same thing no result.
I`m pretty sure that it is some kind of electrical problem (or may be pressure switch?) because when it works sometimes everything seem to be fine (i mean hydraulics unit) beside of ABS light on a dash.

I was looking for some good reference on ABS electrical wiring but couldn't find anything but that book on amazon.com
it says it might take up to a month to get it ... may be someone has it already?
particulary i`m interested in Pressure sensor pinout and relay wirings



Thanks everybody.
(for saving our bucks and educating :cool: )
 
I don't know if this is your problem or not, but I do know that if you have a bad accumulator, the pump runs too much. The pump is not supposed to run very much. If it does it will burn out. Not a good thing. So driving around with the pump running steady is a good way to fry things.
 
Well .. i`ve actually replaced accumulator already. and thanks god thermal protection seems to work fine so far.
And the pump is not running ALL the time. It does only once in a while

Val
 
My guess would be the pressure switch. It senses the system's hydraulic fluid pressure and sends a signal to the pump relay when the pressure drops below range. If the switch is malfunctioning it could be sending a signal to the relay causing the pump to run constantly, then shutting off the signal allowing the pressure to drop to the point that there is no brake assist. You definitly want to have this corrected. I tried to find a pressure switch when my pump stopped operating, but the only one I could find was at a Pontiac dealership for around $175.00 (these switches are difficult to find for some reason). I decided to get a rebuilt pump assembly from Prior with a working switch instead. (I had already been driving around with a bad accumulator for a long time, so I figured the pump might have been damaged from overwork).
 
Well, thats what I suspect too because sometimes I can hear relay clicking like crazy for couple minutes than it stops and my breaks don`t work after.
Anyhow, is there any sure way to check if it`s bad?
I think the rest of hydraulics assembly works fine.
And I found Switch on internet for 95$ so i probably just buy it

Thanks for your replys
Val
 
Back
Top