Jeep Grand Cherokee Forum banner
1 - 4 of 14 Posts

ZJ JIM 96

· Registered
Joined
·
156 Posts
Discussion starter · #1 ·
I am about at my wits' end with the pulsating brakes on my ZJ. Just this week, I have replaced the front rotors with brand new Wagners from O'Reilly ($40 each), brand new Morse pads from Autozone ($40 ceramics) and new hardware and boots ($27) from NAPA.

The net result...NOTHING! I still get terrible pulsations when coming to a gentle stop.

My calipers seem to be fine. No leaks, and I don't think they're sticking (how do you test for that?). Is it possible it's the back brakes? Could it be the brake lines? Would bleeding be any help (the pedal is fine, not soft at all, but the fluid has never been bled)?

Any help or ideas would be greatly appreciated.

Thanks,
--Jim
 
Discussion starter · #4 ·
JayH said:
Does the Jeep itself shimmy? or just a pulsating feeling in the pedal? If the former, check for bent flanges/shafts/housing in the rear. If the latter, its possible you got bad rotors. Probably some other things as well...
The whole Jeep surges or pulsates. It's not really a shimmy, but also not really in the pedal at all.

I agree it could be that I got bad rotors, but it is exactly the same pulsation that I got with the rotors I just took off, so I find it a little strange that both sets would be identically warped.

As for the shafts and housing in the rear, they look straight, and have never taken a bad beating. What are the flanges you are referring to? I will check them, but am not sure exactly how.

What other things do you think it could be? Think it's worth changing the original rear rotors?
 
Discussion starter · #9 ·
XMech said:
...Also, if you weren't feeling the pules in the steering wheel, then it probably is in the rear.
Silkstone said:
...if the pedal pulses
and the steering wheel shakes. its the front, if you get a vehicle vibration
or pedal pulse but no steering wheel shake its the rear...
Thanks for clarifying that. In fact, I don't feel them in the steering wheel, it's just that the whole Jeep lunges. I will definitely turn or replace the rear rotors (and maybe change pads while I'm at it) and see if that helps.

If it's not the rear brakes, I'll go ahead and check the other stuff in front (runout on the new rotors, ball joints and tie rod ends--bearings should still be good, as hub was replaced not too long ago).

I appreciate the advice.

--Jim
 
Discussion starter · #12 ·
Sure enough it was the rear rotors. Replaceing them not only got rid of the pulsating on slow stops, but also got rid of some shimmy at 55-60mph that I thought was bumpsteer, and it got rid of a consistent light thud that seemed like a flat-spotted tire while driving. Wow was that ever worth it!

Thanks for everybody's input. I really appreciate the help.

--Jim
 
1 - 4 of 14 Posts