Right front disc brake sticking?

[65swb45]

Matt, I'm not gonna say you don't need to replace your birfield seals, because you probably do. But if both calipers are now locking up, I would be inclined to agree with beanz2 that the brake booster rod is the culprit.

Have you rebuilt or replaced your master cylinder or booster in the recent past?

 

[buckroseau]

The Master cylinder is pretty new, about 7 months old. I imagine one that new could be faulty, but unlikely?

I don't know what or where the brake booster rod is? If it's what I think, the rod you adjust on the back side of the pedal, inside the cab. I do have quite a bit of pedal play, brakes maybe engage halfway through the stroke, so they aren't engaging at the top of the stroke.

In fact when I was driving down my gravel road I stopped, opened the hood and pulled the booster line off the manifold, thinking that may do something? It did not, still plenty of brake for the remainder 3/4 of a mile home.

I guess what is making lean towards the birfs is all that oil slung all over the inner side wall of the right front tire? Slung from the center out if you know what I mean, I wish I would have taken a pic. I can't say for certain it wasn't brake fluid, but the caliper and lines were all dry.

Thanks, Matt

 

[65swb45]

Try this test instead Matt. Next time it happens, loosen the four nuts that hold the master cylinder to the booster and see if the pressure releases. Then you will understand.

 

[buckroseau]

I am not ruling out the brake booster or rod, but I think what I am going to do first is fix the leaks in my axle. It needs to be done anyway, so I figured I would start there.

I found that website Kurt from Cruiseroutfitters emailed me when I ordered the rebuild kit.

http://www.birfield.com/~morgan/tech/axle/index.html

I'm actually rounding up the races and bearings listed on the fist page of this link as we speak (or type). I don't know if there bad or not, but since I'm in there I'm going to replace them. I've already got it in the shop, as of last night, so this evening I'm going to get the front end up on jack stands and let the fun begin.

Hopefully I can back it out by the weekend? If I don't get any major interuptions that is.

Thanks, Matt

 

[peesalot]

don't worry bout the oil or grease you found on wheel , it is cause the brakes got so hot the knuckle got hot and oozed some , no worries. Your booster and master aint right or you got the brake lines getting hot somewhere , is it touching exhaust somehow ?

 

[buckroseau]

don't worry bout the oil or grease you found on wheel , it is cause the brakes got so hot the knuckle got hot and oozed some , no worries. Your booster and master aint right or you got the brake lines getting hot somewhere , is it touching exhaust somehow ?

No, nothing is touching the exhaust, pretty much routed in the stock location.

I'm not saying I'm totally sold on the gear oil on the pads yet, but it needs to be fixed so I figured I would start there.

I'm assuming to adjust the brake booster rod I need to seperated the master cylinder from the brake booster? I looked at that link on page 9 -61, and I kinda get it??

Matt

 

[buckroseau]

Brake Booster?

Last night I got my shop all cleaned up, drove in the cruiser, got it up on stands and started tearing apart the right hub. All I had time for last night was to get the the lock outs and the hub off, down to the hub nut. I'm going to pick up a hub socket tomorrow from my mechanic buddy.

Anyway, upon closer inspection with the flashlight, I find it hard to believe oil from the axle / birf's is getting on the pads? It seems like the dust shield would prevent that, in fact I can see some crud built up on the back side.

Talking to another buddy of mine, he's thinking Brake booster? He had an old Grand Torino that did the same thing. Brakes just started easing themselves on going down the road. He had also tried adjusting the brake booster rod, with no success. And, I may have mis-diagnosed this myself by saying just the right brake, which I thought it was, at least that's the one that stunk and was the hottest?

Now I am going to continue fixing my axle leak, since I need to do it anyway, but kinda thinking ahead to the next fix? I will still try to adjust that rod, but it seems odd that it has worked for 7,000 miles and now this? Priced a re-man brake booster this morning through the local auto parts store, $240 ouch! I will try the rod first though.

On another note, I'm not very far into this whole axle rebuild thing, but I am afraid already, very afraid. Those little shims and measuring with calipers have me scared!

Few pics from last night.

 

[Poser]

You are getting grease/oil on things from the WHEEL BEARING SEAL, which when it leaks, does EXACTLY what you are talking about....


Brakes sticking creates heat, thins grease, and it leaks past the seal....


Now, why your brakes are sticking....


New, even Toyota master cylinders can fail in a very short period of time, I know of two instances where the master and all brake components were less than 6 mos old, and the master gave up...



Yes you have a grease leak, fix that, but the reason that the brakes are being applied 'by themselves' has nothing to do with a leaking wheel bearing seal...


Good luck!


-Steve



Before you tear anything else apart, I would back the booster to master accuation rod off a full turn, and the brake peddal to booster acctuation rod, I would back that off three turns, and see if you can replicate your issue...


Just me tho...

 

[CRZRJames]

No measuring is required. Just put the shims back in the same positions as they were before and torque all bolts to spec and you'll be fine.

 

[Poser]

No measuring is required. Just put the shims back in the same positions as they were before and torque all bolts to spec and you'll be fine.

So long as you have proper pre-load on the knuckle bearings WITHOUT the seals in place....



Not having proper knuckle bearing pre-load will prevent the steering from staying centered, and promote wandering, which, is a pleantiful issue in and of itself with these vehicles...especially on trucks that run tires larger than stock, lifted suspensions, longer shackles, etc...

 

[too tall]

I was just searching and found this . I'm having this exact problem right now . My seals are good , no leaks and my brakes seem to come on gradually by themselves (the calipers in the front). Wondering what you did to fix this issue ? Sounds exactly like the same set of circumstances . I haven't replaced any of the components related to my brakes in the last 6 months at least but I'm pretty sure everything is in decent shape .

 

[Texican]

Most common cause is the clearance between the booster and the master cylinder too tight, quick test is to fab some cut washers, loosen the MC bolts and stick them in, tighten and test drive.......if it fix's it adjust the rod shorter

 

[too tall]

Thanks I'll give it try in the am . Why would it do this all of a sudden out of the blue ?

 

[Von Chaos]

I had the same problem w\ a front disc conversion. shortened the m\c pushrod and everything works fine. the test is to see if your brake lines are still holding pressure. when they stick open the bleeder it the the pressure releases then its a good chance that the m\c is not letting the fluid back all because of that pushrod