WantACherokee

I recently replaced most of the brake components on my '87 XJ- rotors, drums, shoes, hardware, wheel cylinders, and brake hoses. The Jeep already had nearly new front pads on it. I then flushed and bled the brakes.

Now, the Jeep stops really well, but it shakes badly when braking, especially when braking hard. It is really alarming since it has no carpet or headliner and the entire body shakes so bad it sounds like it might vibrate apart. It does seem to stop just fine though.

When I first drove it after replacing the brakes I didn't have the drums adjusted correctly and I think they were barely contacting the drums. The e-brake didn't even work at all so I adjusted the shoes more outward. I think I went too far as now the e-brake barely needs to be pulled to set it. Does it sound like just a rear brake adjustment issue or are there likely other things going on?

Lyon

I dont know the brand of rotors and drums you got but I've found if you go on the really cheap end, sometimes the NEW rotors or drums can be out of round and still need to be resurfaced. It also sounds like you adjusted the rears just a tad too tight.

You should clean the hub surface really well behind the front rotor before installing it. If there is any build up there, the rotor won't sit flush on the wheel bearing assembly (hub)

Normally if you feel the vibration in the steering wheel it's the fronts.
If you feel it in the brake pedal, it's in the rears.

WantACherokee

I don't feel any vibration in either the wheel or the pedal is what is weird. Just the entire Jeep shaking. I will try adjusting the rear brakes less tight and see if that helps.

dogger15

Have you rotated your tires lately

That Jeep Guy XJMJ

heres a little hint for correctly adjusting your rears... take your rear tires off and see if you can pull your drums off....if you cant even budge them = too tight. If you can slip them off like panties off a hooker = too lose (and stay away from hookers!)....... what you want is a fair amount of resistance... when pulling them off you should feel resistance from the shoe's contacting the drums.... its a finesse thing

KennyG

I had that issue with a customers mid 90's XJ. Found the calipers to be dragging. Kinda unsure of how this equated to a rather violent shudder in the front end on braking, but replacing the calipers DID fix the issue. Don't know if this is your cause or not, but something to check.

Lyon

Were these recently replaced or done a while ago? The orignal post is a little unclear on that. I took it as you did a break job and now you have the problem. How long did you drive it before this started if they weren't just done?

WantACherokee

I did the break job, and then it was driven around only occasionally for a couple months before I adjusted the rear drums, and now after adjusting them I have this shaking problem. I think the rear brake shoes were barely contacting the rear drums before I adjusted them because the e-brake didn't work and the pedal was soft. The car would still stop before I adjusted the drums, just not as well as it does now. It would take longer to stop and the pedal was very vague. However, after adjusting the shoes I have the shaking issue.

So I don't know if the shoes are simply adjusted too far out, or if they were just never really being put to work to stop the car before, which could have hidden an issue with the rear brakes. Hope that makes sense.

Logic would dictate that if I play around with the rear brake adjustment to the point that the car still stops well, has a firm pedal and a working e-brake but the shaking goes away, then I'll have found the problem. But I just wanted to be prepared in case I cannot solve the issue by re-adjusting them, so I made this thread wondering if anyone has dealt with this issue before.

I adjusted the rear drums exactly the way That Jeep Guy XJMJ described, but I suspect they're still too tight as I can set the e-brake fully just pulling the handle up a couple inches.

I haven't rotated or balanced the tires lately although they're pretty new tires (still could have lost a weight somewhere I realize), so I may have the balance checked if the issue continues after playing with the rear drum adjustment.

Lyon

Yes, that does help a little bit. If you had the problem right after adjusting the rears, it's pretty safe to say that the drums are out of round. Or something didn't get assembled correctly going back together. If you can find a shop locally to resurface them, it should only cost about 10- 20 bucks to have them done. And since they are new, they won't have to take off much. You might even be able to exhange them for new ones if there is any kind of warranty on them.

WantACherokee

Thanks, that makes sense to me too I just was thinking that new drums wouldn't be out of round. But you never know, I used to work at a parts store and sometimes even brand new stuff is defective.

Luckily I got the drums at the Napa that is right down the street from my house, so I'm in there all the time, I'm sure I can exchange the drums if they are bad. I will have to get them checked out.