Rear Body Mounts..CHEAP MOD!!!!

i removed the rear body mounts,the ones closet to the front of the car, and replaced them with hockey pucks. it took three,the stock body mount is 81 mm long 3 pucks = 80mm ,plus 1 fat washer to make up the difference and voila! it makes a big diference in cornering and the back end feels alot more controled and sure footed. gone is the side to side mushy feeling. and the car sits a whole lot better. please try this mod and you will see the diference. its dead easy to do ,and pucks are way cheap! i plan on doing the other two mounts,the ones closer to the back of the car.......and that should take care of a lot of vague handling issues.......it might be a good idea to make room for a steel sleeve to go into the pucks but i got a little ahead of myself in that i wanted her on the road, but so far she handled the mod quite well!

When you do the rear ones could you take a few pic's for us.
Thanks

yeah. this mod might need some fine tuning. a puck,s dia is 75mm the dia of the stock mount is 95mm thats a difference of 20mm. it might be a good idea to fill the gap. i have not put many miles on the mod to see if this affects the handling ,but i will.

Should be able to make some from a high durometer polyurethane like what Eric Wolfe did for his motor mounts.
If your not familiar with what he did look under the "Write Ups" section for engine mounts. I believe thats where the write up is.
You could then make it all one piece of the proper thickness and diameter.
From what he said about the process, it should be very easy to make the body mounts after making a mold. The mold could be a piece of PVC pipe of the correct diameter cut down to the correct thickness. Could cut multiple molds and do them all at once.
And you could take a poll and see if anyone else is interested, make some additional mounts, sell them and recoup your expenses.

i think ill stick with the pucks for the mounts. for the engine mounts ill do the poly. as for the rear control arm bushings im going for delrin nylon. almost indestructable. for the rear only. for the front, ill do poly for the rearward bushing,and on the 95 there is a freaky horizontal bushing that im looking to replace with a high misalignment bearing, not an easy mod this one,but doable.

Would you be willing to mail me one of old mounts to use as a template?
Then I can make a mold and try the polyurethane on them before I try it on the engine mounts.

i dont see why not? but why dont you just use yours? or, just get the dia? dont know if the 95 and the 98 have the same ones. maybe they do? poly sets up in a few hours and you can have your cake and eat it too! all you need is the dia,and the length, a piece of alu that you bend into a circle of the dia,pour the mix let dry cut to height, drill hole and there ya go!

again, they are sooo easy to remove...a 14mm socket. and a 21mm socket. boom!

Your right, I'll just pull one of mine out and start / finish in one day.
Sorry, i was experiencing a brain fart.

Haven't seen the stock mounts, are they a softer material than the hockey pucks? Maybe replacing them with OEM would also have a positive effect if the originals are worn badly.

my mounts were in good condition considering theire 14 yrs old. no signs of wear or tear. and they are super soft, i would expect nothing more from a luxury coupe. much softer than i imagined. you can literally wedge a prybar into the space between the rear cradle and chassis ,and move the cradle a good inch or more. that is what made the rear end seem so disjointed. alot of rubber there to make the ride nice and soft for the driver and passenger. i figure for not alot of money i can make my riv as firm a car as any sports car to take full advantage of my new springs and shocks. the mounts are a major obstacle to good handling. not a whole lot i can do about the weight or the wheele base but if i can get her to a point that i can predict what she will do in a fast corner and no surprises ,im happy. i cant say that ill shed tears for the stock mounts,they will make a super ashtray

On the other hand, my pothole filled streets might be better suited for the soft OEM versions.

update on this mod. apparently,after careful scrutiny,something i missed, the mount actually rides somewhat within the cradle ,up and down. im amazed!? this design defies reason. while a floating suspension cradle adds comfort it kills any real performance suspen upgrade. im not sure how im going to work through this but ill find a way. possibly welding the rear cradle to the chassis. will require more study though.......

You think maybe your mounts are just worn?

need to compare with new ones?

Albertj

dont think so A.J. the mounts are pristine. it appears that the rear cradle is on a kind of pivot system. the rear adjustable links are connected the cradle via rear body mounts that attach to the chassis. this link is solid. but the rear forward mounts are in this kind of,i dont know,elevator type hole. hard to explain. jack up the rear of the car, put a stand under the car directly underneath the cradle and slowly lower the car, you will see the cradle move up. darndest thing. its driving me nuts.....

