Rusted Rear Cross Member

I've posted in the past concerning a toe in condition in my rear suspension regardless of ride height. While chasing the origins of this problem I found that the rear crossmember has a sustantial crack on the passenger side were the exhaust tunnel is. In addition I noted that jacking the rear crossmember near the center remedies my toe in condition when the rear crossmember is closes to the underside of the body. Are the electronics of the air suspension responsible for moving rear crossmember up and down? Has anyone replaced a rear crossmember? Is replacing it likely to remedy the toe in condition? How many mounting bolts are there total, looks like (4). I have yet to replace my air ride compressor but did install a set of Monroe air shocks. Others have noted no problems without the air compressor operable. Thanks in advance for all your help. I'm just wanting to get this rear alignment issue rectified first and foremost before I spend money on anything else.

Hey Galen, nice to see another Buffalonian on here. First off, you need to replace that broken crossmember. My car is up on my lift as we speak so I will see how hard it is to change. Unfortunately where we live makes all underbody repairs more difficult do to rusted bolts etc..

As far as the toe on the rear wheels, it is adjustable, but if it is severely out of alignment I would guess it is do to the cracked crossmember or something bent. The air suspension does not move the crossmember. The crossmember should not move at all. The compressor fills the airshocks to raise the rear and a valve releases the air to lower it. A ride height sensor on the rear control arm gives the command to do this.

I will see what is involved in changing the rear crossmember when I get to work.

Its not difficult to replace a cross member.it just takes time. the elc is responsible for the hinged crossmember. and the toe in stays the same regardless of the C.M position.

the reason the rear cross member "moves up and down" is to allow the Riv to have a stock ride height regardless of the weight in the trunk. you know,so the ass isnt jacked all the way up when loaded.

Thanks Dave and Robotennis for all the help and suggestions. It seems that I read somewhere, the crossmember is an hour and a half job. Looks like (4) fasteners to the body, (2) bolts holding trailing arms and the (2) mountings for the links, and of course dropping the exhaust.
Dave you're correct, difficult working underbody in our climate. I wanted to drive my Riv so bad when I got it I repaired brake lines in 20 degree weather. I won't repair hub bearing or P0102 code MAF issue until I get suspension issue sorted, love this car though. I thought about just buying another and parting this one out but with my what this one cost me it's worth playing with even if I spend another 2k.
One thing though, my crossmember definitely moves up and down when I jack it up, I have it supported with bricks now in the center. I don't understand why it won't remain it upward position when the car is moved? I guess my chief concern is if replacing it will fix the problem.

its supposed to move up and down.

Well I don't know what Robo is saying about the crossmember moving but I can asure you it is not suppose to. The crossmember is bolted solid to the unibody of the car.

Galen, if you would like to see my car up in the air, call me at 984-4796. My car will be on the lift for a few more days atleast. My shop is in Depew, on Walden Ave. Maybe if you see mine, you will be able to get an idea of what should be moving or not moving. Feel free to call me if you like.

Oh my... you best get in touch with "black shadow" or "Z-type" they are other members who were recently parting out 95's, they may still have them there. Looks like you may need a few things to get going. You are gonna love this site when it comes to fixing her up.

That first pic would make me a little nervous, looks like in needs some structural repairs?!

Needs a rear crossmember, i've tracked a few down used and am awaiting some info. If not I will bite the bulliet and get one new from GM, at the price of $800.

That is not good. Your going to have some serious, welding too do. Hope it all works out for you!!!

Welding? Just replace it!

Thanks Dave, I'd love the opportunity to see your car on the lift but I'll be in Washington DC for the remainder of this month. I'm looking to source a nice rust free used part, but a new one is only $200 or so. I also don't know how difficult the R&R will be w/o a lift? Perhaps you can give me a quote on the job if you're interested Dave? I'll give you a call when I get back to Buffalo.

@ bigdave.
If you jack the car up,and then place jack stand under the crossmember and then drop the car,watch how the crossmember moves up toward the body. its a design feature. check it out.

Robo, I've looked again and dont see how the crossmember could move. It is bolted to the body as solid as the front cradle. The parts that move are the control arms and tie rods. As weight is added to the rear of the car, the springs compress and the body lowers. A sensor mounted between the left control arm and a bracket on the crossmember sense this and send a signal to turn on the compressor until normal ride height is restored. This is accomplished by filling the shocks with air. As weight is removed and the rear of the car raises, this sensor sends a signal to bleed air out of the system to restore normal ride height. The camber and toe are only correct at the normal ride height ( assuming the rear is properly aligned).

Here are the part numbers and list prices for rear crossmember(rear suspension support) as listed in my estimating software. Call dealer to confirm.

Rear crossmember 95-96 part # 25639940 list price $676.34
97-99 part # 88890012 list price $356.56

Well got the cross member today, dads going to re-enforce it for me tomorrow so the same thing doesn't happen, pull as much rust as we can off and it's getting a treatment of bed liner.

remember to use a rust converter or POR-15 before the bedliner...

"chip guard" by the way works as well as bedliner for this type application, if it costs less to you...

Albertj

Good luck with the R&R of the crossmember on your new ride! I'm currently doing a similar repair of my own on the front (engine cradle) rusted and then subsequently broke after I hit a big pothole. I'm adding reinforcements and gonna also prime and put a finish on it prior to the swap. You seem to have gotten a fair deal on the car and it should clean up nicely and add to the Riviera faithful here at Rivperformance! I hope both of our repairs go smoothly and get these luxobarges that perform(with a little help) back prowling the streets.

Thanks guys, and yeah hopefully getting the new one in today. Been doing a lot of work, just grabbed some pics.

Carpet out getting a nice cleaning (this was nasty before this).



Interior all ripped apart



Floor patch peice (had a nice sized rust hole in floor)



New crossmember cleaned up and in paint



Drivers rear wheelwell needs the next patch



That's as far as I have gotten, going to pick away at it this week, all fluids and filters change, etc. Going to work on picking up a hydrolic flaring too and I need to redo all my brake lines, etc as well as the fuel line atfter the fuel filter.

Great post Brandon, looks like you've done a lot of work and it looks like theres more on the way, great job, +.

BMD wrote:

Great post Brandon, looks like you've done a lot of work and it looks like theres more on the way, great job, +.

Yeah I hope. Ordered the Passenger Headlight and Window Switch from Z-type, hopefully those come this week.