MG-Cars.info

Welcome to our Site for MG, Triumph and Austin-Healey Car Information.

Parts

MG parts spares and accessories are available for MG T Series (TA, MG TB, MG TC, MG TD, MG TF), Magnette, MGA, Twin cam, MGB, MGBGT, MGC, MGC GT, MG Midget, Sprite and other MG models from British car spares company LBCarCo.

MG Midget and Sprite Technical - 1/4 elliptic springs

On the rear springs on my Mk2 Sprite there is a gap to the lower leaf, same both sides.
Guessing this is not correct.
There is quite a clearance between the spring and the cross tube in the C-clamp, is this correct?
Any ideas / suggestions.
Thanks
Les

Les Robinson

Forgot to say, when the axle is dropped, no weight on the spring, then the gap closes up.
Les Robinson

When the gap was there the car was jacked up under the axle diff casing. When lowered onto axle stands the gap disappeared and leaves closed up!
When push up and down on the back of the car the bottom leaves separate slightly - is this normal?
Les
Les Robinson

Les.
Difficult to see from the picture but the bolt that is visible should run through a loosely fitting tube/sleeve under the bottom leaf. Is that present on your car?

The effect of the tube may close that gap up

My frog has no gap in the way that you describe.

Simon
Simon Wood

My frog spring is different to that. The lowermost continuous spring is the one that forms the eye at the back for the mouning point. But below/ outside that is a short spring sort of hairpin shape that loops around the spring eye. Above, on the top of the spring it is short and held in position by the last of the clamps. Underneath it extends forwars of the bottom leaf to about 2" forward of the next clamp, which I think is the one you have photographed.
A photo would have been quickwer and easier than that description!
GuyW

Simon
Yes there is a loose fitting tube/ sleeve but it is clear of the spring.

Guy
My spring is exactly as you describe, the C-clamp shown is the front one.

What I’m not sure about is the required position of the rear clamp, held with plate and two nuts, does it go as far rearwards as possible sitting in the rad of the hairpin shape as it loops over the spring eye.

Les
Les Robinson

Been looking further into this.
First of all, ignoring the initial gap to the lower leaf as shown in the picture. As mentioned this gap disappears when the car is on axle stands, will revisit this.

Now as for the lower leaves separating when weight is applied to the spring I have a theory.
I fitted these springs maybe 5 years ago to replace my knackered originals. They are 15 leaf and came from an ex USA Frogeye, in good condition and ultimately raising the back of the car about an inch.
To my knowledge they were original.
When the spring is in free state with no load on it there is a gap between the front edge of the hairpin spring and the leaf in front of it which is normal. On these springs the gap is about 3 or 4mm. My old spring, and pictures I’ve seen of other springs, its probably more than double that!
When my car is on axle stands (equating to the car being on its wheels) this gap more or less disappears as the leaves all slide against each other, which I’m guessing is normal.
Now as there is no gap then as the spring deflects more the leaves cannot slide against each other and therefore the lower leaves deflect instead, resulting in separation.
A solution would be to shorten the length of the top leading edge of hairpin spring to effectively increase the gap to the leaf in front of it.
I can’t see any issues in doing this, what do you think?

As for the position of the rear C-clamp, I think this should be forward slightly of the corner radius, to sit flat on top of the leaves, and not be over tightened.

Les
Les Robinson

Here is a picture showing the gap I was trying to explain. When the car is on its wheels this gap closes up.
Should there always be a gap even when the spring is fully loaded?

Les Robinson

Les

Just checked mine and there is a gap of 4/5mm with the car on its wheels. My springs are a 20 plus years old but were NOS 15 leaves not repro.
Bob Beaumont

Bob
Thank you for that.
No idea why mine has no gap.
On the basis that I feel there should be a gap for the spring to work properly I will cut 5mm from the front of the hairpin spring to see if it makes any difference.
Les
Les Robinson

I have shortened the spring so there is now a 5mm gap when the car is on its wheels.
And the result is, not a lot of difference!
On the passenger side the lower leaf separates slightly under load (pushing down on rear wing) - no gap otherwise. On the drivers side it is the middle springs that separate slightly. I’m sure it’s not as bad but could be kidding myself!
Anyway I’m sure having the 5mm gap is the right thing to do. When the spring is unloaded the gap is now about 10mm so definitely closes up although less noticeable as the spring flattens out.
So after all this maybe it’s just a result of the springs being old!!
Ride height is fine and suspension works ok so will just leave them.
Les
Les Robinson

This thread was discussed between 23/05/2021 and 24/05/2021

MG Midget and Sprite Technical index

This thread is from the archives. Join the live MG Midget and Sprite Technical BBS now