Powerflex Bushes - Back to Front?

Powerflex Bushes - Back to Front?

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TIIVRS

Original Poster:

78 posts

83 months

Sunday 31st January 2021
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Had my suspension put back together by a TVR specialist after a chassis refurb with powerflex bushes.

The front lower bush that fits into the trailing arm has been replaced with the bush flange facing towards the rear of the car The inside bend of the arm (this is how the OE bushes were when I got the car).

This bush has failed within a couple of thousand miles, on inspection it looks like friction against the big washer has caused this (on dismantling the smaller Delrin washers that were provided as part of the power flex kit were not used - possibly due to thicker powder coating?) and so I plan to use these on re-assembly - this could have caused some of the problem.

What I’d really like help with please is that I have read the instructions for this bush and they clearly state that the powerflex bushes should be positioned on the outside bend of the arm (facing forward) which is in the opposite position to how the OE ones were and also how the ‘expert’ has fitted them recently.

Can anyone help?? Have these bushes been put in the wrong way around, as powerflex seem to indicate, or will the problem simply be because the Delron washer was missing that the bush has failed.

Original - positioned in the inside bend


Failed - positioned in the inside bend


Here is how it looks for the surviving bush.

Instructions - saying bush should be on outside bend


I want to make sure I put this back together the right way.
Powerflex have kindly sent me replacement bushes under warranty.

Does anyone have these bushes fitted and working, how are they placed, it seems odd to me that powerflex would want them positioned the opposite way around as it looks like it will make quite a difference to the suspension geometry....

spitfire4v8

4,018 posts

195 months

Sunday 31st January 2021
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TIIVRS said:
.

this is the correct way .. the bush provides the cushioning against the braking action trying to pull the lower arms rearwards (and the top arms push forwards of course)

The OE rubber bushes exaggerate any brake judder when they get pliable with age and the powerflex bushes neatly reduce this considerably by their nature of being stiffer in compression than the original rubber versions, but judging by your post they will be a service item rather than fit and forget.

spitfire4v8

4,018 posts

195 months

Sunday 31st January 2021
quotequote all
Incidently i also saw the other day that powerflex now supply the rear diff bush in 2 parts. When I originally set all the tvr bushing up with powerflex they sent me a 2 part sample for the diff bush and it squished out / separated somewhat when put in service and I then got them to supply it as a one piece bush instead. It now looks like some oik has convinced them to make it a 2 part bush again.

TwinKam

3,321 posts

109 months

Sunday 31st January 2021
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spitfire4v8 said:
Incidently i also saw the other day that powerflex now supply the rear diff bush in 2 parts. When I originally set all the tvr bushing up with powerflex they sent me a 2 part sample for the diff bush and it squished out / separated somewhat when put in service and I then got them to supply it as a one piece bush instead. It now looks like some oik has convinced them to make it a 2 part bush again.
I was just about to order a set of three from RG (best value), would you advise against these two-piece ones then, Jools? Or maybe reuse my existing one-piece polys? (on a Cerb)
Rik

TIIVRS

Original Poster:

78 posts

83 months

Sunday 31st January 2021
quotequote all
Great thanks, that gives me some confidence, I thought I was going mad, odd they got the instructions so wrong!

I will fit them with the washer in place, hopefully that will sort it, I’ll try and remember to follow up next year to see if it’s sorted..

ukkid35

6,341 posts

187 months

Monday 1st February 2021
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TwinKam said:
I was just about to order a set of three from RG (best value), would you advise against these two-piece ones then, Jools? Or maybe reuse my existing one-piece polys? (on a Cerb)
Rik
This is what I used on mine many years ago, not sure how they can fail as they still look perfect to me

How do you fit the one piece bushes?

I promise I wasn't the oik Joolz mentioned...


TwinKam

3,321 posts

109 months

Monday 1st February 2021
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ukkid35 said:
TwinKam said:
I was just about to order a set of three from RG (best value), would you advise against these two-piece ones then, Jools? Or maybe reuse my existing one-piece polys? (on a Cerb)
Rik
This is what I used on mine many years ago, not sure how they can fail as they still look perfect to me

How do you fit the one piece bushes?

I promise I wasn't the oik Joolz mentioned...

I had a 'chat' with Jools today and he said these looked OK as there was a much larger supporting plate at each end compared to the Powerflex ones that he was referencing.
Cracking price for the set of three from Racing Green so I'll give them a go.
The one piece ones 'just' pull/push in like any other bush (obviously remove the steel centre tube first) and I removed mine intact, but I bet it's a struggle with the body on and all the suspension in place hehe

ukkid35

6,341 posts

187 months

Tuesday 2nd February 2021
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partsfortvrs said:
They are very easy to fit and do not need any special tools to fit however removing the original bushes may not be so easy.
You don't say...