89 XJ Brake Problems

I joined this forum, because I've been reading through it for a while and I feel there are some knowledgeable people who will be able to help with this problem.

My buddy bought an 89 model Cherokee, which was supposed to have Dana 44s under it front and rear, but that ain't the case. The problem we're fighting though, was the guy told him it needed a new brake booster and the brakes would work. We replaced the brake booster and master cylinder, replaced both rear wheel cylinders, bled all the brake lines starting with the right rear and moving up to the front left, but we still can't get any pressure in the brakes -- no brakes at all for that matter. Another thing that seemed odd to us was if we took the cap to the master cylinder off and hit the brake pedal it would shoot brake fluid up to the top of the hood. The guy said he swapped the front axle with a D44, but it looks to me like what he swapped it with was a newer model D30 to bypass the old vacuum D30 (forgive me if I'm wrong, I'm not extremely familiar with XJs).

So, a few things we think may be causing the problem but we're unsure on is that it looks like it doesn't have the right calipers on it because they're not completely seated on the pads, and there is a vacuum leak under the dash. Another issue is some sort of switch that looks like it's supposed to connect to the brake pedal and the vacuum hose is hanging down and we can't figure out what it's for. I'm going to include several pictures for hopes of getting the brakes fixed and hopefully finding out for sure that the front axle is actually a D30 from a new model XJ.

We also haven't messed with the proportioning valve yet, but we haven't ruled out that it could be bad or not functioning properly. We were wondering what other model XJs we could pull one off of and bolt right up.

Thanks in advance for any advice/help.

Here is the white switch that looks like it should be behind the brake pedal, along with the vacuum hose that's unhooked and leaking.

switch dangling under the dash:

This is a pic of the passenger side of the front axle showing there is no vacuum there:

Front axle which appears to be a D30:

Front knuckle on the driver side:

Brake booster vacuum line running into the intake:

Brake booster/master cylinder hooked up:

Driver side rotor/caliper:

This is the front driver side caliper (looks like the wrong caliper, because the piston isn't seating all the way):

Same shot just the whole caliper & setup

Rear axle which is obviously a D35 after looking that the picture:

Any suggestions would really help. I'm completely stumped and still have no brakes. Went back and warrantied the new brake booster/master cylinder and got a brand new one. Bench bled, bled each wheel, and still can't get any brakes.

That front caliper does look odd. It's hard to tell looking here, but see if you can determine if the knuckles are entirely in one piece, or if the caliper slides are a separate bolted-on part. This was changed some time after 89, and I wonder if it has the wrong calipers. It's been a long time since I looked at an older one, so I hope someone else can confirm, but I don't recall the piston overlapping the pad.

Do you have a hard pedal? Do you feel boost when you start the engine? What actually happens when you push the pedal?

I think the extra switch is for cruise control, and if I'm seeing right it has a hose nipple on it for the vacuum hose. If you no longer have cruise, and if you do have a functioning brake light switch, I'd plug the vacuum hose and stuff the rest of the switch up under the dash.

The rear diff looks like a Dana 35.

Dana 30 in front, 35 in back. Front brakes changed in 1990.
If you're not gonna use cruise control. Plug the source to the vac hose that goes to the switch. It should be up near the coolant bottle.

BADDRAPP said:

Try swaping the front calipers to the other sides. Bleed screws need to be at the top of the piston not the bottom. Hopefully this will help. Do you have any brake fluid coming out of the calipers when you bleed them?​

Click to expand...

Whoa! I didn't notice that. This is definitely a must-do before going any further.

yeah your calipers are upside down which means they are on the wrong side

Thanks for the help so far. We flipped the calipers and bled the whole system again. We bled the system with the jeep off and had a decent pedal, but once we started the jeep we get no pedal. I'm not sure if the piston overlapping is preventing us from getting brakes or what.

I'm also not sure on the axle either. The guy the jeep came from said he done an axle swap. I dunno if he got a newer or same model D30. I'm probably wrong, but I was thinking that the older model 30s were vacuum. This D30 doesn't look like it has a vacuum on it. I'm not sure what the calipers came off of, if they're the stock ones for this jeep, or what though. The guy won't answer his phone, so we can't really figure out what the deal with the calipers are.

