Rear Beam Axle

[loonylawyer]

Hi. Have decided to fabricate a new beam for my Mk 2. Am intending construct it from aluminium. Any observations, comments etc?

[Alan D.]

Hi

This is a problem I need to address in the future, but I'm busy at the front end of the car at the moment.

I've not put a lot of thought into the subject as yet. Aluminium would be great as long as you have the facilities for welding it! I think Stuart has put a bit of thought into the problem and tried to source a standard aluminium channel, don't know how far he got with it! The problem that I've found with making things is that you have to buy say a seven metre length to get 1.2 metres! That's not so bad if you make a few extra and recover your costs, buy selling a few.

There are a number of Mini beams on the market and as far as I'm aware the only difference between the Mini & Midas is that the Midas has a narrower track! I wonder if you could buy a Mini beam and cut it down, possibly rejigging the mounting holes etc. One of the problems which I believe occurs on Mk1 & 2's is that the centerline of the front subframe is not the same as the rear subframe centerline, due the holes in the heel board being put in the wrong position during manufacturing of the shell, so the car has a slight crabbing action! If that's the case it's probably best not to use the existing mounting holes and start again setting up the rear beam around say a centralised laser line.

The other advantage about using a Mini beam, is that you can get them which are adjustable for camber and castor.

The other point to think about is the possibility of using Metro Radius arms which would increase the track!

Just brain storming, well you have to start somewhere!

Alan

[loonylawyer]

Hi Alan
Fabrication in ali is no problem for me. I have a 2000 sq.ft. workshop which is nothing more than my toy cupboard in order to keep me sane (I am a criminal defence lawyer!). In my early years I was in the motor trade.

You mention increasing the track at the rear with the use of metro arms, and also the crabbing effect. Any moderately knowledgeable guy with a few basic engineering skills can solve the problem of crabbing. It is a matter of measuring, a flat surface, even load, accurate measuring and a drill! It would probably be an advantage to have a softer alloy to guard against fatigue fractures.

I already have the drawing completed, and have sourced suitable materials. Frankly, it is not a difficult job and should not take too long. In the future I intend to address my leisure talents to the front subframe, and maybe fabricate an item more akin to using coil-overs.

Any thoughts?

Regards

Brod

[loonylawyer]

Hi Alan

Regarding the track, this could be achieved by adjusting the position of the mounting brackets for the arms.

What do you think?

Brod

[Alan D.]

Hi Brod,
Good to hear from you. I too have a little bit of a workshop, tig welding, metal cutting etc. I'm from a engineering background but that's a long time ago. With regards to the rear beam, I think Ali would be great, I hope that you have thought about making the suspension adjustable. That would be great to be able to set the car up for handling. I think in the 80's the car was very good in the handling department, much better than the standard Mini, I'm told! But with the knowledge that we have today it could be superb!

With regards to increasing the rear track, as is always with these things. You do something to one component and you then have to alter another. If you increase the track, you move the bottom suspension mounting on the stub axle further out, you then cannot get the coilover to attach to the stub axle stud as it is to far away. Below is a couple of pictures how we got round this on the Mk3, but the same reasoning would apply to the Mk's 1& 2.

I know that it looks a bit of a long extension, but it's 25mm in diameter and made from EN19 steel and there is not a lot of load on the rear suspension! There are four cars running with this mod and there are no reported problems.

With regards to the front subframe, I've already made one to take a more modern engine. it's been in the car once and it didn't fit. So I altered the subframe and fitted shorter engine mounts and am about to try and fit again when time permits.

I've already got brackets made for front coil overs, but am not happy bolting them to fiberglass inner wings. I think I need to brace them from the steel of the subframe. But one thing at a time, my old brain needs more ROM memory!

I'll keep you informed of any further developments and your welcome to any information which I have, after all this is what this forum is all about. It's about time more people noticed this great little car. But that will only come if we modernise it!

Regards Alan D.

[ACDodd]

The easiest way to form the correct size box section is to weld 2 L sections together along there length. This way any size box section can be accomodated.

AC