2nd Gen Non-Engine/Transmission jumping and shaking when braking

[shendren]

those are the symptoms.



about 50k mi ago i replaced the rotors and pads. it doesn't pull right now. when it does pull, i do the "cram the brakes on in reverse" a dozen or so times and it straightens right up.....



it seems these are the symptoms of bad rotors. could it be something else? i really don't want to have to put new rotors on after only 50k miles...



could it be the caliper(s) sticking?



i don't haul anything (worth noting) with the truck.....



comments would be appreciated as i will take it in in the am to have it checked out... ...



thanks.

scott.

 

[Hogan]

The brake-hard-in-reverse is for the self-adjusting rear drum brakes, not the front disk brakes. If your rears do get out of adjustment they will cause pulling, specifically when one side wears faster than the other or isn't fully retracting. I'd pull the drums and check the shoes to see if one side is more worn than the other. It's possible one side is sticking.



It's also possible one of the front calipers is sticking. If you had an IR heat gun you could see if one side is getting a lot hotter than the other during normal driving.



This is actually one problem I'm going to be looking at myself this weekend since my truck has started pulling hard right under heavy braking. Last time it was a difference in tire pressure up front, but not this time. Time to check and clean the brakes and hardware.

 

[KL]

My front rotors were warped on a previous truck. They were able to turn the rotors and did not have to replace them. KL

 

[Steve Campbell]

If you are going to turn rotors....

know that if they require "much" truing... . you will then have "thick/thin" spots and the chances of warpage in the future are increased.



The IR gun is a good idea.

 

[illflem]

I use the IR temp method to diagnose brake pull quite often and have found with pull to one side you should take your test drive without using the brakes at all if possible. Helps a lot if you live in the country. The pull is usually due to sticking pins or piston that cause drag heating the rotor and causing it to lose efficiency. As a result the side not sticking works harder and will end up hotter while braking when the real problem lies with the cooler side. Just a 50° difference between sides is all it takes.

This assumes that the most common cause of pull, rears out of adjustment due to a poor self adjusting system, isn't the real reason.

 

[Joe G.]

I have 221K miles on the original rotors. The third set of pads is about 1/3 worn. There is a stone grove in one rotor. According to my dial indicator the rotors are still within runout specs. The second set of rear shoes still look good. SO I must be doing a few things right.



Every time I change my oil, which is at about 5K intervals, I do a little PM on my brakes. I pull the rear drums and inspect to see if there are any leaks or anything is wrong. Then I touch up the adjustment. I check the run out on the rotors. Then pull the caliper pins one at a time to clean and lube them. When I clean them I polish them some with crocus cloth. I think this is what keeps the difference in wear between the outside and inside pads to a minumum.



I use my exhaust brake for slowing down. If I have to stop hard I don't let it sit there with the brakes locked. Instead I let it creep a little bit so the pads are not holding the heat in one spot.



This seems to work for me. Now if I could figure out why the ABS light is on I would have no brake problems.

 

[azpete]

Not sure if this may be your problem but if not the rotor or caliper then may be the abs. My long gone 94 was starting to get a shimmy on hard braking. Then going to the lake one day with heavy cabover and boat going down 10 mi. 8% grade just a light application off brakes would shake the truck so bad I thought it was going to dissintegrate. Repair shop as abs module failure. New board was over $500. Had him just unplug the module and all was fine.

 

[CRSmith]

Worn shocks will cause shaking and jumping, especially when the asphalt in front of an intersection has been shoved into little bumps by stopping 18 wheelers. Shocks feel much different than warped rotors though.