brakes

my girl friends 92 cherokee shakes really bad when braking it shakes at the steering wheel, the brake pedal, and the whole car what could that be???? new brakes went on about 4 months ago???? it started on the freeway and only did it at great speed but now it does it almost always???? any imput would be great

Front end shakes while braking could be warped rotors. Stock rotors are rather thin it seems. Mine are warped but evidently not too terribly bad. Only shows up under a lot of braking when thet get hot. I've had bad rear shocks do the same thing tho.

Sarge

we checked the rotors tho and they looked fine there was nothing bad looking about them...... whats the best way to test the rear shocks with out taking them out completly???

If it starts by pressing the brake pedal and the steering wheel shakes the rotors are warped. They will have to be machined. You could just take them off and to a shop to do (save some $). Rotors warping can be caused by undersized rotors, cheap rotors, cheap brake pads (too hard causing excessive heat), or heavy use. If the brakes start a vibration and it continuues after you let off then either the steering dampner is bad also or other front end parts are loose or bad.

How did you check the rotors? Looking at them with Eyeball, Mark I wont work. Use a straight edge laid across the surface (OK) or a dial indicator (better). As for the shocks, bounce a rear corner and see how long it keeps bouncing on its own. Shouldn't do more than about 1/2 a bounce or so. Slightly out of balance front tire(s) would probably do something like that also.

Sarge

Also, on new brakes, if you're really hard on them and don't give them a chance to "break in" they can warp pretty easily.

I have noticed I have a thumping I can't get rid of. It usually happens in right hand curves in the road at about 45 mph or so, but yesterday did it going straight down the road.....untill I hit the brakes and it went away.

I also think my brakes are sticking, as they were squeeling the other day while driving about 5 mph through a parking lot. A quick and hard tap on them and the squeeling went away.

Any suggestions?

99XJSPORT06 said:

Also, on new brakes, if you're really hard on them and don't give them a chance to "break in" they can warp pretty easily.

I have noticed I have a thumping I can't get rid of. It usually happens in right hand curves in the road at about 45 mph or so, but yesterday did it going straight down the road.....untill I hit the brakes and it went away.

I also think my brakes are sticking, as they were squeeling the other day while driving about 5 mph through a parking lot. A quick and hard tap on them and the squeeling went away.

Any suggestions?

Click to expand...

You might take it apart clean and put antiseize on the areas where the pads/caliper slide. There is also some stuff available to put directly onto the pad surface for squeaking.

MJR said:

You might take it apart clean and put antiseize on the areas where the pads/caliper slide. There is also some stuff available to put directly onto the pad surface for squeaking.

Click to expand...

Make sure the master cylinder is real clean also. There should be a very small hole to release pressure which is easily clogged up. If it is clogged the brakes will drag slightly. Sometimes tapping the brake pedal will send a higher pressure surge thru the system opening it for a short period. Happens on old bikes a lot if the bike isn't well taken care of.

Sarge

Do you have all cast rotors or do you have the two piece cast/stamped rotors? My 96 had the two piece from the factory. I fought rotor warpage for months. Every time I would have them turned they would warp within a few weeks again. Finally when I switched to a one piece rotor from napa my brakes are wonderful (fronts anyway).

I took the advice of RichP (I think) and went with a cheap (one piece) rotor for approx. $25/ea. and a good set of pads. I went with a brand called Ceramix. They cost about $85 for the set but they work awesome and do not create any dust. Most importantly, NO MORE ROTOR WARPAGE! Hawk brake pads also have a good reputation.

HTH

well the suqeeling seems to pop up after they've gotten hot, and i've been driving for a decent distance, and they've begun to cool back off and I go to use them lightly. Once the weather makes up it's mind between hot, cold, sun, snow, or ice, i'll pull the wheels off and have a look.

The fact the the owner before me took a decent set of rims off an older XJ Laredo wouldn't have anything to do with it would it? Maybe not enough air is getting in there and they are getting too hot?