Anyone had this rear suspension component fail?

**POD** · 14th March 2025, 11:04 AM

A gap at the rear suspension 'trailing arm to chassis' bush caught my eye the other day and I assumed it was yet another worn-out bush but closer inspection revealed a different problem. The rear suspension trailing arm pushes forward against the bush via a large, thick washer. The washer was distorted, visible in this pic
rear suspension washer 2.jpg
but when I looked closer, especially after removing the washer, it was apparent that the shoulder of the trailing arm was making a pretty good effort at pushing it's way right through the washer
rear suspension washer 1.jpg

Seems to me that if this progressed to the point that the shoulder of the trailing arm pushed it's way through the washer, the axle would suddenly move forward, resulting in all manner of unpleasantness.

I've had too many of these vehicles over the years so there are always spares of whatever floating around the shed somewhere and I located another set of these washers with similar wear that I had not picked up at the time, probably because the disc had remained relatively flat and I didn't look closely at it. The washers (or discs) are of two types; the one that sits on the pushing side of the bush has a chamfer in the hole that sits over a radius on the arm. The one on the other side of the bush does not have this chamfer. I solved my immediate problem by taking a non-chamfered washer and chamfering it with a large 60 degree countersink using a drill press, working incrementally until the chamfer was deep enough for the flat part of the disc to contact the flat part of the shoulder on the trailing arm. I've flattened the other two discs and will henceforth carry them as spares in case one looks near to failing when out and about.

I'm wondering if anyone has experienced a failure where the trailing arm has punched forward through the disc and then through the bush?

**V8Ian** · 14th March 2025, 04:09 PM

Never seen it myself, but I've never looked for it.
It might be worth asking the same question in the D1, D2 and RRC sections, they all share the same basic suspension.

**Blknight.aus** · 14th March 2025, 08:24 PM

yes, it happens if the rubbers are not replaced when needed or the chassis bolt isnt pulled down tight enough. As the axle shunts the radius rod back and forth it turns into a slide hammer.

If the shoulder on the rod is rounded get a new rod or its just going to happen again.

also, you might want to check the threads on that one.

it looks like it might have some thread damage but that could just be the pic.

**POD** · 14th March 2025, 09:04 PM

Originally Posted by Blknight.aus

yes, it happens if the rubbers are not replaced when needed or the chassis bolt isnt pulled down tight enough. As the axle shunts the radius rod back and forth it turns into a slide hammer.

If the shoulder on the rod is rounded get a new rod or its just going to happen again.

also, you might want to check the threads on that one.

it looks like it might have some thread damage but that could just be the pic.

So you have seen these punch through the disc and through the bush? I've never heard of it happening but there definitely appears to be potential there. Would no doubt result in all sorts of damage- I'm picturing bent shockers, damaged tailshaft, broken brake lines etc.

I'm not sure I agree about it being from impact, I rather suspect it's from the effect of what is a tiny surface contact area pushing a heavy vehicle (my 130 would frequently be over 3 tonne) up some very steep terrain whilst articulating the radius arm; fretting corrosion probably a factor, mainly just just plain old heavy wear. Something I will certainly be keeping a close eye on in future.
The thread on the arm is ok but yes there is also some wear to the shoulder of the arm where the disc seats. it would be nice if that friction-welded threaded part had a much larger head to provide some more surface area.

**Blknight.aus** · 14th March 2025, 10:14 PM

Originally Posted by POD

So you have seen these punch through the disc and through the bush? I've never heard of it happening but there definitely appears to be potential there. Would no doubt result in all sorts of damage- I'm picturing bent shockers, damaged tailshaft, broken brake lines etc.

I'm not sure I agree about it being from impact, I rather suspect it's from the effect of what is a tiny surface contact area pushing a heavy vehicle (my 130 would frequently be over 3 tonne) up some very steep terrain whilst articulating the radius arm; fretting corrosion probably a factor, mainly just just plain old heavy wear. Something I will certainly be keeping a close eye on in future.
The thread on the arm is ok but yes there is also some wear to the shoulder of the arm where the disc seats. it would be nice if that friction-welded threaded part had a much larger head to provide some more surface area.

The one I've seen the after effects of personally, was punched into an after market long range fuel tank on the driver side.

**AK83** · 15th March 2025, 07:53 AM

I've seen bent washer myself on some wrecks, but just assumed it was due to rough handling of the hulk.

D1 and RRC has same trailing arm, D2 is different, never seen it on mine.

**p38arover** · 15th March 2025, 11:37 AM

Originally Posted by V8Ian

Never seen it myself, but I've never looked for it.
It might be worth asking the same question in the D1, D2 and RRC sections, they all share the same basic suspension.

No, we don't ask the same question across multiple fora. If anywhere, it should be in Technical Chatter.

**Tins** · 15th March 2025, 11:47 AM

Originally Posted by p38arover

No, we don't ask the same question across multiple fora. If anywhere, it should be in Technical Chatter.

That's a pity, because unless people make regular use of the "New Posts" button the audience is greatly diminished and therefore answers are fewer.

**POD** · 15th March 2025, 12:19 PM

A more likely problem with a heavy 130 anyway I think.

**p38arover** · 15th March 2025, 12:23 PM

Originally Posted by Tins

That's a pity, because unless people make regular use of the "New Posts" button the audience is greatly diminished and therefore answers are fewer.

It’s always been that way on the forum. I can’t help it if people only look at one section of the forum (and some do), e.g., some only look at the section that refers to their vehicle model.

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