"Bent" hubs

[Bret]

Is it possible to check the "true" on the hub before you mount the rotor? Maybe something on the rotor/hub that is causing the wobble when tightened?

Turning on the truck was the only way I got my wobble to go away on my Dodge.

Took to long to type... What straight-said

 

[Plowboy]

Could one of your disks not be seating completely on the hub? That would distort the disk causing the pulse. Might check your rear drums, assuming your rig has drums. If they have been turned a couple of times they can get outaround and cause the pulsing in the pedal.

 

[Fuzzy Logic]

What are we working on here? Make/Model/ Year?

This is a 40 forum

 

[Mace]

This is actually my 60, So the studs are pressed through the rotor and through the hub itself.
The action of torquing the wheel studs should eliminate the possibility of the rotor not seating completely..

Course, Stranger things have happened...

Dial indicator on the hub itself will be the next step. I just am tired already of pressing the studs in and out...

If the rotors can be turned on the truck I am positive that would solve the issue. But it seems like a band aid for a bigger problem.

And, I do not know of any place here in town that will turn rotors on the truck (hell I have never even heard of that)

 

[vk7ybi]

When I did my RDB conversion on my FF hubs, one of the hubs I'd supplied to the machinist he wouldnt modify.. He said my hub was bent, hed marked it with a marker where it was bent, and sure enough theres a bend in it, visible too.. The WMS isnt flat.. I hadnt noticed it with the drum brakes, but it was no good for discs. Bent hubs are possible..

I think about the only things that can cause a pulsating pedal/vibration are excessive runout and variences in thickness of the rotor.. Misalignment of calipers and spindles wont cause pulses, just uneven wear of pads. Turning rotors in situ will fix rotor problems, but if the hub is bent it wont fix rim runout.

 

[grant5127]

This is a 40 forum

Some of these hard core Dudes run Dana and the likes....

Rotor mounting configuration differ from 9/'75~7/'80 to the later 8/'80 on.....

.002" runout per side would be excellent.

A history of impact uses to install the wheels can leave hubs with warpage that will be induced into the rotors. Rust build up on the hub surface under the rotor can cause "rust jacking" a rough uneven surface that the rotor cannot sit flat against.

And then again there is always the possibility of "tire turbulence"

 

[FJ40Jim]

4 thou doesn't sound like much runout for a big stupid land cruiser rotor.
Spec is 5 thou, and even that is not noticeable usually.

You have measured at the outer edge of the rotor?

The problems lately w/ brake pulsation on Cruiser have been because of a lack parallelism on rotor faces. as the thick spot slides into the caliper it increases brake torque on that wheel, which drags the steering that direction, and it shoves brake fluid back into the system, causing the pedal to pulse up.

Chinese quality control, doncha know.

A coupla good links
Autozone info

brake rotor service

 

[Mace]

4 thou doesn't sound like much runout for a big stupid land cruiser rotor.
Spec is 5 thou, and even that is not noticeable usually.

You have measured at the outer edge of the rotor?

The problems lately w/ brake pulsation on Cruiser have been because of a lack parallelism on rotor faces. as the thick spot slides into the caliper it increases brake torque on that wheel, which drags the steering that direction, and it shoves brake fluid back into the system, causing the pedal to pulse up.

Chinese quality control, doncha know.

A coupla good links
Autozone info

brake rotor service

Good point Jim, I'll check that out as well..