P38A Blown rear air spring

BarryA · Jan 12, 2020

Hi All. Was playing off-road yesterday and the rear drivers side air spring blew. It’s cracked the base of the spring where it joins to the axle. Whilst I realise this is the risk of off-roading on air, I have had the motor for 4 years with no issues on the suspension and I’ve now blown the same corner twice in as many months. Question is, as the same corner has gone twice is there anything else I need to be looking at that could be causing this (bushes, shocks etc?)

Datatek · Jan 12, 2020

Worth checking the shock has the correct travel length and that the mountings are good, but may just be coincidence.

oakey · Jan 12, 2020

If that was the only spring you changed then I would suspect perhaps there wasnt air in it when you first put weight on it. That would make it crease and weaken it maybe

Datatek · Jan 12, 2020

oakey said:
If that was the only spring you changed then I would suspect perhaps there wasnt air in it when you first put weight on it. That would make it crease and weaken it maybe

There is an airbag replacement guide in the Technical archive.

BarryA · Jan 12, 2020

Datatek said:
There is an airbag replacement guide in the Technical archive.

Thanks. Will review before starting the replacement.

Grrrrrr · Jan 12, 2020

BarryA said:
Hi All. Was playing off-road yesterday and the rear drivers side air spring blew. It’s cracked the base of the spring where it joins to the axle. Whilst I realise this is the risk of off-roading on air, I have had the motor for 4 years with no issues on the suspension and I’ve now blown the same corner twice in as many months. Question is, as the same corner has got twice is there anything else I need to be looking at that could be causing this (bushes, shocks etc?)

What brand and from where? Dunlop?

BarryA · Jan 12, 2020

Grrrrrr said:
What brand and from where? Dunlop?

It was a Dunlop bag and I bought it from the local 4x4 independent

Grrrrrr · Jan 12, 2020

BarryA said:
It was a Dunlop bag and I bought it from the local 4x4 independent

Should be fine although you never know these days, it might have been a chinese copy. The spring should just absorb the impact. Odd.

Datatek · Jan 12, 2020

Sometime they are very old stock. try somewhere like Island 4 x 4 who have a large turnover of stock.

RangeRoller dt · Jan 12, 2020

On extreme articulation there is quite an angle on the bag.

Grrrrrr · Jan 12, 2020

RangeRoller dt said:
On extreme articulation there is quite an angle on the bag.

Shock should stop it before it extends that far, unless front shocks are on rear.

RangeRoller dt · Jan 12, 2020

+1 shocks fuffed
I presume when you were underneath you checked everything is secure? TerriblyFirms seem to come orf at ends, I was surprised how much longer and stiffer new ones were when I changed mine.

RangeRoller dt · Jan 12, 2020

+1 shocks fuffed
I presume when you were underneath you checked everything is secure? TerriblyFirmas seem to come orf at ends, I was surprised how much longer and stiffer my new shocks were.

wammers · Jan 13, 2020

P38 shocks are two different lengths. Front ones are longer than the rears. This will happen if you fit front shocks in rear positions. Longer than standard length shocks should NOT be fitted to either front or rear on a P38.

BarryA · Jan 13, 2020

wammers said:
P38 shocks are two different lengths. Front ones are longer than the rears. This will happen if you fit front shocks in rear positions. Longer than standard length shocks should NOT be fitted to either front or rear on a P38.

I haven’t touched the shocks since I got the motor 4 years ago but I’ve got a new set of rears ready (Boge) to put on along with the new bag.

dubbleRR · Jan 13, 2020

BarryA said:
It’s cracked the base of the spring where it joins to the axle.

Is the spring base plate on the axle flat where the spring sits .A bad seat might cause fatigue over time ....RR

wammers · Jan 13, 2020

I a

BarryA said:
I haven’t touched the shocks since I got the motor 4 years ago but I’ve got a new set of rears ready (Boge) to put on along with the new bag.

I'm not saying you have changed the shocks, but someone else may have got front and rear mixed up. For road use this would not be a problem, off road using max articulation it certainly will be.

BarryA · Jan 13, 2020

Thanks all for the advice. I’ll be replacing both rear shocks when I do the spring on Wednesday and I’ll compare the lengths. I’ll also check both upper and lower mount plates for flatness. Hopefully I’ll find something and be able to report back. If not I’ve been offered a couple of old springs that can be pushed to destruction in an effort to find out what’s wrong.

BarryA · Jan 17, 2020

Just a quick update. Changed out the spring and noticed that there’s a little distortion on the axle spring mount and therefore the bottom of the spring doesn’t seem to be sitting completely flat. Going to get that fixed and hopefully that solves the problem. Everything including the shocks seem fine. Thanks again for all the advice.

Grrrrrr · Jan 19, 2020

BarryA said:
Just a quick update. Changed out the spring and noticed that there’s a little distortion on the axle spring mount and therefore the bottom of the spring doesn’t seem to be sitting completely flat. Going to get that fitted and hopefully that solves the problem. Everything including the shocks seem fine. Thanks again for all the advice.

I might be wrong but I seem to remember when fitting the rear springs I put the top in and then had to push the bottom down to get it flat and get the pin in. How far out is it

Can anyone else remember from when they did theirs? @pwood999 or @Datatek, maybe?

Datatek · Jan 19, 2020

Grrrrrr said:
I might be wrong but I seem to remember when fitting the rear springs I put the top in and then had to push the bottom down to get it flat and get the pin in. How far out is it

Can anyone else remember from when they did theirs? @pwood999 or @Datatek, maybe?

I did top in first, then popped the bottom in after raising the axle a little. The plate must be flat.

P38A Blown rear air spring

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