PontiacBonnevilleClub.com

This is a mod that I have been Planning for years.

The Stock Bonneville mount setup consists of 2 mounts on each side of the car and one lower front trans mount and a rear trans mount. There is only one mount that is a vertical support that physically attaches to the engine. The Trans case takes all of the restraint and all of the pressure.

The stock lower front trans mount is Jell-o and really lets the motor move around. All Bonneville, Lesaber, Aurora, Deville and Seville use this location for the front lower mount.

The Front mount is really terrible and tends to rip apart. I got mine changed before any thing bad happened to it.



The upgrade is the hockey puck mod






the Trans mount also needed attention also. When I installed the built trans I got a new mount and used Poly to fill it, and that also greatly improved the feel

The stock mount would totally compress the open areas. I could watch the compression when any power was applied.

New Poly Fill on the left stock on the right


The Combo made the car more drivable, and not as soft feeling.


Onto this mod. I had a few students that needed some live hours and said they would be up for this project....so it began.

Stock Parts


Planning the new stuff




Disassembly




Had to remove some metal from the car


This is what was cut out


And it belongs here


Ok so on to the design phase


We decided to use 1 and1/2 inch round stock for this support bar for the mount

Let the welding begin.




Everything is measured, squared up and welded


and now to test on the car






Now fitted, time to sleeve the bolt holes





Final Size of the Sleeves


Sleeves being milled out


Installed


To Retain the factory appearance the Stock support is retained

Scribe line to cut the bottom out of the support






and totally cut


Now for the Mount

Took a stock W body mount and had to....modify it.

Cut in half








Took 2 Dog bones and fabbed up one.


First we Mig'd the Mount together with Tacks and then it was fully Tig'ed




Tig work


Once we mades flanges one more cut to the factory support




and the Final Result... (its not painted in the pics this was still in the shop. I metal finished the welds on the and painted the mount)







With the extra support upfront, the car is 'tied" together more, it does seem to handle better in the corners, and there is still a little Engine movement. Its impossible and not feasable to remove ALL movement. This extra mount adds enough bracing with out any real damaging effects. I have been driving on this setup for 2-3 months now and its like a different car (getting power to the ground) than it was with the stock mounts.

Best thing is that it looks totally stock and factory.....I even had people ask when the Bonneville started to use the dog bones :Thumbs

Nice work, i have thought about that sence I got my bonnie, dont have the time to make a new rad support to handle the stress.. should help keep the engine in place... have allways wondered why they didnt do that from the factory.
IIRC zzp and others sell polly inserts for the stock dog bones. there are other options for dog bone mounts that you can use without cutting and welding, the 3100's had a Dogbone mount that looked like a Dog bone, as did a few other FWD cars if you want a different look. I had a Billet one from a local guy to me that made them for LQ1's and 3X00's:
you can see in this pic.

That Billet piece does look really nice. The Problem that I have is the spaceing between the Rad Support and the engine mount. Nothing "off the shelf" would fit so i had to make a custom.

I did see one off a Older Gen Seville, that was close to the same size and was Aluminum

I think it's West Coast Fiero that will make a dogbone in about any length you want for a pretty decent price.

im sure you can find a stock one the right length, it will be trial and error and measuring at the parts store/salvage yard. the 3X00 ones are pretty long and by the looks ofit its not much different then my LQ1 one. But, a good coat of paint and some polly bushing will perdy up the one you made nicely. Again i like the work

I wonder if these would be the correct length to help dress things up a little.
http://www.ebay.com/itm/MRZ-Billet-Dogb ... 73&vxp=mtr

ya it would be expensive for a experiment. This spring im gonna investigate of the Cadillac upper mounts will work..

Looks great.
Thanks for posting.