One-ton front caliper has been rubbing on disk

[RF_Burns]

While flushing and bleeding my brakes, I broke the siezed front passenger bleeder off. I had kept all the part numbers from when I did the one-ton
upgrade, so I got another Raybestos FRC4417 caliper. When I pulled the old caliper, I noticed the disk edge had been rubbing on the caliper. It
touches at the last inch or so on each end of the caliper, there is plenty of clearance in the middle. The worse area is 0.038" deep.
Question is, should I grind out this area on the new caliper (would this weaken the caliper?). Or should I just let the new one wear in like the old
one did?.

Posted some photos:
http://www.gmcmhphotos.com/photos/g7108-calipers-rubbing-on-disk.html

--
Bruce Hislop
ON Canada
77PB, 455 Dick P. rebuilt, DynamicEFI EBL EFI & ESC.
Hubler 1 ton front end
http://www.gmcmhphotos.com/photos/showphoto.php?photo=29001
My Staff says I never listen to them, or something like that

 

[wrightjohn 2646]

Bruce,
Grind for clearance plus .020 and you should be just fine. 0.050 to .060 is not going to weaken the mount.

J.R. Wright
GMC Great Laker MHC
GMCGL Tech Editor
GMC Eastern States Charter Member
GMCMI
78 GMC Buskirk 30’ Stretch
75 GMC Avion (Under Reconstruction)
Michigan

>
> While flushing and bleeding my brakes, I broke the siezed front passenger bleeder off. I had kept all the part numbers from when I did the one-ton
> upgrade, so I got another Raybestos FRC4417 caliper. When I pulled the old caliper, I noticed the disk edge had been rubbing on the caliper. It
> touches at the last inch or so on each end of the caliper, there is plenty of clearance in the middle. The worse area is 0.038" deep.
> Question is, should I grind out this area on the new caliper (would this weaken the caliper?). Or should I just let the new one wear in like the old
> one did?.
>
> Posted some photos:
> http://www.gmcmhphotos.com/photos/g7108-calipers-rubbing-on-disk.html
>
> --
> Bruce Hislop
> ON Canada
> 77PB, 455 Dick P. rebuilt, DynamicEFI EBL EFI & ESC.
> Hubler 1 ton front end
> http://www.gmcmhphotos.com/photos/showphoto.php?photo=29001
> My Staff says I never listen to them, or something like that

 

[terry1]

If the new caliper rubs also, first check the wheel bearing play. Put the wheel back on to check it so you have enough leverage. Check the rotor
diameter versus the brake pad wear area, maybe you have some extra metal there to get rid of, especially if it is aftermarket and not original GM
stuff. I've had to clearance some calipers for aftermarket rotors before, and like J R said that 50 or 60 thousandths is not going to effect the
strength of that iron casting.
--
Terry Kelpien

ASE Master Technician

73 Glacier 260

Smithfield, Va.

 

[RF_Burns]

Thanks JR and Terry. I've got extra I could take off the disk outside of the wear area, but I don't have a lathe to do a nice job on it. So I'll
grind the bit off each end of the caliper. It doesn't bind so there should not be much to take off... except I guess the caliper moves when the brake
is applied.

I've got some 2" wide electrical tape to wrap the piston to keep the filings away from it.
--
Bruce Hislop
ON Canada
77PB, 455 Dick P. rebuilt, DynamicEFI EBL EFI & ESC.
Hubler 1 ton front end
http://www.gmcmhphotos.com/photos/showphoto.php?photo=29001
My Staff says I never listen to them, or something like that

 

[david h. jarvis]

Jack the front end up, put it in gear, sit down with your grinder and grind away on the rotor.
No?

 

[RF_Burns]

Harry,
I thought of doing that, but Murphy's law is always hot on my tail. I figured I'd get it all out of round too. I tried using the bench grinder on the
caliper but I could not get it close enough inside. So I ended up putting the caliper in the vise and using a die grinder. The pain was getting the
piston protected from the filings. It took a couple times testing it, but there is no rubbing now.

I should also say that before I pulled the wheel, I gave it a few good vertical pulls to be sure the bearing was good.

--
Bruce Hislop
ON Canada
77PB, 455 Dick P. rebuilt, DynamicEFI EBL EFI & ESC.
Hubler 1 ton front end
http://www.gmcmhphotos.com/photos/showphoto.php?photo=29001
My Staff says I never listen to them, or something like that

 

[Ken H.]

Bruce,

Thanks for posting the 1-Ton brakes topic. I noticed a few thousand miles
ago that my pads were getting a little low. Hopefully your reminder will
cause a roundtuit to grow here soon. And I'll be sure to check for
interference too.

Ken H

> Harry,
> I thought of doing that, but Murphy's law is always hot on my tail. I
> figured I'd get it all out of round too. I tried using the bench grinder
> on the
> caliper but I could not get it close enough inside. So I ended up putting
> the caliper in the vise and using a die grinder. The pain was getting the
> piston protected from the filings. It took a couple times testing it, but
> there is no rubbing now.
>
> I should also say that before I pulled the wheel, I gave it a few good
> vertical pulls to be sure the bearing was good.
>
>