Exploded Suspension Polyurethane Bushings

[Tillsy]

G'day guys

On my last drive the rear suspension felt it had a real hash thud to it. I've done some inspections and found something perculious - the top-most polyurethane bushings have exploded.

When I look at the front ones, they are not looking great - like they have dried out and are on their way to doing exactly what the rears have. I'm guessing the weight of the engine at the rear has contributed to the faster death.

Has anyone ever heard of this before? The climate here in Australia is much hotter - have they dried out at a faster rate, or is there meant to be some kind of maintenance done on these things? Or were these defective? Purchased from DMC MidWest 2013.
This is the exploded (top-most) rear...
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This is the dried out (but not yet exploded) front..
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And this is the underside of the top of the rear suspension...
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[Patrick C]

That’s crazy. I’ve never seen anything like that. Is it possible that the hole in the frame that the shock passes through is enlarged and the shock moved around, rubbing the bushing away and ripping it up?

[Bitsyncmaster]

Is the red color the bushing or a grease you used to install?

"Polyurethanes may crumble due to hydrolysis" This problem seems to show up on shoes left damp.

[Patrick C]

Is the red color the bushing or a grease you used to install?

"Polyurethanes may crumble due to hydrolysis" This problem seems to show up on shoes left damp.

The AVO shocks come with red bushings.

[BABIS]

this is the same thing that happened to a friend of mine last summer. AVOs bought when available for the first time, about 8-9 years ago. they were also leaking badly..

[Rich06]

The lower front ones cracked and fell out last summer on 1246 after only 3 years. Same red color ones and they are not cheap.

[Josh]

Stick with the plain old black rubber bushings.

[Tillsy]

Good grief so this WAS a failure waiting to happen - and to think the suspension was one of the few items I've got from DMC that hasn't failed in one way or another.

Heaven help anyone ever buying a "new build" from DMC should they ever eventuate - I legitimately fear they will kill someone one day :(

So what rubber bushings do I need then?

[JETS 81 DMC]

Good grief so this WAS a failure waiting to happen - and to think the suspension was one of the few items I've got from DMC that hasn't failed in one way or another.

Heaven help anyone ever buying a "new build" from DMC should they ever eventuate - I legitimately fear they will kill someone one day :(

So what rubber bushings do I need then?

Rubber bushings:
https://www.deloreango.com/us/rubber-suspension-bushing-kit.html

[Tillsy]

Rubber bushings:
https://www.deloreango.com/us/rubber-suspension-bushing-kit.html

They're not for the top of the shock obsorbers?

[thibaut]

you're looking for these :
https://www.deloreango.com/us/spax-rear-top-bush.html

[Tillsy]

you're looking for these :
https://www.deloreango.com/us/spax-rear-top-bush.html

Legend - thank you, ordered 👍

[Tillsy]

Hi guys, quick question.

With the old poly upper shock bushings I remember it was a piece of cake torquing the nut to whatever spec the shocks said they needed.

Now that I'm fitting rubber bushings instead I am going via the DMC workshop manual which says 28Nm (20Ft/lb). However because the rubber compresses so well I am finding I can just keep tightening and tightening without a trigger at even 10Nm, in fact best I can get is 5Nm.

Do I just keep going - am I being overly cautious here, just worries me it is compressing right down by at 10Nm still no pulse yet... I know there's two bushings to compress but still 20Nm seems it must be insanely tight....
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[Bitsyncmaster]

Hi guys, quick question.

With the old poly upper shock bushings I remember it was a piece of cake torquing the nut to whatever spec the shocks said they needed.

Now that I'm fitting rubber bushings instead I am going via the DMC workshop manual which says 28Nm (20Ft/lb). However because the rubber compresses so well I am finding I can just keep tightening and tightening without a trigger at even 10Nm, in fact best I can get is 5Nm.

Do I just keep going - am I being overly cautious here, just worries me it is compressing right down by at 10Nm still no pulse yet... I know there's two bushings to compress but still 20Nm seems it must be insanely tight....
62720

I just tighten the nut till the bushings look fairly well compressed.

[Tillsy]

Thank you - fronts now complete. Those were still intact but I did them first to ensure the new rubber ones matched the size of the former polys, since the rears don't even exist anymore!

So I've now taken apart the rears - thankfully the hole wasn't widened but the paint was removed from the frame, so in progress of fixing that.

However whilst in there I noticed something concerning, the poly bushing for the bottom of the shock seems to have some room for play... it has flexed around a bit. Still intact thankfully as doesn't appear I can buy replacements for those, but I'm a bit stunned there is room to move (not that I can as it is under pressure, but this still doesn't look right).

