Recurring problem with right rear brake

Maintenance/Repairs
1

A few years ago, the “brake” smell started, and the right rear brake would get very hot. The wheel would be hot to the touch… not good. I replaced the left and right rear pads myself (about 2.5 years ago), had the rotors machined, and took the car to a mechanic to have them put in a new caliper.

It felt like the problem was fixed (no more smell or heat), and then I left the country for a year while the car sat outside. When I started driving it again, It still seemed like everything was working well.

Recently I took it in for a tire rotation/balancing, and they pointed out that the same brake was worn to it’s limit, and they suspected the caliper was sticking. I told them I had had it replaced a couple years ago, and they said “I don’t know, it looks rusted like it’s old”. I just took the wheels off and looked at the brake assemblies… The left brake pad looks new, the right brake pad is grinding, and it’s caliper is extended to near it’s limit. Also, the housing for the caliper that was replaced is rusted, but it looks newer than the oposite side (which is good, that’s the one I paid to have replaced). Also, the suspect caliper has markings on it that read “REMFG”, which leads me to believe that it has, in fact, been replaced with a new part.

So, all I can think of is:

  1. The original mechanic did not replace the caliper, but charged me anyway, or:
  2. The original mechanic replaced it with a “remanufactured” caliper, which has failed, or:
  3. There is some other problem up line, perhaps a blocked brake line, or:
  4. Having the car sit for a long time hurt the new caliper, but didn’t do anything to the rest of the car (what are the chances?).

I’m hesitant to pay for another new caliper, since this one is only a couple years old. If anybody has any other ideas of things I should check before replacing it again, let me know!

Thanks in advance.
-Tim

Below: View of the suspect caliper.

Below: Another view of the suspect caliper.

Below: A view of the opposite side caliper, which is original. Notice the pads are almost 100%, while the previous pictures are at 0%.

2

I should point out that I came to this community initially a couple/few years ago, and new brake lines seemed like a good idea, but they haven’t been replaced. My other question, then, is should I buy just the flexible brake lines that are in the wheel well, or replace all of the lines which run the length of the car?

3

Its generally helpful to know things like year, make & model and at least mileage on the car.

The mechanic did install the caliper and it was remanufactured. Reman parts are very normal to use. Sometimes they are the only thing you can get - or at the very least they have a tendency to be much easier to find. Unfortunately, many reman parts are not very good quality.

However, the first thing to do is make sure that the caliper slides are not sticking. The caliper has to “float” on those mounting bolts. If the slides stick then braking will amount to just having the piston pushing the inboard pad into the caliper. That pad will have a tendency to do most of the work and to continue rubbing after the brakes are released.

You’re going to have to redo the pads on both sides back there. So I would just do that, but in the process I would replace both flexible lines in the rear. (You don’t have to replace any others unless you inspect them and find them suspect in terms of rust). You also want to make sure that you spend some extra time on the caliper slides. You’d also take a close look at the mounting brackets for the pads. Look for anything on there that could bind up the pads even if the caliper floats properly. (Worn in notches or rust globs or anything like that).

After that I would use an infra-red thermometer for a while to check out the rotor temps after driving. If that problem side always reads hotter then you still have a problem. (If you don’t have one, IR thermometers are not that expensive and are just plain handy).

4

Ditto to everything Cig said. It would also be nice to know if your vehicle uses the discs as parking brakes and if you had them applied while you were gone. It looks like a drum in the center of the rotor casting, but I’ve been fooled before.

I’ll add that you cannot reasonably expect any shop to “stand behind” a caliper 2-1/2 years after you have a caliper replaced, one of them wherein the vehicle sat unused.Sitting for a year allows slides to corrode, elastomers to dry, and generally is not good.

5

Replace the rubber flex-lines. They can swell up internally and pinch off the return flow of brake fluid causing the calipers to remain slightly pressurized and drag…Nice pix…Exact same symptoms as a stuck caliper, except if you open the bleeder, the pressure will release and the caliper retract just fine…

6

Thanks guys. It is a 2004 Jeep Liberty with 65,000 miles. The parking brake is inside the drum, it does not use the disc. I will replace the pads, both flex brake lines, and I think the rotors might need to be replaced also, or at least machined. I’ll look up the minimum thickness and see where I stand before I replace those.

Good tip on getting an IR Thermometer. Sounds like a fun toy to have. I can use it in my other hobby as well, RC airplanes.

