MGTF PolyBush compliance bushes

MGTF PolyBush compliance bushes was created by Freshmemes

Posted 3 months 4 days ago #208458
Does anyone have any experience changing the compliance bushes on an MGTF to polybush ones like these found on Rimmerbros https://rimmerbros.com/Item--i-RGU00024050PBO ?
Can it be done with the bushing holders on the car with a simple threaded bushing press/puller?
 
Last Edit:3 months 4 days ago by Freshmemes
Last edit: 3 months 4 days ago by Freshmemes.

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Replied by Delbourt on topic MGTF PolyBush compliance bushes

Posted 3 months 4 days ago #208462
I very much doubt that.
i considered this job and read Roger Parker’s book on some of this stuff and may even have talked to him about it.
In simple terms you need a press to push them in.
To get them out you need to hacksaw through the old bush rubber, then saw the sleeve to the shell surface before knocking the sleeve out.
when you press them in you need a purpose built support for the shell of one of them (the fabrication is set at an angle)
For a reason that I can’t remember you have to drop the subframe about 2 inches to get clearance for some bolt.
There is a high probability of shearing the small bolts and the need to weld in replacement ~ depending on rust etc.

That is my take on the job. A right ****””#
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Replied by Freshmemes on topic MGTF PolyBush compliance bushes

Posted 3 months 3 days ago #208472
I doubted it would be an easy job having had the fun of already replacing the rose joint type bushes at the rear with a threaded type press/puller, I have seen some videos of drilling out bushings in other cars which might work, Ill contact polybush and see if they have a guide.

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Replied by MGB281 on topic MGTF PolyBush compliance bushes

Posted 3 months 3 days ago #208474
I just used a cordless drill to remove the rubber. Then driving a thin narrow chisel between the outer case and the bush outer tube caused it to literally fall out. I pressed the new bushes in with the vice. 
by MGB281

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Replied by Freshmemes on topic MGTF PolyBush compliance bushes

Posted 3 months 2 days ago #208484
Thanks for the info, do they only come out one way, I assumed the have to come out upwards if they were in the car?

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Replied by Goodwood on topic MGTF PolyBush compliance bushes

Posted 3 months 2 days ago #208485
I looked into doing this last year when upgrading my suspension. There is not a lot of information regarding changing these bushes on this site as well as others. I eventually got the impression that it was both a difficult job and not that essential. I was advised by VHS that while upgrading the front suspension with poly is a good idea, the rear was not so necessary. Unless your compliance bushes are really worn and require replacement, I would leave them alone. 
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Replied by Delbourt on topic MGTF PolyBush compliance bushes

Posted 3 months 2 days ago #208486
I would tend to agree with that. Aas stated I considered doing this job for various reasons and accepting various recommendations from people who had worked on my car.
I obtained some spare bushes (metalwork) and cut out the rubber bits . Those needed more than a gentle tap to get them moving. I made a timber support to hold the one with the angled base so it could be supported in line with the axis of the press - very useful apparently as stated by the workshop that did the job.
The workshop had one heck of a job in getting the bolt out of one of the bushes - don’t know which one. As stated one of the nuts used to support the subframe had to be replaced as the bolt sheared off (not unusual apparently).
As observed by Goodwood the new bushes made little if any difference that I could detect.

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Replied by Freshmemes on topic MGTF PolyBush compliance bushes

Posted 3 months 14 hours ago #208521
I'm not sure how worn the bush is but it does have the tell tale clunk that the rubber ring around the top has worn to the point the trailing arm can hit the bushing assembly causing a clunk and also a rattle when setting off. It has been mentioned that you can bodge this with bits of plastic or cutting and making a rubber shim but I'd rather replace bushing and the ring as the car has about 130k miles so its most likely work as well.

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Replied by Freshmemes on topic MGTF PolyBush compliance bushes

Posted 3 months 14 hours ago #208522
My main reason for wanting to replace them is the clunking coming from the rear which is mainly on the left side but also occasionally on the right, having read online it would appear to be because the rubber on the top of the bushing has worn down to the point the metal of the trailing arm hots the bushing assembly.

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Replied by Cobber on topic MGTF PolyBush compliance bushes

Posted 3 months 14 hours ago #208523
A bush that makes clunky noises can’t be good, after all the point of bushes is to allow movement and compliance without banging and clunking!

"Keep calm, relax, focus on the problem & PULL THE BLOODY TRIGGER"

by Cobber

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Replied by Freshmemes on topic MGTF PolyBush compliance bushes

Posted 3 months 13 hours ago #208525
my thoughts too, its only on certain bumps like speed bumps that seem to cause it.

At least from what I can see from the design of the bush it seems more of an issue of the suspension design. As all of the lateral arms allow rotation in more than one direction, the job of constraining the rear Hub's rotation around that axis is also one by the trailing arm, and as the arm is only fixed at on place this also doesn't fully constrain it. that is in my mind why there is a flat plate on the trailing arm where it sits on the bush to stop it from 'complying' left and right as it were. this naturally over time wears down the rubber it sits on till it reaches the metal.

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Replied by Cobber on topic MGTF PolyBush compliance bushes

Posted 3 months 13 hours ago #208526
Are you sure the bush is the cause of the noise? It maybe that although the bush looks suspect and that’s what you found when you looked, that’s what you found that didn’t look right, but the cause of the actual noise is something else? Like a shock absorber perhaps?

"Keep calm, relax, focus on the problem & PULL THE BLOODY TRIGGER"

Last Edit:3 months 13 hours ago by Cobber
Last edit: 3 months 13 hours ago by Cobber.

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