I can't find the original install/spec notes for those shocks so I don't know what they were meant to be torqued to - so consulted the DMC workshop manual for the standard specs and they aren't listed in the rear suspension section. Anyone know what this should be torqued to? Although whatever it is is what I would have done at the time - perhaps some friction caused my tool to prematurely trigger early... although BOTH sides are like this so that doesn't sound right...

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[painterdave72]

chris.. contact ed uding and he can sell u a set of those. mine did the same thing on the bottom ones and had a hole rubbed in the top inside of them.. Dave..

[Bitsyncmaster]

Those rear bushings do not look like they are the correct part. Maybe they were not installed in the right direction and the nut was not tightened enough.

[Tillsy]

Those rear bushings do not look like they are the correct part. Maybe they were not installed in the right direction and the nut was not tightened enough.

I don't have a photograph with me, but when originally installed they sat beautifully flush they didn't look anything like the buckled mess they are now :(

[Tillsy]

chris.. contact ed uding and he can sell u a set of those. mine did the same thing on the bottom ones and had a hole rubbed in the top inside of them.. Dave..

So Ed has confirmed there was a bad batch of these many years ago. Great :(

[Tillsy]

So this is the only real picture I could find from my original install where I could zoom in on these bushings.

They look fine here - exactly as I remembered, a perfect fit after torquing.

So regardless of a flaw, I still don't get how they've ended up as they are with so much room.... you can see the nut is still in the same position, has the bushing compressed or something?!

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[Tillsy]

So I have the replacement bushings from Ed - and can now see the originals have definitely compressed and buckled (and per painterdave72 a tiny hole has worn too).

Next dilemma - after finally freeing the rear shocks I see these bushings seem to be sleeved... how the hell do I swap them??? @painterdave72 what did you do to replace yours?

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[Tillsy]

Okay found the problem - Ed had mentioned something about washers being an issue too and would include replacements for me. They didn't unfortunately come, but it had me thinking looking at that picture... there seems to be what looked like a washer wedged in there. Sure enough, I popped it out... so hence all the problems, too small to be alongside and too large to wedge itself inside hence the damage.

62975

So was then able to easily slide out that inner sleeve and rip off the old bushing. Now the final question, how on earth do I push the new bushing in... it's too firm for the wedge to go through. Do I smother it in grease perhaps?

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[painterdave72]

yes those are a bitch to push in. I heated mine with a heat gun on low setting to soften them up .. then pushed one side in and sort of folded it upon itself a little to push thru. I also used a rounded center punch to push as not to damage it.. works well enough. .I suppose u could use a press but that seems like overkill.. the heat really makes it much more pliable though...hope that helps..

[Ron]

62975

I have the same set up. The washer in your pic goes between the nut and another washer, which has a much larger OD. Its OD is about the same as the OD on the tube at the bottom of the shock:

62984

I agree with Bitsy -- Tighten the nut until the bushing bulges a bit, ~filling the face of the washer.
(Make sure that the bolt is pulled tight against the rest of the assembly first!)

[IIRC, the torque spec is for OEM types where the washer tightens against the inner spacer and stops at the correct preload automatically.]

P.S. Spray silicone is your friend during assembly.

[Tillsy]

Legends, thanks both of you 👍

62985

[Tillsy]

Keep forgetting to update that I finally completed the work and have had her on the road a couple weeks now.

I installed my shock and suspension upgrade a long time back and, while I dialled the hardness down somewhat, was used to the suspension having quite a harsh feel directly into the frame of the car.

To that end switching those top bushings to rubber has been nothing short of amazing - totally and utterly new car. There is no longer the harsh feel of the past - I'm not talking soft suspension, I still have it dialled up, I'm just talking about actual cushioning when hitting something hard like bumps in the road or going up a driveway.

Super happy - albeit still overall pissed that, like everything that goes wrong with DMC parts, we just have to suck it up ourselves really frustrating.

[82DMC12]

Keep forgetting to update that I finally completed the work and have had her on the road a couple weeks now.

I installed my shock and suspension upgrade a long time back and, while I dialled the hardness down somewhat, was used to the suspension having quite a harsh feel directly into the frame of the car.

To that end switching those top bushings to rubber has been nothing short of amazing - totally and utterly new car. There is no longer the harsh feel of the past - I'm not talking soft suspension, I still have it dialled up, I'm just talking about actual cushioning when hitting something hard like bumps in the road or going up a driveway.

Super happy - albeit still overall pissed that, like everything that goes wrong with DMC parts, we just have to suck it up ourselves really frustrating.

