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I've fitted 2 bearings based on this design to my Maxi and so far
have travelled 5,000 miles without any problems. The design above
involves replacing the rubber in the original bush by a mild steel
block with plain polymer bearings pressed into the centre from both
ends. (The rubber can be drilled out but I find placing the original
bush in a small fire at the top of the garden works better) The
mild steel block is machined to interference fit into the machined-out
outer part of the bush then locked in place with two high tensile
bolts. A new internal shaft is machined to fit the polymer bearings
with a flange on the inner end to prevent outward movement of the
radius arm. (The internal diameter of the polymer bearing is 35mm
whilst the original shaft has an outer diameter of 34mm) The outer
end is machined to mimic the end of the original shaft (34mm) so
the washer will fit as it should.
A later - improved - design of mine is similar except that the
two polymer bearings have flanges to prevent movement. The inner
shaft has it’s flange the same width as the flange on the
bearing. These flange surfaces should help to prolong the life of
the bearing. One final note - before pressing in the polymer bearings
the unit is pained.
The modern polymer bearing is self lubricating and needs no additional
lubrication. It fits a wide spectrum of applications and if development
continues as I expect then it will eventually replace the traditional
ball and roller bearing. I selected a bearing most suited to this
particular application - type W300 - item number WFM-3539-16. It's
self lubricating, works well in a wet abrasive environments and
has shock absorbing properties. The company that supplied me with
the bearings is called Igus
- my contact being a Rob
Dumayne
You can expect to pay about £5.00 per bearing and you’ll
need two per bush. Machining will cost about £65.00 per bush.
Both sides of the car should be replaced at the same time. The diagram
and description are only suggestions. If anyone wishes to reproduce
their own bushes for their own use they do so at their own risk
I have found that the bearing tends to “grunt” on occasions.......
a dose of WD40 or similar curtails the problem.
If I were to modify the bearing in any way I'd extend the inner
shaft flange out beyond the polymer bearing flange and machine a
groove in the block to take an O ring (repeated on the other side)
....... in order to help keep water out. I might even go one further
and use an oil seal ring! "
Pip Taylor
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