Drivers side Brake caliper stuck shut? ABS engaged all the time.
 

Running wilwood bbk up front.

So just 2 days ago, i was driving and any time i press on the brakes with forward momentum, i believe the ABS is kicking in. It immediately makes a studdering/shuddering sound. If i revers and brake, no problem.

I pulled the wheels off, inspected the rotors, pulled the pads, inspected all looks good. What i noticed is up on the lift, the pass wheel freely spins, so lets call that 0% brake engagement, with the typical minor rotor/pad rubbing.

Drivers i would say is 80% engaged, takes a lot of force to get the tire to rotate, and even then, does not spin, as the rotor and pads are essentially engaged.

Its making me think that this is the reason for the sound when braking, since the drivers side is almost completely engaged already, as soon as i brake, abs sees that as being locked up and engages.

I took some video and will try to post shortly, have to see if its even good enough quality to hear problem.

Is there a way to completely eliminate the ABS to check without it? I tried pulling both fuses, but that didnt seem to make a difference.

Trying to trouble shoot, maybe possible the ABS unit is bad? Or thinking that maybe the caliper is going bad, starting to seize.

About 3 days agao i was driving and came around a corner and had to quickly brake, maybe 65 down to 30, it locked the tires, not sure if that did something. It didnt start up righat after that though, it wa a day later that i noticed this.

Sounds like a seized caliper? Disassemble caliper, apply high temp brake grease to slider pins. I would recommend doing a full caliper rebuild while you're at it (cleaning piston surfaces, replacing seals, slider pin boots..). Google caliper rebuild kit for this car.

Yeah, seems like a seized caliper to me as well, im gion gto pull that off tomorrow and check it, lube it, etc..Its less than a year old, and probably has about 2500 miles total on the caliper, so not too happy about that.

No slider pins on these calipers, but going to rip it apart tomorrow and clean / lube the pistons.

There are slide pins. Check the caliper Rebuild Guide:
http://www.ft86club.com/forums/showthread.php?t=60896

Edit: NVM realized we're talking about after market BBK

Could be a caliper piston got stuck.

Pulled the whole caliper off, pulled the pistons, cleaned them, relubed and resinstalled, as well as bled the brake system. Seems to have helped just a bit.

The wheel now freespins a few revolutions, same as pass, so in that regards, the piston sticking seems to have been fixed. But, the ABS still seems to be engaging on any braking.

At this point, i guess next step is to get a new abs controller and swap that out. ugh.

Have you considered putting OEM calipers back on?

Yes, i might try that. Problem is you have to modify the brake line mount to fit the wilwood, and not sure if it will be real easy to put back, but i will possibly try that as my next next.

It sounds more like a warped rotor to me. If you pull the fuse the ABS can't work. If the calliper was seized its not hard to imagine the extra heat warping the rotor.

I could see that, especially to the point of the abs fuse being pulled. I pulled both the 40 and the 25 amp fuses, and it does the exact same thing, so maybe its not the ABS, and its actually the rotor being uneven and causing the strange sound.

Maybe i will pull the rotors and check for uneveness. Not great, but a quick fix if i just replace a rotor, like $200 bucks.

Make sure they're well bled as well...I've seen calipers with air in them that start to grab the rotor when they heat up and the air expands.

i ordered a complete rebuild kit, new rotors and some other items. Im going to try a few things this weekend and see what i can find.

Have you checked to make sure that your hat to ring bolts are all tight?

I totally spaced that, but i will be pulling these all apart tonight, so will check that too.

Here is a video with it.
Shot a few runs with the camera outside next to wheel, and also have it with the camera sitting underhood next to the ABS module.

https://youtu.be/B-M_zj2oWJQ

Maybe the wheel speed sensor is borked? Damaged wire?

Wouldn't explain binding when the car is off but would explain the ABS kicking in...

I thought about the speed sensors, but they are tied to the ABS correct. I am almost positive its not ABS. I just disconnected the ABS control completely. Sounds still happens. So while it sounds like an abs thing, i think its something more related to the brakes themselves.

I have all just got delivered, brake fluid, new pads, rotors, pistons, gaskets, mounts, etc. basically i ordered everythign but new rotor hats and calipers, but everything to rebuild the calipers. At this point, my next steps are in this order. If at anypoint the step does not resolve, move on to the next step.

1. Bleed system completely. Full flush. NO LUCK
2. check rotor runout, if this is in spec, then on to next step, if not, swap rotors. Willwood spec is .005 - .008 Pass.005, Drivers.004
3. If rotors are in spec, sand rotors lightly to remove any build up NO LUCK
4. Replace pads, possibly use more aggressive track pads to help with caliper smoothing, i have 2 new sets a bp10 (street) compound, and a polymatrix (track) compound. Wilwood actually recommends something like this. NO LUCK
5. Swap to stock rotors. calipers, lines. Put factory back on the drivers side, problem gone. Looks like its something with the wilwood setup on drivers side. Now to figure out if its the rotor, rotor hat or a caliper issue. Going to swap rotor first, then rebuild caliper, new pistons, then go from there.
6. New Rotor
7. caliper full rebuild

Think that makes sense

I think it's rattling before you even hit the brakes, but hard to really tell from the video. Check those bolts for sure!

So far not making any progress, but at least eliminating a few things

Im now going to remove the entire BBK and put factory back on,

Well. After a lot of time, and unfortunately around $700 in parts from wilwood I'm still no better off.

Still does it. I completely rebuilt the caliper, new orings, new pistons, new seals.

New brake pads, new rotors. Same old problem.

I'm stumped.