Write-Up: Subframe/Cradle Mount Insulators & Bushings

I went to one of the yards today for some other stuff for my friend's t-bird mainly and found a '99 aurora that pretty much had all the front bumper and fender liners off so I stopped and took a close look around the cradle mounts for access ways to the nuts. I don't really see anything other than what I already knew about. Here's some cell phone pics.


passenger side rear two mounts
If you look right where the bent-to-shit inner tie rod is, you can see the access hole in the frame for the one cradle mount nut. That is on the driver and passenger sides.

Here's a few shots of the front cradle mount and surroundings






Let's just hope those other 4 top nuts hold themselves together...


bonus pic from the yard...

I've tried getting them off, a number of times,they always brake.Maybe a hand held torch,heat them up then they will break free?

the best thing to do with those bell shaped washers is to weld them to the cradle and hard mount the cradle to the frame. i just thought of that,and like an ass i threw them out along time ago before i had a welder. i bet you wouldn't experience a whole lot of difference anyway,the motor mounts are way soft and soak up alot of the jarring

robotennis61 wrote:

the best thing to do with those bell shaped washers is to weld them to the cradle and hard mount the cradle to the frame. i just thought of that,and like an ass i threw them out along time ago before i had a welder. i bet you wouldn't experience a whole lot of difference anyway,the motor mounts are way soft and soak up a lot of the jarring

So what are you trying to say. Is it best to replace what i have with good OEM parts or do i need to have something made for a stock Riviera that isn't driven hard.
Or do I need to have something custom made that is driven hard.? i'm trying to figure all this out as well.
please provide some feedback on this subject, not smoke and mirror's.
Rick

well...if you want to replace all the cradle bushings(isolators) then its a good idea. but if your looking to get a little more handling performance out of the riv,then it would be best to take the bell shaped cupped washers in turtles photo and weld them to the cradle,cut down the bolts and hard mount the cradle to the frame. and just do away with the rubber isolators in between.
when the car corners hard,and along with the very soft control arm bushings,the entire cradle is allowd,by the isolators,to move around. to prove this,all you need to do is take a square piece of wood and at each corner place a small cylinder of rubber,doesnt matter what size,but big enough to visually analyze the movement the square of wood is subjected to. attach the rubber cylinders to the block and then attach the model to a table or something. now take the block in your hand and move it around. it moves for and aft and side to side.the control arms attached to the cradle are along for the ride too! this is movement that causes vague and downright scary handling at higher speeds. it was engineered into the system to isolate the driver from road shock. if you like to DRIVE then this is isolation that you can do without.
IMO.if one is satisfied with the stock riv ride and doesnt push the car to do things that it would need upgrading to do,then the riv is just fine. ive considered that hard mounting the front cradle to the chassis would transmit alot of vibration to the car and that the motor mounts can fail prematurlly. oh well. a mount here a mount there,as long as you have the ability to fabricate your own mounts then premature weare of the mounts should not be a worry. the surrounding components,rack,engine,suspension,should not get anymore stressed than they allready are. the next step in the plan is to replace the stock rubber bushings with poly or nylon. back and front. believe me. the riv will open your eyes to another world of handling and corner grip. dont forget to get a stiffer than front swaybar. (im working on it). hope that clears it up for anybody interested.

Thanks for your input Robo, I have already replaced the front and rear sway bars with something much more substantial.
Now due to the missing(due to corrosion) front mount washers, i am very interested in doing more of a permanent mount for the front cradle.

I'll deal with the rear cradle later.

Thanks for your input.,
Rick

thanks. and another newtons advantage to the oh so soft cradle mount isolators is, when taking a corner hard,the engine is allowed to move ahead of the car oh so slightly causing a stunted slingshot effect.very unsettling and the suspension agrees too.

here is a pic of hard body mounts that might work with the riv. good luck trying to get diameters and measurements from global west or jegs!





anybody who has removed the stock cradle mounts/isolators, recognizes the similarity.

robotennis61 wrote:

here is a pic of hard body mounts that might work with the riv. good luck trying to get diameters and measurements from global west or jegs!





anybody who has removed the stock cradle mounts/isolators, recognizes the similarity.

