Having brake issues and need to get this fixed tonight!!! Please help.

Hey guys, I have another issue yet again that I need your expertise on. I have an 89 XJ 4x4 Auto Trans RENIX 4.0 NON ABS and I’m having brake problems.

I replaced my front pads recently and the installation went smoothly. When I drove it, the XJ felt like it didn’t want to move and shortly after about a mile, the brake pads started smoking, so I brought it right home and parked it.

I then tried trouble shooting the issue, thinking the pads were maybe too thick (since I bought the pads at Auto Zone). I took the inside pad out of the driver side and replaced it with the old one to see if anything would happen.

I then drove it around the block a few times and the problem shifted to my passenger side! So the passenger side pads were smoking now. I told my buddy’s neighbor, a mechanic, my symptoms and he said it was the master cylinder for sure. So, I naively replaced the master cylinder, bench bled the master cylinder and bled the brakes at all 4 corners. The exact problem still remains.

So after doing some research on here, I decided what the heck, and replaced both front calipers, both front rubber brake hoses, made sure to swap the old inner pad on the driver side with the new one again, and bled the front brakes again. At this time, the brakes were working again and the issue had disappeared. I drove it around the block a few times and everything felt great and normal.

I head out to work this morning and notice the brake pedal getting just a little squishy and the XJ not rolling down the street as freely as it should. I drive about a mile then I smell my brakes burning. I pull over and yup, the driver side is smoking again now. My coworker says it may be the proportioning valve, but I am unsure and I feel broken down inside at this point, LOL.

Any advice, help, or miracle would be greatly appreciated. I would also like to know where to buy the correct proportioning valve at in Southern California around Chino Hills other than the dealer, if anyone knows. Thanks.

Something is definitely sticking. Do another bleed on the fronts but run quite a bit of fluid through. The tiniest pieces of dirt can keep a caliper from releasing pressure. If that doesn't help look into the proportioning valve. It is about the only thing left that you haven't replaced that could affect pressure like that. Also i just remembered check your caliper pins. I just assumed they are ok since you replaced the calipers but make sure the caliper slides freely on them. Get some synthetic brake lube to put on the pins to keep them free. Many other vehicles, like ford and chevy trucks, have problems with caliper pins seizing.

Thanks for the info mongolchuck!

I just called my local dealer and was told that they can't look up parts for my 89 because it's too old. Where even online can I order the correct proportioning valve?

p.s. my hanes manual calls it a combination valve but everywhere else calls it a proportioning valve.

get the calipers back of and check the caliper slides for wear. the get get worn and hang the calipers up.

RNMedic said:

get the calipers back of and check the caliper slides for wear. the get get worn and hang the calipers up.

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I will, but I doubt that is the issue. The calipers are remanufactured and slides are new. I have bled the heck out of the brakes and so I am starting to believe that it may be the proportioning valve since there isn't much left to do to it.

1.) are you 100% sure the axle came from an '89 XJ?

2.) are you 100% sure the pads and calipers matched your old ones?

3.) did you change rotors?

all of the above are model year specific and can cause caliper/pad vs. rotor interference if used in the incorrect application.

If the answers to the above questions don't steer you in the right direction, I'd pull both wheels and try to get each caliper to move freely with "gentle persuasion" ( I like to depress the brake pedal to set the caliper on the rotor and "tap" the caliper with a rubber mallet. If it releases enough to turn the rotor without much effort, it probably isn't hanging up on it's guides)

Shorty said:

1.) are you 100% sure the axle came from an '89 XJ?

2.) are you 100% sure the pads and calipers matched your old ones?

3.) did you change rotors?

all of the above are model year specific and can cause caliper/pad vs. rotor interference if used in the incorrect application.

If the answers to the above questions don't steer you in the right direction, I'd pull both wheels and try to get each caliper to move freely with "gentle persuasion" ( I like to depress the brake pedal to set the caliper on the rotor and "tap" the caliper with a rubber mallet. If it releases enough to turn the rotor without much effort, it probably isn't hanging up on it's guides)

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1) I'm not 100% sure if the axle is from an 89 other than knowing that it has the mounts for the vacuum unit on the axle even though the vacuum unit was bypassed previously to me purchasing the XJ/

2) The calipers looked identical to one another new and old. The pads are a tough call since the old ones were worn down quite a bit, but the new ones had the exact same curves and fit in the calipers just liek the old ones do. The little thin squeak shields from the back side of the old pads also fit perfectly on the new pads, so I am assuming they are the right ones.

3) No. But with my rotors being thinner than they were originally (they still have lots of life left) I don't see how they would affect the situation at all other than if they had a substantial groove that sat above the normal surface area (which they don't).

Are your knuckles two piece? In other words, does the caliper bracket bolt to the knuckle(not the caliper itself but the bracket it rests in). If so you have 89 and earlier knuckles which means you need the older style unit bearings and rotors. If your knuckles are one piece then you need rotors and bearings for the 90+ models

I'd definitely investigate the free movement of the calipers. Assuming you didn't have the same problems before the brake change, I'd doubt a proportioning/combination valve problem.

