I apologize, I miss-read the thread.

james

 

Interesting MixmanSC thinks the lines going to the bags are 6mm, and another question do the lines come out of the bags come straight out and up or are they molded 90 degrees? I think I will go with the FirestoneWR17602097 which is a analog system
that has an analog gauge with a rocker switch to raise or lower the pressure. Still looking for a source of the 6mm lines, do think I would need much as I will switch over to 1/4 inch to interface with the "T" then its back to the compressor.

I am also looking at bags, the GM ones are big bucks (and as I understand it made by firestone for GM) There are lots of aftermarket ones on ebay but I question the quality.

 

Out of the bags they go straight up but then make a turn a few inches up from that to go over to the compressor. I dont think that they are 6mm, I know they are for fact. Early on when I was replacing the air lines to the springs on mine I found markings on the original tubing and looking that number up online is where I found that it was 6mm tubing. Also the lines on the compressor shelf between the air drier, etc are 8mm.

I still have a couple of cut bits of the factory air line with a compressor I have. The smaller lines that go to the air springs are marked DIN 74324 6x1 PA12 PHLY 41 3290 UIB L3 552. The 6x1 is the metric size 6mm OD x 1mm wall thickness. I also just put a caliper on the tube to be sure. Exactly 6.00mm OD which is a bit smaller than 1/4" (6mm = .02362205 inches). I'd venture to guess that you can probably get 1/4" tubing to go into the 6mm fittings on the bags as the orings in the push fittings have to allow for a tiny bit of play. You might have to chamfer the end of the tube a tiny bit. It will be a very tight fit though as the fittings are intended for the ever so slightly smaller metric tubes.

I did get some cheaper air springs when I replaced mine. They did work fine but the retainer tab at the top which locked the spring into the upper seat on the frame did not really want to stick up and lock it in place well so I cut a small bit of very very firm foam and stuck that under the retaining tab. They rotate and lock into place on the upper mount. Couple of pics.... Also as you can see, the fitting on the air spring is molded in. If it were a threaded push fitting you could simply replace it with a 1/4" but that is not possible, at least not with the air springs I bought. The air springs that were on it when I bought it were actually branded but they were not Firestone, they were Westar so my guess is they were not original.

 

Thanks for that Mixman, I was confident that you were correct (as usual) about the line size but I did think it was strange GM could have possibly used different sizes depending what part of the system you are looking at. As far as the turn on the line I think I could take a heat gun and carefully bend the line to the point it will not create any clearance issues. If possible I will run the 6mm line through a Tee to both bags and convert the single line to 1/4 when it hits the compressor. I have been searching to junk yards to possibly find an empty compressor. Otherwise i will use some 3/16 or 1/4 inch hot rolled plate steel and make one myself. This might be the best bet as most of the stuff coming out of junkyards today are usually a rusted mess.