Brake problem, got any ideas??

[Red Monkey]

I don't have 'axle wrap' or axle twisting. I have been around trucks long enough to know what axle wrap feels like and it an't there.
I have checked everything on the rear end, shocks, sway bar, u-bolts, u-joints caliper bolts, NOTHING is loose. It doesn't 'CLUNK' like metal to metal in has a 'bounce' that you can feel in the front seat as you apply the brakes on an easy stop. In a HARD stop it doesn't do it. You can sometimes feel pulsing like when rotors are warped and they grab at a certin point as they turn inside the caliper. That's why I replaced the rear rotors and pads bUT, it still does it!!!
JLDickmon asked if I replaced the brake shims. Well, my truck had no shims between the pads and the caliper. Should there have been shims??? All of the Toyotas I have worked on had shims, this is the first Ford I have had so I have VERY little experience with SD's.
Could the lack of shims cause the pulsing? Maybe, I don't know.
Could the calipers be bad, not sliding smoothly cause the problem?
Could it be something in the ABS system causing the problem?
I haven't been abl to find any other post on this type problem...
I'm still open for ideas.

 

[iracemine]

well I might be a punk kid, but in all my few years of racing cutting rotors never ever got rid of a warp.... (the warp is set in the memory of the metal) and when I was scoping out trucks everyone who was anyone always said that the SD had bad front rotor warp isues. Mine has a bad hop too when I bought it (used) but I just figured it was my front rotors, and I dont care. They have 90K on them and I was just going to get new ones when I got to my brake job. So obviosly Im going to ride the pads to the bolts and then do them and my uper ball joints too.

 

[Red Monkey]

Maybe mine are the front rotors...Everything on the back is new.
I was talking to a buddy of mine today and he said his SD did the same thing SOMETIMES but not all of the time. It may be something I'll have to put up with in order to have a SD.

 

[iracemine]

yup. sometimes it pisses me off to notice and sometimes im to bussy to notice. still wouldent trade her for anything!

 

[bushpilot]

ive HEARD that some of the "warp" issues really arent warp at all...rather
they are pad wear issues (un even wear or pad differential wear)...

 

[johnrrogers]

You might try having someone ride beside the rear of the truck (in a car of course) with a video camera and take some video of the rear wheels and also do the same thing from the rear to see if any sounds show up or any visible things move around in the video. If you have an old video camera you could mount a "rear axle" cam under the truck and tape what is happening but I would not try it with a new camera.

 

[JLDickmon]

You can sometimes feel pulsing like when rotors are warped and they grab at a certin point as they turn inside the caliper. That's why I replaced the rear rotors and pads bUT, it still does it!!!
JLDickmon asked if I replaced the brake shims. Well, my truck had no shims between the pads and the caliper. Should there have been shims??? All of the Toyotas I have worked on had shims, this is the first Ford I have had so I have VERY little experience with SD's.
Could the lack of shims cause the pulsing? Maybe, I don't know.
Could the calipers be bad, not sliding smoothly cause the problem?
Could it be something in the ABS system causing the problem?
I haven't been abl to find any other post on this type problem...
I'm still open for ideas.

I asked about the shims and rattle clips for where the pads seat in the caliper bridge.

If you replaced them, but never cleaned off the rust undeneath on the bridges, then you may be binding the pads and causing problems that way.

But you actually brought up the point which I didn't think of, and may be the root cause of your problem..

where you said

"and they grab at a certin point as they turn inside the caliper."

Did the rotors have a non-directional swirl finish on them? If not, yes, they may have a rough spot in them from machining, and yes, that could cause your brake stutter...

 

[iracemine]

You might try having someone ride beside the rear of the truck (in a car of course) with a video camera and take some video of the rear wheels and also do the same thing from the rear to see if any sounds show up or any visible things move around in the video. If you have an old video camera you could mount a "rear axle" cam under the truck and tape what is happening but I would not try it with a new camera.

ever hear of the movie tommy boy?

 

[Butch Cassidy]

Ok, heres the deal. I have an 01 SD 4x4, 265x17 Firestones, extended cab with a little over 100,000 miles. Almost everytime I brake the truck bounces as if the rear rotors are warped, I can feel it in the seat. I took the stock rear rotors and had them turned, they were warped a little. It didn't help at all, still the bounce. So, I replaced the rear rotors with O'rilley lifetime rotors AND pads. I knew this was going to solve my problem but NO...it did help some but I still get the 'bounce in the seat' most of the time. Every now and then I can feel a shimmy in the steering wheel, like the front rotors are warped when stopping but not very often.
This problem has me stumped. I almost feel that the money spent on the new rear rotors and pads was a waste and I don't want to spend more money on the front and not solve the problem.
I really don't know how to solve this problem. One other thing, I'm going to need tires soon. I wonder if the old worn tires could be the problem?
Do any of you guys have any ideas of suggestions. Other than this I love the SD, except for the price of diesel but that's another story.
I hope someone has a fresh idea.

Red Monkey,

If you have access to a dial indicator, ger some TIR readings on each of the rotors to see if / if not you arew w/in spec.

Other causes: pad hangup in caliper, loose suspension and/or misaligned suspension parts.

Start with the dial indicator first.

Hopes this helps,

Butch Cassidy

 

[Red Monkey]

Thanks for ann of the ideas.
I'm going to check with the Ford stealership to see if I should have any shims on the rear pads, here were none on the old pads.
Next I think I will pull the caliper pins and make sure they are lubed and everything is slidding nice and smooth. Before I put them back on I'll break out the dial indicator and get some readings on the rotors
Thanks again for all of the help.
Hal