It's always possible that you pushed dirt/crud back into the lines when depressing the caliper piston, but the proportioning valve doesn't have a "quick take-up valve" like older G.M. master cylinders (probably why the "mechanic" thought the M.C,. was the problem)

xjtrailrider said:

Are your knuckles two piece? In other words, does the caliper bracket bolt to the knuckle(not the caliper itself but the bracket it rests in). If so you have 89 and earlier knuckles which means you need the older style unit bearings and rotors. If your knuckles are one piece then you need rotors and bearings for the 90+ models

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The caliper is the old style single piston where the 2 caliper slide bolts, bolt the caliper directly to the knuckle. In other words, I slide the bolts, one on the top of the caliper and the other on the bottom of the caliper, through the caliper itself, and then the bolts hit the knuckle where I ratchet them in using a 7mm allen head socket.

Shorty said:

I'd definitely investigate the free movement of the calipers. Assuming you didn't have the same problems before the brake change, I'd doubt a proportioning/combination valve problem.

It's always possible that you pushed dirt/crud back into the lines when depressing the caliper piston, but the proportioning valve doesn't have a "quick take-up valve" like older G.M. master cylinders (probably why the "mechanic" thought the M.C,. was the problem)

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My coworker, who has worked on cars for many years, dropped me off at home last night and took a look at my XJ. We trouble shot it the best we could and now we think the rotor may be warped on the driver side. Reason being, we jacked the XJ up off the ground and simply spun the tires. The passenger side spun freely and smooth. The driver side was stuck solid. We then took the wheel, caliper, pads, and rotor off and started from square one.

First we bolted the wheel up to just the hub to see if the bearings might be bad or atleast be what's causing the issue, the wheel spun freely.

Next we put just the rotor on and bolted the wheel up, it spun freely.

Then we put the rotor, caliper, pads, and bolted the wheel up, it spun about a quarter turn and it froze up.

I then untightened the lug nuts and just hand tightened them, it spun but not completely freely.

I then took the wheel off and spun the brake assembly from the studs while holding the rotor in place. It would spin until a certain point, then I heard metal on metal contact, like the rotor hitting the dust/rock shield and it would be more difficult to turn at that point.

So that is why I now believe it could be that rotor causing the issue. Any affirmations or suggestions would be great. Thanks!

The old style brake caliper does not bolt directly to the knuckle. It has an adapter that first bolts to the knuckle then the caliper to the adapter.

A warped rotor would not cause the brakes to bind like you say they are. Maybe bent, like severely bent. Make sure that the caliper moves freely on the pins, as the caliper does float. I wonder if at some point someone put the wrong rotors on.

Talyn said:

The old style brake caliper does not bolt directly to the knuckle. It has an adapter that first bolts to the knuckle then the caliper to the adapter.

A warped rotor would not cause the brakes to bind like you say they are. Maybe bent, like severely bent. Make sure that the caliper moves freely on the pins, as the caliper does float. I wonder if at some point someone put the wrong rotors on.

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It very well could be the wrong rotors. The guy who owned it before me messed everything up that he did to this poor XJ. I've been correcting his mistakes since I bought it. All I know is that the correct parts are going on the XJ now and I will post pics up tonight if the rotors don't solve my binding issue.

My brakes are finally fixed! Thank you everyone for your help. It ended up being the freaking caliper slide bolts. They must be the wrong size or the autozone pads are too thick or something, but my wheel was locking up because when everything was together and tightened down, the tip of the caliper slide bolt was pushing too hard against the back of the inner brake pad. The weird thing about my brake setup is I found out that I have the calipers and pads for an 89 set up but I have the hub and rotor for a 90+ set up.

My question now is, are the caliper pins supposed to touch the back of the inner brake pad at all? If not, how much space should be between the brake pad and the pins? Thanks again!

pad's just dont mistakenly come 'too thick' it doesnt work that way. see my post over in the socal thread perks any truth
it seems from the post in socal, that you have a 2wd?.... i cannot express how important that peice of info was in both of your threads, yet is nowhere to be found =\\\

Could the PO have broken a bolt and replaced it with one that was too long?

When I had my pass side caliper off a couple months ago I snapped one of the old bolts and had to use a temporary replacement - It was too long and hit the pad - I needed to shim it with a few washers so i could make it to the store to get the right bolt.

They should not be close to touching the pad IIRC

xcm said:

it seems from the post in socal, that you have a 2wd?.... i cannot express how important that peice of info was in both of your threads, yet is nowhere to be found =\\\

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X2, this is EXTREMELY important info for 84-early 90s (think the split was 91 or 92, not sure, will look later) XJs. Basically if you have 2wd and your front axle has the spindle style brakes instead of the unit bearing, dummy stub shaft, and rotor style brakes, you need parts that are 2wd specific. It was stupid and required stocking a lot of extra SKUs and knowing what you were working on, which is why they switched it over in later years to simplify parts stocking and interchangeability.