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MG Midget and Sprite Technical - Changing front dampers

I'm intending to change tbe Frog's front dampers in the next few weeks (having acquired a decent used pair), together with poly trunnion bushes. It's some time since I've done this in situ so want to make sure I've got it right.

I intend to jack underneath the outer end of the suspension pan to take the weight of the car (hence holding the coil spring in compression), then remove damper pinch bolt, upper trunnion bolt and damper, replace trunnion bushes then replace damper and bolt back up.

Is that correct? Are trunnion bushes easy enough to change in situ? Seems to be what Haynes says. If so, what are the chances of the coil spring trying to escape towards me? I realise the jack has to be stable.
Bill B

Yes I have done it this way with no problem, sometimes the weight of the hub will tip it towards you and put a bit of strain on the brake flexi pipe so watch out for that . Just make sure the wishbone is well supported on the jack or I have lowered mine onto a big wooden block.
Mike Fairclough

Axle stands or suitable wood blocks under H frame or body - safety first.

I would jack the car up first and rest it on these, then jack up under the wishbone.
Tim C

As above. Also have a spare axle stand ready to rest the hub on when you've disconnected the top link.

As long as the top trunnion bolt isn't rusted into the bushes, it should be easy.
Dave O'Neill 2

Thanks everyone for your suggestions - much appreciated!
Bill B

Bill,
I'm halfway doing through what you're doing (the removal bit) and did it with axle stands under the H section and trolley jacks holding up the hubs as the spare axle stands are holding up the rear axle.
All 4 shockers are currently with V&C Engineering for refurbishing so I'll be interested in your experience of fitting poly bushes as there is a set of superpros waiting to be fitted.
Jeremy MkIII

Hi Jeremy
Thanks. I don't know when I'll get it done but will certainly let you know about the poly bushes.
Bill B

The only thing I might add is that if the shoulder on the polybush is a bit thicker than the rubber it can be difficult get enough gap between the lever arm and the top trunnion. I loosened the shock absorber bolts to give enough wriggle room.
Mike Fairclough

I’ve done the same as you Bill, and the others posting here.

The process should go smoothly for you.
Philip Sellen

Mike, Philip, thanks.
Bill B

Cheers Bill,
if I get to fit them first, I'll post the experience here! 🤨
Jeremy MkIII

Just changed my offside front shock. The arm became loose on the shaft somehow. Loads of fore and aft movement. Nut still too tight to undo. No idea how it's worn itself loose, but it was bought as a good used pair. Hey ho.

Anyway, all I did was jack up under the wishbone spring pad, wheel off, loosened the fulcrum nut, removed the fulcrum clamp bolt, squeezed out the fulcrum an swapped out the shagged shock. I wasn't changing the bushes, but took me about 40 min's.

Luckily one of the easiest jobs on a Spridget I think.

Looking forward to your results Jeremy, I might get my shocks done if yours are done well by vc.






anamnesis

I use a bottle jack inserted into the bottom inverted spring turret of the wishbone. less in the way than a trolley jack and can't be displaced.
The Small shock arm pinch bolt is prone to shearing if you aren't careful. Give it plenty of a good penetrating oil soak and maybe use some heat if it's tight as if it does shear it's a major PITA
Although I agree about safe use of supporting stands under the car, to keep the spring in place and compressed you will need the weight of the car (with engine in place) to be taken on the wishbone jack, not the body frame stands. And you may need to encourage Sheila to sit on the inner wing to compress the spring on reassembly.
GuyW

Thanks Anam.

Guy, I had thought that most of the weight should be acting on the wishbone although I also agree about using axle stands that others have alluded to. So, have the stands in place under the crossmember, but not taking much weight maybe.

I'll have the glamorous assistant standing by. 🤣

(I realise I'm probably overthinking all this, but have become more risk averse as I've become older, especially after hurting my hand last year).
Bill B

Support under the chassis, reduces pressure on the spring, making it more likely the spring will expand, making it more difficult to free and refit the fulcrum. I don't support under the chassis. Never felt the need doing this job.

