Brake problem, got any ideas??

[Red Monkey]

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.

 

[bushpilot]

sounds like a SUSPENSION issue...could the REAR axle be ROLLING when you apply the brakes...id be checking bushings and springs etc...maybe even drive line (althought this doesnt sound u-joint or carrier bearing "like")

whats the condition of the shocks ? is there a sway bar on the back ?

honestly ive NEVER heard of rear rotors warping...they only carry about 25-30% of the braking
load on any car/truck or motorcycle..

id be looking all over the front suspension as well for ANYTHING loose.

 

[Red Monkey]

Bushpilot,
Thanks for the ideas.
The truck has the 'camper package' with front and rear sway bars and a set of rear 'helper' springs above the standard rear springs.
The shocks are replacements, not OEM's and are about a year old.
There is no center carrier bearing on the drive shaft, it's a one piece shaft. But, as you said it doesn't sound like a u-joint problem, no clunking.
I haven't checked the spring bushings but if they were worn I guess it could cause the symptoms I'm having.
I'll check out everything front and rear in the AM when I have some light. Man, that SD is so heavy it isn't like working on my Toyota Offroad truck.

 

[JLDickmon]

tell me what you torqued the rear lug nuts to when you remounted the wheel..

I also want to know if you put new shims and rattle clips on the rear pads..

 

[Red Monkey]

The rear lugs were torqued, in a star pattern, to 145 ft.lbs. using a torque wrench, NOT one of the color coded torque sticks on an impact gun.
When I took the old pads off there were NO shims on them so...I didn't put any shims on the new pads. I reused the rattle clips.

 

[Tbar]

Firestones........broken belt ???


Tbar

 

[Red Monkey]

Hey, be nice Tbar, they came on the truck. I will more than likely go with a set of 285x75x17 BFG's soon.
I just checked my rear spring bushings and sway bar, everything is tight.
But, I did see where the 'helper spring', the one on top of the main spring pack, had been hitting/rubbing its bumpstop on both ends of the spring. Is this normal? I think that's kind of strange as I have not had a load on the truck. This may indicate that the rear axle IS rolling as Bushpilot suggested. I'm going to use some chalk to color both front and rear areas of the spring tomorrow and take her on a ride. After the ride if any of the chalk has transfered onto the spring bump stop then I'll know the rear axle if rolling or bouncing.

 

[iracemine]

axel leak?

 

[Red Monkey]

No axle leak.

 

[bushpilot]

lets see....if the axle were twisting how far could it twist
w/out messin' up the rear/pinion bearing / gear etc ?
i guess the ujoints would allow for some movement.

a bearing goin' in the rear will SING eventually...LOUD...

do you feel anything when you let off the brakes or take off quickly ?
(wondering if its a one way rear axle twist)...could the floating axle
(inside the casing) be loose or twisting around the wheel/brake a
little when you stop ?

seems to me youd feel something when you took off from a stop if the
axle were rolling/twisting.

could the rear sway bar be loose / twisting where its
U-Clamp'd around the axle tubes ?