1996 Wagon Air Shock Questions

I'm not that familiar with my new to me wagon yet but I knew I needed new shocks in the back. Pushing down on the bumper caused a lot of bounce. I also found out why my compressor was running even after the car was off. The PO replaced the air shocks with non-air shocks and left the compressor fuse in and cut the air lines. So I hastily purchased these Monroe's (MA717).

Monroe MA717

I like the way Monroe's ride in my 94 deVille so I figured I'd try Monroe's in the wagon. The wagon is such a heavier car in the rear than the FWD deVille but the shocks are surprisingly puny compared to the ones in the deVille. Does anyone have experience with these Monroe's? It seems that Gabriel and KYB are the favored brands on here along with the Monroe Severe Service.

My second question has to do with something in the FSM. On page 3D-8 there is a picture of the rear shock setup (figure 13). It shows a part 39, shield, rear shock absorber boot heat. It looks like it sits on top of the shock. There was not one of these on the car and I can't find it in a diagram anywhere. Is this something I need? Also if there were to be something else on top of the shock, the mounting bolt would not be long enough. One of the steps states, position so that "V" notch near clamp is 180 degrees from air tube fitting and rim of shield is seated against rubber rim of shock absorber boot. I'm confused.

The shield you see in the FSM is not listed or shown in the GM parts book. In any case, the large diameter original shocks, with one fitting on one side, and two fittings on the other, are no longer available.

The GM replacements, and the aftermarket air shocks offered, are smaller in diameter, and use a different style boot for the air support. Even if you could find one of these mysterious heat shields, they probably wouldn't fit anything except the original style shocks.

The heat shield is probably the exhaust heat shield, and is related to the gas tank more so than the shock. In the 92 book, there is no mention of a heat shield, and the picture shows the tank heat shield behind the shock.

I can not address the preference for one shock over another. It may be the ease of adapting one or more to the pressure lines. You may need an adapter for the port on the shock.

Ok. Thanks for the replies. I will proceed without the heat shield.

I got the right side shock off without much drama. But now I have a couple of questions.

1. What is the routing for the air lines in the rear? The right side line was cut and the left side was just dangling with the connector intact. I imagine there would have to be a T somewhere. Does it matter where? I figure I'll put it within easy reach in the center between the two shocks for future repairs if it doesn't matter.

2. How in the hell do you get access to the air line on the compressor? I can't even see it. And that's after I removed the splash guard. I can see where the line goes but I can't see the actual connection. I would have to fly blind replacing the air line at this end. I thought maybe I could get there from the top so I started removing the air box but the computer is under it.

I figured out #2. I removed the whole air compressor. Good thing as the line that goes from one port to the other on the compressor with the T between was sitting inside the splash shield after rotting off the fittings.

As far as #1 goes I'm going to do as planned and run new line from the compressor to a T between the two shocks near the center of the vehicle.

Now I need to find a plastic union for the hard air line. The lengths in the various kits I've accumulated are not long enough. I just got back from a tour around town to all the parts stores and no one seems to have anything. I swear I saw hard line fittings in one of them at some point. Does a union for the hard air line exist or do you use a T and somehow block it off?

You can probably find the hard line connectors/tees at your local hardware store.

The factory set up ran the air line to an original shock that had two air fittings on it. A jumper line then ran to the other shock that had one air fitting on it.

Whenever the shocks were replaced, a "Tee" fitting had to be installed because the replacement shocks only have one air fitting on them.

This would be one source for fittings if you can't find them locally:

https://www.fastenal.com/products/hydraulics-pneumatics/fittings/compression-fittings/unions?term=union&r=~|categoryl1:"603388 Hydraulics 9and Pneumatics"|~ ~|categoryl2:"611532 Fittings"|~ ~|categoryl3:"611514 Compression Fittings"|~ ~|categoryl4:"611529 Unions"|~ ~|sattr01:^1/8"$|~

Thanks for the replies. I got everything back together and replaced the hard air lines. I have a couple more questions.

