My front brake pads were worn out on my '03 2wd. I replaced the pads, had the rotors turned, cleaned and packed the bearings, and replaced the inner seal.

I loosened the nut to release brake fluid when I compressed the caliper pistons with a C clamp. I then bled the brakes and put it back together. I test drove it and the brakes felt firm and stopped good. I even braked hard in the sand to cause brakes to lock up and slide to make sure they seemed equal and attempt to rule out air in the line. Everything seemed good and my wife drove it to work. When she came home she said they smelled hot and didn't smell that way in the morning. I felt them and sure enough they were hot and both now have substantial pad rub. I bled the brakes again and checked the 'slides' which are real smooth. I am now at a loss about what is wrong since both brakes are effected. I could tear into them and clean them well, or replace all the fluid, and/or replace the calipers but I figured I would ask here first and see if anyone has any suggestions.

Here are some additional details. When I first removed the calipers I took out the larger bolts that mount the 'pad holder' to the suspension so that the entire caliper, holder, and pads came off as one unit (let me know if any technical jargon needs to be explained). I watched some videos afterwards and everyone removed the bolts that screw into the slides and connects the caliper/pistons to the pad holder. Can't imagine this would make a difference.

In videos I also saw that everyone compressed pistons without loosening nut and releasing fluid. Some took cap off master cylinder, some didn't. This could make a difference because it introduced a little air to system that I'm fairly certain was removed when brakes bled.

I filled reservoir with correct brake fluid when I was done. The bottle appeared sealed but was probably a few years old. When I pulled foil up there was a layer of plastic that seemed to be separated from foil. Thinking back I suppose the foil could have been loose. I am in a very humid area of Florida and my understanding is that brake fluid is hygroscopic and can absorb water which is why you are supposed to always use a new unopened bottle. Being around for a few years in a shop with no AC, I suppose it could have absorbed a significant amount of water. Could potentially cause problems and all fluid should maybe be replaced with new?

Seeing the videos, I have now taken the calipers off with the bolts that screw into slides. The slides seem very smooth and slide in and then out on their own by, I assume, pressure from the rubber boots. Definitely should allow pad holder and pads to easily center on the rotors. Shouldn't be a problem.

Sorry for the long post. Hopefully it didn't scare everyone away. Just wanted to provide all information I can think of. Thanks and hopefully someone has some ideas!

 

How did you tighten the spindle nut? Which torque procedure did you use.

Did you grease the caliper slides?

How did the piston feel when you were compressing it? Did it feel notchy or smooth?

And finally the "pad holder" is commonly called caliper bracket

 

Thanks.

I didn't have torque specs for spindle nut. So I tightened it down pretty tight where rotor just began to get a little harder to turn then backed off and did it again, then backed off and got nut about finger tight and went a few more degrees. Turned rotor at end when doing final tightening and it didn't get any more resistance as when loose. Pulled in and out on rotor to check for slop in bearing and felt none.

Have not greased slides yet because I don't really know what to do to fix problem at this point. Do plan on doing it but as I mentioned they are very smooth. Just the rubber boots will push slides back out so very little resistance.

The piston felt Ok from what I remember. The C clamp pushed it in fairly easy though there was resistance even with blender valve just barely opened. I don't remember it feeling notchy and that is something I would remember if I had felt it. Brakes were OK before, just squealing some. Both brakes are now dragging so I can't imagine both calipers going bad at same time but stranger things have happened.

And thanks for help with my made up 'jargon'. I'm sure there are others in there.

 

I'd grease the slides, the boot is only there to keep dirt and moisture off the slides.

With the bleeder open they should be almost no resistance when compressing the piston

 

I guess I will tear them back apart and will check the pistons out when I compress them. I just barely opened the blender valve to try a minimize fluid loss since I was by myself and didn't have an extra set of hands. I would assume if bleed valve just barely open there would still be resistance compared to being wide open.

I just feel like if I'm only doing the same thing over again, nothing will change. But at this point it is the only thing I know to try. If it was just one side I could understand, but both sides seems like I'm over looking something.

Could fluid with water contamination cause problems? I could see the water boiling off when things get hot and making brakes spongy or even tight. But it seems like as soon as things cooled off it would go from vapor to liquid and problems would go away.