Matthew Currie said:

That front caliper does look odd. It's hard to tell looking here, but see if you can determine if the knuckles are entirely in one piece, or if the caliper slides are a separate bolted-on part. This was changed some time after 89, and I wonder if it has the wrong calipers. It's been a long time since I looked at an older one, so I hope someone else can confirm, but I don't recall the piston overlapping the pad.

Do you have a hard pedal? Do you feel boost when you start the engine? What actually happens when you push the pedal?

I think the extra switch is for cruise control, and if I'm seeing right it has a hose nipple on it for the vacuum hose. If you no longer have cruise, and if you do have a functioning brake light switch, I'd plug the vacuum hose and stuff the rest of the switch up under the dash.

The rear diff looks like a Dana 35.

Click to expand...

To answer your questions. There is a slightly hard pedal when the jeep is off; however, when we turn it on the pedal goes straight to the floor. So, I'm guessing you could say we feel a boost when the engine is started, but it's not a positive boost. When we turn the jeep on the brakes move a very tiny bit, definitely not enough for any pressure, nor to stop the jeep.

Also I got to looking and the driver side rear brakes are getting hung up. When the brakes hit and it's expanded the left pad will not compress back to where it's supposed to be. I've tried adjusting, but I lack of knowledge with drum brakes. Here's two pictures of the brakes (I undone the e-brake cable before I took the picture to see if it was causing problems, but it wasn't and the cable is now connected; however, the brakes are still doing the same thing). Again I appreciate any help, because me and my buddies are completely blank at this point.

Complete view of the driver side rear brakes, notice the left pad isn't seating right after we let off the pedal:

Here's a closeup showing that the pad isn't seating right:

It's hard to tell at a distance, of course, and any lens distortion might contribute too, but it looks to me as if the rear brakes are not together right. The slave cylinder pushrods are skewed, and the brake shoe on the left is too high, so it's not coming back properly to the post. I can't see clearly but I suspect the parking brake strut (the bar that goes between the two shoes) may not be seated properly in the shoes. The strut has slots and I think they must align with slots in the shoes. The springs don't look too healthy either, but first thing I'd do is try to get those shoes lined up right. Until they're correctly lined up at the top, you can't adjust them at the bottom, and the brakes just won't work.

I suspect the previous owner botched the brake job and you may have to take the whole thing apart, and make sure you have the right shoes in the right way around, and the strut right way around, etc.

As for the axle, check the steering knuckle. On the original 89 knuckle you should see that the brake caliper mounting, with the slides, is bolted to the main body of the knuckle. ON later models, the caliper mounting is integral with the knuckle. That might at least tell you if the axle was swapped with a later one. In your year range, full time 4WD models also did not have a disconnect, so the lack of a disconnect is not 100% indicative that it's a later type.

I don't even know if early calipers would fit on a later axle. I've never checked. At this point, though, I think I'd concentrate on getting the rear brakes together right, and see if that helps your pedal any. It sounds as if you're getting boost all right, and the MC is working.

On the rear brake shoe setup, you are missing the steel wire cable.

4x4xj89 said:

On the rear brake shoe setup, you are missing the steel wire cable.

Click to expand...

That will disable the self adjusters, but should not affect the brakes if they're manually adjusted right.

It does look, though, as if the previous owner did not do a very good job putting things together. I'd recommend a new spring kit and self adjuster cable. Maybe new adjusters too if the teeth are worn. Common auto parts store stuff, not very expensive.

My rears shoes were similar to your on one side. it turned out that my ebrake wasnt releaseing on one side. i took out the e brake bar on one side. and no more problems

Sorry for the delayed response. I've been quite busy. But, I though I'd come back to clear some things up in case anyone else is having the same problem. Flipping the caliper and putting them on the right side fixed the brakes and gave us a good pedal. The rear brakes were a different story. We ended up disconnecting the e-brake on it and it seemed to fix itself. I appreciate all the help from everyone though. Thanks again everyone.