J666AYP
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| posted on 6/5/20 at 09:54 PM |
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Bushing question
Hi all,
In the process of sorting out the rear suspension and I'm having a real nightmare with the bushings and crush tubes.
I'm thinking about ditching the polyurethane bushes as they seem very squishy and are a complete b****** to press into the wishbones. My idea is
to get some heavy duty nylon bar and turn it down on the lathe so I can get an exact fit without destroying anything...
Can anyone see any issues with doing this?
Jay
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paulf
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| posted on 6/5/20 at 10:13 PM |
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You need some movement in the rear bushes as uneven road surfaces could cause solid bushes to bind due to the twisting forces as the rear trailing
arms operate.If you want it to have less give then the rear arms would be best fitted with rose joints.
Paul.
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CosKev3
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| posted on 7/5/20 at 12:14 PM |
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You must have the wrong size poly bushes,they push in with a strong hand,or if not a tap with a hammer.
Then the crush tube normally goes in without much force as it needs to be able to turn inside the bush.
Westfield sell nylon bushes,they are pretty harsh though with zero flex.
Can make getting the bolts through tricky if you have some very slight mis-alignment in your wishbones or brackets.
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adithorp
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| posted on 7/5/20 at 12:33 PM |
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What coskev said ^
I'd be searching for some that got better. If you use nylon bushes there'd be no vibration absorption either so you would have a very
harsh ride and possibly risk of chassis/brackets/arms cracking in addition to the binding issue mentioned above.
"A witty saying proves nothing" Voltaire
http://jpsc.org.uk/forum/
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rusty nuts
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| posted on 7/5/20 at 12:57 PM |
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All of my bushes pushed in easily by hand, as already pointed out, yours may be wrong
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jps
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| posted on 7/5/20 at 01:23 PM |
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I assume my bushes are polyurethane - but they certainly don't feel squishy, they are very solid. Where did you get yours from?
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Mr Whippy
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| posted on 7/5/20 at 01:45 PM |
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Squishy polyurethane bushes?! that doesn't sound right at all, indeed none of what you said sounds right tbh
The crush tube should just be a nice sliding fit a couple of mm longer than the assembled bush, usually a doddle to fit. I just chapped the bushes
into the wishbone with some light taps of the hammer.
If your using bushes more like rubber ones they are usually drawn in using a long bolt (washing up liquid) and some washers. Youtube fitting
suspension bushes.
take a picture of them
[Edited on 7/5/20 by Mr Whippy]
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voucht
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| posted on 7/5/20 at 02:54 PM |
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I used my vice to fit the bushes in the triangles, as well as to fit the crush tubes into the bushes. If you keep the parts perfectly perpendicular to
the die surface, its goes like a hot knife in butter.
https://vouchtroadster.blogspot.com/
https://cafrazx550.blogspot.com/
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J666AYP
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| posted on 7/5/20 at 08:44 PM |
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Hi gents,
They are duraflex bushes from Ebay. Apparently they are 80 or 90 shore rating. I highly doubt this though as without the insert I can squash them like
soft rubber.
It seems that the bushes are too fat for the holes and are not all the same diameter (+/- 1.5mm between them) the supplied crush tubes are also too
thick so when the bushes are pressed in it's nearly impossible to press the crush tube in.
I think the only option is to run a nice Sharp reamer through the centre of the bushes too open them up slightly and turn a few thou off the crush
tubes.
Nothings ever easy on this thing.
[Edited on 7/5/20 by J666AYP]
[Edited on 7/5/20 by J666AYP]
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christim
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| posted on 7/5/20 at 10:58 PM |
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Hi Jay I had/have exactly the same bushes and the same concerns as you!...bushes squidgy, very tight to get in, when they are in I need a vice to push
the crush tubes in, then they're solid and in some cases need to press them out again
Also my wishbone tubes are perfectly round so they're not being deformed
I called Duraflex to discuss, the owner said they make these bushes for kit car manufacturers and they work fine on those cars (that's not to
say their wishbones have the same diameter as ours though!)
The crushing of these bushes takes them up to their stated shore rating, and I guess the squishyness gives them the movement they need rather than
pivoting around the crush tube like other bushes
I still have concerns though, but I'm going to put them in as is and see if there's any issues.
My main concern is actually getting the fitted wishbones onto their brackets...as when the bushes and crush tubes are in they 'bulge' out
either side of the wishbone tube (Im thinking some sort of washer-and-clamp setup to 'push' them into the wishbone tube further to get rid
of the bulge)
For info I have a 19mm reamer and did try reaming one, but no good as these things are squishy enough that they just expand out of the way of the
reamer
All this applies only to Duraflex bushes specifically! I've read nearly every thread on this board about bushes - really - trying to work out
whether what I was seeing was normal and no normally wishbones need to pivot around the crush tube
Cheers,
Chris
p.s. here's their website for those interested:
https://www.duraflexpubushes.com/
[Edited on 7/5/20 by christim]
My Build Thread
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J666AYP
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| posted on 13/5/20 at 09:14 PM |
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quote:
Originally posted by christim
Hi Jay I had/have exactly the same bushes and the same concerns as you!...bushes squidgy, very tight to get in, when they are in I need a vice to push
the crush tubes in, then they're solid and in some cases need to press them out again
Also my wishbone tubes are perfectly round so they're not being deformed
I called Duraflex to discuss, the owner said they make these bushes for kit car manufacturers and they work fine on those cars (that's not to
say their wishbones have the same diameter as ours though!)
The crushing of these bushes takes them up to their stated shore rating, and I guess the squishyness gives them the movement they need rather than
pivoting around the crush tube like other bushes
I still have concerns though, but I'm going to put them in as is and see if there's any issues.
My main concern is actually getting the fitted wishbones onto their brackets...as when the bushes and crush tubes are in they 'bulge' out
either side of the wishbone tube (Im thinking some sort of washer-and-clamp setup to 'push' them into the wishbone tube further to get rid
of the bulge)
For info I have a 19mm reamer and did try reaming one, but no good as these things are squishy enough that they just expand out of the way of the
reamer
All this applies only to Duraflex bushes specifically! I've read nearly every thread on this board about bushes - really - trying to work out
whether what I was seeing was normal and no normally wishbones need to pivot around the crush tube
Cheers,
Chris
p.s. here's their website for those interested:
https://www.duraflexpubushes.com/
[Edited on 7/5/20 by christim]
Hi, sorry about the late response. Apparently the lockdown does not include rail workers.
Duraflex originally sent me the wrong set, then after several calls and a months wait they finaly sent out the 'correct' set. After some
head scratching I have found a way to make them work, I had to turn down the crush tubes by a few thou, and bore out the wishbone bush tubes by a few
thou also. It turns out the part of the bushings that goes into the wishbones is too fat and flexes inwards reducing the ID for crush tubes.
Safe to say next time I will be looking at a different manufacturer.
I have some stainless pipe/tube on order if you need some adapted crush tubes knocking up.
J
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christim
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| posted on 14/5/20 at 02:00 PM |
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Yeah that's the only way I can think to fix the issue. I bought the full set from them including s/s crush tubes, so will have to fire up the
lathe and turn them down a bit. (Wishbones have just been powder coated so won't be touching them)
Though tbh I don't like the amount of space between their crush tubes and the 12mm bolt either...may look at turning some s/s bar to the right
size and ream to 12mm
My Build Thread
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