Intermittent brake lock up

Wondering if anyone on this site can help troubleshoot an intermittent brake lock up problem?

My 2001 Chevy Silverado 2500HD Duramax 4x4 ext cab long bed with 233k mi on it has been experiencing intermittent brake lock up at what appears to the rear passenger wheel. It only happens under light braking and never happens under hard braking.

Prior to this I had been getting ABS/Brake warning light that would go away after turning off engine and restarting, but would still show C0262 in the history. This indicated bad ABS module which I replaced but didn’t solve the problem, however it did throw anther code, C0238 which is “wheel speed mismatch”. ( I do have oversized wheels tires but I’ve always had them). This two would go away after turning off engine and restarting but still in history.

My mechanic connected his Scanner and confirmed the front 2 wheel speed sensors are working and show the same speeds as well as the rear speed indication. The ABS module also shows to be good.

We thought maybe the rear brake lines might be partially collapsed or restricted so those, as well as the common flex brake lines were replaced.

Note: A few thousand miles prior this issue I did have all four rotors, calipers, pads and front brake lines replaced because all were in bad shape. Not sure if this might be the issue because it didn’t immediately happen.

Any help much appreciated.

The usual suspect is a lube or brake fluid leak at the rear wheel, but it appears you surely would have noticed that with all the hands and eyes on the area. Considering all you've done to correct other issues, I suspect the ABS module hasn't been bled properly. The procedure is specific, and almost always requires a Tech II or other capable scan tool. Air in the system can cause over/under-pressure braking issues at individual wheels. Other than that, suspect a damaged or failed ABS module or a related connector.

DmaxMaverick, thanks for your reply.

Interesting, I’ll have to discuss with my mechanic. I know he used his scanner to test the ABS module and found everything working normal. However I wasn’t aware of a specific bleeding procedure. I talked to him about that.

Just to confirm, the issue surfaced after replacing all the calipers (reread the OP)? If so, after replacing the ABS module (requires bleeding, probably done right), it continued. I'd suspect a bad caliper or component associated with only that wheel. The calipers are corner-specific, so swapping them is not an option (that would be too easy). Can you confirm that the driver side is working, or both are working at the same time? Jack both rear wheels and roll in D (chock front wheels, 2wd, obviously), at idle or slightly above, while very slowly adding pressure to the brake pedal. Note any chattering or instant locking, or anything else not normal. You may also try brake-locking on a dirt road. The problem may not be the locking wheel, if the other isn't getting enough friction, for whatever reason.

After discussing with my mechanic he confirmed he successfully completed the ABS bleed with his Scan II. The driver side rear appears to be ok, I can hear the passenger side wheel locking up, however neither of us have been able to physically see the wheel lock.

What I find strange was that the truck had been driven a few thousand miles after replacing caliper, pads and rotors before this issue occurred.

We too are leaning towards a bad caliper even though he physically watch the calipers contracting and releasing without any obvious issues, of course the vehicle was not in motion. It makes sense that it’s a specific wheel/brake issue since the brakes are a three channel set up.

Funny thing is that I drove the truck yesterday about 60 mi. and couldn’t get it to lock up.

I gonna try what you suggested.

Again I do really appreciate your input.

I’ll keep you posted.

Update:
Sorry for the late follow up but wanted to make sure I wasn’t premature in my post.

Unfortunately I have not been able to verify the cause of the brake lock up issue, but it has not done it since my last post. I’ve driven short distances and long distances and never experienced it again nor could I make it is make it lock up like it did before.

I never performed any other checks of tests. It just seems to have gone away.������������
I want to thank all who chimed with thoughts and suggestions.

Hopefully the problem doesn’t resurface, but if it does I’ll try the other suggestions and report the results later.

Thanks.

Thanks for the update. I haven't had to do a brake job on my 2001 yet (unbelievable, but they still stop like new with ~50% left, at 200K; knock wood), but have on many others, since and for many years before. The old practice was/is, to "burnish" new pads and rotors. That is, to do several "panic stops" to very quickly bring them up to temperature, and let them cool between cycles. This did a few things (again, old school). It lapped the previously foreign (unmatched) materials, tested the brake system at extreme before placing into regular service, and allowed any significant problems to surface much sooner under controlled conditions (as well as reduce odors more quickly, especially with non-metallic or organic pads/shoes). Most problems were discovered very quickly, while not doing it wouldn't, necessarily, make the brakes any better, but likely prevented situations similar to yours. Not saying that's your problem, but a possibility.