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Polyurethane bushes for diff. mount

PostPosted: Mon Jun 24, 2019 10:14
by Timothy North
Hi. Has anyone any experience of replacing the differential mountings with polyurethane ones. I ask because I need to replace mine and the £471 cost of a replacement mounting (the lower one) is too much and justifies looking for an alternative.

Re: Polyurethane bushes for diff. mount

PostPosted: Mon Jun 24, 2019 23:19
by Ian Linden
I've not had to do this, but I understand there are mounting bush specialists who stock every known size. If you go to a non-franchised garage, who normally gets parts from non-car-manufacturer sources, they should be able to identify the size and press them in for you.

Re: Polyurethane bushes for diff. mount

PostPosted: Sun Jul 14, 2019 19:24
by George Mercer
Hi,

I have replaced my diff bushes with polly bushes that I found on Ebay for £100 but I have only just passed the MOT so haven't driven it more than a few miles to find out if they work. That was back in May. I don't see them anymore on Ebay but here is the seller

https://rover.ebay.com/rover/0/e11401.m ... Tags=bu=bu

Monster Sport Japan are advertising them for £140 and they have a UK office but I haven't tried them.

https://www.monster-sport.com/e/car/cap.html

Re: Polyurethane bushes for diff. mount

PostPosted: Thu Aug 22, 2019 13:31
by Stuart Paterson
I'm a similar position - I had a diff bush fail during a grass autotest last month. Monster sport quoted me £150 for the bushings + £75 postagage + taxes - They apparently only maintain their Japanese webiste now and sell directly via email and bank transfer or through Rakuten.
That felt a bit steep for me though so I've dived into the process of trying to make my own bushings. I'm planning to machine a polyurethane bush with a delrin sleeve to prevent squeaking.
The old bushes are out and I'm just waiting for the plastic to arrive. If you're still looking for a replacement bush I can keep you updated on how difficult this process turns out to be..

Re: Polyurethane bushes for diff. mount

PostPosted: Sat Sep 07, 2019 19:05
by George Mercer
Update on poly bush diff mount. I completed a couple of hundred miles on the poly diff mounts but there has been a constant drone/buzzing noise/vibration from the rear end on trailing throttle. I wasn't sure it was the diff mounts, as I replaced them with poly bushes before I even drove the car, so I had no reference point as too whether the noise was there before. In the meantime, a diff mount with what looked like reasonable bushes came up on Ebay for a good price. The mount needed cleaning up but the bushes weren't too bad. I thought it was worth a try as it's only a half hour to change it. What a transformation :D . The noise/vibration has gone. The slight knocking when going on/off throttle quickly has also gone. The car feels so refined, the whole powertrain is smooth and quiet. I think a set of the Monster Sport parts will be money well spent. Perhaps a few people who would like them ( myself included ) could get together and pay for one set of postage only. My conclusion is that poly bushes might get the car back on the road but the refinement will be missing, though softer poly bushes may work better than mine.

Re: Polyurethane bushes for diff. mount

PostPosted: Fri Jan 31, 2020 18:59
by Stuart Paterson
I completed the home made bushings a few months ago and I think you're correct, I got the exact same noise/vibration as you described after replacing the bushings with poly.
I dont mind the change, the capp was never the quietest in the cabin and I enjoy the extra noise feedback during a quick spin.
I used shore 90A polyurethane and a delrin sleeve (apparently eliminates squeaking). I wanted to buy softer poly but it's very hard to source.
The home made bushings were a fair bit of effort but can provide pictures, drawings and advice to anyone that needs them.
I like the idea of group monster sport orders, the postage savings may justify ordering new suspension bushings rather than making them!