Rubber Body Mount Cushions
 

The body is going back on my 71 soon, I decided to go with the Rubber bushings vs. poly or aluminum. Wanted to do what I could to improve ride quality and minimize the vibs from the solid motor mounts for the 490 ft lbs of torgue. I know I am sacrificing some handling but will not be autocrossing.

Anyways my question is , could I soak the new rubber cushions in anything before installation to help increase service life ?

Let me know if you have any suggestions.

Thanks

I am interested in this also.

I have a 71 and plan on moving to rubber cushions for a softer ride when I drop the body early next year.

ttt

I can't think of anything you'd want to soak them in. They'll last a long time.

I don't understand why you think they would hurt handling?

No need to soak the rubber, just install them and enjoy the ride...I switched to rubber on my 68, the ride quality is amazing compared to the aluminum mounts...no more cringing the teeth when approaching some rough roads... :thumbs:

The compounds used in today's rubber parts are much hardier and long lived. I've read that the old parts were made of a Butyl compound where as the new stuff is EDPM.

I replaced my "disc" with poly's

Just curious for those that have changed to rubber or poly -- I've read that when Chevrolet switched from aluminum, the body mount brackets on the frame were also dropped 3/4" because the rubber mounts were thicker. Assuming that's true, are you guys using the thicker mounts on the '68 - '72 and if so, is the 3/4" body lift you get noticable? Or, is someone making replacement rubber mounts for the older cars that are the right thickness? I'm not trying to hijack b71vette's thread here, just curious and seriously thinking about this swap as well.

Zwede / Yukon - Thanks for all the feedback ! more questions
 

Zwede, I was just assuming it may affect handling based on what others have said, I'm not sure since I haven't driven mine yet.

Yukon, that's an interesting point , I hadn't compared the original alum to the new rubber bushings I just got. Little concerned now.

Zwede did u have any issues when you switched your 71 from alum to rubber ? Did u lower the mounts on the frame ?

The body mount change to the frame is mentioned here if you look at the change to '73 frame:

http://www.71corvette.com/frames.html

and I can't find the link now but I read a step by step on this and they mentioned having to loosen the steering column to re-line it up with the box since the body sits a little higher with the rubber mounts.

None at all. Just had to line up the steering column but there's enough adjustment so it's not a problem.

The body sits maybe 3/8" higher. Not noticable.

I heard of the lowering of the mounting bracket on 73-up but I have my doubts if that is really true. I helped a buddy swap a 73 frame into a 72 and the mounts looked the same to me. He started with 72 aluminum mounts and if they really did lower the brackets on the 73 frame his body should have hit the frame. Well, the body didn't hit and fit just fine. He later swapped to rubber mounts and they fit fine also.

Man this Forum is Soooo Great!!! Thanks
 

Yukon and Zwede Thanks For all the help. Sounds like there will be about 3/8" higher, not enough to chop and reweld brackets. Glad to know about the steering column adjustment required too.

Zwede, how did u go about shimming to get the body alignment. When I removed the body I recorded the number of shims at each mount, now that I am switching to rubber should I use the same # of shims or try to reduce since the rubber mounts are thicker ?

Mine only had one shim on each mount so I left them out. I think it would be a good idea to remove the same number of shims at all mounts to minimize the increase in height.

Thanks for all the help Zwede and other Forum Members
 

This Forum is Great!!!

The aluminum disc don't change heigth. Guess what happens when you pinch the poly's or later rubbers mounts that are 3/4" taller between the body and frame? Yup...only about 3/8" higher here as well and very small adjustment on the steering shaft after the conversion. :thumbs:

Great thread. I have always wanted to do this mod but have been afraid to do it because of some of the horror stories I have read about the nuts breaking loose in thier mounts. If you have Steeroids this may even help with that alignment also.

Eddie70, if you are really going to be doing this
 

start soaking the body mount bolts periodically with PB blaster, there are a total of 8, 4 mounts each side. The more you soak them the better change of it getting into the threads and freeing them up.

I hesitated about changing over to the rubber on my 71, but the more I read the better I feel I am going the correct route. I was glad to hear from forum members like Zwede who have moded their engine and going to the rubber and getting good results with no impact to handling and smoother less gut wrenching/road pounding ride.

Does anyone make rubber or poly mounts that are shorter and don't raise the body?

I replaced the solid mounts with GM rubber about 15 years ago and have had no problems. Body sits about 1/2" higher. Inserted the same shims as OE.
Huge improvement in ride quality - especially when coupled with composite springs.