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MG MGA - Rear Spring bushes

I have just replaced my nearside rear spring bushes because the lower pair on the link was split. When I removed the link the leaf spring sprung up about 30mm even though the chassis was jacked up on both sides. When I removed the bushes the lower pair was worn right through suggesting that the link was bearing directly onto the spring loop. See photo.

I am guessing that the geometry of the two springs and the attachments is not even. So possibly the offside spring is better aligned with the rear link than the nearside spring. I'm not surprised by that. However, I am surprised that the lower bushes have worn right through. The top bushes are still in reasonably good shape.
Has anyone experienced the same kind of excessive wear on the bushes on one side or have any knowledge of how it can be prevented in the future? I'm not sure if its poor quality poly bushes.
John



John Francis

John,
not all polybushes are equal who's are those?
Nigel Atkins

Nigel

They were fitted by Bob West during the rebuild in 2009 so I don't know the source but I assume they would be Ok.

John
John Francis

Fair enough John just a recent subject, if it's not a simple answer then it's beyond me.
Nigel Atkins

Maybe they were'nt lubed up when they were fitted or the shackle pin surface is rough or rusty causing them to chop out
Having preload on the spring when jacked up is normal, the checkstrap prevents the spring from dropping right down
A wooden or other wedge between the springeye and the top eye to hold the spring in the right plane before removing the shackle is the go
As Nigel says not all bushes are equal
They were originally colour coded for material hardness but that seems to have been forgotten in favour of prettiness
Also, some bushes come with an inner metal sleeve for the bush to run on and some don't
If the inner hole of yours is too big for the pins maybe the sleeve was missing to start with--you will need to check your new ones for fit/size and the condition of the pin surface if they are a direct fit + grease
William Revit

William
I forgot about the check strap holding it up and thanks for confirming that it is normal for the spring to be preloaded. I did use a long wooden bar to lever the spring down to reassemble it all. The shackle pins were in good clean condition but no sign of much grease. I have greased the new ones with the silicone grease provided in the kit. They seem a good fit and the hole is the right size for the pin.
I'm now wondering if I should replace the offside bushes too. They seem ok so wasn't going to change them.
John Francis

For suspension, brakes and tyres generally it's best to change as pairs but with our old cars they're not exactly precision made so have so many variances anyway so perhaps less important with some parts. However I'd still change the other side as they are 10 years older and as you don't know the make of the ones in the photo the new ones you fitted are a different make so may also perform differently apart from the not being aged.

The real test would be to drive the car enthusiastically with the current set up of different bushes and see if you notice a difference - but do check all nuts, bolts and fixings are still tight before and after doing so.
Nigel Atkins

Just to complete the story with the car jacked up both sides I removed all the rear bushes and the check straps and checked the position of the end of the springs in relation to the chassis. The pictures show that both springs close the gap up to the chassis in the free state and the nearside spring (with new blue bushes) closes the gap up more than the offside. There is also a picture of the spring hangers which are in good condition. Finally there is a picture of the old bushes which shows the nearside ones worn through.

I am a little puzzled why the unloaded springs move upwards but I guess its complicated by the prop shaft and other bits and pieces still attached to the axle and twisting it. The front attachments on the springs should I assume just be pivots.
John



John Francis

Picture of Old bushes and spring hangers. PS I think I flipped one of the photos in the previous message so the two pictures on the right are actually the same picture of offside but lower one is reversed.


John Francis

This thread was discussed between 27/06/2019 and 20/07/2019

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