At 05:25 PM 7/11/98 -0400, Philip Hubbard wrote:
>
>I have a 1974 Midget and just installed my rebuilt brake calipers, new
pads, new rotors, new flex hoses and new wheel bearings. .... then tried
the rotors. Passenger's side turns freely most of the way around and has
an all too significant grab at some point in the rotation.
Slightly misaligned rotor. Disassemble it again and check for dirt, rust
or paint between the bearing hub and the rotor. Sandpaper these mating
surfaces clean, reassemble it and try again.
>Driver's side drags all the way around and makes a ticking sound at one
point in the rotation as if the outside of the rotors is rubbing against
the caliper interior.
Draging all the way around is a result of a piston not retracting. The
internal seal should drag a bit on the piston due to friction, and that
small force deflects the rubber seal a bit as it slides along the wall of
the piston. When you release the brake the piston should retract a couple
thousanths of an inch do to elastic rebound of the rubber seal. When you
first assemble a brake caliper, a little brake lubricant or brake fluid on
the piston can reduce the seal friction to nil. This can cause the piston
not to retract for a short while. If you can turn the rotor by hand, the
piston is probably not stuck. I recommend driving it for a bit to get the
brakes warmed up and the pads seated and run in. By that time the piston
and seal should be working in proper fashion. Check again then and let us
know.
>Did I read on the list here that one should have the rotors skimmed (was
that the word) or slightly turned before first installation?
I would not recommend refacing your new rotors. Brand new Midget rotors
are barely 0.010 inch thicker than the minimum thickness requirement for
safe brakes. Good thing they're cheap, because these are generally throw
away parts. It's not likely that they can ever be refaced even once
without reducing the thickness below the minimum spec.
>Could an incorrect bleeding procedure cause this?
Probably not. If you have air in the lines the brakes would feel mushy or
not work. A collapsed hose could cause the brake to drag, but you said you
installed new hoses.
>The reason I had the brake calipers rebuilt is that the pistons were stuck
closed at one point.
Classic symptom of a collapsed hose. But it could have been a frozen caliper.
>Maybe I should just have bought newly remanufactured brake calipers ....
Have a local parts store who could get them for $100 the pair.
It's so nice to own a car with cheap parts. I wish mine was like that.
Cheers,
Barney Gaylord
1958 MGA with an attitude
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