Hey guys, I did some searching but didn't find an answer to my specific issue. Hopefully you guys can help me out. I have an '01 Cherokee Sport. My mechanic friend and I replaced the shoes and drums during the summer (from O'Reilly's). Ever since then, I have had some weird issues. The brakes seem fine at first, but when they heat up there's a pulsation. When they pulsate, they make a weird noise... It's not a squeal or squeak, but more like a whine that starts and stops as it pulsates until the car stops. If I brake suddenly or hard, the rear brakes lock up. As soon as I let off the brakes, they are no longer locked up and work as normal. My mechanic friend and I have taken them apart and checked them many times. We thought at first that they were too tight, so we loosened them up. Same issues. Then we thought maybe it was the drums, so we took them back and got a new set. All was fine until they heated up, then same problems. We also replaced the wheel cylinders. We can't seem to figure it out. Any other ideas on what could be the problem? It's driving me crazy Thanks in advance for any ideas.

 

Pulsing is often the front rotors. Sometimes might be OK until they heat up some. They warp and make the petal pulse.

 

This is why it's equipped with a proportioning valve, if the front brakes lock first, there goes the steering and you are screwed.
The problem you describe boils down to warped front rotors. My suggestion would be to drive for the conditions so you are not constantly slamming on and heating the crap of the brakes and find a new "mechanic" friend.

 

Try adjusting your rear brakes first.
The pulsing is comming from the front.
The pulse is from a rotor that has hot spots or is warped.
This was probably caused by sticking calipers, or divits or corrosion on your knuckles.
It's the spot that the front pads ride on.
I had the same thing happen to mine.
Look at my photos or do a search on front brake issues.
Let us know.

 

I drive for conditions, and I don't slam on the brakes or brake quickly by choice. Sometimes other people do stupid things (run stop signs or red lights) and I have to react quickly to avoid an accident. It's one of the downsides to living in a very populated area where traffic laws are rarely enforced.

 

Thanks for the replies. If it were the front rotors, why would the noise that occurs with the pulsation be coming from the rear? Also, we tried adjusting the brakes a few times now, but there was no change regarding the issues I've been experiencing, unfortunately.

 

Do you get the same noise or pulsing if you pull the emergency brake?

 

Two different size rear shoes. One smaller than other make sure one of each is on each side. Longer shoe mounts towards front.

 

like stated there is a primary shoe and a secondary shoe. you sure you put them in the proper location? did you clean and grease everything as it should hav been while going together?

 

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That's nice Joe!!

 

OP,the pulse is comming from your front brakes.
As far as a sound goes,can you describe the sound?
When u apply the brakes only? When u pull on the e brake slightly while moving?
Or does it make a sound while u r moving & not applying the brakes?

 

I don't know, because the emergency brake doesn't work. It's on the list of things to fix.

Thanks for the diagrams. I will have to double check everything, hopefully tomorrow.

The noise only occurs while applying the brakes. I listened to a bunch of brake noises on YouTube trying to find one that sounds like mine, but none of them do. Forgive my odd attempt at a description, but the noise is like a "waa.. waa.. waaa.... waaa...... waaa" that starts and stops as it pulsates, as well as slows down as the Jeep slows. I made a joke to a coworker that it sounds like some sort of aquatic animal or something.

 

Just in case you didn't already know....lots of parts stores have a lathe in back and can check and turn rotors. Check should be free. Now, turning might be 1/2 the price of new...Something to cover anyway, since you are having pulsing why not rule that out.

I can't say I recall ever having drums pulse. Not saying one never will, but been there, have a few T shirts. I'd have those rotors checked.

Drums can be turned as well, normally because of scoring from metal after the shoe wears away. They both have a minimum thickness, cast right on them. Heck, take in all four in and your problems will almost surely be gone.

 

Discs can pulse and drums can pulse.

Need park brake to work in order to determine which it is.