1. The new shocks came with a spacer but didn't explain how it mounts so I guessed. The old shocks did not have a spacer. They were mounted directly to the car's mounting tab. I installed the spacer with the flat side against the vehicle and the beveled side (not sure how to explain but the other side is not flat) against the shock. Does that sound right and does the picture look right?

2. The PO left the air compressor fuse in even though they abandoned the system. I assume it has been running constantly for some time and has been damaged. When I turn the key to run i can hear it do the initial test. If I sit on the tailgate I can hear the compressor come on. It will run for a couple minutes then shut off but the shocks do not inflate. I disconnected the air line at the compressor and installed a temporary short length of line and when the compressor is running I do not feel any air coming out. Is this something that can be repaired or must I replace it? BTW, the shock in the picture is inflated because I installed the manual fill valve, temporarily, to make sure the back end of the system did not have leaks. It held 20 pounds of air for 5 minutes so I think I am good back there.

Thanks.

If you are a fix it kinda guy,. this might help i stole it off the interwebs,.

Quote :

Remove the compressor from the vehicle. Check the resistance between the connector pins. It should read about 21 ohms. If it reads open, then the solenoid winding has an open circuit. You can get access to the solenoid by removing the silicone rubber over the solenoid cover then prying up the tabs holding the cover on. Once you have the cover off, the solenoid is inside. The solenoid winding wire is very small gauge, maybe 26 or 32 gauge. The most likely failure point is near where the fine solenoid wires connect to the heavier connector wires. This is where my solenoid wiring failed 2 times. The first time I fixed it, I just soldered the ends of the broken wire back together. That only lasted a few weeks. The next time, I made a jumper of heavier wire and soldered the jumper between the broken ends. You can check your repair work with a voltmeter as you work on it. When you consistently have about 21 ohms for between the leads of the connector, your repair is complete. While you have the unit out of the vehicle, check the dryer and dessicant. It may be full of rusty water. Be careful when you open the dryer, there are a lot of dessicant beads. You can put the beads in an oven safe pot or dish and bake them in an oven at 250 for an hour or two to dry the dessicant beads. Or you can buy a dessicant repair kit. Put everything back together and apply some silicone caulk over the re-bent down solenoid cover tabs. Put the compressor back in the vehicle.

Picture looks OK. The original shocks came with the lower mounting installed, so you put the spacer on the replacements in the right place.

E-Bay usually lists a number of these compressors, if yours is no longer serviceable.

I had an old compressor laying around, so i mounted it in the storage compartment in the rear to keep it dry. I mounted mine on a switch, because I didn't want all the trouble of the factory system.

phantom 309 wrote:

If you are a fix it kinda guy,. this might help i stole it off the interwebs,.

Quote :

Remove the compressor from the vehicle. Check the resistance between the connector pins. It should read about 21 ohms. If it reads open, then the solenoid winding has an open circuit. You can get access to the solenoid by removing the silicone rubber over the solenoid cover then prying up the tabs holding the cover on. Once you have the cover off, the solenoid is inside. The solenoid winding wire is very small gauge, maybe 26 or 32 gauge. The most likely failure point is near where the fine solenoid wires connect to the heavier connector wires. This is where my solenoid wiring failed 2 times. The first time I fixed it, I just soldered the ends of the broken wire back together. That only lasted a few weeks. The next time, I made a jumper of heavier wire and soldered the jumper between the broken ends. You can check your repair work with a voltmeter as you work on it. When you consistently have about 21 ohms for between the leads of the connector, your repair is complete. While you have the unit out of the vehicle, check the dryer and dessicant. It may be full of rusty water. Be careful when you open the dryer, there are a lot of dessicant beads. You can put the beads in an oven safe pot or dish and bake them in an oven at 250 for an hour or two to dry the dessicant beads. Or you can buy a dessicant repair kit. Put everything back together and apply some silicone caulk over the re-bent down solenoid cover tabs. Put the compressor back in the vehicle.

