heyzee
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| posted on 7/8/03 at 02:39 PM |
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help with bushes please
today ive purchased some wishbone bush tube 25mm o.d and a wall thickness of 2.04mm,id 21 mm as required in the book,im useing triumph bushes qh 419
the thing that im not to impressed with is they seem to push in with ease.i thought i would have to either draw them in or press them in.the same as
when you fit a new bush to a modern day car.this has realy got me stumped as i am wanting to get on and make my wishbones,ive heard a mention on here
of glueing them in but firstly with what glue?and should this be nessecery.has anyone else had these problems and how have they overcome them.any
suggestions would be great
[Edited on 8/8/03 by ChrisW]
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JoelP
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| posted on 7/8/03 at 03:31 PM |
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they shouldnt go in easy i think. no ideas really, there have been previous discussions about the precise wall thickness i think. people talk about
freezing them so they shrink!
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Hornet
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| posted on 7/8/03 at 03:33 PM |
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Sorry to hear your probs m8
Try measuring inside Dia with Vernier gauge and post dimensions...
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heyzee
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| posted on 7/8/03 at 06:20 PM |
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bush tubes
the tubes are 21 mm inside diameter,a few of the bushes slide in with ease and the others need to be pushed in.but will be able to push them in by
hand is this acceptable or not.this is causing me a real problem
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Mark Allanson
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| posted on 7/8/03 at 07:27 PM |
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I used 25mm 2mm wall thickness seamless tube and had to use a bolt and several washers to drive the frozen and lubricated bushes into position, I used
BMW bush adhesive which is a lubricant when wet and dries to vuncanise the rubber to the steel.
 
Rescued attachment BushAdhesive.jpg
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heyzee
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| posted on 7/8/03 at 08:52 PM |
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bushes
mark did you purchase the glue direct from b.m.w.and what did you freeze ?the bushes or the wishbones?allso how mutch movement is in the bushes when
they are just pushed in by hand?i seem to have a few loose ones so i think ill order a few replacements
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Mark Allanson
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| posted on 7/8/03 at 10:12 PM |
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Yes, the 'stuff' cam direct from the BMW parts department complete with BMW part number.
I froze the bushes, when pushed in by hand, they went in about 5mm easily. I trial pushed one in using shampoo as a lubricant (it does not contain
salt like washing up liquid does) and it did go in really easily (mild pressure using a workmate).
I suggest you get a left over piece of tube and try one. Make sure you ream the bushes to 10mm BEFORE you fit them if this is the size of bolt you are
using.
I have about 10 bushes left over as I used Bluebird rear arms after I bought the bushes, if you bugger some bushes up I could send some to help you
out if required
 
Rescued attachment Ream.jpg
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JoelP
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| posted on 7/8/03 at 10:13 PM |
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someone chilled the bushes so they shrank apparently, warm up to a tight fit.
i think there should be no movement, because movement will cause them to wear out eventually, the flex comes from the actual rubber twisting up.
when i tried getting the old shockers off my sierra backend, you could move them thru 90 degrees without any real movement, only flex.
mark, when you reamed them was that the rubber or the crush tube you drilled?
[Edited on 7/8/03 by JoelP]
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Mark Allanson
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| posted on 8/8/03 at 06:49 AM |
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Your'e right, the only movement should be in the rubber, I bored a 3/4" hole in the centre of my workmate to hold the bush and then reamed
the crush tube. I tried it without the holding method, and the crush tube sheared away from the rubber.
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blueshift
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| posted on 8/8/03 at 11:36 AM |
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Aaaaah, so THAT's how bushes work. Now I see the light!
btw.. does the bush take the axial stresses as well (front to back forces on the wheels)? or does the tube clonk against the bracket or something.
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pbura
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| posted on 8/8/03 at 12:49 PM |
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quote:
Originally posted by blueshift
Aaaaah, so THAT's how bushes work. Now I see the light!
btw.. does the bush take the axial stresses as well (front to back forces on the wheels)? or does the tube clonk against the bracket or something.
It's amazing how much controversy there is about bushings.
According to some discussion on the NA list recently, RC himself said that the crush tube should spin on the bolt. If that's so, then when
exactly would the bushing take any torsion (if I'm using the correct term)? And why go to all the bother to have a crappy unlubricated
metal-on-metal joint?
The only setup that makes sense to me is for the bushing be a force fit in the tube (per the book), and for the crush tube to be immobile between the
brackets making the bushing work in torsion (if rubber) or as a bearing (if anything else). Poly bushings with no crush tubes can just spin on the
bolt.
As far as fore and aft movement, there's really no cushion unless you use a 2-piece bushing with material on either end of the bush tube. The
Spitfire bushings are one piece, but I remember the Spitfire as having a very cushy ride, so maybe the longitudinal shocks are not that important.
Pete
[Edited on 8/8/03 by pbura]
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James
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| posted on 8/8/03 at 02:58 PM |
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Please Pete- you'll only set people off! 
Rorty, Syd- don't reply to this- we know you don't agree with each other!
James
[Edited on 8/8/03 by James]
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Alan B
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| posted on 8/8/03 at 03:38 PM |
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quote:
Originally posted by pbura
......RC himself said that the crush tube should spin on the bolt.......
But then again RC said you can build a car for 250 pounds too........
No Pete you are right, there is NO controversy.....the steel tube in a metalastic bushing is intended to be clamped up and be non-rotating....
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JoelP
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| posted on 8/8/03 at 05:33 PM |
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thats one dappa car you got as the avatar alan. you built it? blinding bodywork if you did...
well, blinding anyway i suppose, but you must be buzzin if you did do it!
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Alan B
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| posted on 8/8/03 at 05:47 PM |
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Thanks Joel.....
That is how it will look in a few months after I rework it...
Meanwhile check out...
http://www.desicodesign.com/meerkat/
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JoelP
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| posted on 8/8/03 at 07:15 PM |
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stuck it on favs, i'll be back when i got a rolling thing going! Looks tricky and time consuming, i think mines just gonna be an ugly duckling!
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pbura
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| posted on 9/8/03 at 04:17 AM |
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quote:
Please Pete- you'll only set people off!
quote:
No Pete you are right, there is NO controversy.....the steel tube in a metalastic bushing is intended to be clamped up and be
non-rotating....
Phew! That's good. Don't want to cause trouble, just to get the car right 
Ya pays yer money and ya takes yer chances...
Looking forward to your next glassing push, Alan, after the August heat
Pete B.
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Peteff
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| posted on 9/8/03 at 11:22 AM |
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The orange tin from BMW in Mark's picture with Terpentin Ersatz on it, that means turpentine substitute, or white spirit as we call it. Has it
been transferred to another tin?
yours, Pete.
yours, Pete
I went into the RSPCA office the other day. It was so small you could hardly swing a cat in there.
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Mark Allanson
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| posted on 9/8/03 at 03:10 PM |
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No the container was sealed, perhaps white spirit does the trick, it was only £2.38 inc VAT for the litre, so its cannot be too technical.
I does work well though
You freeze the bushes, not to make them shrink, it is to stop the rubber mushrooming as you press them in
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