Chris, I'm getting ready to order some parts from DeLoreanGo including the AVO shocks. So if I'm correct, you're using the poly bushings at the bottom of the shocks but you're using the black rubber bushings for the top mounts? On all four shocks? I want a dampened feel, not harsh ride, and if your experience can help someone else it sounds like I should ask for rubber tops instead of poly tops when I order?

[Tillsy]

Chris, I'm getting ready to order some parts from DeLoreanGo including the AVO shocks. So if I'm correct, you're using the poly bushings at the bottom of the shocks but you're using the black rubber bushings for the top mounts? On all four shocks? I want a dampened feel, not harsh ride, and if your experience can help someone else it sounds like I should ask for rubber tops instead of poly tops when I order?

Correct - poly bottom, rubber top, all four.

You can dial the shocks to any feel you like - but with the poly bushings there was a harshness transferred directly into the frame, whereas with the rubber it's a totally and utterly different (and glorious) feel. I'd never go poly at the top again personally - regardless of whether they explore or not

[Patrick C]

Correct - poly bottom, rubber top, all four.

You can dial the shocks to any feel you like - but with the poly bushings there was a harshness transferred directly into the frame, whereas with the rubber it's a totally and utterly different (and glorious) feel. I'd never go poly at the top again personally - regardless of whether they explore or not

This is good to know, as I HATE how harsh my AVO shocks are up front. Maybe this was my problem all along and I had been blaming my low profile tires and larger wheels.

[ssdelorean]

Correct - poly bottom, rubber top, all four.

You can dial the shocks to any feel you like - but with the poly bushings there was a harshness transferred directly into the frame, whereas with the rubber it's a totally and utterly different (and glorious) feel. I'd never go poly at the top again personally - regardless of whether they explore or not

Did Ed provide or did you source the rubber bushings else where? (Energy Suspension / Summit Racing, etc ?)

[DMC02766]

Did Ed provide or did you source the rubber bushings else where? (Energy Suspension / Summit Racing, etc ?)

Glad I came across this thread- Im in the process of a frame off restoration and havent even driven on this suspension yet and here is what it looks like. This is just from sitting parked in the shop... very frustrating to spend that kind of money on performance parts that apparently had a flaw in them. I coated these in energy suspension grease before installing for the sole purpose of not having something like this happen. Anyone know what the warranty is on these? I have no intentions on spending money with the vendor I got these from to purchase replacement parts on something that shouldn't have broken like that to begin with. Thanks for the tip on the front suspension- going to be ordering those bushings soon from D-GO.

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[merfeldma]

Glad to see I'm not the only one with this problem. Last week I was driving and could hear some rattling when I would go over bumps. First I thought it was the louvres rattling, but when I got out and started pushing on the suspension I could hear it. These were installed in 2014 by DMC FL with the Eibach Performance Pro-Kit. Eibach doesn't list any of the individual parts and I was able to get a temporary solution from O'Reilly until the rubber bushings from DeLoreanGo arrive.
Anyone with these red polyurethane bushings, be warned that they could go at any time.
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[DMC-81]

Well, I'll add my experience to this thread.
I also suffered top polyurethane bushing failure in July 2021 on AVO shocks installed in September 2015. It has been almost 6 years, but only 3,000 miles. Of the two per shock, as reported above the uppermost rear bushing exploded and the bottom one was cracked. The front bushings were also cracked.

Here are the rear bushings or what's left of them:
http://dmctalk.org/attachment.php?attachmentid=66804&d=1626490090

Here was the carnage on the uppermost rear AVO polyurethane bushing after it disentegrated/exploded:
http://dmctalk.org/attachment.php?attachmentid=66805&d=1626490509
Here is the bottom rear upper AVO polyurethane bushing cracked:
http://dmctalk.org/attachment.php?attachmentid=66806&d=1626491297

Here is the front uppermost AVO polyurethane bushing cracked:
http://dmctalk.org/attachment.php?attachmentid=66807&d=1626491581
The other ones were not as hard as they were originally, so clearly they are breaking down.

Original install in September 2015:
http://dmctalk.org/attachment.php?attachmentid=36801&d=1442183506
http://dmctalk.org/attachment.php?attachmentid=36810&d=1442185761

I chose rubber replacement bushings #109087 from DeLoreanGo:
http://dmctalk.org/attachment.php?attachmentid=66808&d=1626492029


Here are the rear rubber bushings installed. I used 13 ft/lbs torque on the nut, as the OEM 20 ft/lbs was too much torque for this application:
http://dmctalk.org/attachment.php?attachmentid=66809&d=1626492548

Here are the front bushings installed:
http://dmctalk.org/attachment.php?attachmentid=66810&d=1626492810.