What does Jegs sell these for.? You know better than buying something that is not made for our cars, otherwise you would have already bought the set and be doing a drive cycle with them.

I don't have the details but Ewolfe mentioned something very doable that was along the lines of either switching to GP hardware or GP insulators for increased firmness. I know I'm keeping that stuff stock myself but it sounds like a pretty reachable option if you're going to buy the parts anyway. Maybe he'll chime in with the details.

$ 96 bucks. competition engineering sells a set for $52 bucks. i might just take the plunge and get a set to f..k around with.pretty cheap for a alu set. the problem is that the manufacturer wont give out the sets measurements. they wont budge on this. these sets are car specific and if you don't have the car they are made for they wont give you the measurements.

turtleman wrote:

I don't have the details but Ewolfe mentioned something very doable that was along the lines of either switching to GP hardware or GP insulators for increased firmness. I know I'm keeping that stuff stock myself but it sounds like a pretty reachable option if you're going to buy the parts anyway. Maybe he'll chime in with the details.

that be nice. the isolators are useless.

turtleman wrote:

I don't have the details but Ewolfe mentioned something very doable that was along the lines of either switching to GP hardware or GP insulators for increased firmness. I know I'm keeping that stuff stock myself but it sounds like a pretty reachable option if you're going to buy the parts anyway. Maybe he'll chime in with the details.

What exactly do you plan on keeping stock, when you ordered a bonny subframe and bushings.
Are you assuming the the parts you receive will be the same as stock.?
Just curious.?

Rickw wrote:

turtleman wrote:

I don't have the details but Ewolfe mentioned something very doable that was along the lines of either switching to GP hardware or GP insulators for increased firmness. I know I'm keeping that stuff stock myself but it sounds like a pretty reachable option if you're going to buy the parts anyway. Maybe he'll chime in with the details.

What exactly do you plan on keeping stock, when you ordered a bonny subframe and bushings.
Are you assuming the the parts you receive will be the same as stock.?
Just curious.?

All the cradle hardware I got is exact stock stuff for the riv.
My hope is that when I'm done with this, It'll be pretty much exactly like a 98-99 riv is. I'm counting on the bonne cradle being essentially the same as mine with the known provisable exceptions.

EDIT: Since the rear trans mount brackets all seem to bolt up to all these newer cradles the same way, I'll probably reuse my original rear trans mount bracket and buy a new insert and reinforce it with the window weld. The front trans mount is going to have to be like the Bonneville. The frame doesn't have a through hole for the riv mount. This is fine because I can just use the bonne bracket and hockey puck mount I already have and it'll be a solid mount.

Yes the bonnie part's will work i used them,they rotted out to ,so i took up the rugs drilled through the floor hockey pucks ,plates ,welded down .they never moved again.corning was dive free pretty much.When they go in my 93 thats what i'm doin again!!!

flyineagle96 wrote:

Yes the bonnie part's will work i used them,they rotted out to ,so i took up the rugs drilled through the floor hockey pucks ,plates ,welded down .they never moved again.corning was dive free pretty much.When they go in my 93 thats what i'm doin again!!!

i like the way you think buddy

Rickw wrote:

