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Topic: 99 U320 won’t air up right front (Read 683 times) previous topic - next topic

99 U320 won’t air up right front

Started my coach today, as a shut it off there was a loud pop and the right front dropped, and now I can hear air leaking under the front. Bags all seem ok, from what I can see without being able to get under it is one of the solenoids on the 6 pack is loose from the metal block. I can push on it with a rod from the wheel well and make the tone of the air leak change. Anyone had that issue before? I need to figure out a way to get the corner aired up to safely get at the valves.
1999 U320 4200 DGFE

Re: 99 U320 won’t air up right front

Reply #1 –
Been around here for a while, and this is a new one on me.  Sounds like a rare structural failure where the actual threaded portion of the valve let go allowing it to partially separate from the manifold.  Could have been caused by over torquing the valve when it was installed.

I'm trying to think of a alternate way to rise the right front so you can insert your safety stands and work on the 6-pack...

I don't suppose you have access to a suitable sized air/hydraulic jack that could lift the right corner?
1993 U280 SE 40' WTBI, Build: 4359
C8.3 300hp, 6-Speed, Exhaust Brake
960 watts on the roof (6 x 160)
Sorento (or BOLT) on a Kar Kaddy SS
"Nature abhors a vacuum"

Re: 99 U320 won’t air up right front

Reply #2 –
Try getting a 2x12 and cut it to stack the pieces and drive up on them.  4 pieces would give you about 8". My guess on the 6 pack it you blew out an o-ring.



Keith
The selected media item is not currently available.Keith & Jo
2003 U320T 4025 PBBS Designer series
Build 6203    Cummins 500hp
2000 U320 4010 WTFE / Build 5762 —Sold—
Motorcade #18070   
Pasadena, Texas
2015 Jeep Wrangler Sahara-Sunset Orange pearl coat
Don't argue with a fool, people watching might not be able to tell the difference.

Re: 99 U320 won’t air up right front

Reply #3 –
I have a diesel repair shop, and have all sorts of jacks there, but of course the coach is in my driveway at home. I think I'm going to make me an airline to tie the 2 right side bags together and air up with an air hose. All the other bags function as they should
1999 U320 4200 DGFE

Re: 99 U320 won’t air up right front

Reply #4 –
With the right selection of fittings and some 3/8" DOT plastic air line tubing, it might be possible to rig up a temporary way to pressure up the right front airbags with a portable air compressor.  I don't know how much access you have to the air line connections on the top of the front air bags on a U320, so not sure if this is possible.

Edit:  I see (above) you have the same idea.
1993 U280 SE 40' WTBI, Build: 4359
C8.3 300hp, 6-Speed, Exhaust Brake
960 watts on the roof (6 x 160)
Sorento (or BOLT) on a Kar Kaddy SS
"Nature abhors a vacuum"

Re: 99 U320 won’t air up right front

Reply #5 –
Let us know if that idea works, and what you find when you get a look at the 6-pack.
1993 U280 SE 40' WTBI, Build: 4359
C8.3 300hp, 6-Speed, Exhaust Brake
960 watts on the roof (6 x 160)
Sorento (or BOLT) on a Kar Kaddy SS
"Nature abhors a vacuum"

Re: 99 U320 won’t air up right front

Reply #6 –
I'll report back tomorrow afternoon what I find. Scheduled for a Florida trip leaving on the 10th so I hope it's nothing major. Is there a way to bypass the 6 pack and just run the coach with the suspension leveling valves? I'll be parked on flat ground the whole trip, I can do without leveling once I get there if parts availability is an issue
1999 U320 4200 DGFE

Re: 99 U320 won’t air up right front

Reply #7 –
Quote from: Dbraskett –
Is there a way to bypass the 6 pack and just run the coach with the suspension leveling valves?
Yes - looking at my air system schematic, I think it would be possible to do that.  The HWH leveling system is basically doing nothing when the coach is in travel mode.  Air pressure goes to the front height control valve, and from there it is routed straight through the 6-pack manifold via the travel valves, then on to the air bags in each front corner.

Theoretically, you could connect the air lines from the front height control valve directly to the air bags with a dual "Y" tubing setup.

I'm sure other members will chime in on this subject and tell me I'm overlooking some critical detail.



1993 U280 SE 40' WTBI, Build: 4359
C8.3 300hp, 6-Speed, Exhaust Brake
960 watts on the roof (6 x 160)
Sorento (or BOLT) on a Kar Kaddy SS
"Nature abhors a vacuum"

Re: 99 U320 won’t air up right front

Reply #8 –
Quote from: Dbraskett –
Started my coach today, as a shut it off there was a loud pop and the right front dropped, and now I can hear air leaking under the front. Bags all seem ok, from what I can see without being able to get under it is one of the solenoids on the 6 pack is loose from the metal block. I can push on it with a rod from the wheel well and make the tone of the air leak change. Anyone had that issue before? I need to figure out a way to get the corner aired up to safely get at the valves.

