[SEL] OT - 3/4 ton truck question (for the pros) Help pleasE?

[jbcast at charter.net]

---- bill at antique-engines.com wrote: 
> That's my initial thought. The brakes themselves are easily moved - the
> calipers can be slid by hand, the pistons are free. If there was much out
> of parallel, the outer surfaces on each/both rotors would not have been
> well under spec, IMO. If the outer surfaces are true, that means any out
> of parallel would have to be fully and totally on the inside surfaces.
> Hard to imagine, possible I suppose, but hard to imagine the outer
> remaining true while the inside only warps, esp with smooth moving
> calipers that move freely.
If this truck were in my shop I would resurface the rotors before doing anything else. If you look at how a rotor is made, the outside is a solid disc all the way into the hub. The inside is a small disc supported by the fins. Which side has the better heat sink? Spring wrap and wheel hop is a rear axle problem under hard acceleration. The  springs wrap up under torque and when the wheels break loose they unwrap, causing them to hop. If your front rotors are smooth there shouldn't be a pulsing to cause the springs to wrap and unwrap. I would keep it simple, if that doesn't work look farther. The brake hoses that give trouble are the ones with a bracket clamped around them. The hose expands and where the bracket is clamped it can only go inward, constricting the line.
J.B.