Okay, it has been three weeks or so since I replaced the front pads and rotors on the Jimmy. The truck has been driven a few hundred miles since, with no problems. Today, though, was a different story. I was out on an errand, on the interstate, and noticed that it seemed to be hard to get to the speed limit, and hard to maintain speed. When we were almost home, I started to notice a smell. When I pulled into the driveway, I noticed that the driver's wheel area was hotter than the passenger, and the smell was definitely coming from the brakes. So it looks like I have a dragging issue. When I did the brake job, I greased all the parts. The caliper easily compressed, so I don't think that it is seized. Could be wrong, though. I searched the forum a bit, and it seems that a collapsed brake line, seized caliper, or lack of lube are the likely culprits. What's the proper way to diagnose this? My crappy Haynes doesn't even address the issue in the troubleshooting section. I don't want to blindly replace parts. I don't think I made any dumb mistakes during the brake job, but it's possible. Anyone know where I should start? Thank you all.

 

"a collapsed brake line, seized caliper, or lack of lube are the likely culprits."

Binding guide pins: remove the wheel and push the caliper piston all the way into the caliper bore. The caliper should slide inward and outward very easily with one hand. If not, the guide pins are binding.

Seized caliper piston: The piston should compress into the caliper bore smoothly and easily using a prying action with a screwdriver.

Collapsed line: Raise both front wheels off the ground, have an assistant apply the brakes, apply rotational pressure on the wheel and release the brake, it should release immediately and the wheel should turn freely, if not, suspect a collapsed or restricted flex line.

 

Thanks for the guidance. Do the brake lines go bad because of dirty fluid? I was planning on flushing the old fluid when I do the rear brakes since it seems pretty dirty.

 

Flex lines are damaged by letting the caliper hang by the hose while doing the brakes. Care needs to be taken not to twist, stretch or kink the flex line. Using incorrect fluid can also damage them, especially automatic transmission fluid.

 

Hmm, when I removed the caliper I hung it with a bungee cord. As long as I've had the truck only brake fluid has been used. I won't get to look at it until next weekend, so I guess I'll see what happens.

 

So it looks as if the flex hose is to blame. I had a little free time after getting out of work early, and tried to see what the problem was. I jacked up the truck and tried to turn the wheel. It would not budge. So I took off the wheel and used a c-clamp to drive the piston back into the caliper. Of course the wheel turned freely after this. The caliper moved back and forth on the pins, so I'm pretty sure that there wasn't any binding there. So I stepped on the brake pedal, and the wheel wouldn't budge again after releasing the pedal. So I'm assuming this means that the hose is bad. In the Haynes manual, it says that the weight of the truck must be on the suspension when positioning the hose. Is this the right way to do this? It must be a PITA to install the hose with the wheel on. Thanks to all.

 

By checking it like you did, it could possibly be the caliper piston binding also, but if it retracted easily, it's probably the flex line.

If you replace the flex line, Put a jack stand under the lower control arm as close as possible to the ball joint, and make sure the wheels are straight ahead. Very important not to twist the line.

 

Captain Hook, thanks for the advice and guidance. Since using the clamp might not have ruled out the caliper binding, I just took the caliper off to check it out further. So now I'm thinking that the caliper is what is causing the problem. After taking off the caliper, I pressed the brake pedal slightly to see how hard/easy it would be to compress the pistons. Well, one of the pistons did not move from where it was much at all, while the other protruded quite a bit. I was able to compress the more protruded piston easily with just my thumbs. The other, though, would not budge from its slightly protruded state. I was able to get it to budge with the clamp, but it took what seemed to be way too much force. So now it looks as if I will be replacing the caliper. I will probably replace the flex line as well, since it is pretty cheap and it's pretty old. Thanks again, Captain Hook for your doubt. Probably saved me some headaches.

 

Don't let the master cylinder reservoir run dry! It causes an air bubble in the ABS unit and then you need an ABS capable scan tool to perform the automated bleed.

After the new line and caliper are installed, do not pump the brake pedal! Remove the reservoir cover, fill the reservoir with brake fluid, leave the cover off, open the bleeder at the caliper and wait for the fluid to flow with no bubbles. Close the bleeder, fill the reservoir again, then slowly pump the pedal a few times to extend the pistons. Then pump the pedal a few times and hold pressure, open the bleeder slightly. repeat until no bubbles are present.

 

Yeah I was keeping an eye on the fluid level the whole time, it never got low. I am going to try to flush out the old fluid, it is pretty dirty. Are calipers one of those things that should be replaced in pairs? The passenger side seems to be okay. I'm planning on putting in new loaded calipers and rotors for the rear, the parts are coming Friday. Don't feel like waiting for the front caliper to be delivered, I guess I'll go to Napa.