Low trac, low ideas...

[myk]

It makes sense that now the Z is running again I have a new problem.

Anyway, coming to a slow stop with moderate braking, the brakes seem to "slip" for a second, letting the car continue, then the brakes suddenly decide to clamp down and stop the car; while this happens the low trac light comes on.

Now, I've read quite a few threads regarding possible ABS and other brake system problems, but I just wanted to know where I should start first. I figure taking the wheels off, checking the sensors and cleaning them? Checking the wiring that goes to the sensors and cleaning them? Checking the ABS module itself? What I wouldn't give for a scanner.

Thanks in advance guys!

[Blown1993Z28]

While youre in there bleed the brakes until you get fresh clear fluid. It propably is the ABS though.

[Paulster2]

Scanners are nice, but the typical scanner you get for your car (Datamaster) and the like will not read the ABS issues. I went through this when my ABS light was stuck on. I agree with Rob, bleed the crap out of your brakes and see if that helps. It should be done regularly, anyway. You could have a sticking brake piston. Is there any wheel which seems to lock up just before the "brakes seem to slip"? The only sensor you can clean is the one in the rear. The two up front are sealed. You can check you sensors by using this procedure. I would bet they are good though or the ABS light would be on all the time.

[Badazz 97 T/A]

what does the pedal feel like when it slips and then all of a sudden grabs. Does the pedal get mooshy or does it feel normal the whole time?

[Tony]

That is an ABS issue. When I got my car, it did it to me and about made me shat myself lol. I took the friggin relays out and got rid of it all together so that crap wouldn't happen again. You have a wheel sensor somewhere that is going out, or the reluctor gear is missing some teeth.

[Blown1993Z28]

That is an ABS issue. When I got my car, it did it to me and about made me shat myself lol. I took the friggin relays out and got rid of it all together so that crap wouldn't happen again. You have a wheel sensor somewhere that is going out, or the reluctor gear is missing some teeth.

Ditto on my TCS. I disconnected it after it kicked off on me after a high speed emergency lane shift on the highway. I had the car straight and the STUPID TCS kicked off. I had already corrected enough and was straight. The TCS light flashed it tried to straighten me out again and sent me spinning. At low speed in the snow it might help but I don't want my car trying to drive itself (unless it's name is KITT)

[myk]

what does the pedal feel like when it slips and then all of a sudden grabs. Does the pedal get mooshy or does it feel normal the whole time?

I think.....it gets mooshy for a split second and then goes back to being firm and normal. It only feels that way for as long as the low trac light and the sensation of the car slipping forward takes place.

I guess I'll check out my rear wheel sensors. Christ, those lines haven't been bled since...1997 probably lol...

[Blown1993Z28]

I think.....it gets mooshy for a split second and then goes back to being firm and normal. It only feels that way for as long as the low trac light and the sensation of the car slipping forward takes place.

I guess I'll check out my rear wheel sensors. Christ, those lines haven't been bled since...1997 probably lol...

So I'm taking it you bled the rusty old fluid out and it didn't help? I bleed mine whenever I replace the brake pads but you're right most people NEVER bleed them. On my '85 Monte SS I even packed the bearings every time I did the brakes. You might want to consider letting the dealership check the brake electronics. There is a special computer tester just for the brakes that most small shops don't have. I try to avoid the dealership like the plague and would personally replace all the sensors blindly before paying $95 an hour for diagnostics. Its all up to your wallet.

[Paulster2]

So I'm taking it you bled the rusty old fluid out and it didn't help? I bleed mine whenever I replace the brake pads but you're right most people NEVER bleed them. On my '85 Monte SS I even packed the bearings every time I did the brakes. You might want to consider letting the dealership check the brake electronics. There is a special computer tester just for the brakes that most small shops don't have. I try to avoid the dealership like the plague and would personally replace all the sensors blindly before paying $95 an hour for diagnostics. Its all up to your wallet.

I hope you actually mean "change" and not "bleed" the fluid in your braking system. Getting the air out of the system is one thing, but changing fluid is a whole different thing.

[myk]

I think they mean change the fluid. I'll start out with the wheel sensors in the back, the wiring and then take it from there. If it has to go to a shop then so be it...

[Blown1993Z28]

I hope you actually mean "change" and not "bleed" the fluid in your braking system. Getting the air out of the system is one thing, but changing fluid is a whole different thing.

Ummm, maybe I've been doing it wrong. I top off the fluid in the reservoir, then attach the one man bleeder tool, then open the valve on the caliper a little bit, then pump a couple of times on the brakes and repeat as necessary until clear fluid is in the bleeder tube.

[Tony]

You should not "pump" the pedal with the bleeder open. You will get a crap load of air in the system. I just fill the res, or make something to where I can put the bottle on the res, and let gravity do all the work for me. also called "gravity bleeding". Works great when you have a case of beer, cause it takes forever lol.

[Blown1993Z28]

You should not "pump" the pedal with the bleeder open. You will get a crap load of air in the system. I just fill the res, or make something to where I can put the bottle on the res, and let gravity do all the work for me. also called "gravity bleeding". Works great when you have a case of beer, cause it takes forever lol.

I've never heard of that gravity method. That "one man bleeder kit" has a rubber fitting that seals on the brake calipers bleed port and then runs down into a jar like a straw in a cup. I can watch the bubbles flow down into the cup, bubble up and then when you release the brake it sucks a little pure fluid back through the straw. You gotta just open the valve just a little bit or like you said you can suck air in through the valve.

Beats the Hell out of "OK pump the brake, open valve, close valve, OK let it up" repeated 10 or so times!

[Paulster2]

Yah, Tony, the one man bleeder kit has a check valve so you don't get air back into the system. EDIT: You can also get the screw in type for each caliper which replaces the bleeder screw directly. Just throw your rubber hose on there, crack it open, top off your system, and pump away.

Yes, Rob, sounds like you are not bleeding the system, but changing it. Just your terminology was a bit off. Running it clear (and a little bit more) at each wheel is about the best you can do.

[Tony]

I know what the one man bleeder kit is. There is a bleeder that has one built in that I have thought about getting for my own car. I thought he was just letting the fluid run into a pan and when the pedal came up, it was sucking air into the caliper.