Making progress.

Got the AC Delco 504-511 shocks installed and with the help of the included Gabriel 141099 kit, plus the seperate 141248 kit that I had to order, I got them installed. I can scan the included directions or go into greater detail if anyone is interested. Everything went according to plan and the system appears to have no more leaks! I am happy with these shocks, but it's making me want to do the fronts. I think the car rides very nicely and I still think it's not a bad handler, at least around 45mph. You can whip it around on backroads and it does just fine. And that's FE1.

I was going to adjust the rear drums due to the low pedal after doing the front brakes. Pulled the drums off, which was a fight on the driver's side. Both drums had a ridge, but the driver's side required me to punch out the adjuster hole and back off the star wheel to get the drum off. After that, I noticed that the driver's side wheel cylinder was leaking. So to Napa I went. I got two, because it would be stupid, imo, to replace one and not the other. With my luck it would have gone in 2 weeks anyway. The shoes had some life left, but when I do those I will definitely also replace the drums, as well as the springs. I cleaned and greased everything, then adjusted the wheel with a brake spoon (screwdriver works fine, too). The pedal feels great now! MUCH higher and the overall braking effort feels like a Cadillac finally. Just effortless how this 4500lb car glides to a stop. Happy with the front Napa pads, as well. In fact, I am quite happy with the car...this is fun. More to do though.

Judging by the ride height this morning, it looks like the shocks leaked down overnight. Is this a problem? I'm guessing no, but I seem to recall people claiming that a proper performing system will maintain pressure for days.

Hmm...when sitting idle for a while, it will go down a BIT, but should largely stay up and level. Another way to tell is if it sits there consistently pumping up every so often while sitting, as it sinks...a sign there's a leak/weakness. My '95 used to only really pump up when first started for a second and then with load and otherwise never do a thing, but developed a leak in the fall and now runs off and on while parked and takes longer to get up with load, if it fully can at all.

How much lower did it sink to overnight?

I should measure officially but it looks to be about 2 inches. The skirt is almost even with the top part of the centercap.

When inflated, it also rides higher than before.

It definitely doesn't seem to run much at all since I replaced them. Before it would run every few minutes to maintain height. Hard to say where the leak is. Could be in the lines I rigged up. Or the compressor head. It's slow enough that I don't think I'll chase the problem.

EDIT: Here's a pic of where it sits after overnight.
http://www.kevinallenmoore.com/photo/d/60253-2/DSCF0712.jpg

Hmm, that doesn't look unordinarily low after sitting, but hard to tell based on ours, at least.

Yeah, I think I am doing ok. It's probably fine.

I brought a car load of people to lunch on friday (5 including myself) which was the acid test for the load leveling system. It inflated fine and when we got there and exited the car, the fender skirts were clear up at the vents on the wheels. Unfortunately, my fears were confirmed and it stayed that way. Won't go back down, except for very slowly as the system leaks down (like overnight or longer).

Got out the FSM and followed the test chart. I pinned it down to a dead exhaust control solenoid inside the compressor head. Just like my rear speakers, it appears electrically dead (pins B and C on the compressor harness plug). I tried shocking the compressor head with a hammer and a long extension but this was before I realized the solenoid was actually dead. I guess that was pointless.

Other than removing the compressor, and taking apart the head to try to see what's going on, it looks like I need to replace at least the compressor head. Though it would be less work to replace the whole thing if the price was right. Sigh. I can get a brand new GM head for $124. I suppose I could find a used working compressor assembly for that, but it's used...thoughts?

I was expecting the solenoid to be stuck maybe, since the rear shocks leaked so bad it probably never needed to kick on. But open circuit?? What the hell...

Status update:

I received a 95 Roadmaster compressor and he threw in the leveling sensor as a pair. The 95 RM compressor harness has 7 pins. My stock 95 FWB compressor harness has 6, and interestingly, my 93 Caprice FSM tells me it would also have 6 pins on the compressor harness. Funny that the Roadmaster is the oddball here. Anyway, I removed my old one, put in the one from a 95 RM and ........ same problem. Pumps up fine, but won't bleed air. So I swapped the leveling sensor/controller over (well not swapped but plugged in and moved the arm). I noticed that it had 6 pins and my stock one had 5. 93 Caprice FSM says 5 for the 93, so again, the Buick has an extra wire here and I have no idea what it does.

Anyway, the other sensor did the same thing. Pumps up, but not down. The pins on the 95 RM compressor that went to the exhaust solenoid also show open circuit just like my original 95 FWB compressor, which is strange. But I want to obtain a wiring diagram (should be page 8A-42-0) to verify what everything does.

This is pretty frustrating. I also don't think it's a wiring problem. I am being sent a compressor from a 94 FWB I think. That will be my next try. After that, I might have to pony up for a brand new compressor head at $137 shipped from GM Parts Direct.

FINAL status update (yes, good news):

Received the 94 FWB compressor as expected. Had the same 7-pin harness as the 95 RM compressor which tells me that the 95 RM was the same as the 94 FWB, but for some reason in 95-96 they changed it to 6-pin on the FWB only (which is the same as a 93 Caprice)...anyway.

First thing I did was check the resistance across pins B and C on the harness. Yay, 28-ohms! Sounds like a solenoid to me. Bolted it up - yup, working exhaust solenoid. It vents excess pressure when the rear is high, until it comes down to level, then shuts off. Perfect. What a saga. I have to believe this is a common problem but people either have leaking systems so it isn't as noticable or they just rip the system off entirely...or don't load up their car ever, which is a shame since it holds so much people and stuff.

I did have a little bit of a restriction back in my plumbing. I think it was a combination of my T and the air tubes that go into each shock. I think I had too much tube sticking into the fittings and it was causing the air to bleed out too slowly. I loosened them and pulled some tube out and it seems better now. Yay. If this one gives me a problem in the future, I am just going to order a new compressor head from GM (which has the exhaust solenoid inside of it). GM Parts Direct sells it for $137 shipped.