Now that it's warming up around here I'm back to sorting out the air shock compressor. I got it off the car and took it apart. As mentioned previously, the compressor runs but does not output any air. I got the piston out and the piston ring is nearly worn down to nothing. When it was in i could clearly see a gap between the piston ring and cylinder wall. It seems logical that this is the reason for not putting out any air. The ring appears to be one solid piece, not split. Does anyone know if it is possible to replace the piston ring? It seems such a waste to toss the whole unit for what seems should be a cheap part.

For the price of the compressor, just buy another one, or find one at the local PNP junk yard. Save the old one for parts...you do realize that the worn out part on yours is probably the same worn out part on all of them that do not work.

These compressors were made by Kipp (now VMAC) systems in Canada. It is hard to believe that someone, somewhere doesn't offer parts. A lot are available used, but it is kind of like buying a used battery.

So the same ma-717 part number shows a little different from amazon/rockauto  did yours come white with white lines?
mine are black with black lines.  Think there is a difference on the inside?  the specs all seem the same from what I can tell.

AH! I didn't see that picture you posted.  Yours came black too.

Fred Kiehl wrote:

For the price of the compressor, just buy another one, ...

Not sure what this means. New air compressors, which are not available, are not cheap for cars that they are available for. Used ones, for at least $150 are not cheap. And the used ones which claim to be rebuilt only seem to have new or rebuilt air dryers. So the internals are still questionable. The only cheap option is the junk yard find which is a crap shoot. I did end up going the junk yard route at $15. I went under the assumption that most GM vehicles between the 80's and maybe 2000 would have the same or similar compressors aside from the mounting bracket.

There were lots of Cadillacs in the yard but the compressors were all mounted above the rear suspension making it somewhat difficult to get to. I finally found a 92 RM sedan. The underside looked like it was pulled up from the depths of the Titanic. I pulled the compressor and was ready to take my chances on it when I saw the final Cadillac I had not looked at yet. It was a 90 Deville and lo and behold the compressor was mounted in the engine compartment. It was totally rust free so I took that one instead of the one from the RM. What I didn't realize until I got home is that the relay was not attached to the compressor. It must have been mounted in the engine compartment. I had planned on taking the piston out of the "good" one and putting it into my original. After I had the "new" one opened up I realized how scored the piston wall of my original was. The new one looked really good, surprising really. It must have been replaced at some point. So I decided to splice the wires, with relay, from my original to the new one.

I got the wiring connected and all put back together into the mounting bracket. Now I need it to warm up and stop raining to get it installed. I have a DC power supply so I'm going to see if I can get it to run on the bench. The FSM shows that you can supply 12 volts to the 3rd pin and ground the first pin. However my connector is not flat with 4 pins like the FSM shows. It is square with 6 pins. Anyway, I'll try and figure it out. If not I'll test it on the car.

My wagon has this system on it but of course it doesn't work. People I bought it from just put a regular set of air shocks on it with a port at the back bumper. Have been meaning to see just how high the butt will go, lol. When I do the suspension I'm just going with regular shocks/springs and pull the rest of the factory stuff off.

Question for you. Are your rear Springs bolted to the rear end?

94Woody wrote:

My wagon has this system on it but of course it doesn't work. People I bought it from just put a regular set of air shocks on it with a port at the back bumper. Have been meaning to see just how high the butt will go, lol. When I do the suspension I'm just going with regular shocks/springs and pull the rest of the factory stuff off.

Question for you. Are your rear Springs bolted to the rear end?

I'm not sure. I have not looked closely at my rear springs yet. It's too cold for me to crawl under there today to have a look.

Rear springs are not bolted to the rear end.

""New air compressors, which are not available,"" The direct replacement new ones are close to $400.00, but they are still available new. If you think the electronics you have are alive, this might be an alternative to the new GM unit:

http://www.truckspring.com/products/Air-Lift-100C-Compressor__16130.aspx

Plumbing and wiring would have to be field adapted to fit. But the autolevel is a good system if you regularly carry "stuff".

Fred Kiehl wrote:

Rear springs are not bolted to the rear end.

You've been under his car?

