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MG Midget and Sprite Technical - Rear Leaf Spring Replacement

1974 MG midget 1275cc. I checked the archives, but didn't see where anyone asked this question. I am getting ready to remove my rear leafs to replace worn bushings (bad front leaf bush caused a strange knock over my right shoulder). While out, I figured I'd have the springs re-arched. This seems to be the most widely recommended approach as opposed to new units from Moss, and even Peter Mays seemed to have had some problems with height. My whimpy question is: How much of a bitch is it to remove/replace leaf springs? Having never done this job before, I just want to know how bad (or easy) it's going to be, and how much time to realistically allow for the whole job (not counting spring shop time).
Mentally preparing, Matthew
M Moment

Matthew,
It isn't that hard. Assume that you will probably want to replace the sping pads where the spring attaches to the axle, the u-bolts and nuts, front and shackle bushings (I would strongly recommend using polyurethane bushes), possibly the axle limit straps, perhaps the front plates that attach the springs to the body, and you should not be surprised if you need new shackles as well. Start soaking all the bolts with penetrating oil NOW.

I tend to prefer removing the whole assembly; three bolts on each side hold the rear bracket to the boot floor; four bolts on each side hold the front plates to the floor. On the front plates, the front two bolts come down from the inside, accessible from behind the seats with the seat pushed forwards on the rails and tilted forwards... an impact wrench helps with all of the bolts involved. Of course, you also have the two u-bolts on each side holding the axle to the springs.

Support the car with a couple of jackstands ahead of the front plates, preferably with a largeish board to spread the load. Use another jack to support the weight of the diff. I would start by removing the u-bolts, then the rear shackles, then finally the front plates.

Getting the front bush out can be challenging. A press is nice here, alternatively, a bench vise and assorted sockets can suffice, but ideally you will have the spring re-arching company (look for places that work on truck springs) remove them for you.

You don't really want too much arch, the car should sit level, otherwise the fine handling will be adversely affected.

Pay attention to the plastic washers at the front bushing when you disassemble.

Reassembly is the ... Never mind. When it is time to get it back together, bolt up the front plate first, then attach the axle, then get the rear shackles back on. Can be helpful to remove the limit straps, but not if you break the attachment points in the process. After you drive it a couple times, re-tighten the bolts, especially the u-bolts.
David "waiting for some warmth" Lieb
David Lieb

Hi Matthew

Just done this job on mine, only I dismantled and swopped the leaves on the springs rather than re-arching.
David's answer covers about everything - wish I'd thought to ask the question here before I started! The only things I would add is that it's helpful to use yet another jack under the u-bolt bottom plate when refitting the U bolts and to make sure the curved spacer plates on the top of the rear axle are in place before you start tightening the u-bolt nuts. Mine had a tendency to slide out sideways.
I replaced the front bushings by using a nut and bolt, with a socket as a spacer, to extract the old bush. Then a pressed the new one in using a socket again in the vice.

Harvey
Harvey '71 Sprite

Oh yes, I have a piece of 2x4 under the workbench that I have used for several of these jobs. It is about 7" long and has a notch cut out of the edge so that it can be placed on edge under the spring pad to jack it into place without having it in the way of starting the four nuts.
David "always surprised to find it again the next time I do springs" Lieb
David Lieb

I'll second David on one piece of advice he gave above. Order ALL new mounting hardware before beginning, because you'll quite likely need it. Back when I was a naive "newby" to the Midget world, I was installing new rear shackle bushes to replace what was left of the old ones. And the first nut I turned to remove a shackle snapped the threaded bit right off, so it was back to the catalog for new shackles, and a few more days of not driving. Of course the new shackles were necessary anyway, because the surfaces of the pins were pretty rough, but that didn't even occur to me when I started.

So bushes, shackles, all nuts, washers, lock washers, U-bolts, rubber (or poly) stuff, you name it... order the lot.

Cheers,

-:G:-
Gryf Ketcherside

New springs are really scarce at the moment (factory not making leaf springs anymore apparantly), so check on availability before throwing out the old ones if replacing.
John Collinson

If you can find new ones I bet they will be rubbish too

My latest new springs have "corners" where the curves are kinked every ten inches or so and sank faster than Titanic

Keep old ones and find someone to re-temper them, that was very good advice!

And even re-tempered springs will flatten so expect a certain amount of "sink"

The removing advice already given should cover it for you, all-new ironmongery is a basic "must do"
Bill

I am soooo glad I read this thread. I'm having a look under my rear ends this spring to see if anything needs replacing. I already know the rebound straps on my '72 are shot...

