MG-Cars.net

Welcome to our resource for MG Car Information.

Recommendations

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 - LA Dampers diy full strip. 2026. Shockingly easy.

Before sending a pair off to V&C for refurbing, I spent a few hours taking apart some of my other spare, worn, front lever arm dampers.

One I picked up very cheap, has very good damping but had a bent arm. Turned out to be quite easy to pull the arm off, and swap it with an arm from a very knackered damper.

Putting the good arm back on was just as easy. Pulled it on with the nut; new split pin, job done.

On the left with red arrow, good damping but bent arm. Gawd knows how it got bent like that. On the right, slop in the shaft, but a bad damping.

So successful it was, that I've bunged it on my Sprite, and since my lhs is good, I may not send any fronts to V&C after all.

Next up full strip of another pair of fronts.






anamnesis

Until today, I thought stripping these dampers was hard to impossible diy. So I'd never tried.

Actually it's pretty easy.

I also thought you had to take the arm off to strip the damper. Not so, because the shaft isn't held in at the arm end. All you need do is drill through the core plug at the opposite end of the shaft, and use a hammer and drift through the hole on the end of the shaft, to push it out of the body. Then you pull out the pistons.





anamnesis

And what shocked me most, is how the shaft is retained in the body. Now I know how lateral movement happens such as in this picture somebody posted here some years ago.

ALL that holds the shaft in the body is one of these sleeves, hammered into a groove in the shaft.

If the sleeve hasn't been hammered in sufficiently, it doesn't hold the shaft in tight enough.

When you either press or hammer/drift the shaft out of thr body, all you are doing is pushing the shaft through this 'crushed' steel sleeve. That's it. That's the only thing keeping the shaft and therefore the lever arm, attached to the damper.

No wonder so many end up coming loose. Don't you think?







anamnesis

My guess is, these sleeves are reused, in refurbished dampers.

I think many dampers can be refurbed DIY, -- AT LEAST AS WELL AS, sending them off and paying someone else to do it. All we need is the source for new seals if needed.

Worn shaft? Speedy sleeve?





anamnesis

For clarity.


anamnesis

Anam
Interesting. Well done. I presume a fly press or similar is needed then. How did you hammer the sleeve back in?
Bill B

Hi Bill,

That last picture is BEFORE I took the shaft out.

The point is, no press used. A hammer and a drift is all I used. It was assuming a press was needed, that stopped me and no doubt others over the years from attempting to diy this.

No doubt it is easier with a press, but it's not hard using a hammer on a drift through the hole drilled in the welch plug. The end result is the same.

Reassembly is just a reverse process, except it's even easier.

When refitting, the shaft will go in very easily, because the 'crush' sleeve is a slight interference fit on the shaft, until it's hammered into the groove with a chisel, between the splined sections of the shaft.

Those splines are what the piston's rocker/cam are driven by.






anamnesis

Splined.

This is genuine Armstrong.


anamnesis

A quick thought is that as the staking is still largely present after removal then the spacer sleeve has likely stretched and would be best replaced with new. Maybe why it was easy to remove as it may have been apart before judging by the bit of damage to the serration next to the groove and maybe the sleeve was reused and poorly staked. I have a pair here that don't appear to have been apart before and I intend to take an impression of the staking to try and replicate the tool used before taking them apart.

The shaft will need to be carefully measured to see how they've worn, not much point in a Speedi sleeve if it's tapered and not round and of course the bores in the body need to be checked for wear also. IIRC NOS Imports (Peter Caldwell) make their own repair sleeve for this task.

When I pulled the arms off a pair for Les Rose it took about 5 tons, one requiring a small amount of heat for persuasion.
David Billington

I took two apart.

One embossed Armstrong, and the other an unbranded copy.

Yep the Armstrong may well have been apart, but the copy appeared un got at.

And, you DON'T need to take the arm off anyway to take the shaft out of the body to remove the pistons. That's what I hadn't realised until today. But my puller, with a little help from a hammer, gets the arms off. 😁😁. See the first post in this thread.

Yep new sleeves will have to be made, I can't find anyone selling them. Or piston seals for that matter.

Where do V&C get their new seals and sleeves?






anamnesis

The 'crush' sleeve (for want of a better term), can be used again I reckon. On the uninterfered with unbranded copy, the sleeve has only been chiseled/staked/dented on one side.

Just spin it 180 degrees, and dent it into the groove again.


anamnesis

The original seals are fairly average anyway, best to get some lip seals from a bearing shop. MGB shockers use the same seal size as the gear selector on Honda quad bikes and it's a good double lip weatherproof seal--don't really know if that's the same on a midget/Sprite shocker --?
Just be aware before dismantling these shocks to check the droop of the arm so that you get it back on the correct spline otherwise the pistons can bottom out at full travel.
Also check inside that it actually has a creased in sleeve holding the shaft. I have had a few that have had an aftermarket sleeve with a grub screw and locknut.
William Revit

"Just be aware before dismantling these shocks to check the droop of the arm --"

Did I? 🤣

Actually I did on the pair I swapped a bent arm for a good one. But I forgot when dismantling the other pair. So when I next take a front off my Sprite, I'll do some marking for assembly.

anamnesis

I've never done anything more than clean, repaint and change the oil in my shocks. Even that was probably more than was done at one time when 'reconditioned' shocks cost just £9.95
But looking at these photos and sectional drawings they are rather a nice bit of engineering. Especially considering the damper system on my Austin 7's which from many aspects was a precursor to the A30 that these shocks were used on before Spridgets. And the A7 system was basically a disc of clutch type friction, about the size of a mini angle grinder, sandwiched by a giant star washer. Quite an advance in design and functionality to go from that to an Armstrong!
GuyW

Yep I agree Guy. Yet they seem both simple and impressive -- now I understand how they work and are put together.