7

Check that lhe left side is working and not frozen. If the left side is not working that will prematurely. Also if your left front is also almost worn out while the left rear and right front are like new that points to a master cylinder problem.

8

oldtimer has a good point, but if the fronts are wearing evenly, you might have one other problem. some of these type vehicles have a load compensator built into the rear brakes. If the load compensator is defective, it maybe applying more force to that one brake because it thinks that there is a heavy load in the rear of the vehicle.

9

@keith - Looking through the Haynes manual, there is no mention of any sort of load compensator.

@oldtimer 11 - I don’t think this is the case, but I will certainly check on it. it’s good to know how they’re connected to each other.

10

Looking at your images, I don’t see any brake lubricant grease on the caliper where the brake pads mount. There should be.

Tester

11

My impression of the description was that only one pad (the inboard pad) on only one side in the rear was wearing. Perhaps clarification could help.

12

Sorry that wasn’t clear, both pads on the right rear are worn to 0%. The caliper assembly is floating around properly, but something is causing that brake to keep pressure on even when the pedal is not being stepped on. It’s not enough that I can notice it while driving (no pull to that side, and acceleration doesn’t seem to be effected), but it’s enough to make the pads disappear fast.

13

Look at where the brake pads are mounted. These are called the brake pad slides. You apply caliper grease to those surfaces so the brake pads can slide away from the rotor when the caliper does. If those surfaces are rusted the brake pads might not release from the brake rotor when the caliper does.

Tester

14

I know the part that you are talking about… I didn’t notice any rust on it when I had the tires off, but I will double check next time. The guide pins are lubed, I know that for a fact, if anybody is thinking that might be another cause.

15

I have acquired the parts, and started to work on the car today. I ran into a problem when it came to separating the hose from the line. The new hoses look like the old ones, except that the ends are female threaded. The old hoses that I want to remove don’t look like they have any threads to unscrew, which is why I’m posting. I can’t get them apart.

How would you go about separating the hose from the line?

I do not have the tools cut the line and put a new flare in, but I suppose I could buy the tools and learn how to do that. I’d like to avoid that, though. That would also require new brake lines on the back, because there isn’t any extra length available to cut.

16

Just a couple of thoughts of most likely possibilities:

  • The remanufactured caliper could just plain be faulty. Be aware you may need to replace it again if the above suggestions don’t work.

  • One of the rubber brake hoses could be collapsing. When this happens, the brake fluid doesn’t depressurize like it should when you take your foot off the brake peddle. This would be unusual in a 2004, but it’s possible.

  • Make sure the brake fluid is in good condition, and the entire system is properly bled.

17

Thanks, @GeorgeSanJose. The second bulletin point is the reason I’m changing the hoses. After I get that done, I have an infrared thermometer to see if that brake is still grabbing, then I’ll go from there.

18

In the picture above, it seems like where the black metal line goes from left to right into the rusty colored fitting, there should be a wrench pattern around it, but it’s just round. If you go a tiny bit further you can see a place to hook a wrench around, but that’s the only place you can do it.

19

The black metal bit goes to that brass cylinder. That should be a threaded male fitting on a flared end and once loosened should be able to spin. That Hex pattern on the larger piece with the round metal collar is where you put the wrench. What you really need to do is a) douse that fitting really well with a good penetrating oil - something like PB Blaster or DeepCreep, and b) ideally, use a tight fitting flare nut wrench. Take your time with it since a little patience at the front end can save long and annoying headaches if you wreck strip the hex. If you do get there, and are stuck, you could move on to grinding a couple of parallel flat spots on that round collar to get a wrench on there. You might also get good use out of a high quality small pipe wrench or high quality pair of channel lock pliers. The key will be breaking the hold of the rust on the threads.

20

Update: I took it to a mechanic. They called a dealer to see about the problem I’m having (right rear brake not releasing all the way), and I guess the original brake lines have this problem quite a bit, and dealerships want to charge $400 for a new “improved” right rear brake hose. That’s just for the part.

My mechanic is trying to figure out what’s going on with that price. I was looking at the replacement hose I bought and I’m not sure if it’s the same for both sides. I think the banjo bolt hole pattern is different on the right side than on the left, but hopefully my $25 hose will fit and my problem will be solved. Alternately, maybe the mechanic can use the old banjo bolt and custom make a brake hose.

tldr: I gave up on replacing the hose myself, dealer wants to charge $400 for a new/improved hose, I’m hoping my $25 hose will fit.