Rear Suspension bags - Page 3

wildtoad · 03-07-2004, 06:01 AM

Thanks for the reply and yes I did check the manual. It seems that the pages in the manual show and discuss the system for vehicles with tag axles. There is nothing that shows anything close to what is in mine.

wildtoad · 03-19-2004, 05:19 PM

Jim, I wonder if I could get one more bit of detail from you. Still having a bit of a problem, but I may have found a/the probable solution. On the rear axle there is a height control valve (HCV) that is connected between the air tank and the rear suspension bags. The HCV has three connections: one is connected to the air supply (tank) one is connected to the left side air bag, and one is used to dump excess air.

Could you look at yours and tell me which one is connected to the air bag? I bet it's the middle one of the three. If so then it could explain why mine does not work correctly.

Now, if I remove the air lines from this HCV, will the rig fall on me ?

dbyar · 03-19-2004, 07:42 PM

Great information and pics. It seems that each coach has its air compressor tank and dump valve located in a different place.

I have not been able to locate the air bag compressor dump valve on my '92 350le. There is a tank mounted behind the stairs, but to access it we will have to grind the welds off of the box covering it -which doesn't sound like a regular
maintenance procedure to just to dump condensation (as I understand that it should be).

Does anyone else have a '91/92 350le who could tell me where their tank and valve are located? Thanks.

dybar
350le

jim8860 · 03-19-2004, 08:16 PM

Quote:

Now, if I remove the air lines from this HCV, will the rig fall on me ?

YES!! The air bags have no check valves in them. All the air will empty out. As for the input and output of the height control valve lines I will look for you as soon as some of snow we just got again

melts off. I could get back to you Monday or Tuesday. What the camper doing? Jim

swebster · 03-19-2004, 08:37 PM

check for a Schrader valve mounted to the tag axle assemble between the drive and tag wheels. Could be on the curbside.

That's where mine is and I've seen the same on newer Classics.

wildtoad · 03-20-2004, 05:59 AM

Jim,

On the way to the beach, it seems that things were better as the pressure gauge averaged 70-80 psi with very little fluctuation. Parked, set the levelers, all the air vented out as expected. On the way back, pressure fluctuated between 20-90 psi, pump on a great deal as in most of the time.

I did go to the website of the manufacturer of the HCV (HALDEX) and while they don't have an installaion manual online it does state what valve (three of them) goes where. Based on this info, and looking at mine I think that the guys at the shop simply switched the air supply line and the bag feed line. So I like to compare what works (your rig) and the diagram.

Here's my theory... the HCV acts as a check valve and under normal operation only allows air to come FROM the tank when required and TO the air bag except when it releases air from the bag based on need then refills the bag from the tank when required. If the connections are reversed then the HCV actually releases air from the TANK, so the bag doesn't really lose air. Maybe all wet, but that's what I think.

Thanks,

wildtoad · 03-20-2004, 03:06 PM

And now for an update for those that just want to know...

I crawled under the coach today and compared the connections at the HCV to the picture from the manufacturers web site and low and behold the connections appeared to be reversed. So I set off to rectify this.

I first chocked the wheels and set the levelers just enough to make sure the levelers were holding the rig and not the rear tires. As expected a good bit of air came from the exhaust side of the HCV, but the bags were still full... (the Air tank was empty). So I manually released the air from the bags by loosening the connnection, rig did not move, so levelers were doing the job, felt somewhat secure in proceeding.

Crawled under the Airstream and swapped the connections at the HCV. While still being supported by the levelers, I turned the key and the pump pressurized the tank and turned off which is what I expected. (bags still way empty). Lowered the Airstream off of the levelers and the tank immediately started replenishing the bags, pump turned on and continued to run until the bags were full and the tank was full again.

The real test will of course be when I drive the unit and raise it up on the levelers again.

Now I know probably more than I ever wanted to know about the HCV, but it is knowledge....

jim8860 · 03-21-2004, 09:01 PM

Quote:

Jim, On the way to the beach,

That the first problem

I still have some snow here (only kidding). So I crawled under my MH today and snaped this photo of my valve. It has been changed from factory, but I do think you are correct on you therory.I hope your problems are fixed now.Jim