If you have these polyurethane bushings, I would replace them before they fail.

[Michael]

I recently installed the AVO shocks from DeLoreango. I was indeed warned by a well respected vendor the bushings had a reputation for premature failure but were not that hard to replace. I will definitely be keeping an eye on them. After reading this thread, I have to wonder why people would replace any rubber bushing with poly. Seems like it causes more problems...in fact it seems like it accelerates the problem they were supposed to solve.

[DMC-81]

I recently installed the AVO shocks from DeLoreango. I was indeed warned by a well respected vendor the bushings had a reputation for premature failure but were not that hard to replace. I will definitely be keeping an eye on them. After reading this thread, I have to wonder why people would replace any rubber bushing with poly. Seems like it causes more problems...in fact it seems like it accelerates the problem they were supposed to solve.

I agree. I installed polyurethane bushings on my V8 Fiero 20+ years ago, and in terms or ride quality, I forgot how harsh they were. I test drove the DeLorean today after the work, and like Tillsey reported above, it made quite a difference. There is a noticeable improvement in cushioning against road imperfections. Before, no matter how much I dialed down the shock settings, a drive down a brick street telegraphed every crack through the car. That's gone now, and the car has a more balanced feel of tightness you'd expect from a sport suspension without the harshness. I'm really happy.

Bottom line, I still really like the AVO shocks and I'd buy them again, but I wish I'd discovered these 8 little rubber bushing replacements sooner.

[DMC-Ron]

In addition to the 109087 rubber bushings, do you also need the 10989 washers. I have the AVO shocks. And can the top bushings be replaced without removing the shock (car on lift with spring extended)? I recall the bottom connection was tight to install.

Ron

[DMC-81]

In addition to the 109087 rubber bushings, do you also need the 10989 washers. I have the AVO shocks. And can the top bushings be replaced without removing the shock (car on lift with spring extended)? I recall the bottom connection was tight to install.

Ron

If your AVO washers are still good, you don't need washer 109089. I confirmed that these are identical to the AVO washers and the rubber replacement bushings fit nicely with them.
The front bushings can be replaced without taking the spring out. With the car on jackstands or a lift, just lift each front side up with a jack under the lower ball joint enough to relieve the pressure on the top 9/16" nuts. Then, remove the nuts and next the lower bolt and slide the shock out the bottom.
For the rear you would do the same thing to relieve the pressure, but you'll need spring compressors to lower the coil over unit down enough to replace the bushings.
I used the Workshop Manual torque specs on the lower bolts.

[Helirich]

On polyurethane bushings,

Polyurethane should last way longer than rubber. In the OP issue, I suspect that company mixed a bad batch. Of course they probably made hundreds of bushings with that batch. They may keep selling till they run out.

Now having said that, you might think I endorse them. I do not. Polyurethane bushings have almost no give to them. The whole purpose of a rubber bushing is to isolate the part alittle. That's why people complain of vibrations. You might as well mount it solid. I've seen polyurethane bushings crack steel in some locations where the rubber never would have.

There maybe a few locations where going poly makes sense, but not many.

[Josh]

On polyurethane bushings,

Polyurethane should last way longer than rubber. In the OP issue, I suspect that company mixed a bad batch. Of course they probably made hundreds of bushings with that batch. They may keep selling till they run out.

Now having said that, you might think I endorse them. I do not. Polyurethane bushings have almost no give to them. The whole purpose of a rubber bushing is to isolate the part alittle. That's why people complain of vibrations. You might as well mount it solid. I've seen polyurethane bushings crack steel in some locations where the rubber never would have.

There maybe a few locations where going poly makes sense, but not many.

i used to think this way. However I installed a full poly setup (superflex) in my rear suspension to combat wheel hop issues. They ride better than stock. Especially with the awful failing TAB bushings we have available now, this is a great alternative.

These AVO poly bushings are a known failure item, they messed something up.

[Tillsy]

On recent drive I could hear a metal knocking sound coming from the front.

Took quite a bit of troubleshooting to find the source but, drumroll, turns out the FRONT bottom poly bushings have failed now.

So originally the rear top poly bushings literally exploded/crumbled 6.5 years after purchase and install. In the process of replacing the top of all four with rubber discovered the rear poly bushings were not in good shape either, and replaced those with like for like poly (no rubber alternative).

And now 4.5 years later the FRONT bottom poly bushings have failed. Well one is simply completely missing (hence the metal knocking sound), the other looks like it could be corroding.

https://dmctalk.org/attachment.php?attachmentid=70785&d=1723878076

https://dmctalk.org/attachment.php?attachmentid=70784&d=1723878076