Turtle,
When you do this job will you take some measurements for me. I'm specifically interested in the dimensions of the hole spacing for the Steering Rack. I need to know the distance the bolt holes are apart from each other so I can try and determine if a Non-Magna-steer Rack will bolt to the Riv. Does the rack bolt to the cradle.? If so, you will be finding out if your using a Bonneville cradle and the Riv steering rack.
I've been wanting to change this over for the past couple of years but can't seem to get any of the Rack re-builders that I have contacted to tell me the mounting dimensions for either the Riv and a Bonny.
The Bonny came with or without Magna-steer as an option so it would be a good candidate to use for a swap.
I know someone local that has a SSEI that came with Magna-steer and he was able to install a non-Magna-steer as they list P/N's for both to fit that car. He finished the job and returned or got rid of the old rack before I had a chance to do any measuring. I can't go to the junk yards and crawl under cars to take measurements because of my back problems. As it is I will have to pay someone to swap the rack for me, if I can find one that fits.
The dude with the Bonny was irritated by the same highway vibrations that I and others, experience with the Riv's and he was able to eliminate it by eliminating the sensitivity by changing to non-magna-steer. All I have to do is find out if a certain year bonny or whatever will fit the Riv and I'll replace the pump as well and get rid of the over sensitive magna-steer.
Regardless of the vibration issue, I do not like the magna-steer and it's limited effect on the highway. I want a firmer steering input and feedback.
Thanks for any info you can provide.
Also, what was that front sway bar out of that I bought from you. I forget. Having that installed tomorrow hopefully along with some other work I cannot do.

If the cradle you get from the 00 Bonny has a steering Rack on it and it is non-electronic and you are not going to use it, let me know. I'll try it if it has any life left in it.

Rick

I have the cradle now. I took everything off and Pete and I are stripping it down of paint to eliminate all rust and refinish it.
I measured the two mounting ears for the steering rack to be 16 3/4" center-center.
There's no good pictures to reference so I'm gonna have to take another look under the riv to see what those two bolts on top of the rear trans mount are all about. The 2000 bonne mount and the trans mount on a 1999 riv (which are the same) don't seem to have that.

how did you support the motor? or does it just hang there? i havnt really looked into removing it, but if i want to hard mount it to the chassis its gonna have to come off

turtleman wrote:

EDIT: Since the rear trans mount brackets all seem to bolt up to all these newer cradles the same way, I'll probably reuse my original rear trans mount bracket and buy a new insert and reinforce it with the window weld. The front trans mount is going to have to be like the Bonneville. The frame doesn't have a through hole for the riv mount. This is fine because I can just use the bonne bracket and hockey puck mount I already have and it'll be a solid mount.

I thought you said you ordered a NEW rear mount from one of the GM suppliers.?
I read that somewhere along the way and have asked you where you ordered it from, but didn't receive a response, assuming you didn't see my question.
I have been waiting to use an Advance Auto Part rubber mount that I bought for $50.00.
Should I just attempt to use this one I have or do you potentially have something better on it's way.????
I just need to remove the rubber from a spare steel assembly I have and install the new rubber part and use window weld to fill in the gaps.
DID you get a GM rear mount.? Yes or No.?? Inquiring minds need to know.!!!!!

What happened to the mount you said you ordered from the unknown GM supplier.???
Just curious, because if what you received was better, I was going to go that route.

Congrat's on receiving the new/used cradle. Found 2 of my cradle mount retainers missing due to rust last week and ordered new from the dealer.

Also, can you tell me if the Riv Steering Rack will bolt to the 00 Bonneville cradle.???

Will I be able to buy a Bonneville Steering Rack (Non Magna-Steer) and mount it to the car as is, or does it require modification.?????????? Will the bolt hole line up and if you know, do the hose connections line up.?

Thanks for any and all info you can provide. I need to get this done before the real cold weather sets in. Thanks again.

Rick

Cody,
What's going on.? How about an update.?

Inquiring minds need to know.

Hope all is going well with the cradle install, etc.

flyineagle96 wrote:

I've tried getting them off, a number of times,they always brake.Maybe a hand held torch,heat them up then they will break free?

They are a little tough. The main problem is that most of the shock you can apply to them with a hammer to break them loost gets absorbed by the rubber. Torch helps a little bit but what worked the best for me, that I found out by the last two, is WD40. Soak em with it and and they'll break free from the frame a lot easier.

Rickw wrote:

Cody,
What's going on.? How about an update.?

Inquiring minds need to know.

Hope all is going well with the cradle install, etc.

I'll try to update this post with pics later but for now, this is what I've found.

