I recently had the front end of my '95 F150 4x4 apart to replace the u-joints on the front drive axles. After reassembling the front end and taking it for a test drive, my front brakes are sticking really badly. When I took the brake calipers off to get at the axle shafts, I just compressed the pistons with a c-clamp, I did not open the bleed valve. So, no air should have entered the system. The truck drives and stops, but the front brakes and hubs get extremely hot from the brakes rubbing. I did manage to strip the threads on one of the bolts for the passenger side caliper, so now it's only being held on by 1 bolt instead of two. The caliper piston looks like it retracts when one lets of the brake pedal, but the pads stay pressed hard on the rotors.

I attempted to bleed some brake fluid from the brake today, but couldn't get the bleed valve open. I cracked the bolt at the brake line, compressed the caliper piston all the way in with a c-clamp and a piece of wood as my girlfriend stepped on the brake pedal in the cab. I reassembled the brakes and gave them a try, they still stick hard.

I'm thinking of replacing the pads and seeing if that helps. The inner pad is worn pretty bad at the bottom, but is still pretty good at the top. The outer pad is worn evenly with plenty of pad left. I'm thinking the badly worn inner pad might be causing the brakes to stick. Does that make sense at all?

So, I guess my questions are as follows:

Does anyone think that my caliper won't work properly with only 1 bolt holding it down?

Does anyone think my brakes are sticking because my pads are bad (very uneven wear on the inner pad)?

Does anyone think that a total brake fluid flush would cure this?

Thanks in advance!

CPB

 

Usually when uneven wear is experienced the caliper is sticking and not freely able to slide back and forth as intended. You definately need the 2 bolts holding it down. If you have antilock brakes in front there might be a problem when you forced brake fluid backwards by compressing with a c-clamp. Was there any room for additional brake fluid in the master? It could be overfilled??? Just my $.02

 

My guess is you have a bad brake line. The rubber one from the fram to the caliper. The lines do go bad and will cause a caliper to stick. I think you damage the line while working on the front of the truck. Were the calipers hanging by the lines?

I would never run a caliper with one bolt. Your asking for problems. This could cause the piston to lock sideways in the piston bore? It may have to extend a ways before that happens. But one never knows. The deisgned was for two bolts and I am sure for good reason.

 

The truck has rear ABS only, so I don't think compressing the caliper with a c-clamp caused any harm.

I did not allow the calipers to dangle by the brake line. I used bungee cords to hang them from the coil spring. I don't believe I damaged the lines in any way. I did not overflow the master cylinder when I compressed the pistons.

Isn't it somewhat normal to have the inner pad wear faster than the outer pad, as the inner pad is closer to the piston? It just seems odd to me that the lower part of the inner pad is wearing faster than the upper part. I figured it would be more uniform across the length of the pad. This uneven wear leads me to believe the caliper piston is sticking a bit, as it might be applying more pressure to the bottom of the pad than the top. Am I reaching a bit with that analysis?

I'm really mad I cross threaded the bolt hole for one of the caliper bolts. I hope that I can make it work somehow (retap the hole?).

CPB

 

A hanging caliper will cause the truck to pull to one side. Now that I see what you saying I would say you do not have a stuck caliper. The inner brake always wears faster thean the outside one. It is the pad that sees the most force and sooner. As ofr the uneven wear of the pad I would say the one bolt is your problem. The bad threads mat clean up with a tap. Its worth a shot. If you cross threaded the bolt all the way through then you may need to helicoil it.

 

The truck doesn't pull at all. In fact, if I wouldn't have been checking the temperature of the hubs by touching them with my hands, I never would have known there was a problem.

I just stripped the caliper bolt last week, and have driven the truck a total of 5 miles with 1 bolt. The pads have been on the truck for around 50k miles (with both bolts holding the calipers in place), so the unever inner pad wear was not caused by the missing caliper bolt.

I'm pretty sure I messed up the hole all the way thru, so I may have to look into this "helicoil" thing you mentioned. Anyway, I think I talked myself into getting new pads and calipers tonight, so hopefully that will do the trick.

Keep the suggestions coming though!

CPB

 

I would just bet you forgot to put back the inner bearings on your hub.
The hubs usually has two bearings the inner bearings and outer bearings. OR
You inner bearing is worn out.

Don't forget to grease the two side ears or the metal part of the pads that help it stay in place and help it slide side-to-side.

 

Nope, I'm sure the inner bearings are in. The rotor assembly spins great when the brakes are off of it! No end play, no bad sounds, just smooth rolling.

I found out at work today what a "helicoil" is. That sounds like it should work to fix the mess I made out of the bolt hole.

After talking with some people at work, I decided that I'm going to change the pads out tonight and go from there. Why replace calipers if I don't have to, right?

Thanks for the ideas.

CPB

 

Unless the disks are near perfect, I would have them turned when you change the pads. After 50K, they need to be turned.

 

I put on new pads tonight and it didn't fix the issue. The brakes are still sticking hard. Now the driver's side more so than the pass. side. The good news is that I bought a new caliper bolt and it worked in the hole, so I don't need to helicoil it after all. My next step is getting new calipers, and if that doesn't solve it, I guess I'll be taking off the master cylinder and checking the brake booster adjustment rod. I don't feel like pulling the m.c., so hopefully the new calipers will do the trick.

The rotors are in good shape yet and I just threw on a set of cheap pads, so I didn't bother having the rotors turned.

This has been quite a learning experience for me...hopefully I won't be pulling the front end apart again for a while.

CPB

 

When changing calipers its a good idea to change the flexible line as well.