Just to verify - it's obviously one of the solenoids at the manifold block and not the mini regulator that hangs near the front axle and has a dial gauge on it, correct?
Learn every day, but especially from the experiences of others. It's cheaper!  - John C. Bogle

2000 U320 36' non-slide / WildEBeest Rescue
2003 U320

Re: 99 U320 won’t air up right front

Reply #9 –
D,
Purchase two 10 foot 2x12s.  Have each one cut at 4 feet, at 3 feet and 2 feet.  Place the two 4 foot sections in front of each steer tire.  Then the 3 foot sections on the top of the 4 footer even with the end away from the tire.  Follow that with the 2 foot sections and finally the 1 foot sections.  Pull the coach forward slowly till the steer tires are on the 1 foot sections.  Block the drive tires to prevent any rolling forward.  You will have pleanty of room to get under the front and all will be safe.
Rudy Legett
2003 U320 4010 ISM 450 hp
2001 U320 4220 ISM 450 hp
1995 U320 M11 400 hp
1990 Granvilla 300 hp 3208T
Aqua Hot Service Houston and Southeast Texas

Re: 99 U320 won’t air up right front

Reply #10 –
Got the coach aired up with a fitting I made for the right side air bag, and the top right solenoid on the 6 pack was blown out of the manifold. Threads in the manifold itself look to be ok, but the solenoid threads look to be messed up. Also looks like this solenoid has been replaced before, it doesn't match the other 5.
1999 U320 4200 DGFE

Re: 99 U320 won’t air up right front

Reply #11 –
I am surprised that the aluminum threads in the manifold are still good. They are softer than the brass on the solenoid. 
1999 40 ft. U-320 wtfe build 5563 Chuck & Lynda's "Rollin' Inn"  2030 watts solar
prev. mh's 71 GMC 5 yrs. 73 Pace Setter 1 yr. 78 Vogue 5 yrs 81 FTX 40ft all electric 18 yrs. 1996 Monaco Signature 3 yrs.
2014 Grand Cherokee Overland
Dream as if you will live forever. Live as if you will die today.  James Dean

Re: 99 U320 won’t air up right front

Reply #12 –
Quote from: craneman –
I am surprised that the aluminum threads in the manifold are still good. They are softer than the brass on the solenoid.

I'm surprised as well. I'm happy about it though. Should be able to replace the solenoid if I can get one quick enough.
1999 U320 4200 DGFE

Re: 99 U320 won’t air up right front

Reply #13 –
Quote from: Dbraskett –
...the solenoid threads look to be messed up. Also looks like this solenoid has been replaced before, it doesn't match the other 5.
I wonder if that was a previously used (junkyard) solenoid?  Perhaps the threads were already damaged when it was installed on your coach.
1993 U280 SE 40' WTBI, Build: 4359
C8.3 300hp, 6-Speed, Exhaust Brake
960 watts on the roof (6 x 160)
Sorento (or BOLT) on a Kar Kaddy SS
"Nature abhors a vacuum"

Re: 99 U320 won’t air up right front

Reply #14 –
Best photo I can get underneath the coach, but the threads look just fine in the manifold
1999 U320 4200 DGFE

Re: 99 U320 won’t air up right front

Reply #15 –
A thought would be to find a threaded fastener with size and thread pitch of solenoid, screw into manifold block and wiggle it to see how much (if any) play there is in threads.
Future Foretravel Owners
2019 Jeep Cherokee Trailhawk
Retired USAF, Retired DOD Civ's
FAA A&P, Indust. Eng., Acft Depot Lvl. Maint.
Larry and Becky Rountree

Re: 99 U320 won’t air up right front

Reply #16 –
To update this, got the new solenoid this morning. Threads definitely look better than the old one. Screwed it to the manifold and now the coach airs up properly. The right front won't dump now from the control panel, checked all the coils with a multimeter, and cleaned out the exhaust ports, but that's a problem for another day.
1999 U320 4200 DGFE

Re: 99 U320 won’t air up right front

Reply #17 –
Don't let the coach twist as it can damage the windshield. You need the right front to dump when the left one does.
1999 40 ft. U-320 wtfe build 5563 Chuck & Lynda's "Rollin' Inn"  2030 watts solar
prev. mh's 71 GMC 5 yrs. 73 Pace Setter 1 yr. 78 Vogue 5 yrs 81 FTX 40ft all electric 18 yrs. 1996 Monaco Signature 3 yrs.
2014 Grand Cherokee Overland
Dream as if you will live forever. Live as if you will die today.  James Dean

Re: 99 U320 won’t air up right front

Reply #18 –
Quote from: craneman –
Don't let the coach twist as it can damage the windshield. You need the right front to dump when the left one does.

It levels in travel mode just fine. I'll keep an eye on it this trip, and try to troubleshoot while I'm parked next week. I've seen people pop windshields out twisting a coach, for sure don't need those headaches
1999 U320 4200 DGFE