Yours may not be but mine are secured to the bottom perch with a fat u bolt that physically holds the spring to the rear end. Never seen it before so I was asking another person (not you) if perhaps they had the same setup on their car. While I doubt it and feel someone added this for what ever reason, it doesn't hurt to ask.

Rev Bob wrote:

""New air compressors, which are not available,"" The direct replacement new ones are close to $400.00, but they are still available new. If you think the electronics you have are alive, this might be an alternative to the new GM unit:

http://www.truckspring.com/products/Air-Lift-100C-Compressor__16130.aspx

Plumbing and wiring would have to be field adapted to fit. But the autolevel is a good system if you regularly carry "stuff".

Hopefully I won't have to go the aftermarket route for quite some time. I definitely won't be spending the $400+ for an OEM unit. Has anyone installed an aftermarket unit in the factory location? I have plans for the spare space in the rear. I'm ok doing the wiring and plumbing but I'm quite deficient in fabrication if something needs to be made for mounting.

I was not able to figure out how to get the compressor running on the bench so I just plugged it into the car. I initially had the air line disconnected. Turned the key to run and waited for the air replenishment cycle. The cycle started as it was supposed to (but kept going because I had the air line disconnected) and I was getting what seemed like a good amount of air coming out the port. Got it all hooked back up and let the cycle run again and this time it completed in a very short amount of time. Hopefully today I can load up the trunk and test the leveling operation.

""Hopefully today I can load up the trunk""

Or just sit on the open tailgate.

Rev Bob wrote:

""Hopefully today I can load up the trunk""

Or just sit on the open tailgate.

I rounded up the family and did just that. We had to try it several times. The first few times the pump came on but would not stop within a few minutes. After the 4th or 5th try it finally stopped on its own. The previous attempts we had to get off the tailgate and let it come back up for it to stop. And each time it vented and dropped down a little. By the 4th time we seem to be good. Is that normal?

The very first fill on my shocks took a long time, since they were "empty". They have also gotten faster since first fill. Did your kit come with 2 of the ak-16 kits? mine did, It only required 1, but with the second kit I could add a remote fill to the whole system so that I could use a gauge to see pressure. I'm seriously contemplating adding that for easy of diagnosis.

turnofftheradio wrote:

Did your kit come with 2 of the ak-16 kits?

I don't remember exactly but I thought I had to buy the manual fill kit separate. I did not have 2. I could be confusing it with when I did the air shocks on my Deville. I did use it to inflate the shocks initially to test for leaks. I like the idea of adding the manual fill as a secondary backup in the event the compressor or one of the electronic components fail. Then I could manually fill them in a pinch when away from home. Would there be any issues with manually filling the shocks while the air line is still attached to the compressor? Aside from a leak within the compressor.

From what I can tell from stock photos... the kits have changed a little over the years and some seem a little different.  Some sets, the tee appears to be housing the schrader valve, some the tee is just a tee and has a seperate schrader port.


mine looked like this but without the molded right angle ends.  for some reason it came with two of these sets.  which gave me two tees and two fill valves and two sets of lines.  check you hardware pack, you might have all that stuff too.

Also, I think I had the ak number wrong.  I think it came with two ak-29 kits.  I'll have to look at the bags.

Haze5736 wrote:

Would there be any issues with manually filling the shocks while the air line is still attached to the compressor? Aside from a leak within the compressor.

I see no issue with this, Ill let you know my results. there are some plugs as well in the kit. Should the solenoid or compressor fail, it would be very easy to cap off that side of the line at the tee (assuming i leave the plugs in the emergency kit..), manually fill and be on my way again quickly. I like a redundant backup plan. I'm planning on hiding the fill under the hood where it wont see snow/rain, and teeing off near the compressor. that might give a strange high gauge reading while the compressor is running, but accurate if it is not.

Wow too many numbers in my head. Actually ak 18. Lol.

and, just to confirm about the tee, last night I put the 2nd tee up front by the compressor. I ran the line up to the engine bay. It works great as a gauge port or extra fill valve. It also showed my compressor was leaking under heavy loads