Supercharged111

Ahem.

You'll want to disassemble that caliper to inspect it. If nothing is galled, reassemble with new seals. If only the pistons are galled, you can get SS pistons for it. If the bores are galled, you should probably look for a new caliper.

Phiber Optik

Update:

I just rebuilt the front calipers with drm ss pistons and new gm seal kit, the driver side had some white corrosion at the base of the bore, that I cleaned up with a wire brush and reassembled with Russell ss brake lines.

When I was bleeding the back brakes (using motive pressure bleeder) the driver side wasn't passing fluid! So I took the fitting off the caliper and still no fluid, so I disconnect the line at the hard line... Still no fluid! Then I figured I must have a pinched hardline and that was the problem all along... Traced the line back to the abs pump and then up to the master. No crush. With the line disconnected i pushed the brake pedal and fluid came out, So then I blew the lines out with compressed air and put the lines back together then applied 15psi from the motive pressure bleeder and fluid started to flow from the bleeder screw. Then i took the car for a spin...still same problem! Wtf???

I did notice the abs is coming on fairly easily, but even with light brake pressure it feels like it's pulling to the right.

Any suggestions?

Phiber Optik

I'm thinking the abs pump might have a sticky valve, the drivers rear was stuck closed that's why I got no fluid originally then I blew it open and it bled, but then when I hit the brakes and the pressure of the master cylinder pushed it closed again...? Thoughts

Phiber Optik

Update - dealer tech came by with tech2 to do an abs bleed and still not better!

We also checked the suspension again and found no issues.

We even tried swapping the front tires but the problem is still pulling to the passenger side under braking.

We checked the steering angle and The tech2 said it is bang on center, so it wasn't from not properly putting the steering rack back in after the crank pulley install.

I pulled the rear calipers and they aren't seized, they are really the only component it could be but it really doesn't seem like it is...

Does anyone have any ideas?

Bill Curlee

Pull Eng Compart Fuses ABS Maxi Fuse 52 & ABS ELEC maxi fuse 53. That will disabel ALL ABS action. If you still have an issue, its not elecronic related.

Post results

martysauto

See post 16 if post 25 doesn't prove it to be an abs problem. Are all the brake hoses original?

Bill Curlee

Hoses would have been my NEXT recommended repair. I just had to eliminate the electrical potential as being the issue.

If your car is pulling to the RIGHT,,, here are some possibilities

= Left side caliper isn't clamping/applying properly during stop
= Right side caliper is dragging.
= ABS/AH system applying brakes to the left wheel, releasing brakes to the right wheel during stop.

Use a inferred thermometer to see if there is a significant difference in left and right rotor temp after the issue happens.

BC

Bill

Phiber Optik

Hi guys thanks for the replies,

As previously mentioned I installed Russell SS lines when I rebuilt the front calipers with drm pistons, didn't help...

I checked with an IR gun and all rotors were equal temps side to side with the rears slightly cooler than the fronts.

I will pull the abs fuses and see if it helps, I doubt it as there are no codes and the steering has been confirmed as centered...

Bill Curlee

If the EBTCM micro processor thinks its functioning correctly, it will NOT throw any DTCs even though its malfunctioning.

My O2 ZO6 would pulsate the brakes on all four wheels on flat level road at slow speeds. Zero DTCs displayed.
Ended up being a bad EBTCM.

Bill

martysauto

Bill, I have seen wheel speed sensor cause low speed activation as well. Also with no codes, we graph all 4 and will see one flat line at 0 mph while the others are still still 7-8 mph. Abs activates just as it flatlines. If it's a front, the car will pull abruptly as it happens.

jgump

I have some low speed (sub 10 mph) pulling issues as well when braking. Speed sensor is interesting.....

Smokin Joe

Isolate the problem front to rear. Be careful when doing this. Use a parking lot, or long open, empty road.

Take two small locking needle nose pliers. Pinch off the rear brake lines in a way that won't catch the locking pliers in anything. Test drive, brake, and see if still pulls. You are disabling the rear brakes in this test, effectively taking them out of the equation.

I'd be very careful doing this in the front, as most of your stopping power is up front, and you have more going on mechanically with less clearance, and you definitely don't want to get the pliers bound up in anything and ripping apart a brake line and damaging other components. You should be able to tell from just doing this to the rears.

03newjersey

If you still have the problem..... I had a stock 92 Camaro Z28 that all of a sudden would pull to the passenger side when braking. I read up on the subject and helpful people made all kinds of suggestions but one person suggested to simply replace the brake line whether it looked good with no cracks or obvious defects. Sometimes the brake line fails internally and the fault can't be seen (such was my case), maybe even more unseen if the brake line is clad in stainless steel. I know you said that you have new Russell SS Brake lines but what if you got a defective line? My suggestion is to buy the cheapest, front only, rubber brake lines from your local store for test purposes and replace just the passenger side and take the car out for a test drive. Then if you still have the problem try the other side. It solved my problem.
Goodluck!

Phiber Optik

I pulled the 2 abs fuses as mentioned above. Still the same problem!

As previously mentioned several times, after I discovered the problem I replaced the brake flexlines with new stainless steel lines, and the problem persisted. I am fairly confident the problem is NOT in the flex lines.