Features
Rear Suspension Bush

What do you do when your Maxi fails its M.O.T. and you can't find that all important spare part. Well Pip Taylor designed a replacement and had it made. Here's his story.......

"In August 2001 my Maxi failed it’s MOT due to defective Rear Radius Arm Bushes. I tried fitting two non standard ones but they soon collapsed. Because the original “Metalistic” bushes were hard to find I decided to design my own. I originally thought of a design using sealed roller bearings and an internal spring to mimic the torque of the rubber. However investigation soon revealed that there were no suitably sized bearings for the job. After a great deal of thought I came up with the following simple design.


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

Original BL Rear Radius Arm Bush
Part Number 21H406

Pips replacement bush

Postscript
It seems that Pip's idea is catching on - he recently lent fellow Midlands Maxi Owner Alan Scott a new new bush so that he could machine his own.
Pip tells me that he's even shown the new bush to Alex Moulton and that he's given it the thumbs up. Visitors to this site will know that Alex Moulton is the engineer who designed the cars suspension system.

The small print: Whilst we hope that this article has been helpful, we cannot guarantee as laymen that any of the information/ views/ opinions expressed on this or indeed any other page on this website are accurate, appropriate and or safe. For this reason we recommend that you consult a competent qualified person(s) prior to undertaking any task on your vehicle.