It's been a while since my last post, but, I knew exactly where to go for the best advice available.
Anyway, my brakes have been real touchy and lock up(skidding)when I tap the brake pedal. It's seems to be worse when the truck has sat for a while(overnight/during working hours). It does this at lower speeds mainly. Right from a stop light or from a parked position usually.
The truck is a 1/2 ton 4wd, w/ front disc and rear drum brakes. I did a front and rear brake rebuild about a year ago and this current problem wasn't evident until a month or two ago. I rebuilt the calipers which weren't a year old to begin with. I installed new rotors,pads,lines, etc. I rebuilt the rear setup with new drums,shoes, internals, the whole nine yards.
Other than some air in the system at first, I had the whole brake system working great for several months.
Any ideas? I'd appreciate the help.
Thanks,
FITTnFISH
Is the front or rear locking up? Which tire seems to be dragging?
(07-30-2011 04:18 PM)LegendKiller89 Wrote: [ -> ]Is the front or rear locking up? Which tire seems to be dragging?
I'm not sure, but, I know when it does it locks instantly. As expected, it makes a loud squeeling/burn out noise. Kind of loud at 5AM when I leave for work. If I had to guess, I'd say it seems like the rear is locking up.
I had a similar problem before when I did some brake work. However, the ABS light was on that time and it turned out to be air in the system. I bled the brakes and it got rid of the light and the lockup problem. From my research that time it had something to do with the ABS system and the proportioning valve that's located in the engine bay.
None of those symptoms are present with this episode of the brakes locking up. How do I know for sure which one is locking with out actually leaving skid marks?
Any ideas from that description? If not, I'll investigate further and provide more to go on.
Thanks,
FITTnFISH
Well I'm just gonna give a few ''possibles''.
If it's the rear drums it could only be a couple of things. Either the brake shows are out of adjustment, or you could have a build of junk on the shoes themselves. I would take the drums off and see what it looks like. Have run into some circumstances where there is brake fluid on the shoes and it causes a lock up. Lots of times I've seen where it is just a bunch of dirt built up... kind of hard to explain... like brake dust between the shoes and the drum itself. That would cause that as well.
Only way to know which side is if you got lucky enough and someone saw the side dragging. Either way pound the drums off and take a look if you have a buildup of crap in there.
If you have air in the lines it will do that.
That is probably your most likely cause of the problem.
Leave a skid mark and the one that locks up the soonest willl have the most air. Is the fluid level down at all?
(08-01-2011 06:47 PM)Tango Wrote: [ -> ]If you have air in the lines it will do that.
That is probably your most likely cause of the problem.
Leave a skid mark and the one that locks up the soonest willl have the most air. Is the fluid level down at all?
No, the fluid is right at the full line. The weird thing is that it was operating just fine for quite a while before it started this [censored].
Don't get me wrong, I understand that in the mean time there's a million things that could have happened to cause air to get into the system. There's no leaks that I've found that would constitute an opening in the system. I haven't had the cylinder cap off since the last time I did all the work to it so that's not a possibility. I even replaced the cap with a brand new one.
The cap wasn't an exact match to the original, but, it was damn near. For that fact alone I checked the fit about ten times and went over the damn thing with a fine tooth comb to make sure it was going to work. The part # and description from autozone was for my make and model truck. IDK, maybe the POS aftermarket cap is the culprit.
I'm more inclined to think that one of the more significant components in the system has failed... metering valve, prop valve, etc. Maybe, the wheel cylinders are bad on the rear. They're the only thing I didn't replace when I rebuilt the rear brakes. I totally forgot about those not being replaced.
I'm working six days a week right now and bursitis in my left elbow(had to have fluid drained from it the other day) so time and ability is a precious commodity right now. I should have taken a picture of my elbow before the doc drained it. I could have posted it on here. It looked like elephantitis(sp) of the elbow. Still looks like a ping pong ball is stuck in there. Anyway, thanks for the suggestions and I'll get some feedback asap.
Well if you go to bleed it and it doesn't have air you'll know it right way, since you will get pure brake fluid vs. air and brake fluid out.
If it's not air, I would go with the proportioning valve, thought I've rarely seen them go out, and a failure usually does not make your brakes touchy.
I had one truck do that same thing, and it ended up being a small crack in the brake line right where it attaches to the rear brake plate. The fluid must have gone down a little on my truck, but I never noticed it. The crack would only open when the axels really bounced.
That's usually the case with me. It's always some obscure and hard to find solution to these problems that I encounter so often with this truck.
It may also be the wheel cylinders... if they were not replaced.
What LedgendKiller89 saying is also a possibility. If one wheel cylinder is semi-frozen up then all the preasure would go to the wheel with the working wheel cylinder. So the tire that skid would be the side that's ok and e other side would have a bad cylinder/calaper.