tony-devon
|
| posted on 4/7/10 at 05:22 PM |
|
|
tightness of crush tubes in bushes/stiff wishbones
greetings all 
looking for some advice/opinions from the learned members of this forum
Im building a bike engined trike, using sierra diff etc, I have to build the diff cage to my own design as its nothing like the car design, but coming
together well, however today just to mock things up and work out the visuals etc, I tightened up the suspension pivot bolts and it just goes solid,
you can just about move the wishbones but takes major effort
I greased the bush tube in the wishbone to press the bushes in, and I greased the crush tube for installation
should I look at skimming a gnats cock off and polishing them before the final build?
or will they bed in after a few miles?
as it is at the moment I could do without shocks and just leave it LOL
heavy is good, heavy is reliable, and if it breaks, hit them with it
|
|
|
|
|
Peteff
|
| posted on 4/7/10 at 05:28 PM |
|
|
You should not grease the tube in the wishbone, it would be better glued in place. Only the crush tube to bush surface should move and the weight of
the chassis plus yourself bouncing on it should be enough to free it up.
yours, Pete
I went into the RSPCA office the other day. It was so small you could hardly swing a cat in there.
|
|
|
mark chandler
|
| posted on 4/7/10 at 09:27 PM |
|
|
If you are using polybushes then just tighten up and leave, if using bonded bushes do not tighten until the trike is at its running height or you will
destroy the bush.
Regards Mark
|
|
|
tony-devon
|
| posted on 4/7/10 at 10:15 PM |
|
|
thanks guys, they are polybushes
I put a small amount of grease in the wishbone tube just to aid fitment, but they will be getting blasted and cleaned then powdercoated and lacquered
before final build, so I will install them dry for that (after removing any powdercoat that crept in there ) LOL
heavy is good, heavy is reliable, and if it breaks, hit them with it
|
|
|
Frosty
|
| posted on 5/7/10 at 09:35 AM |
|
|
I don't agree with the above. The bushes should form a pivot point and should move freely and accurately, so if it's virtually solid,
it's not much good.
1) Ensure that the rubber itself fits nicely into the wishbone bush carrier. If it deforms at all, or you have to force it in, the deformation will
cause stiction when tight.
2) Ensure that the crush tubes are marginally longer than the fitted rubber. If they are shorter, when tightened the rubber will cause friction
against the wishbone bracket.
I would grease the crush tubes, and also the faces of the bushes which lightly contact the wishbone brackets.
|
|
|
procomp
|
| posted on 5/7/10 at 09:44 AM |
|
|
Hi
As Frosty above. This problem alone is whats stopping so many cars/trikes Etc from having sufficient suspension compliance and buggering up so much of
the handling on so many cars.
Cheers Matt
|
|
|
40inches
|
| posted on 5/7/10 at 11:10 AM |
|
|
quote:
Originally posted by Frosty
I don't agree with the above. The bushes should form a pivot point and should move freely and accurately, so if it's virtually solid,
it's not much good.
1) Ensure that the rubber itself fits nicely into the wishbone bush carrier. If it deforms at all, or you have to force it in, the deformation will
cause stiction when tight.
I should also add that the MK bushes and crush tubes are differant sizes (at least mine are
2) Ensure that the crush tubes are marginally longer than the fitted rubber. If they are shorter, when tightened the rubber will cause friction
against the wishbone bracket.
I would grease the crush tubes, and also the faces of the bushes which lightly contact the wishbone brackets.
Totally agree, if you have to resort to pressing the bushes into the wishbone tube with a vice they are WAY tight, and will not work properly 
I had to ease mine considerably, so that they would fit by pushing them in with HARD thumb pressure only, only then did they pivot easily.
I should add that the bushes and crush tubes on my Indy are differant sizes I had to mix and match to get them into sets that needed the least
amount of work to get them to pivot freely, it still took on average 1hrs work on EACH wishbone 
[Edited on 5-7-10 by 40inches]
|
|
|
phelpsa
|
| posted on 5/7/10 at 12:23 PM |
|
|
When when we took ours to Procomp the suspension was practically locked due to the bushes binding! I've systematically taken every crush tube
out, cleaned and greased them and now its much better but not perfect as essentially the crush tubes arent long enough. Matt (procomp) recommended
getting some longer stainless ones made, which is being sorted at the moment, which should make a bigger difference!
[Edited on 5-7-10 by phelpsa]
|
|
|
rusty nuts
|
| posted on 5/7/10 at 06:10 PM |
|
|
Common problem with Luego's as already covered on several occasions . When I first built my car the arms were tight and eventually I got fed up
with the harsh ride and squeeking. Stripped the worst offending arm off the car , cleaned out and weld penetration from inside the eye and checked the
assembled arm/bush/crushtube would rotate when clamped in a vice. Ended up skimming about 0.025"from the outer end of each bush before the arm
would pivot. Why can't kit suppliers sort this problem out ? I wonder if tight bush assemblies caused any of the wishbone failures we have seen
in the past?
[Edited on 5/7/10 by rusty nuts]
|
|
|
40inches
|
| posted on 5/7/10 at 09:14 PM |
|
|
quote:
Originally posted by rusty nuts
I wonder if tight bush assemblies caused any of the wishbone failures we have seen in the past?
