'73 front disc brakes mystery.... • The Dodge Challenger Message Board

by **blackmagic73** » 15 Jun 2008 20:28

So I am rebuilding the front suspension on my '73. It came equipped with disc brakes and the discs on it had plenty of material so I had them turned. Had to get new calipers as one was missing and the other was rusted through. Now comes the fun part...
I put one of the brake assemblies back together and everything fit perfectly, no issues whatsoever (which should've warned me the second one would give me trouble...). Upon reassembling the second one, I discovered first that the entire assembly sat far enough out on the spindle to make it difficult to install the cotter pin. Next, I found it was impossible to remount the caliper due to clearance issues with the pad and the rotor. Comparing the two assemblies, it seems the troublesome rotor sits about 1/8" or so farther out on the spindle than its companion, leading to the difficulties with the new brake pads.
The mystery then is what is causing the discrepancy? Did I miss something along the way?
Other notes: I disassembled it again and the rotor seemed to be contacting the base of the spindle (judging by the transfer of grease from the bearing). I did get new seals for the rotors, but the bearings looked clean, no galling or pitting, so I gave them some new grease and reused them. It is possible that the bearings between the two got swapped (I'll blame the brake shop on that one for not keeping them separated), but they seem in all respects identical, so I didn't think they would cause a difference that major.
Any thoughts on this little problem of mine?

by **dave-r** » 15 Jun 2008 20:34

Check the inner bearing seat (is that the correct term?) in the back of the disc has not been removed or is not seated correctly. It just taps in and out so it may have been removed or damaged when you had the discs worked on.

Also check the discs are using the same size inner bearing. Just in case someone fitted an earlier disc on one side for some reason. 1970-72 use a smaller inner bearing and a two piece disc.

by **blackmagic73** » 15 Jun 2008 21:25

Thanks for the tips, Dave. Looks like I have some disassembly to do...

by **blackmagic73** » 15 Jun 2008 21:37

Well, sure enough, when I pulled both rotors off, the bearing seat on the problem rotor is not pressed in all the way. Don't know how I didn't catch that before, I guess that's what assuming will do to you....
Thanks again, Dave.