Cheers,

Glen
G. D. Phillips

I feel so lucky to have this BBS. I can’t tell you how many hours of work I have saved by asking what seems (at first) to be a silly question.
Thank you David so much for your response. You not only answered my question, but went above and beyond with information I didn’t even realize I needed.
One thing several people have mentioned (and I saw in archives) was placing a board (2x4) across the bottom of the car to support and distribute the weight of the rear end. This sounded like a great idea until I stuck my head under (while liberally soaking nuts and bolts with penetrate) and saw the exhaust, brake lines and such. I guess there is no choice for me but to use two individual “blocks” to spread the load. Man, that makes me nervous.
Thank you especially for reminding me of the “false economy” of trying to (or thinking I might be able to) re-use any connecting parts like these. You’d think after 30 some years of MG ownership, it would be automatic by now. A new baby and a wife on maternity leave can really make you think cheap. Thanks for the reminder; I would have been really pissed when that first shackle pin assembly broke!
Matthew
M Moment

Harvey:
Tell me more about leaf "swopping" I know nothing about this. Do you mean (I can only imagine),flipping the leaves over to re-present the curve in an opposite direction? What if they are already (like mine) basically flat (horizontally)? Am I better off re-arching? I'm thinking yes.
Interested.
Matthew
M Moment

Matthew

The leaf swopping idea came from postings here.
It's to solve the problem of 'drivers side droop' where the driver's side of the car sags, probably from mainly solo driving, leaving one spring lower than the other.
You remove both springs, dismantle them by removing the securing bolt and carefully bending back the guide clips at the end of each leaf. I gave each leaf a good clean up, a couple of coats of hamerite then re- assembled swopping alternate leaves from each side. The end result is hopefully 2 springs the same height, well it worked for me!
Harvey '71 Sprite

It certainly DID work for Harvey as this recent picture shows....

I do it in a slightly different way to Harvey, the leaf swapping from side to side hadn't occurred to me. I compare each leaf from side to side and with the judicial use of large hammer, leather gauntlets (ESSENTIAL) and my anvil, It reset each leaf so they are the same for both sides. I then re-assemble using a Black Molly grease between the leaves. Oh, if you want to be a little more fussy, I sometimes file a champhered radius at the end of each leaf.

Mark.


Mark Boldry

The cost of 'doing away' with the rear springs has dropped since Lotus 7 replicas really took off. Similar weight so often a straight bolt-on.
Easier to adjust or re-spring and the weight of the components is much less. Takes a while to weld it all up but not impossible to do at home if you are a little adventurous.


http://www.spritespot.com/gallery/view_photo.php?set_albumName=toomanyspridgets&id=qa4


....and....


http://www.spritespot.com/gallery/view_photo.php?set_albumName=toomanyspridgets&id=robsdisc2_025

...if you want to just bolt it all together without having to do any welding at all. Just add a bolt-on Panhard rod kit.
rob multi-sheds thomas

One last (I hope) question before I embark on this project. Looking forward, when it comes time to remount my leaf springs to the car, is there any provision for ensuring that the rear axle is not askew? In other words, is it possible to reassemble the rear end and wind up with the axles NOT perpendicular to the center line of the car? If so, how do I prevent that from happening?
Thanks, Matthew
M Moment

It is pretty hard, Matt. Make sure you keep track of which is the front of each spring (pictures of before you started help) and make sure that the shackles are facing the right way. The axle is pretty well located by the bolts and holes.
David "Waiting for the next shoe to drop" Lieb
David Lieb

About midpoint through this project. Have all disassembled, parts being cleaned up, purchased all new poly bushes, shackles, u-bolts etc. During removal, I noticed the presence of anti-seize compound. This got me thinking “Were these springs replaced by the PO?” After going through the pile of receipts provided with the car I discovered, sure enough, a pair of leaf springs were purchased in 1989 from Victoria British and installed. Now my concern is; are these the inferior, cheapo springs everyone has been complaining about in the archives? Is there any way to tell? I don’t want to waste money having garbage springs re-arched (being done as I write), but I’m not sure I have any choice. If anyone has thoughts on this, please let me know.

Second question: on the front bolts that hold the springs to the bracket, there were four washers on each. Two steel, and two plastic. Is this correct? If so, should I also use those plastic washers with the new poly bushes?

Thanks, Matthew
Matthew Moment

The front bush of the leaf spring is a metalastic type, I'm not aware of polybush replacements being used here, a new original type will be more than adequate I think.
David Smith(davidDOTsmithATstonesDOTcom

I have used the poly bushes in the front of the spring. After all, I got them with the set, so why not? I found that it was not physically possible to use all four of the original washers and ended up only using the metal ones under the assumption that the poly was substituting for the nylon washers.
David "dunno what's right" Lieb
David Lieb

This thread was discussed between 29/03/2008 and 08/04/2008

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