[Stan Kaminski]

Does anybody know the minimum distance needed between the brake caliper to rim on a 1968 GTO with the factory 4 piston disc brake calipers and Rally II wheels? I need to know minimum distance between the outboard side of caliper to back of spokes on rim. This is where some Rally II rims hit the caliper. There is a raised Delco Moraine symbol on the outboard side of the caliper and it being the highest spot, hits the backs of the rims, specifically on the back edge of the spoke holes.
Check this link for pictures.

http://picasaweb.google.com/PontiacP...eat=directlink

I tried 21 Rally II rims for fits. Only 3 rims didn’t hit the calipers, but they were close as they had just .157” or 4MM clearance between the edge of the spokes and caliper. Maybe this is correct clearance, or perhaps it’s not enough. Without any factory specs I’m just guessing what’s acceptable.
None of these 21 rims contacted the caliper anywhere else. The only place they hit were on the Delco Moraine symbol or about a quarter of an inch before it, depending on the wheel. I thought the rims might hit the top or bottom of caliper, but that was not the case.
I just installed the complete factory kit from Inline Tube for my 1968 Le Mans and have three Rally II wheels to use on them as they don’t hit the calipers. But I’m afraid they may be too close and contact the calipers when driven as the wheels may flex in hard cornering. I have 3/16 of an inch clearance between the spokes to the caliper. If anybody has the answer from an original car or a kit like mine I would greatly appreciate any help. There is very little information or pictures on these brakes, even in the GM Parts books or shop manuals.
Two of the Rally II rims that cleared the calipers were JC code with 4 1/8” backspace and the other was JT code with 4 3/8” backspace. Incidentally, the two letter code stamped next to the valve stem is the one to use for identifying rims, not the ones inside the rim. The date is also next to the valve stem.

Thank you for your time and answers!
Stan Kaminski

[Half-Inch Stud]

I installed the semi-complete factory kit from Inline Tube for my brother's 1968 Le Mans and...

The Rally II rims would scrape along the Caliper Bracket outer edges, which I had to grind-down. Contact was along the rim area that holds air, not the spoke-plate.
Conceivably, the problem could come back huh.

[68gtoMN]

I have several factory-equipped 4-piston caliper cars and some spare sets. However, each car with this setup is tucked away for the winter and inaccessible to me. There are several threads on the topic. Check this post

http://forums.maxperformanceinc.com/...31&postcount=5

Entire thread here
http://forums.maxperformanceinc.com/...els+disc+brake

I hope that helps!

[PaulatFast]

Originally Posted by 68gtoMN

I have several factory-equipped 4-piston caliper cars and some spare sets. However, each car with this setup is tucked away for the winter and inaccessible to me. There are several threads on the topic. Check this post

http://forums.maxperformanceinc.com/...31&postcount=5

Entire thread here
http://forums.maxperformanceinc.com/...els+disc+brake

I hope that helps!

I don't think that will help! It is full of WRONG information. Back in 2002, that info might have been accepted as fact, not any more...

All 68's recieved JC wheels, regardless of brake selection. All 69's recieved JA's. It was a miss-conception that the Ja's were off-set to clear the calipers... They were actually offest more to the inside to account for the thicker hub that the disc brakes used.

As far as the question asked here... I always try to get at least an eighth of an inch of clearance. A little less won't hurt a thing.