What are you saying is the 'cradle'? Can you take a picture? The part I think you are describing... I'm pretty sure it doesn't move on my car.

the cradle as i call it, in the service manual is called, "rear suspension support assembly" the "forward body mounts" are what im attempting to modify. the ,f.b.m.s are installed in the r.s.s.a as are the "rear body mounts" efectively allowing the r.s.s.a to float! astounding? while this allowes a level of comfort any true handling modification is rendered usless until this problem is addresed. what it does is prevent the suspension from acting "immediately". it acts on its own, then, the suspension does the rest. this can lead to squirrly handling. i have a few ideas to solidly attach the r.s.s.a to the chasis but this invloves welding threaded nuts to the chasis and through bolts to tighten it down. the r.s.s.a has to be removable to allow dropping the tank if need be. i believe this mod has potential to improve the handling of this rather heavy car but until i perfect this mod the stockers are going back on. pity, for now......

p.s deek. if you jack up the car at the rear side jack point,place another stand under the r.s.s.a and slowly allow the car to rest on the r.s.s.a. watch closley and you will see the movement that im talking about and is preventing me from enjoying my sex life,my beer,and generaly throwing me into a hissy......

It's a good thing that you observed this. The next time i have my car on the lift I'm definitely going to be checking this out.
I can visualize what your talking about and find it amazing that it works this way also. We can put all the heavy duty sway bars and add an STB, etc.to the rear but it doesn't do much good if the cradle can float within a certain range regardless of the condition of the bushings.
I agree that this this needs to be stabilized somehow.

you nailed it rick!

If you can share your fix or ideas here after you've had time to test your theory's it would be greatly appreciated.
It's somewhat funny that this thread started out with the title of "Cheap Mod", may not end up being such a cheap mod after all. But a GOOD mod.

Rickw wrote:

We can put all the heavy duty sway bars and add an STB, etc.to the rear but it doesn't do much good

The rear STB and ranchos work great!

There is no reason to do any more at all to the rear suspension until we can figure out how to further beef up the front suspension.

Jack the R wrote:

Rickw wrote:

We can put all the heavy duty sway bars and add an STB, etc.to the rear but it doesn't do much good

The rear STB and ranchos work great!

There is no reason to do any more at all to the rear suspension until we can figure out how to further beef up the front suspension.

You forget to include the rest of my statement ...."if the cradle can float within a certain range regardless of the condition of the bushings."
If this is true then it must be corrected to feel the full benefits of any rear suspension mod's.
Remember I haven't seen it yet but I will be looking at the cradle / subframe or whatever you want to call it and making some conclusions soon.

The rear STB and ranchos work great!

Jack the R wrote:

There is no reason to do any more at all to the rear suspension until we can figure out how to further beef up the front suspension.

i think i gotta disagree with ya there pal. its my understanding that stiffening up the rear of a front wheel drive car is what makes the rear work in unison with the front. any lost movement back there throws the handling way off. too stiff a front sway bar and you invite understeer. too stiff a rear sway bar and you have oversteer. the secret here is to find a rear sway bar that acts just enough so that you can feel the rear end "walking out" and be able to control that,thats called "riding on the edge" its the best way to control a car at the limits of its traction. i do understand where you are coming from though j.r. imo, isolating the rear r.s.s.a is the first step in finding a definitive solution to extraneous movement from the rear. it might be interesting to find out how efective or inefective the aftermarket sway bar is after modififying the r.s.s.a. ? because if the claims of swaybar manufactures are correct , they surely did not engineer theire s.b with this mod in mind? but s.b manufactures usually engineer on the side of caution. but from where i stand, im glad i found this out,at least i think i did, because after modifying the r.s.s.a, ill have a better sense of the direction i want to take the rivi in..........

Rickw - I didn't forget the rest of your statement, I don't see how it's relevent. My r.s.s.a. is stock, but the changes I made to the rear suspension made a huge improvement. If they hadn't made an improvement, you'd be right, but they did.

robotennis61 - According to your sig "mods are in the works." Why not try the STB's and ranchos and see if you don't agree the front is what's holding the car back?