Even the unbranded copy is pretty good, and doesn't seem unduly worn internally.

I wonder if ALL new Armstrong copy shocks are so bad. Are they ALL getting a bad name unfairly?

I'm going to fully clean and reassemble both as is, with a new welch plug and fresh oil and see how they are then.

As an aside, what *IS* the correct grade of damper oil for SPRIDGET lever arms?

Is it 20 or 30? I've read both.

According to the BMC manual, section L, both Spridget and Mgb, it's Armstrong super thin, -- or a good sae 20 mineral oil; albeit in not too cold conditions.

I read about your STP mix Guy. Now I've seen the insides, I can understand how too viscous an oil could put strain on the rocker and piston pins, and cause wear there. But given how long you've used that mix without trouble, I reckon those pins are made of stern stuff.

Edit:
Note the seal on the right hand piston (bump?). It's just like a brake wheel cylinder seal.






anamnesis

As well as the manually adjustable ones they also made some which were electrically adjustable while driving.

Armstrong Selectaride https://mgaguru.com/mgtech/literature/pdf/safety_fast_aug65_shocks.pdf . I've seen them mentioned before as fitted to some Aston Martin models.
David Billington

Yep David, I read about those in an Armstrong catalogue I downloaded. Pretty advanced for the times.

anamnesis

The mk3 Sprite I had in the 70s had electrically adjustable rear shocks. I should have removed them and kept them for the Frog.....

I'm still surprised the shock arms are only held in place by "dented" or staked sleeves. No wonder they sometimes come loose.....

I think Peter Caldwell makes Delrin inserts for the shaft entry in case of leaks (although ISTR him stating they will leak slightly anyway).
Bill B

an. as you say thick oil isn't really much good for these shocks. I believe the spec is as you say 20 wt mineral oil but most here use 30 weight fork oil from motorcycle shops. The trouble with thick oil is that if you hit that big bump the shocker can't vent the oil quick enough and you risk damaging the shock or stub axle. The thick oil stiffens both compression and rebound---you don't want stiff compression, it's the rebound that needs tuning to your car. If you give the car a good push down and let go it should come up and stop without any bouncing--if it bounces the rebound needs adjusting on the valve by tightening the little nut up, usually they'll take about 5 turns(nearly right in) to get it feeling good. The compression is pretty right as is with 30 oil but if it needs to be a bit stiffer--not usually needed, that's done by subtracting shims from the outside of the valve where it screws into the body.
It's good fun if you have both your shocks out togetherand you can play with the valve adjustments to match them using weights and timing the travel
willy
William Revit

Anam, My STP /oil mix was a temporary experiment. I did a couple of track days and the instructor on one was impressed at how :flat' it cornered. I probably left the mix in for about 6 months of regular road use before a drain and refill. I then just used normal 20/50 engine oil.
GuyW

Ah right Guy. I misunderstood. I thought you ran the stp mix for longer than that.


Willy, are there any rough guide figures for weights and times to hang on damper arms, applicable to Spridgets? That'd be pretty useful I reckon.




anamnesis

Bill B,

That was a mistake in hindsight letting them go as they likely increased the value of the car considerably to someone that knew what they were.

I'm reminded of a guy I know that's involved with Lotus Cortina racing and he bought a pair of them and spares and as he was leaving the guy threw in a couple of telescopic dampers that had been lying around outside for awhile. They didn't look like much so went on his scrap metal pile but then he thought better and cleaned them up a bit and put them on ebay and towards then end of the listing the price went ballistic and ended at IIRC £960. It turns out they were only fitted to factory cars and factory customer cars as an option for 2 years and so were eligible for historic racing making them rather valuable.
David Billington

I use synthetic motor bike fork oil, principally because it's more heat stable than mineral oil. Damping becomes softer when the dampers warm up
Also it's quite easy to adjust the damp rates too. Two adjustments, one for bump, and one for rebound!!
Allan Reeling

As Dave B says, he got the arms off my dampers but we now know you don't need to do that. I put a Speedi-Sleeve on one of them, with a lipseal, and so far no more leaks. I had to get the arms really hot to get them back on. And the dampers in the freezer.
Les Rose

Hi Les,

Did you record the sizes of the lip seal and speedy sleeve?

anamnesis

Back in the day ISTR Glycerine was the fluid to add to the shockers to stiffen them a bit essentially when worn.

