Air Spring Ass'y (Air Bags)

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Air Spring Ass'y (Air Bags)

March 01, 2011, 08:03:52 pm

I'm the proud new owner of a 40 ft. '93 Grand Villa. The Air Springs are showing cracks and I'm wondering if I should carry a spare or change all of them before a failure? Is the Air Spring the same things as the visible air bags used in the leveling system? The Part Number in the manual shows 7000391, it this correct? Where would I find a supplier for the Air Spring or bag?

Thank you,

Doug

Doug Hubbard

Re: Air Spring Ass'y (Air Bags)

Reply #1 – March 01, 2011, 08:39:54 pm

If you are still in the Yuma area, you can try these people. They can get them for you.

Google MapsOtts Truck & Auto Supply 1203 South Pacific Avenue, Yuma - (928) 783-0113

Jon Twork

Re: Air Spring Ass'y (Air Bags)

Reply #2 – March 01, 2011, 09:01:25 pm

Doug,

For what is is worth, several years ago someone on the old forum or the Prevost forum (don't remember which) posted he replaced his bags for visible cracking and then cut through the sidewall of the old bags and found the cracking to only be on the surface and the bags were really good to go except for the surface appearance.

Re: Air Spring Ass'y (Air Bags)

Reply #3 – March 01, 2011, 09:13:18 pm

Doug,

Call Keith at Encor RV in Nac. He has a done a few replacement and told me he NEVER has seen one that really need to be replaced.... One of the best MECHANICS in the area...FWIW...

Re: Air Spring Ass'y (Air Bags)

Reply #4 – March 01, 2011, 10:10:13 pm

Doug:
I suggest that you air up the coach and then hit the RAISE button and hold it until the coach is at its maximum height. Turn off the key and then go out and look at the part of the bottom of the air bag that you could not see prior to raising the coach. If you have cords showing and some are frayed I would suggest changing them as soon as conditions permit. It is a PITA to do it but, not technically difficult. Check the archives as I did mine in a parking lot last year and did an extensive write up about it a couple times. I ended up not knowing that mine were as bad as they were due to not checking them at full ride height. I had an air leak on Ogilby Rd. Timmy the BLM terrorist made me leave before fixing them but, we made it. Good luck

Regards,
Jon Twork

Re: Air Spring Ass'y (Air Bags)

Reply #5 – March 01, 2011, 11:08:40 pm

When we bought our 1997 U295 about a year ago, I was concerned about the dry rubber, slight flaking, and hint of cords showing on a couple of air bags. I asked MOT to specifically inspect the air bags. They told me the bags were fine. If there are frayed cords showing, or damage such as a cut, it might be time to replace a bag.

As always, your choices and results may vary.

Re: Air Spring Ass'y (Air Bags)

Reply #6 – March 02, 2011, 12:12:52 pm

Doug,
One of our members has a very comprehensive collection of information from various sources on all things Foretravel:
FORETRAVEL Motorhomes service and Repair Information

Here's the specific page on air springs:
Air Bags

Barry's website is a wonderful asset for us. Thank you Barry.

Re: Air Spring Ass'y (Air Bags)

Reply #7 – March 03, 2011, 12:11:40 pm

Doug,

Same coach as yours and with the same cracking. A couple of mine look really shot (rearmost bags) but understand they are very thick. I have a neighbor who owned a trucking company that had airbags on all the trucks. He replaced one but said it was rare. He changed his by the side of the road in a short time. Might be nice to have a spare as it could be hard to find way down Baja or other isolated spot without UPS. Cheapest is about $137 new (from above post). A set of belts and a spare tire (w/tools) were the highest on my priority list but will probably pick up a used airbag if and when I find one. Suggest you go to the site and print a copy to keep on board to refer to just in case along with R&R tips.

Pierce & Gaylie Stewart
93' U300/36

Re: Air Spring Ass'y (Air Bags)

Reply #8 – March 03, 2011, 03:23:53 pm

By all means, go to Barry's site and learn. And study Jon Twork's material on his air bag change. These components and the air system itself is/are something you don't want to be a mystery.

First thing you need are safety blocks to hold the coach up after raising it. Mine are 8.5 inches tall, 2x2 steel, placed between the axle frame and the house frame, on all four wheel wells. Do not get under your coach without it being blocked in case of a sudden airleak.

