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Polybush hardness
craigdiver - 9/10/17 at 07:56 PM

I have two sets of polybushes, a black set which are very hard with virtually no elasticity - these are fitted to my car and were a pain in the ass to fit/mount wishbones as there is no play. The other set of polybushes I have are made of a more rubbery material and are great to work with.

Will there be a noticeable difference in handling with the softer wishbone bushes? Reason I’m asking as could do with taking front wishbones off to panel the front of the car but the wishbones were a pig to fit with the hard bushes.

[Edited on 9/10/17 by craigdiver]

Bluemoon - 10/10/17 at 06:14 AM

Why is it a pig to fit with the hard bushes? You shouldn't need to remove them from the bones to disassemble..??

craigdiver - 10/10/17 at 07:17 AM

quote:
Originally posted by Bluemoon
Why is it a pig to fit with the hard bushes? You shouldn't need to remove them from the bones to disassemble..??


I bought wishbones that someone else had already made and on a couple of the wishbone bushes they don’t line up perfectly so the bolt goes in through the bracket, through the bush tube/polybush/crush tube and is a mm or two out on the 2nd hole in the wishbone bracket. As the polybushes are very hard, takes some persuasion to get through.

I’m not entirely happy with this but too late to change at this stage.

Bluemoon - 10/10/17 at 09:35 AM

quote:
Originally posted by craigdiver
quote:
Originally posted by Bluemoon
Why is it a pig to fit with the hard bushes? You shouldn't need to remove them from the bones to disassemble..??


I bought wishbones that someone else had already made and on a couple of the wishbone bushes they don’t line up perfectly so the bolt goes in through the bracket, through the bush tube/polybush/crush tube and is a mm or two out on the 2nd hole in the wishbone bracket. As the polybushes are very hard, takes some persuasion to get through.

I’m not entirely happy with this but too late to change at this stage.


MK's ones are a struggle to get in (the arms deform slightly after welding, i.e. spring out or in a bit) but you can slide the bolts in once in place, and it all moves nice and smoothly. The bushes should be slightly tight on the crush tube diameter, with a little backward and forwards play. The wishbones tend to just drop with there own weight once every thing is bolted up..

craigdiver - 10/10/17 at 10:29 AM

quote:
Originally posted by BluemoonMK's ones are a struggle to get in (the arms deform slightly after welding, i.e. spring out or in a bit) but you can slide the bolts in once in place, and it all moves nice and smoothly. The bushes should be slightly tight on the crush tube diameter, with a little backward and forwards play. The wishbones tend to just drop with there own weight once every thing is bolted up..


Think I need to change out my polybushes - I broke a vice whilst inserting them and are very tight on both the wishbone bush tube and crush tube. A bit of force is required to move the wishbones when clamped up.

procomp - 10/10/17 at 01:46 PM

Hi.
The currently fitted bushes sound like the usual kitcar ones not much good and the new ones are likely to be genuine poly bushes with a shore rating of 80-85. If wishbones are removed just change the bushes the difference in freedom off movement will be a significant improvement.

Cheers Matt

craigdiver - 10/10/17 at 03:57 PM

quote:
Originally posted by procomp
Hi.
The currently fitted bushes sound like the usual kitcar ones not much good and the new ones are likely to be genuine poly bushes with a shore rating of 80-85. If wishbones are removed just change the bushes the difference in freedom off movement will be a significant improvement.

Cheers Matt


Hi Matt, hope all is well.

The current ones are solid, the other ones feel a bit more rubbery and can be deformed slightly if squeezed by hand.

craigdiver - 11/10/17 at 04:27 PM

Matt, you were spot on. Took one of the wishbones off and replaced the hard bushes with the softer ones and what a difference in refitting the wishbone and much easier movement once tightened. You can actually feel the bracket tightening down onto the crush tube.

Only 20 more to replace ;-0

OliilO - 12/10/17 at 09:17 AM

Where is the best place to get wishbone bushes from? I need to replace some on my car shortly.

craigdiver - 12/10/17 at 10:15 AM

quote:
Originally posted by OliilO
Where is the best place to get wishbone bushes from? I need to replace some on my car shortly.


That is a great question, wish I had known, would have saved me £50 or so on the wrong ones.