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MG Midget and Sprite Technical - Broken Rear spring

Help!
I live in South Africa and have just driven my 1973 midget home to discover it has broken two blades on the Right( Driver side here) leaf spring.
Can anybody help me with specifications for a new spring' (length, width loading etc) and anything else that may be useful so that I can approach a spring company to make or source a suitable replacement.I realise these are available From Moss or Victoria , but we are subject to horrendous import duties and so I would like to see what is available here first.
B R Roux

Hi B.R, here in the UK all we would do is simply take the spring to a spring maker and they would simply make 2 new leafs for it.
I am lucky that I have a maker only a few miles away from where I live so for me it is not a problem. If you don't know where your local maker is then ask a local haulier (lorry operator) where he buys his springs from?
Robert (Bob) Midget Turbo

Arie is probably the one with the best for info sources for custom rear springs, he has been thur this and actualy knows an old school blacksmith that he gotten alot on insight from. Id also give a shotout to Mark boldry, I know he has been making special custom rear springs for about a year that im aware of, he would have the inside track as well for info your going to need.

but if your in a pinch on time, you can pull the good spring from the other side and use it as a templete...unfortantly I dont know how you would determine the tensil strenght/springyiness/metal softess/metal chemisty/ect. ect.

prop
Prop

The leaves should be 1.5" wide and 11/64" thick. you should be able to measure the length from the markings of the old spring?
The official factory manual lists the working load as 375 lb and the free camber as 4.437 inches.

Watch the leaf thickness!!
Over here spring makers seem only to have 1/4" thich spring steel in 1.5" width, which makes the spring way to hard - and dangerous.

If the whole spring is made of this stiff, it sits about 3" too high, oversteers alarmingly and swaps ends readily.

If just one or two leaves are repaired with this, the extra thickness makes the spring uneven in its load bearing, with a stress raiser where the thick "repaired" leaf finishes below an original correct thickness one. It wears away at the leaf above and evenually it snaps. Then the cycle repeats with the next leaf up. And so on until the top leaf ... and the whole spring the let's go.

We've had both forms of bodge job on Midgets we have bought. Fortunately the one which broke a spring clean in two (between the axle and front mount) was doing 3mph turning into the driveway at the time. Mind boggles if this had happened on the motorway.

So we checked the other cars, and found another like it. That made 3 out of 4 Midgets with bodged springs. The 4th one's PO had fortunately fitted new ones not long before.
Paul Walbran

Having one spring repaired may bring the risk of differing spring rates between the right and left springs. Ideally, you want a matched pair.

-:G:-
Gryf Ketcherside

Never seen that kind of thing here Paul but will keep checking. The spring maker I use used to supply all rear springs until the 3rd world started making them for next to nothing. So he doesn't bother now, he reckoned it would cost about £80 to retail Spridget springs today, yet 3rd world springs are about £40 so why bother.

Gryf you are correct but I would expect anyone having a spring repaired would take in the pair and have them rearched at the same time.
However have you seen the springs you can buy today? not exactly a matched set are they?
Robert (Bob) Midget Turbo

Robert,

I can attest to what your saying,,,I was noticing my spring higth just last week, it seems a bit off from side to side, im hoping its just due to the fact its been sitting so long and the shocks have settled. but thats an issue for later on.

What is your opinion on those aftermarket leaf spring helpers...I know we talked about them last summer, but I dont know if any firm consensious was ever reached....there was a few designs that I did find interesting.

Prop
Prop

Thanks all
I am in the process of getting both springs off and will take them on a tour of local spring makers.Paul ,I'll look out for 11/64(+-4mm) thick leaves-maybe light trailers use something similar.
Any thoughts on Rubber vs Poly-urethane bushes as mine are 36yrs old and probably due for replacement( I foresee mainly road use with some dirt road a possibility). Should I replace the U-bolts and shackles-the present ones look OK but then so does the spring where it isn't broken.
Bryant Roux
B R Roux

Poly all the way...

I wish I had chossen poly the 1st time, my rubber is all shot after just 5-6 years
Prop

Here is a picture of the springs that I have just had rearched. For those with a keen eye you will notice I have had an extra leaf made and fitted to stiffen up the springs a bit. Hope I have not gone too far :-)

As you will see Paul the leaf is the same section as the originals


Robert (Bob) Midget Turbo

A closer image of the extra leaf


Robert (Bob) Midget Turbo

Good looking job. It would be nice to have such ready access to the right material over here!
Paul Walbran

This happened with the last 3rd world springs i bought:




Btw, they maybe cheaper produced but are still sold for original price...
A ridiculous profit on selling crap!


Arie de Best

But NEVER THROW AWAY THE OLD LEAFSPRINGS!!!

I toke my old worn ones and the crap 3rd world ones to a local springguy(like Prop mentioned i did) and he made them working again by redoing the heating/tensioning proces.
Thats what they dont do in the 3rd world countrys, they just bent the "soft" steel in the right shape clamp them together and thats it.
The steel needs its heating proces to become hard and give it its spring effect.

Refurbished springs:


Arie de Best

This thread was discussed between 29/11/2009 and 02/12/2009

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