My story-
I had a rear bag explode while parked in a friend's driveway. This of course immediately let all the air out of the suspension system and the coach sat on the tires-frame to frame. So even good looking bags are vulnerable. The rear bags are more accessible than the front (requires removing the fender). UPS brought me a 6 ton jack from Harbor Freight and a bag from MOT. The friend had many 4x4s and 6x6 blocks so the job is not difficult.

Recently I had a front bag with a slow leak. I replaced this bag after driving 1200 mile while using the RAISE button every 90 seconds to get to my destination (family reunion). Leaks are discovered by listening--young ears work best for this--and by a soapy solution sprayed onto the bags, connections, lines. This means crawling under the raised motorhome with a flashlight and a spray bottle and patience.

While waiting for UPS, I constructed a terminal piece for the air supply going to the leaking bag. Someone on this forum informed me that one bag will hold a corner/wheel up. This indeed is true. I would suggest constructing and carrying a terminal piece that fits the line either at the coupling at a bag or to go into a cut line. I carry this now instead of a spare bag.

Andy1

Re: Air Spring Ass'y (Air Bags)

Reply #9 – March 03, 2011, 07:14:49 pm

I replaced all 8 of my air bags last year at this time. My '92 U-280 was finished in November of '91, so
the airbags were 19 years old when I replaced them.
The rubber on all the bags was rubbing off easily, but only the forward bags
showed exposed cords (an inch below the top plate) on the street side
(generator is on that side in the '92 Grandvilla). I suggest at the least checking the forward
(front bag in each wheel well) airbags closely. Apparently they receive the
brunt of the punishment.

The worse damage wasn't revealed until the airbags were removed: an inch long gash in one of the front bags was on
the inside of the coach. The gash had just touched the cords, but not severed them.

I cut through one of the old bags and found that the rubber on the inside
looked good with no weathering, but did exhibit "fatigue creases" at the
point of greatest curvature at the top and to a lesser extent, at the
bottom. The rubber is about 5/16" thick, outside to inside. The outermost 1/8" is solid rubber and shows the most wear. Next is 1/16" nylon (?) cords, about 2 plies. The innermost layer, another 1/8", is solid rubber.

I took pictures, but can't find them now. If I find them, I'll post ASAP.

In the Grandvilla's at least, the "fenders" had to come off to get access to one bolt on each bag. Apparently Jon Twork, in his 270 (bus style) didn't have to remove the fender.

Hope this helps.

Re: Air Spring Ass'y (Air Bags)

Reply #10 – March 03, 2011, 11:49:07 pm

Thanks everyone for the great information on the Air Springs. I now understand quite a bit more about what to do and I will pick up a spare.

Doug

Re: Air Spring Ass'y (Air Bags)

Reply #11 – March 04, 2011, 12:53:48 am

Don:
Regarding removing the "fenders". If by "fenders" you mean the fibreglass wheel well covers, I DID have to remove ALL of them to adequately access the air bags. There is no way that I could see to do it without removing them.

Regards,
Jon Twork

Re: Air Spring Ass'y (Air Bags)

Reply #12 – March 04, 2011, 10:26:57 am

I replaced the front ones on a 1996 4 years ago. I was going to replace the rear ones also, but I cut one with the most cracks in it and it was on the surface only so I took the rear ones back to the store.PLUS they were a pain to install.
I sold it loc. and today it has the original rear air bags.

Ben Harris
1999 u320

Re: Air Spring Ass'y (Air Bags)

Reply #13 – March 04, 2011, 02:07:41 pm

I bought our 96 U320 last June and the air bags looked cracked & weathered , I changed out the back first , I did it without removing fender skirts. I cut open a used bag and found out there is a lot of rubber there, But ! where the rubber rolls around the bottom , a few patches of rubber were missing, So when I can I will change out the front, Probably over kill. I bought the rear bags from Foretravel, I think they were $ 150.00 each plus $ 80.00 shipping. I found them on line for the same price , no shipping. I think when I buy the fronts, I will still buy the from Foretravel because they are great to work with, they have been very helpful with the, bringing back to life of our coach.
Art

Re: Air Spring Ass'y (Air Bags)

Reply #14 – March 04, 2011, 05:18:28 pm

Quote from: Don Hay – March 03, 2011, 07:14:49 pm

I replaced all 8 of my air bags last year at this time. My '92 U-280 was finished in November of '91, so
the airbags were 19 years old when I replaced them.
The rubber on all the bags was rubbing off easily, but only the forward bags
showed exposed cords (an inch below the top plate) on the street side
(generator is on that side in the '92 Grandvilla). I suggest at the least checking the forward
(front bag in each wheel well) airbags closely. Apparently they receive the
brunt of the punishment.

