Hello all, I'm struggling with an issue on my '96 XJ that has me about to scrap it--that's how frustrated I am. The front brake calipers stick. It'll be fine for a month and then I'll brake and the brakes will lock and I'll have it towed home. Three times in the past six months. Calipers are new (twice over), pads are new, rotors are new, and the flexible rubber lines (that I read on this forum can swell internally) are new too. And it's not side specific. First tow was left front sticking. Next time was right. Help! Thank you.

Neil Graham

 

How did you get them unstuck?

Have you checked the caliper brackets? Sometimes they get gouged where the pads ride and can prevent the brake(s) from releasing.

if one is still locked, or when one locks up again, crack the bleeder on the stuck one and see if it releases. If it does, you need to check further upstream like the distribution valve, master cyl and perhaps booster.

 

Just to get started....
assuming you did all this work yourself..

1 when you disconnect the brake line from the hung up caliper does brake fluid sorta drip out or does it squirt out like it's under pressure?

2. Do the pistons in the hung calipers push in manually as easily as on the new calipers or are they indeed stuck ?

3 and,of course, are there deep wear notches on the caliper/pad rails on the knuckles?

I hate working on brakes

 

Grooves in the steering knuckle!

From jmh9000:



You can try grinding it smooth but far far better to repair the hole with the welder.

 

Also do you have ABS braking system ?

 

Knuckle grooves are my guess,

 

The knuckles are new on both sides. Appreciate your note.

 

Yes, ABS is fitted. Thanks.

 

Thanks, useful info.

 

Or just use the abutment clips that come with the new set of brake pads that you probably threw out. Groove or no groove, doesn't matter. That's the point of abutment clips. To provide a smooth surface.

 

Do the pads slide freely on the knuckles? I mean, there's "snug" and there's "don't move"?

 

I think we're back to the "how did you get them unstuck" question.

Did they unstick when you disconnected the brake line or, after you disconnected the brake line, did you have to pry the pads/pistons back into the caliper to get the caliper off the rotor?

 

Problem could be in the master cylinder as well

 

I had a similar problem on my 99, ended up getting new Black Magic calipers. Brake pads are top notch too.
Price is pretty reasonably and it saved me a trip to the junk-yard.

https://www.shop.blackmagicbrakes.co...4258021-22.htm

Sorry Niel, I re-read your post having "new calipers".

 

if its both sides, I doubt its the calipers, could be master or proportioning valve

Should be able to get around needing a tow by releasing pressure at the front caliper bleeders, prop valve or MC "front" output nuts

It helps to make sure you can break these nuts free, they are usually factory tight, some penetrant, and even heat will allow you to loosen them off a bit, should be no need to bleed anything if you are careful