Like this one?
|
|
|
Johneturbo
|
| posted on 5/7/10 at 09:44 PM |
|
|
I'm trying to get my head around how it works
So the crush tube should bolt up against the bone brackets and the bush should pivot around the tube as the suspension moves, is that right?
|
|
|
40inches
|
| posted on 5/7/10 at 11:01 PM |
|
|
quote:
Originally posted by Johneturbo
I'm trying to get my head around how it works
So the crush tube should bolt up against the bone brackets and the bush should pivot around the tube as the suspension moves, is that right?
Exactly
|
|
|
hobbsy
|
| posted on 6/7/10 at 11:54 AM |
|
|
Apologies for the slight thread hijack but...
What sort of grease is recommended for poly or metalastic bushes?
Mine seems to creak an awful lot at the moment and I think a good strip, clean and lube (oo-er) might help just not sure which type of grease is best.
|
|
|
40inches
|
| posted on 6/7/10 at 12:17 PM |
|
|
quote:
Originally posted by hobbsy
Apologies for the slight thread hijack but...
What sort of grease is recommended for poly or metalastic bushes?
Mine seems to creak an awful lot at the moment and I think a good strip, clean and lube (oo-er) might help just not sure which type of grease is best.
I use this product
|
|
|
hobbsy
|
| posted on 6/7/10 at 12:25 PM |
|
|
Ok, I think I've got some similar stuff already at home. It's white and thick right?
|
|
|
tony-devon
|
| posted on 6/7/10 at 12:31 PM |
|
|
thanks for the advice guys, I am going to leave as is for now, but will chuck all the bushes in the lathe, skim the faces by a smidge, but also take
the crush tubes down a thou or 2 and also polish the hell out of them
bushes were a proper tight fit in the wishbones, but was rather shocked at the way the crush tubes went in, or rather didnt go in!
it was a proper vice job to get them in
didnt feel right to me and appears now that its certainly not right.
this is all dry build so will make notes in the lil black book of ideas and jobs to do, then sort on final build
thanks all
heavy is good, heavy is reliable, and if it breaks, hit them with it
|
|
|
40inches
|
| posted on 6/7/10 at 12:34 PM |
|
|
quote:
Originally posted by hobbsy
Ok, I think I've got some similar stuff already at home. It's white and thick right?
Thats the stuff
|
|
|
procomp
|
| posted on 6/7/10 at 01:39 PM |
|
|
Hi
Regardless of what product you use to lubricate the inner pivot/bushes with it will never really prevent damp/moisture getting to the mild steel inner
pivots and corroding. The better solution is to replace with stainless. That's how genuine polyurethane bushes come as STD.
If you are going to put the effort into correcting the problem it will be far easier to do it right first time than end up having to do it anyhow
eventually. 
Cheers Matt
|
|
|
hobbsy
|
| posted on 6/7/10 at 01:47 PM |
|
|
I would like to replacement my metalastic bushes in the Fury with polybushes but from what you said when we spoke some time ago Matt they aren't
available in sizes to suit?
I get a fair bit of stiction at the moment as you saw when setting it up.
If enough people requested a set for a certain application then I guess we could get some made?
|
|
|
40inches
|
| posted on 6/7/10 at 02:16 PM |
|
|
quote:
Originally posted by procomp
Hi
Regardless of what product you use to lubricate the inner pivot/bushes with it will never really prevent damp/moisture getting to the mild steel inner
pivots and corroding. The better solution is to replace with stainless. That's how genuine polyurethane bushes come as STD.
If you are going to put the effort into correcting the problem it will be far easier to do it right first time than end up having to do it anyhow
eventually.
Cheers Matt
True
|
|
|
40inches
|
| posted on 6/7/10 at 02:37 PM |
|
|
quote:
Originally posted by hobbsy
I would like to replacement my metalastic bushes in the Fury with polybushes but from what you said when we spoke some time ago Matt they aren't
available in sizes to suit?
I get a fair bit of stiction at the moment as you saw when setting it up.
If enough people requested a set for a certain application then I guess we could get some made?
Do you know what car the metalastic bushes are off, or are they specific to the Fury?
Powerfex web site, Polybush,
Superflex and round bar to make
your own
|
|
|
Frosty
|
| posted on 6/7/10 at 02:51 PM |
|
|
quote:
Originally posted by hobbsy
I would like to replacement my metalastic bushes in the Fury with polybushes but from what you said when we spoke some time ago Matt they aren't
available in sizes to suit?
I get a fair bit of stiction at the moment as you saw when setting it up.
If enough people requested a set for a certain application then I guess we could get some made?
You get stiction from metalastic bushes? I didn't know this could happen unless they are too long for the wishbone.
|
|
|
procomp
|
| posted on 6/7/10 at 03:26 PM |
|
|
Hi
Slight confusion regarding the stiction there. It's not stiction that the metalastic bushes give. They are a bonded bush so the rubber is bonded
to the inner crush tube if you like and the outer housing. This gives resistance to wishbone movement. By replacing with poly bushes you remove the
resistance and gain compliance. That's not to say that you cant account for the resistance by adding it into the springing setup. But far better
to let the wishbones move freely and let the damper/spring do that job.
Hence the reason you have to slacken all the suspension bushes when setting the car up if it has metalastic bushes fitted and re tighten when the car
is set and back at a finished ride height.
Hope that sort of makes sense. was typed in a rush.
Cheers Matt
|
|
|
hobbsy
|
| posted on 6/7/10 at 04:56 PM |
|
|
Yes that makes sense. I now understand the problem a bit better.
I don't know what sizes the bushes are without measuring them or what they are off but I was lead to believe I can't get them off the
shelf in polyurethane
|
|
|
.jpg)
