rear supension

[wheelman]

Well,,,,I'm new here...so I'm sure this has been asked....but here goes... ..what has been done to redo or replace the rear shocks on r m wagons that has a bum auto leveling system... I've been told that you can't get new and used ones might not be so hot either.... my thoughts are just plain old air them up manually airshocks.....what you guys think?

 

[buickwagon]

I did plain airshocks on my 92, and they were fine as far as it goes. However, airshocks have their own issues especially in freezing conditions with ordinary air. With my 95, I opted for Sensa-trak load adjusting shocks (auxilliary springs around the shock) instead. The ride height and load capacity is nice, but I'm not pleased with the shocks themselves -- a bit too soft for my taste.

A lot of guys like the air bags (eg: air lift 1000s) with Biltstien or Munroe Severe Service shocks. However I recently saw a thread where the air lifts failed on a long tow trip.

 

[Al H.]

Be fine to just eliminate the compressor and use manual air shocks. I don't know who said you can't get the shocks for the leveling system, they're just regular air shocks. AC Delco has a set that are specified for them, I think they have an angled air fitting instead of going straight out.
You can check them out at Rockauto.

 

[The Roadagon]

air shocks put alot of stress on the upper shock brackets,so they are less than the best way to go. the coil over shocks would be a slightly better approach. I have been using the air lift air bags for about 2 years now without any problems. If you take you time and plumb the air lines correctly,keep them away from the exhaust pipes and shield the bags from
excessive heat you should have a good set up. good luck ed

 

[RMSWFAN]

If the auto-leveling system and compressor on your car still work, you can buy air shocks from AC Delco, Monroe, Gabriel (I read somewhere that Gabriel makes the shocks for AC Delco), etc., and just put a “T” to split the line from the compressor. SAVE the air line that goes between the left side (driver’s side) shock and the right side shock (if still original one from factory). This air line is 0.125” OD and about 0.030” ID, and you should use it from one side of the “T” to the right side shock. Reason I say save it is because I spent hours and hours searching the internet for this particular part/air line dimensions and could not find it.

I bought my wagon new in 1994. The 1st time the shock needed replacement they were replaced with the original type and they gave me a lifetime warranty. The 2nd time they needed replacement the left side shock was no longer available and since the auto-level and compressor were also malfunctioning, I opted for the air shocks with the “T” fill valve mounted under the rear bumper.

With this installation the car leaned much more in the turns; both air lines from the “T” were 0.125” OD and about 0.070” ID. While I was checking under the car I noticed that they left a piece of the air line that went from the left shock to the right one; this is where I also noticed that the ID of the air line was about the size of a sewing needle (0.030” ID).

Since I couldn’t find this type of air line, I found that some of these “straws” that they have on the spray cans of WD-40, throttle body spray cleaners, etc., have about a 0.030” ID and are about 0.070” OD. I had to sand the OD a little to fit into the air line that goes to the right shock (mounted the straw in a drill and used sandpaper), and the length of the straw I inserted was about ½ inch. This helped out a lot with the body lean in the turns. The theory is that the air doesn’t rush as fast from one shock to the other during turns. The other option is to install a rear stabilizer bar, or separate fill lines for each shock.

As for the stress on the shock mounts with air shocks, if the car came so equipped from factory, then certainly GM accounted for it in the design.

Hope others and mine experiences help you in your decision as to which shock/system to use.

 

[95 Roadmaster]

I put the 'coil over' shocks on the front of my RMW, as the stock springs seemed to be sagging a little. I thought the ride would be too stiff, but it's actually great! The rears have been replaced before I bought it, with a very stiff shock, but the car handles great! If those go, I think I'll do the 'coil overs'. I put a set on my wife's Grand Marquis, and the car rides, and handles much better! I just put stock type shocks on the front of that car. I also put the 'coil overs' on the rear of my '77 LTD, and once again, they didn't disappoint!

John

 

[paart]

As for the stress on the shock mounts with air shocks, if the car came so equipped from factory, then certainly GM accounted for it in the design.