If the jack under the wishbone is secure, as Guy says, in/under the inverted spring turret, you're good to go. How will it slip?

Extra weight? Maybe if you have uprated springs. But I've always found standard springs, even when new, are compressed by the weight of the car -- engine in.

I've never found it to be a difficult job.

I always grease the fulcrum and clamp bolt to prevent the seizure Guy describes. Learned that from experience.


Edit.
(I realise I'm probably overthinking all this, but have become more risk averse as I've become older, especially after hurting my hand last year).

Yep. See your point. My bloody hand still isn't normal, and I confess to being more concerned than I ever used to be.

anamnesis

I agree, Anamn, mostly you wouldn't need spring compressing assistance. But if using uprated springs, or doing the work with the bonnet off (its a frogeye) it can help. And anyway it's more fun.
I once in younger days, attempted this with the engine out and couldn't work out why the spring wasn't compressing!
GuyW

Will let you know what happens with the shocks Anam. I went there as Bernie's experience was positive.
Risk adverse increasing as getting older? Definitely. I even bought a couple of pairs of spring compressors from ebay for £12 - just in case 😱
Jeremy MkIII

Hi Jeremy,

How much for all 4 shocks at VC?

And how long have they taken to do them?

anamnesis

Well I've hit a problem. Changed the O/S front damper today - trunnion and old bushes came apart easily. I inserted the new inner poly bush (blue super pro) fairly easily (between trunnion and shock arm) but I can't get the trunnion bolt back in, whatever I try. I've lubricated the bush, as instructed.

I *think* the inner poly bush bulges inwards a bit when compressed in place, as there is no internal metal sleeve, and this stops the bolt even when trying to hammer it in (even though it will hammer in from the shock end as that must be relaxing it enough. It shouldn't be this difficult - am I missing something here, those who've done it? I've temporarily replaced the rubber bushes for now. N/S not done yet.
Bill B

Fit the bolt into the bush then insert ?
Tim C

Well I just lost a long post I thought I had sent !

So here is a condensed version in case it doesn’t reappear !

Try cleaning out the trunnions well and lube including bolt.

If necessary try a cramp such as an old school valve compressor- it has a forked end tho hat allows the threaded bolt to pass through. Assume the Superpro bushes have the thick washers.

If you want to borrow one you know where I am !

Regards

R.

richard b

Tim, I mean the inside bush sandwiched between the trunnion and the shock arm - you have to insert it first and try to hold its washer in alignment as you insert the trunnion bolt (pin).

Richard, I have cleaned and lubed. I'll try a G cramp. The superpro bushes have separate washers (unlike the integrated rubber bush ones) and the inner one is a fiddle to align. I don't think they've made it easy!
Bill B

The benefit of the valve spring compressor is the open end to let the bolt pass through !
richard b

You could remove the top trunnion from the kingpin, assemble with bushes and pin on the bench, fit to damper arm then slide the trunnion back onto the kingpin.
Dave O'Neill 2

Richard, yes I understand that but a standard clamp might be useful to push the bolt in and get it through the bush before it emerges. But I'll bear your kind offer in mind.
Bill B

Dave, thanks, I wondered about doing that. I'll try it if all else fails but don't know how well the bushes will hold in the trunnion I.e. so there'll be enough bolt thread emerging to get the nut started.
Bill B

All done now using suggestions from Dave and Richard. "New" front shocks and blue super pro trunnion bushes. I removed the trunnions from the kingpins which made it a lot easier to install the bushes. I used an improvised G clamp with mole grip jaws as a spacer, around the trunnion ends to allow the trunnion bolt threads to emerge. I found the poly bushes don't just push in like rubber ones so need some assistance via the clamp. Front ends feels more responsive now.




Bill B

This thread was discussed between 26/02/2026 and 10/03/2026

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