P38A "Popping Air Suspension

When I bought my 1999 P38A DSE I had suspension airbags fitted. One, the rear offside , was very tired. Within a week it had blown off its bottom fitting. I assumed that my mechanic had fitted it incorrecty I bought a replacement and had it fitted by my local expert.
It's been fine for a while. Saturday night I was towing my trailer home. Our house is well protected by so called speed traps whose chief purpose is suspension wrecking. This time a Speed pillow caught out the
trailer (at 5mph). The trailer dipped then rose up abruptly. Loud squeeky pop and lowered suspension resultd.The air bag in question has folded over and com off the base for half its diameter.
Can any one explain and suggest a fix? The bags in question were Dunlops, Could a spring assister help?

sounds like the trailer movement has literally ripped the bag of its seat!!
few light hearted suggestions...
1, move house!
2, convert to coils!(swearing)
3, put a complaint into the council with a garage report and demand they pay to upgrade to arnott generation 3 airbags.
it does sound like your bus was lifted out if its airbag travel range!! Although you shock absorbers shouldn't allow them to go to far??
are your shocks standard?

Something very wrong. Either fitted wrong again or somthing bent or out of line. Check all the suspention components are actually there ie roll bar. Check bag mountins for damage

but the rear air bags fit or won't fit, remember there are two R'pins, one above and one below?
my thought was upgraded shocks with extra travel?

unless it's a duff airbag??

New one on me. Ive just done 1k mile to france with 2ton van on back no prob on some bad roads

Only other suggestions are a leaky valve letting them overinflate but then the handling would be all over the place and you'd need steps to get in.
Either way, as said above, the shocks should limit the travel and stop the bags getting torn off.
Other thing could be the lateral bar missing or so worn it allows lots of sideways movement maybe.
Certainly shouldn't be wrecking airbags like that.

It should not be possible for the air bag to over extend and come off. Sounds like someone has fitted the longer front shocks on the rear. On full extension this would cause a bow to the rear in the bag centre area, then when weight is reapplied the bow has increased and the bag has folded then flipped off the bottom mount.

my thoughts are the shocks as well. Have you had any work, other than the airbags on the rear done recently?

wammers said:

It should not be possible for the air bag to over extend and come off. Sounds like someone has fitted the longer front shocks on the rear. On full extension this would cause a bow to the rear in the bag centre area, then when weight is reapplied the bow has increased and the bag has folded then flipped off the bottom mount.

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Its either that or 2 in extended shocks have been fitted

wammers said:

It should not be possible for the air bag to over extend and come off. Sounds like someone has fitted the longer front shocks on the rear. On full extension this would cause a bow to the rear in the bag centre area, then when weight is reapplied the bow has increased and the bag has folded then flipped off the bottom mount.

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You are so correct! The bag(s) have all been folded in the middle and the front edge of the the lower seal has lifted off the base. He ho, new dampers reguired.
You are all so helpful, many thanks.
Martin

Martin Knott said:

You are so correct! The bag(s) have all been folded in the middle and the front edge of the the lower seal has lifted off the base. He ho, new dampers reguired.
You are all so helpful, many thanks.
Martin

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Make sure when you get new shocks they are standard ones and the longer fronts are indeed fitted on the front. Extended shocks CANNOT be fitted to cars with standard bags or they will cause a world of pain.

Well, Everyone was part correct. I bought new Standard dampers. My dear Son took the old ones off in pouring rain (so glad I trained him from the age of four up!) The ones on were standard but the offside rear must have leaked at some time and had about four inches of undamped movement as it approached full extension. So, whilst it was limiting the extension of the air bag it was allowing very rapid extension, and subsequent collapse on the extreme of movement, such as speed bumps with a trailer on. Problem solved. Thanks to everyone.
Martin

Now you mention it, that might be how my rear one popped off. The front damper had snapped so maybe the front dipped too low popping the rear off.

It appears to me that the condition of the dampers is critical in cases where the air bags have pulled off the base and have no other damage. My three bags have all shown this, although the first one was well worn it should no sign of leakage, just folded over and off the base.