Mark Stahl

Hi, everyone-
Just looking for some ideas here. When I hit a medium-to-large sized bounce in my '86 928, there's about a 50/50 chance that the antilock light will come on (and the antilock will stop working, though the brakes stil stop just fine). Restarting the car clears the problem until the next big bump. Seems to me like a loose electrical connection somewhere.

Question is: where do I start looking? I get the feeling that it's somewhere up front , but who knows. I did check the fuse/relays and they seem fine.

Thanks all
-Mark

---
1986 928S
Ott X-over, custom dual exhaust

T Colvin

I was spraying the brake pad dust off my wheels just last week and the anti-lock light came on the next day driving to work. I was going to check it when I get home, but it never came back on again. Don't know if that bit of information help.

Rich9928p

The three major sources of the ABS light on are

a. corroded connections or broken sensor wires

b. metal filings on the ABS sensor ends/tone rings

c. ABS Relay

pasa

I another source is a corroded fuse I once had one that caused my ABS and PSD warning to come on. The fuse was making a bad contact.


Regards Dan 1990 928 GT

Rod Underwood

I have an interesting twist on the ABS light. Mine was on - continuously - and I replaced the relay. The light went off - great - but.... I noticed that it stays off as I back out of the garage but as soon as I start to move forward, it comes on. This now happens every time is leave the garage.

I assume the relay was bad since it was on continuously previously, but now I assume that one or all of the sensors needs to be cleaned. Is that a reasonable assumption?

I've checked the shop manual, but can't find any images of the sensor(s) -probably not looking in the right place, but the digital version is a PITA to use.. Could one of you kind experts direct me to a site that has an image and recommend a proper cleaning technique?

Thanks
Rod

IcemanG17

try this link...

http://www.nichols.nu/tip608.htm

ColinB

There are more relays, two IIRC, on the ABS actuator which is mounted high in the left front wheelbay behind the forward splash panel.

Colin 89GT

Rod Underwood

Thanks Brian and Colin.

This will be my next weekend job.

Rod

BrianG

My '86.5 car was doing exactly the same thing. Turned out to be the main relay.

Rod Underwood

Hmmm... I replaced the main relay and it changed the problem from a constant on to an "on", not when I back out of the garage, but only after I start moving forward. Not to say I couldn't have replaced the relay with another faulty one but just not "quite" as faulty. ;-)

Oh well, lot of interesting problems to solve.

Rod

Baby's growing up, she's getting a bit of a makeover today. nose, mirrors and new wing paint. She'll be "spiffy" in a few days, I hope.

IcemanG17

Rod
I had an odd intermittant warning usually at start up that would go away with the "windows fix" of turning the car off & starting it again. Eventually the light came on while driving and stayed on. Turned out the main relay (like yours) was blown....changed it out (after breaking the fuse panel!!) & all is good now! It does sound like one of the other relays at the motor-pump are also bad or the wheel sensors are gunked up!

Rod Underwood

Are these actually inside the wheel bay behind the front splash panel - requires cover removal? Does anyone have an image? I'm a visual guy.

Thanks
Rod

Daryl

Mark,
I had a simular problem with my 88 S-4. The light would come on when I hit a bump with the left wheel. On my car there is a ground wire under the hood on the left side inner fender just before the master cylinder. I cleaned it up and no more problem. I have also found fuses that look good that don't work. I think the legs get corroded.

Mark Stahl

Good suggestions, everyone, thanks. Does anyone know for sure if/where there's a relay behind the front splash panel in an '86? Obviously I'll just look but I'm with Rod in wanting a picture if at all possible. And I have absolutely no idea what the sensor I should be cleaning off should look like!

Thanks,
Mark

ColinB

Rod
Don't have a pic but I think your 87 will be the same as mine. To access the actuator you have to remove the LF wheel and the forward splash panel, on the back (actually front) of which you should find a duct feeding clean air to the alternator. Not difficult to dismantle. (FYI ithe probe in the duct is an outside air temperature sensor) The actuator is behind the bulge at the upper edge of the panel with the relays under a cover on the inboard end.

Mark. Sorry. Don't really know if the above applies to '86.

Colin. 89GT