rear trailing arm brake mount??????

[jly535]

I am in the process of upgrading my 77 930 brakes to 85 930 calipers and rotors. I noticed my rear trailing arms have the rear caliper mounting bosses that are not milled, drilled and tapped for anything. Does anyone know what these bosses are actually for? My brake calipers mount to the front of rear spindles? I would much rather machine the trailing arms to 3.500" spacing to accept later turbo calipers instead of machining calipers to fit 3.00" spacing. The drivers side is actually machined flat with drilled but not tapped holes and the passenger side is just the cast bosses that would need machining. Are these trailing arms maybe a transition cast between the early turbo and later turbo and can be adapted to later style rear mounted calipers?

[DW SD]

Convention is to machine the calipers to accept adaptors which offset the spacing to 3".
VCI offers this service, as do others.
I used Clint Smith, who rebuilt and restored my 930 calipers and machined the calipers to a great end result.


****note, convention is for the 911 trailing arms. I don't know if 77 had the 930 arms. I assume it did, but cannot be certain.***** Sorry for the dumb a$$ answer to your specific question ****

Doug

[cole930]

jly,

Not at all unusual to see this condition. 930 trailing arms seem to come in many forms. Some only have one set of mounting bosses. My ROW 930 had both but the trailing position bosses were the only ones tapped. As side note rear 930 calipers have a spacing nearer 3 9/16 in. So whatever spacing you go with measure caliper spacing carefully before drilling. If you prefer the trailing position
thats fine. You might leave a thread for Bill V and see if there is any particular advantage to either position.

Cole