I also remember an Armstrong test rig ? to check for bounce / rebound - gauge on the wing and wing bounced up and down and let to settle - then a paper trace was produced that indicated if OK or not ! Tried it on my boy racer Morry Minor ! Hence the Glycerine !

Would be good if new collars were available - could a two part bolted solution work with a lip filling the groove ? What is the purpose of the splined part of the collar other than location and spacing ?
The benefit of staking i guess is that it does allow for varying tolerances to be taken up/ end float etc in manufacture which may be difficult with a machined lip defining position.

R.
richard b

Good job Anam, that's going to be a decent saving you're making there😊
No idea how V&C disassemble them - there were several large presses in the workshop - but he did point out that one of my shockers had had the arm welded to the spines.
It wasn't an issue for him - which makes me think he may use a method similar to yours but he pointed it out so I didn't think it was something he'd done.

Didn't Malc sell seals in his refurb kits?
Jeremy MkIII

Richard B,

I'm not sure about glycerine as it's not miscible with mineral oil.

Armstrong test rig sounds interesting but likely a rare beasty these days, made me think though of smart phones and their sensors so maybe an app and sure enough there are apps which may do the job such as https://apps.apple.com/us/app/gabriel-shock-test/id1076701012 and some others.

I was thinking along the same lines with a 2 part collar, basically a split shaft collar machined to suitable dimensions.
David Billington

Yep much easier and a lot quicker with a press Jeremy. Wish I had room for one.

Might save me money if they are ok and not leaking when I put them back together. Lol. We'll see.

One of my damper's arm was loose on the shaft. I' not sure if the nut had pulled the arm down tight enough or if somehow the arm splines had worn enough to create movement. But if it's common that would explain yours being welded to the shaft.

There are 2 seals needed. The shaft seal to prevent leaking, and the piston seal to create the oil pressure needed for damping.

I wonder if V&C would sell the seals they use, or tell where to get them?


anamnesis

I'm all for alterations/mod's/improvements, but does the sleeve really need a redesign?

When we could buy these dampers new from BMC, they were cheap. So cheap, that along with fwb's I used to replace them almost as service items.

The only time I ever had the problem with the shaft moving in and out of the body, was with even cheaper recon's bought from car spares shops. Never had trouble with BMC factory recon's though.

I think made properly, and rebuilt properly, these levr arm dampers are actually really very good. Sure, a 2nd arm at the back, A la mgb dampers, would have been a good idea. But still, even without that, they still make for pretty good handling without even 'uprating' them.

Now I've personally pulled these apart, I can form my own opinion, instead of reading other's. These dampers are as Guy put it, a nice bit of engineering. They do the job pretty well.

Staked in properly, the sleeve does its job well.

It's only when pulled apart and not staked as well in the rebuild that the problem occurs. I don't think the sleeve needs altering, just fitting properly.

anamnesis

About the seals. Maybe give V&C a ring or contact through the website? His name is Iain. Worst he can say is no.
Jeremy MkIII

Yep on my list of things to do Jeremy.

Maybe someone else might bell 'em and ask.





anamnesis

Thoughts
Would it be a good idea to replace the sleeve with a machined sleeve with a roll-pin through it and the spindle?
Alan Anstead

With regards arm position I asked Peter Caldwell and he sent me this reply.

"David, Fully up, the bottom of the arm at the trunnion pin bulge is 2-1/2" to the table. We have a gauge tool to set them. We NEVER EVER remove the arm from the shaft. We machine the body to accept an oil seal, as there is no off-the-shelf seal available, and the bore usually isn't reliably round or concentric to the shaft as the original was a packing. We further sleeve the shaft with a stainless steel sleeve we manufacture. We go a bit overboard with the technique, tools, and supplies we use. We need them to be as good as they can be, which is why we can guarantee them. Good luck.

Peter"
David Billington

That's a very useful reply David.

Sounds like V&C must machine for a lip seal too then, since there's nothing standard available off the shelf.

On the pistons seals, I found a number of companies who make/supply piston seals. Need to ring them for sizes.

These are just three of them. Must be one out there who can supply the right shape/material/size of piston seal for our Armstrong la dampers.

https://www.swanseals.co.uk/collections/imperial-piston-seals/products/fabric-u-ring-symmetrical-imperial

https://www.fpeseals.com/seals/piston-seals/u-ring-seals

https://www.fpeseals.com/seals/piston-seals/u-ring-seals






anamnesis



https://www.skf.com/group/products/industrial-seals/hydraulic-seals/piston-seals/single-acting-piston-seals/unp-profile-data


anamnesis

Anam,

promised to let you know how the reconditioned shocks from V&C Engineering performed.
Finally fitted them, along with Superpro bushes (a faff as we all know) and an Austin Healey Sprite & midget top Trunnion Needle Roller Bearing Upgrade Kit (easy).
The ride and handling are much improved. More controlled, no crashing over bad bumps, a significant improvement. So can recommend V&C if you haven't already refurbished your own Armstrongs.
Jeremy MkIII

This thread was discussed between 11/03/2026 and 25/04/2026

MG Midget and Sprite Technical index

This thread is from the archive. The Live MG Midget and Sprite Technical BBS is active now.