I wish I had that same confidence in GM's engineering, (or financial department, which ever is applicable.) I've changed rear shocks on a few GM B-body vehicles, and I didn't notice any additional "beef" on either the upper or lower shock mounts on my RMW. That doesn't mean that it's not there, but more than one poster on this forum has noted that the rear air shocks are hard on the mounts.

I however, did break a shock mount, while using air shocks on a vehicle of another manufacturer. Snapped it right off! That's when I changed to air bags. Air bags are generally pretty durable. Failure to keep minimum recommend pressure in them can lead to damage due to pinching of the bag by coil springs.

 

[stealth126]

Do all Roadmasters have the auto leveling system? Mine is sagging in the front which I gather is pretty common, but I'm trying to figure out what I need to do with the rear suspension because it appears to be sitting too high.

 

[PatDTN]

I worked over the entire suspension on my '96 RMW with 160k miles last fall. I replaced all the bushings, tie rod ends, center link, and even bought boxed rear lower control arms. Dunno about those control arms. I put fresh springs in; I went for Moog springs that were uprated from stock but stock height. The rears I put in are progressive for slightly better give on rough roads. I paired those with Bilstein heavy duty shocks and the Airlift 1000s in the back hooked to the stock load leveling setup.

The car is smooth on the road with just a bit of extra firmness. I wonder how it compares to a brand new RMW coming off the showroom floor. It handles better with less sway because it takes more to squash the springs at any corner of the car. Little bumps are barely noticeable and big bumps are damped out in one oscillation. It's a sweet feeling.

I like that I didn't add load to those rear upper shock mounts like an air shock or coilover does. I did take time routing the air lines to the airbags so they don't get pinched or melted. I also used the heat shields provided with the air bags around my exhaust to keep that heat away from the bags.

The only things I'd change if I did it again are I would buy the front a-arms with bushings in place instead of replacing the bushings myself. That was a lot of extra work. I also would not do those rear lower control arms. The loss of flex stresses the bushings more and those bushings are not rubber so I have to grease them. Rubber bushings grip the inner and outer sides so there's no slide and the torsion of the rubber adds to the suspension's effectiveness.

I'm still not completely happy with my alignment but can't throw more money in to get it done really well. These cars don't lend themselves to having caster and camber adjusted which I think I need.

 

[The Roadagon]

Pat, Sounds like you effectively used everyones advice from the forum,took your time researching the parts and have gotten good
results from the car. ed

 

[PatDTN]

Pat, Sounds like you effectively used everyones advice from the forum,took your time researching the parts and have gotten good
results from the car. ed

I did but this wasn't the first time for at least parts of the suspension. I went to the airbags fairly early on. At that time I bought a full set of shocks that were recommended here and they left my wagon vague and floaty. Nowhere near the amount of damping I prefer.

For those getting ready to do any kind of work based on recomendations on this or any other forum make sure the end result is what you're shooting for.

I've owned several BMWs and built a BMW race car for SCCA. I like a firmer ride than most folks do. On my race car I bought a firm suspension setup - struts, shocks, springs, sway bars - from a reputable race shop. After a couple of races I bought MUCH stiffer springs, removed the rear sway bar, and set the front on its stiffest setting. I sent the struts and shocks back and had them revalved for much more damping. Then the car handled the way I wanted. I was able to drive past cheating competitors in the twisty bits only to have them blast past me on the straights. I was happy. I got to do it again in the next set of twisties. 😎 When we raced on a really rough track I adjusted the bump setting way back towards loose but left the rebound set high. At the end of the front straight I think my car was nearly an inch lower than at the start. It finished rising later.

If you're looking for something that floats down the road my setup is not going to be for you. I did leave stock sized tires on my car to help dampen some potholes and such. Those make the handling a little less sharp than it could be. I could go +1 or even +2 to sharpen that out but then those potholes would be costing me money.

If you read something and like the sound of it you should ask questions to make sure you're getting what you want. In the case of the shocks I didn't like it wouldn't help to ask if they're good shocks (vs. just cheap) because the response is "the perfect amount of damping" which wasn't perfect for me.