pointvirus

I did a search, and I couldn't quite find what I was looking for.
Basically when coming to a stop, right before the car is completely stopped, the car feels like the brakes let go for just a split second, the car rolls forward just a tiny bit, and the low trac light comes on. It's very interment. It's nothing "major" at the moment, as it just barely rolls forward for a fraction of a second going 1 mph.
I bleed the rear brakes last weekend (one of the bleeder screws on the front is stuck and I didn't want to strip it), and I thought it had gone away. But it just did it again today. I'm almost thinking it's something driveline wise.
I change the gear oil regularly as best I can with a siphon pump. I'll pop it open this weekend to do a full gear oil flush. The car's stock rear end wise.
Any ideas on what might be happening?

pointvirus

I should also add that there's no whining, clunking, grinding, codes, or anything else out of the ordinary. It drives just normal up until the last part of "feathering" the brakes.

98boxer

iTrader: (7)

Have you replaced both front and rear brakes?

Is it raining where you're at, tires in good shape?

pointvirus

No rain, tires are good. Replaced pads and rotors this last summer. Still plenty of pad and no cracks or warpage.

cre81r

I have the same problem,i notice that if I don't press the brakes all the way down,it'll creep and make a horrible noise.Except I haven't noticed the low trac light.So try pressing your brakes all the way down.I know it's weird i say we have too much torque!!hehehe

keliente

iTrader: (22)

It sounds like your ABS is kicking in. It pulses the brakes, which is why you feel like the car rolls forward. Why it is activating in this situation is what you need to find out. Do you have any codes in your EBCM? Perhaps a wheel speed sensor is on the way out. If that's the case then the car may be seeing false wheel slip, and activating ABS...

pointvirus

Oh! I hadn't even thought about the ABS system. That sounds really plausible. Havn't checked for codes yet, I really need to get a scanner.
Is there anything apart from the obvious fluid check with diagnosing ABS? Or perhaps there's a way to check wheel speed sensors?

SparkyJJO

iTrader: (11)

I know it is a totally different vehicle, but my parents had a windstar (pile of crap that thing was) and it had an ABS sensor go bad and cause the ABS to kick in when stopping randomly. Unnerving because it would all of a sudden not be stopping as quick.

keliente

iTrader: (22)

It wouldn't hurt to check the brake fluid in the master cylinder, however if that was low the BRAKE (like e-brake) light would illuminate on your dash.

The best thing for saving time diagnosing ABS problems is to start with the codes (if there are any). There are probably 100 faults in the system, but you're just chasing your tail if you can't narrow it down. Hopefully there will be a couple stored codes in the EBCM for you to go on or at least point you in the right direction.

pointvirus

Sweet. I'll be swinging by a dealership today to pickup a rear end gasket, so while I'm there I'll see if they'll let me get a scan. Out of curiosity, does the EBCM typically get scanned with a personal handheld OBDI scanner?

chavez885

iTrader: (12)

I don't think a scan will pick up ABS issues (definitely don't pay for it). You could pull your ABS fuse and drive the car and see if it still does it, if it doesn't you'd know for sure its the ABS.

keliente

iTrader: (22)

If you're at a dealership, their Tech 2 scan tool can pull codes from the EBCM. Most of the cheapy handheld scanners just read PCM codes though.

pointvirus

I'll try the fuse trick and see if that stops it too.

I was reading Chilton's last night and it was talking about how you can't service the VSS on the front wheels. I guess you have to get a whole new hub. Hopefully it doesn't come down to that.

Thanks for the help guys, I really appreciate it!

Marc 85Z28

iTrader: (8)

The ABS is activating due to a false wheel lockup reading. One of the sensors has an excessive airgap issue due to either a missing reluctor tooth or more likely corrosion moving the sensor away from the reluctor ring.

Use a scanner with datastreaming to determine which sensor is causing the issue, and then inspect it (if scanner is not available, service all sensors). If you see any kind of rust buildup on the machined surface where the sensor presses in, that's your problem. Remove the sensor and pack the hole with grease. The file the rust off. Clean the debris from the hole and reinstall the sensor.

Viper

iTrader: (6)

I know it's a month later but did you figure it out? I had this happen in my 99 under warranty and it was the entire ABS computer, to the tune of $800.