The worse damage wasn't revealed until the airbags were removed: an inch long gash in one of the front bags was on
the inside of the coach. The gash had just touched the cords, but not severed them.

I cut through one of the old bags and found that the rubber on the inside
looked good with no weathering, but did exhibit "fatigue creases" at the
point of greatest curvature at the top and to a lesser extent, at the
bottom. The rubber is about 5/16" thick, outside to inside. The outermost 1/8" is solid rubber and shows the most wear. Next is 1/16" nylon (?) cords, about 2 plies. The innermost layer, another 1/8", is solid rubber.

I took pictures, but can't find them now. If I find them, I'll post ASAP.

In the Grandvilla's at least, the "fenders" had to come off to get access to one bolt on each bag. Apparently Jon Twork, in his 270 (bus style) didn't have to remove the fender.

Hope this helps.

Don,
Good follow up with the pictures. That is how to get your karma boosted.
Thanks,

Re: Air Spring Ass'y (Air Bags)

Reply #15 – March 11, 2011, 10:32:58 am

FWIW, Firestone no longer sells just the bag with top plate attached. You will have to buy the assembly which includes the piston (bottom part). Places that sell parts for large trucks might have them or be able to get them, since most large trucks (semi tractors) now use air spring suspension. On my coach the rear axle components (bags and shocks) wear faster due the extra weight vs the front axle.

Re: Air Spring Ass'y (Air Bags)

Reply #16 – March 11, 2011, 11:31:46 am

Quote from: Lewis Anderson – March 03, 2011, 03:23:53 pm

Recently I had a front bag with a slow leak. I replaced this bag after driving 1200 mile while using the RAISE button every 90 seconds to get to my destination (family reunion). Leaks are discovered by listening--young ears work best for this--and by a soapy solution sprayed onto the bags, connections, lines. This means crawling under the raised motorhome with a flashlight and a spray bottle and patience.

Andy1

I think I may have found my air leak I have been looking for months because my aux compressor was coming on way to often.
I did not expect it to be an air bag but there it was bubbling like a fountain.
It is on the tag.
Chewing gum did not help stop the leak.

So I will need to have it replaced.

Re: Air Spring Ass'y (Air Bags)

Reply #17 – March 12, 2011, 07:49:32 am

Wow Barry, that is amazing that it failed like that. Your coach is not that old but you did have that broken mount a couple years ago. Do you think that could have caused it?

Re: Air Spring Ass'y (Air Bags)

Reply #18 – March 12, 2011, 08:11:41 am

Quote from: John Sichenze

Wow Barry, that is amazing that it failed like that. Your coach is not that old but you did have that broken mount a couple years ago. Do you think that could have caused it?

2001 42' double slide U320
2007 24' Born Free
Yellow Jeep Wrangler

No way to know. The broken shock mount was on the other side though. It looks like it is a tiny pinhole leak.
I think the level of the coach sometimes must have sealed the leak which is why it appeared intermittent and has taken me so long to locate it.

Re: Air Spring Ass'y (Air Bags)

Reply #19 – March 12, 2011, 08:44:23 am

Quote from: Barry Beam – March 12, 2011, 08:11:41 am

I think the level of the coach sometimes must have sealed the leak which is why it appeared intermittent and has taken me so long to locate it.

Did you happen to notice a pattern - perhaps in a site where the back of the coach was squatted when level - where it didn't seem to leak?

We're having an odd leveling problem that HWH believes is the level sensor - on a perfectly level site our coach will noodle exhausting air and settle almost every hour (Rance at Xtreme even commented on it while he was doing our step conversion). Each time here at Camp FT where the back end is squatted and the front up pretty high, it's been perfectly content. We have other symptoms such as too long a response to out-of-level situation and the coach taking itself out of level. We have a new sensor on order, but since we have the same coach as you it got me thinking.

(Steve hates when I do that

)

Michelle

Re: Air Spring Ass'y (Air Bags)

Reply #20 – March 12, 2011, 09:00:09 am

Interesting Michelle, mine does the opposite. On a steep slope with the front end up it will relevel a lot but with the rear up it does not. It also does not move if we are on the level so in the shop they can not replicate it. I had MOT put it out in front of the bay and we put the level system on and it went up and down like it I had reported. They put in a whole new silver HWH box. I think yours looks different than my 01.

