Rear end chassis mount

w6df · #1 (**permalink**) 08-10-2014, 05:50 PM

I have a 67 E-M with C4 suspension. The nut and bolt assembly that secures the Corvette rear end to the chassis came loose. I want to replace the old rubber bushings and hardware, but should this bolt be completely tight or should there be some play? Has anybody just used a nut and bolt (steel washers) without the rubber inserts which would secure the rear end solid?

w6df · #2 (**permalink**) 08-11-2014, 10:49 AM

This mounting bolt holds the nose of the diff to the chassis. I am going to replace it with a 1" thick 3'x3" aluminum spacer to hold the pinion angle constant. This is an IRS suspension, so I think the diff should not move up or down. What do you guys think?
Jim

COBRA427 · #3 (**permalink**) 08-11-2014, 11:17 AM

I have the same set up as you.

Email me : 67cobra@cox.net

Ed

w6df · #4 (**permalink**) 08-15-2014, 09:35 AM

What a different car !!! I now have the diff securely mounted to the frame with a 1.200" x 3.00" aluminum spacer and a 5/8" grade 8 bolt. The spacer thickness (1.200") was found by making the center line of the pinion parallel to the output shaft of the transmission. Using a magnetic level placed on the u-joint yoke of the transmission the angle was 4 degrees. Then using a wedge, the angle on the u-joint yoke of the diff was made to be 4 degrees (1.200"). The drive shaft is now at 3 degrees, so there is now a 1 degree difference between the parallel trans and diff. No more wheel hop, weird clanking and vibration feeling. Many thanks to Ed for all the help on this project.

PS: Real race cars use ROUND TUBING !! E-M

Jim