The bolt spacing at the back of the frame for the rear trans mount assembly is different between the two cradles, which I didn't know about. Also, my '97 cradle actually has 2 bolts vertically and 2 more bolts horizontally for the rear mount bracket going into the cradle. The bonne cradle (and '99 riv cradle) don't have the horizontal bolts, but they do have a 3rd verticle one. Any any case, that means they cannot be swapped with eachother. This also means the steering rack is much different. The drivers side of the 95-98 riv steering rack mounts with two bolts right into the top of the rear trans mount bracket. The 00 bonne cradle and 99 riv both have mounts for the steering rack that are independent of the rear trans mount. Of course this means, the racks cannot be swapped unless you have a cradle and steering rack that match and have the corresponding rear trans mount. Although, the style of the 99 riv rack and 00 bonne rack is exactly the same, who's to say something else isn't different mounting-wise. They are different part numbers so I wouldn't count on them be interchangable after what I've been seeing. As for your endevour for getting a non-magnasteer rack into your <1999 riv, anything newer is not an option. I haven't looked much at steering racks on pre '99 full size cars but if you were to find something, it would have to be older and also have pretty much the same rear trans mount is the riv.

What this all means to me is that I'm probably not going to use this cradle at all. I could get a steering rack that mounts to it and use the 99+ rear trans mount and hope there are no further discrepencies but I'm thinking more about just calling it a loss and getting a more expensive '98 riv cradle and retaining everything I want while still getting the better control arms. The bracket for the rear trans mount on my car also has 4 bolts that go into the trans. The newer style only has 3. (I'll post pictures of this later on) Overall, this turned into kind-of a toss up and I like the 98 riv cradle option much better. A steering rack would be much cheaper than buying a 2nd cradle but it still leaves room for unforseeable problems and I don't really have any more time for that.

I've given more though into just reusing my original cradle and replacing the mounts and sway bar and just calling it a day but that leaves way for future problems. (original control arms & ball joints hitting 200k mi and no parts to replace them with and then there's the scar from the failed front hockey puck mount) I would rather spend more now and get it done once and for all.

Will update...

Cody, I don't know how all this plays into what you just said, other than the fact that you have been referring to the 99 Riv and the later Bonneville cradle.
How does this translate into the fact that I have a 98 Riv and am looking for a rack that will fit it.
Sorry for beating a dead horse, but you left the door open for a possible fitment for the 98 Riv and another steering rack fitting it.
Is this true or should I completely give up on this proposition.?

Thanks for all your hard work and sorry that the cradle you received isn't going to work on your car. Will it fit anything else that you are aware of or does it need to be returned.?
Was it shipped to you with the understanding that it would fit or was it under the understanding that they weren't sure it would fit your year. They are the ones that are supposed to have all the fitment sheets for all these parts.?

Thanks,
Rick

Rickw wrote:

Cody, I don't know how all this plays into what you just said, other than the fact that you have been referring to the 99 Riv and the later Bonneville cradle.
How does this translate into the fact that I have a 98 Riv and am looking for a rack that will fit it.
Sorry for beating a dead horse, but you left the door open for a possible fitment for the 98 Riv and another steering rack fitting it.
Is this true or should I completely give up on this proposition.?

Thanks for all your hard work and sorry that the cradle you received isn't going to work on your car. Will it fit anything else that you are aware of or does it need to be returned.?
Was it shipped to you with the understanding that it would fit or was it under the understanding that they weren't sure it would fit your year. They are the ones that are supposed to have all the fitment sheets for all these parts.?

Thanks,
Rick

You have a '98 so everything that applies to me applies the same to you. Your setup is exactly like mine.
All I can really tell you is that everything that I have looked at in the way of alternate steering racks will not work on a riv with it's stock cradle in place and changing the cradle still has potential for more bumps that I don't know about, that I don't care to find. I can't return it. The risk was on me. I can't say whether to give up yet. I was just informing you that if you are to find another rack to fit your riv, look for earlier years, not later, because I've pretty much confirmed that nothing newer than a 98 anything will work without a still risky cradle swap. I'm just sharing what I've learned and it certainly does apply to you.

Thanks for all your research. Even though you had to put in all the labor and expense, it benefits all of us.

Sorry for your disappointment and expense.

Rick