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MG Midget and Sprite Technical - Front suspension replace or repair options

I have started to take the front suspension off my 1500. I don’t think the suspension has been serviced for a long time.

The top trunnion bushes are perished as are the bushes for the a/r drop links and the rubber on the track rod ends. There is a bit of vertical play in the stub axle with two shims fitted. Taking them out would probably cure that.

There is wear in the fulcrum pin, with around one mm of play at the top trunnion.. The cotter pin is stuck and haven’t shifted despite a punch and hammer. So I need to work out how to get this out.

The bushes at the end of the wishbone look ok, but the bolts are well and truly seized. The wishbones themselves seem ok, just very rusty.

I don’t really want to leave the wishbones on the car as it feels like just delaying a tricky job for later and the chances are the bushes are worse than they look. All the various separators and pullers I have won’t fit in the space to push the bolts out. Is there another tool suitable?

Otherwise I guess it’s out with the angle grinder and cutting disk?

When I eventually get the wishbones off am I best getting a reconditioned set of king pins and stub axles plus new fulcrum pin as both the king pin and fulcrum pin will be worn? I don’t have access to the reamer.


C MADGE

Yes all sounds very sensible.
Try Manor Garage at Wantage for the best priced exchange uprights & kingpins. Richard has the reamer and does them himself.
David Smith

I must be physic, but missed bolts to pins.

The orientation of that photo has given me vertigo.

I take it you’re cutting the nuts or are they already off, either way careful not to damge the wishbones.

All looks very dry give everything not being cut a good drink of PlusGas.

Sounds like David has given you a very good lead.

I’ll take that steering rack gaiter off you it looks there to be in better condition that a modern one would be.
Nigel Atkins

Check your front wheel bearings and brake system. I prefer to everything in the front at one time, then all I need to do is grease every so often. Nigel will reference the owners manual and tell you exactly how often.
J Bubela

I always take the good book as a starting point but with this as with other matters I allow for the 40+ years that have passed and actually grease the front more often than book shcedule, every 3 months/3,000 miles and just before annual MoT test.

ETA: I'll definitely have that jack, clean, polish and on display to show it off.
Nigel Atkins

If the two inner fulcrum pins won't come out of the wishbone, you will be surprised how quick it is to cut through them with a hacksaw blade. And you will do less damage than clouting things with a hammer and/or applying heat. (I learnt that particular lesson many years ago!)

Regarding shims at the top of the kingpin, I recently ordered some from Moss but had to send them back because they had burrs on. It looked as if they had been punched out with a damaged tool. I got some from Sussex Classic Car parts and they were much better.

As for the bronze thrust washer at the top of the kingpin, I got some from AH Spares and I had to tidy those up because they were slightly wider just at the inside edge (possibly from where they had been parted off on a lathe).

If you can get reconditioned exchange uprights and kingpins, that is probably a good way to go. Or if you can get them preassembled on wishbones, that might be even better (then you can stop worrying about getting the cotter pin out).
Jonathan Severn

Thanks for the replies.
I’m a bit wary of the cutter on the angle grinder as it’s easy to end up damaging other things as you cut.

The hack saw blade idea I like, i’ll give that a go.

The wishbones look good so ideally I would just replace king pin and stub axle with a recon unit if I can get the cotter pin out.

However I have read that the fulcrum pin threads can wear in the wishbones as well? I which case it’s a wishbone and kingpin with stubaxle replacement?
C MADGE

Chris,
once the wishbone is off the car you can give it a good clean and inspection and go from there, if it's cracked you'll be replacing it anyway.

Hacksaw or cutter whichever you feel most comfortable with.

Generally, I'm not sure how much applies on this job, you can break nuts off (usually when you don't want to) by applying (too) much force when trying to undo them, make temporary welds to hold or remove something (bars, sacrificial tool, etc.).

For bushes, cut, chisel or drill them or around them or perhaps burn them out - although I wouldn't especially indoors as you never know what toxins they may have in or on them.

I also wondered if, as you're more used to high end racing cycles rather than older "pushbikes", that you might not be familiar with cotter pins (that went in the cheaper pedal cranks), the taper.

If nothing else it might remind you on reassembly and future servicing to use the likes of coppergrease, grease gun, oil can, etc..

Again generally not on this car(?), if you see a car that's been in flood water walk away from it don't buy it to restore. I remember when we had the floods in Northampton (1998) a chap wanted to buy his car back off the insurance and was told his car would be totally taken out of supply and crushed, possibility of Weil's disease I think (nanny state protecting him from a rare possibility of a nasty death or insurance company covering themselves from possible future litigation - you decide). :)
Nigel Atkins

The weakest point in the front suspension, as far as wear goes, are the bushes for the bottom fulcrum pin, and that means a new lower wishbone pan. So if the kingpin is worn, unless the wishbone pan has already been replaced, it's a safe bet that it will be seriously worn as well.

Feeling for movement in these joints is easy enough, but fulcrum pin wear is most obvious if you release the top trunnion and see how much fore and aft rocking there is in the kingpin. Wear will be very obvious. If you have already confirmed kingpin wear and you need a new wishbone you may as well get a complete exchange unit and save having to dismantle the cotter pin etc.
GuyW

Nigel - i’m familiar with cotter pins and their taper. I remember then from some of the cheaper chainsets I have owned as a lad

GuyW - thanks. Ok i’m coming around to idea that replacing the wishbones as well is the better option and saves drilling out the cotter pins. It’s a simpler replacement solution.

C MADGE

Probably, but do check them first! A cotter pin is a whole lot cheaper than a new wishbone !!

Plus, as you may have seen from recent threads here, the quality of wishbones currently available is very variable. If buying a new wishbone, familiarise yourself so that you fully aware of what key points to look out for.
GuyW

I thought I’d put another post up earlier but it’s not there so I must have clicked on the wrong button.

Can you get a made up set with stub axle, kingpin and wishbone(?), if so and if the wishbone is also a reconditioned one(?) and not new (Guy has now covered the point about new ones with Jan’s and other recent threads) then that would be an easy swap.

I think you’d have to be careful about drilling the cotter pin out if you want to keep all the other parts, I’d try a three days of repeated spraying PlusGas and leaving to soak then a sharp concentrated blow with a heavy hammer on to perhaps something used as a drift, the assembly would need solid support to lessen bounce. I’m a fan of the two hammers shock/vibration technique where you can get the hammers in (after letting the chemicals do their work of course).

Chainset, that was the word I couldn’t remember, I thought of cast crankset but it didn’t seem right.

Nigel Atkins

First one off with hacksaw blade, jig saw, and cutting disc
Plusgas in pic for Nigel
Now to get the cotter pin out.........


C MADGE

Well done.

I hope that can is nearly empty now!

How come the photo is presented in the correct orientation, have you ditched the i-phone! :)

Are you able to contribute to the V888 thread.

Nigel Atkins

This thread was discussed between 28/02/2018 and 04/03/2018

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