Hello helpful folks,

I'm driving a 2000 Grand Cherokee Limited, 175000 miles, AWD in the warm and cold conditions of Montana. I've owned this for 2 years and 35000 miles. I just replaced my front hub/bearing assembly, rotors and pads(the ones with retaining spring and allen key fasteners) on passenger and driver side front axle. During my test drive(2 miles with one hard brake at the end) I stopped and noticed my driver side brakes were smoking pretty good. There is even a little discoloration between the hat of the rotor and the braking surface. additionally, while parked on a minor hill, I noticed quite a bit of resistance in the roll down the hill. not good. It would seam that the caliper will not back off. I opened everything back up, checked for obvious mistakes in the reinstall but found nothing. It should be noted that I did not bleed the fluid after initial reinstall but I changed this after my second go. Some of the fluid to come out was dark, but eventually cleared a bit. the reservoir appears to be dark as well. During my drive back to the house, I used as little brake input as possible. Almost none even. The DS rotor was quite hot while the PS was quite cool. FACK!

I think I may have a bad caliper possibly caused by over compressing the cylinders when compressing them with a c-clamp. Is that something that could cause a failure? If I ruined my caliper, can a person replace just the problematic one while waiting for funds and still drive safely?

 

I had a sticky DS caliper on my '03 WJ, after a brake job, and the solution for me was to go back and get the slide rods extra clean and re-lube with a high quality disc caliper slide lube. Also, when bleeding the lines, I siphoned the reservoir out and refilled with fresh fluid prior to flushing the squid ink from the wheel cylinders, to assure new fluid top to bottom. With the slides exposed to hot and cold can get sticky with age.

 

Wow. I don't think I understood how those worked. I was really confused as to why they were not really fastening the calipers. That makes a lot of sense now. Ill give that a try and update.

 

Remove the caliper and check it for proper operation. I usually just use channel locks to depress the caliper piston going very slowly. Sometimes using wood to spread the load but usually don't have a problem with it.

Grease the slides and if the caliper looks rusty or really bad - just replace it for peace of mind. I usually do both sides at the same time (replace in pairs)

 

Possible you still have the original TEVES calipers - these are prone to sticking.
Replace with the later AKEBONO calipers - you must replace them as a pair.

 

Use the brakes. Get the brake to stick.

Now crack the bleeder and see if it releases pressure and the brake.

If it does could be a bad brake hose.

If it doesn't then the caliper is probably just stuck.

 

Yes, the dual piston calipers on WJs are known for sticking pistons. Especially the Teves calipers. They are also known for warping rotors because of dragging. You have to press BOTH pistons back together or risk blowing the seal on one or popping it out of it's bore. Make sure the slider pins are well greased or the caliper will **** and cause it to drag. I chased problems for 4 years with my Teves setup, then changed to Akebono calipers and ended my problems. The Akebono require different mounting brackets as well. If you buy loaded calipers, they come with them. Also, stay away from ceramic pads. They will squeak constantly! Stay away from drilled and slotted rotors as well. I've had the best luck with cheap organic pads and plain rotors. The Akebono caliper slider pins are much better protected in good rubber boots. Make sure with either that you get grease INSIDE the bushings because if you just lube the pins and slide them in, the grease gets wiped off.

 

Thanks for all the feedback. My $$$ situation right now is pretty bad because I'm an ***. I think my plan for now is to test my calipers to see if both pistons back off, continue to use my Teves pads(4 miles old but been hot once) and calipers, lube the sliders like a **** set and see if I can buy time before doing it right this spring or summer. The good news, is that the loaded reman Akebono calipers are $50 a side at NAPA.

 

If you find that you have a bad caliper because the pistons release when you crack the bleeder isn't 100% proof that its the caliper. It could be the flex brake line collapsing inside acting as a check valve. Pressure from the brake system forces fluid through the line when braking but it doesn't release because of a faulty flex brake line. Just because you can blow through the line doesn't mean a lot either. I had this problem on a 70 Karmann Ghia and after two caliper rebuilds and then NEW calipers it turned out to be the freakin rubber flex lines. With that said, if I had to guess, it sounds like your calipers are not floating or drifting properly and a good clean up and greasing like previously said will probably keep you going until you can address the problem in full.

 

Welp, so far, the adult film set approach of cleaning the shaft and plenty of high quality lube was not the solution. I'm off to the store to purchase new caliper.

 

About brake hoses. If you let the caliper hang on the hose while doing the work or drop it to hang on the hose, you can rupture the inner lining of the hose and cause a blockage. This can allow hydraulic pressure to set the caliper, but impede flow back to the master cylinder when released. After you get them back together, try hitting the brake while it's jacked up, then try turning the tire after releasing them. If you can't, open the bleeder valve to see if it's still pressurized.

The pistons don't move hardly at all between set or released. They are only retracted by the square piston seal being twisted under pressure, then springing back on release. The pads just barely clear the rotor and any stiffness can cause them to drag. There are no retracting springs like on drum brakes. Every time I had trouble with my front calipers, it was because one of the piston pair was locked and refused to move. They even came out with phenolic pistons instead of steel, but it didn't make much difference.

Dual piston calipers work great for hard stops from high speed, but other than that, I don't see any great value to them. WJs aren't THAT much heavier than ZJs anyway. Registration weight for my WJ is 3980 lbs. Yup! 2 tons!

 

I had phenolic pistons come out of the caliper in peace's once't. I hope replacing the caliper works. I look at the flexible brake lines almost like a trans flush or spark plugs these days that you change at 100,000 miles. If I'm doing brakes and the lines in the front that work the hardest and are constantly being flexed are 100,000 miles plus, then I spring for a new set in the front. Dave your right, the lines can break down inside and act as a check valve. There's a reason every repair manual say's to hang up or support the break caliper and to not just let it hang, this could cause damage to the flexible break line...

 

Well, I have seen success in my issue for now. I replaced the questionable caliper. If you are wondering, I will definitely replace the second next week. To add, I never let my calipers hang on the brake lines, I only hang them with bungie cables or something else.