 

Yes contaminated fluid can cause brakes to engage while driving due to boiling water expanding in the lines

 

I cleaned up the slides and greased them and pressed the pistons in. This time I didn't loosen the bleed valve and they compressed fairly easy and didn't feel rough. Put the pads in and the caliper back on. I pumped the pedal and it took a few pumps but got hard. I turned the rotor and it spun, only dragging some where there is some rust. I started the truck and pressed the brake and it didn't feel as firm as when engine not running but feels normal. After starting the engine the brake is tight on the rotor like the pedal is being pushed down. Before it was tight but I could still turn it and now I can't turn it. This was only done on one side that I had the tire off of. I have no clue what is going on.

Anyone know what retracts the pistons back into the calipers?

 

You could have worn out flex lines (the ones that attach to the caliper). When you apply the brakes they swell or bulge. Then when you let off the brakes they don't allow the piston to return because the lines are acting like balloons and putting a small amount of pressure into the caliper.

Hope that makes sense. Have someone step on the brakes while you look at the lines, they shouldn't bulge on you at all.

Good luck

 

not really, no.
If the fluid in the brake system expands for some reason, it will just push back through the lines and the master cylinder and into the reservoir.

And if he somehow managed to boil his brake fluid, then he would really know it cause his brake pedal travel would be huge.

The seal in the caliper is designed such that it "pulls" the caliper piston back when you release the pressure. If your caliper pistons are not pulling back a hair when you release it then you probably need new caliper seals.

I think they sell seal kits for calipers... maybe??? I've never had to replace seals. And I mean the seals inside the caliper... not the dust boots...

If you can't buy the internal seals then you might just need to replace the entire calipers.

 

The pistons actually dont retract,, thats the purpose of those boots and pins. Thats why its so important to make sure those pins move easy.

I would replace the fluid you have in there and see what happens??? You might try a new caliper on one side and see what happens????

The piston pushes on one pad and the rest of the caliper pulls the other pad toward the rotor. Caliper rides on those pins and boots,, when you release the pedal the caliper slides back on the pins. If that makes any sense. Like rebound.

Also look at the hard wear that is attached to the caliper,,, they sell kits for the front end.

good luck

 

Actually the pistons DO retract. The piston seals create the retraction forces, like I said before.

The purpose of the "boots and pins" is 2-fold.
The purpose of the sliding pins is to transmit the brake force to the opposite side of the rotor. You only have a caliper piston on the one side so it has to be able to slide back and forth on the pins to transmit the force equally on both sides of the rotor.
The purpose of the boots is to keep the pins clean and rust-free.

IF you don't keep the pins cleaned and greased, the assembly might not slide back and forth properly. This can cause the outside pad to drag on the rotor.
So yes, I agree on that last point... make sure your pins slide easy...

 

So did he get fixed????

 

No I still haven't got it fixed. I opened the bleed valve and released pressure and fluid didn't not spurt out like it was under pressure but just dripped out. I again tried to turn the rotor and it was still tight so the pistons did not release.

I am assuming the calipers are bad and bought new calipers and lines. They did not have calipers with new brackets so I tried using the old on the first caliper and there was a ton of resistance trying to get the bracket to move on the slides. I used both new and old slides with same result. Just by eyeballing, it doesn't appear the slides are parallel so I don't know if something could be off a few degrees on the new caliper?

I ended up having to leave the middle of last week for a wedding and then spent the rest of the holiday at the coast. I am disabled and had a few Dr appointments this week and haven't got to mess with it again. Hopefully tomorrow I will be able to figure something out.

If anything I have said gives anyone an idea I'm still open for any possible problems I'm encountering.

Thanks!

 

So if the fluid wasn't under pressure, then its not the flex lines causing it to lock up.

It must be the sliders binding so tight that its dragging.

You should be on the right track to replace the caliper.

And since your truck is 10 years old, I would still replace the flex lines too... since you have to bleed the system anyway...

 

Well with the original calipers and sliders, the sliders are butter smooth. It is only with the new calipers that the sliders are binding up. Still not sure what originally caused the problem. But I think if I can get the bracket to slide smoothly on the calipers that things will work out.

Now if I wasn't disabled and felt like working on it. This is dragging out to be ridiculous for a front brake job.