Re: Air Spring Ass'y (Air Bags)

Reply #21 – March 12, 2011, 09:49:15 am

Quote from: Steve & Michelle

Quote from: Barry Beam

I think the level of the coach sometimes must have sealed the leak which is why it appeared intermittent and has taken me so long to locate it.

Did you happen to notice a pattern - perhaps in a site where the back of the coach was squatted when level - where it didn't seem to leak?

We're having an odd leveling problem that HWH believes is the level sensor - on a perfectly level site our coach will noodle and settle almost every hour (Rance at Xtreme even commented on it while he was doing our step conversion). Each time here at Camp FT where the back end is squatted and the front up pretty high, it's been perfectly content. We have other symptoms such as too long a response to out-of-level situation and we have a new sensor on order, but since we have the same coach as you it got me thinking.

(Steve hates when I do that )

Michelle
'03 U320 40' coach 6106
'03 Honda CR-V
and the Posse

My coach is in my driveway. I have not had a chance to notice a pattern since I just found the leak.
But my thoughts were if the coach was sitting closer to the ground vs up higher maybe the leak would self seal as my intermittent slide bladder leak did.

Re: Air Spring Ass'y (Air Bags)

Reply #22 – March 17, 2011, 11:00:13 am

Quote from: Steve & Michelle – March 12, 2011, 08:44:23 am

We're having an odd leveling problem that HWH believes is the level sensor - on a perfectly level site our coach will noodle exhausting air and settle almost every hour. Each time here at Camp FT where the back end is squatted and the front up pretty high, it's been perfectly content. We have other symptoms such as too long a response to out-of-level situation and the coach taking itself out of level. We have a new sensor on order, but since we have the same coach as you it got me thinking.

Well, nothing around the air bags bubbling with the soapy water. We hit them with a spray bottle as best we could, not having blocks with us to get under the coach safely.

I thought for sure we'd find a leaking tag air bag like Barry has. It certainly seemed possible since the coach was very happy with the back down - not once while in the unlevel site at Camp FT did it adjust itself. And in a level situation it eventually got itself so bizarrely out of level that the front slide came in biased to the rear of the opening (the second time this has happened).

Steve thinks maybe a check valve isn't "checking" and letting air move from the back to the front OR filling one of the front air bags when it's not supposed to. The new sensor should be here any day now, so we'll see what that does, but we're not entirely convinced that's the only problem. It's a pain to diagnose since most of it is just letting the coach sit for hours while you observe its behavior.

Michelle

Re: Air Spring Ass'y (Air Bags)

Reply #23 – March 17, 2011, 11:19:57 am

Quote from: Steve & Michelle – March 12, 2011, 08:44:23 am

Well, nothing around the air bags bubbling with the soapy water. We hit them with a spray bottle as best we could, not having blocks with us to get under the coach safely.

I thought for sure we'd find a leaking tag air bag like Barry has. It certainly seemed possible since the coach was very happy with the back down - not once while in the unlevel site at Camp FT did it adjust itself. And in a level situation it eventually got itself so bizarrely out of level that the front slide came in biased to the rear of the opening (the second time this has happened).

Steve thinks maybe a check valve isn't "checking" and letting air move from the back to the front OR filling one of the front air bags when it's not supposed to. The new sensor should be here any day now, so we'll see what that does, but we're not entirely convinced that's the only problem. It's a pain to diagnose since most of it is just letting the coach sit for hours while you observe its behavior.

Michelle

I have lowered the coach to where the air bag leak appears to be sealing itself.
I have not lost hardly any air in 4 days & the aux compressor has not come on.
The new air bag should be here any day to be replaced.
I think finally I may have this long intermittent issue solved.

Re: Air Spring Ass'y (Air Bags)

Reply #24 – March 17, 2011, 03:32:00 pm

We are having all our airbags replaced, as I type. We have been days addressing an air leak that will cause our system to bleed down from 110 to 60 in about 90 minutes. The step cover partially closes or goes in and out in a demented manner. The auxiliary pump adds air, the coach vents air ... it has been making us nuts. For 3 days techs at MOT have been checking every thing they can think of. Several weeks ago techs at FOT checked everything, cleaned and reconditioned air valves, etc. This morning the guys at MOT sprayed all our airbags, and enough of them were bubbling madly that we made the call to replace them all at one shot. Sigh. Interior decorating will be pushed back a bit farther.

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