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MG Midget and Sprite Technical - Front suspension help - greasing issue

Hi all.

My wishbones have grease fittings on the front and the back at the bottom. This is great, BUT, I've run into an issue.

Doing the standard greasing of the king pins and sundries I put some into the bottom bushes. This has had the effect of pushing the little screw on thingy out of the end of the bush. The grease fitting is still in it, but the little cap that screws in after the threaded bush is fitted pops out under application of the grease gun :(

Anybody got any bright ideas on how to keep it in? I've pushed/screwed it back in for now and it's stayed in, but I can't grease the bottom bush on one side cos it pops the end off!

Rather not swap for other wishbones - these are Barry King's last set of -2.5 degree ones, and they make the car corner like it's on rails.

I had thought about a little clamp but I'd have to drill a hole in the wishbone - not too keen on that.
Rob Armstrong

See if you can swage the A arm to hold it in. 3 or 4 dimples should do it.
Martin

The screw plug threads usually deteriorate with age, so either get a new one from A H Spares or degrease and Loctite the old one back in.
Fergus

I think the threads in the end have stripped - they look a lot finer than the threads on the purchasable caps....

Hadn't thought about swaging it in. The grease caps are cheap so I could get some and see if they thread in nicely, if not then dimpling the surrounding is likely the solution. Not sure why I didn't think of that...

I'll let you know if it works!

Rob Armstrong

One of each, a new threaded thing in one end, went in nicely. Applied the grease gun, then popped the pressed in plug off the back.... Swaged that in by spoiling the ends of the tube after tapping it back in. Took a good solid go on the grease gun but I think it's better now.

Is the tube that the trunnion bush lives in made of steel?
Rob Armstrong

"Is the tube that the trunnion bush lives in made of steel?"

All one piece in everyone I've seen and yes steel and brazed in the originals but modern replacements wishbones may have them welded in.
David Billington

Dave,
from Rob's OP - "these are Barry King's last set of -2.5 degree ones"

and that's the name I couldn't think of earlier.

Perhaps it was best that I missed out on the last sets of these.
Nigel Atkins

I think the issue is the trunnion pin has a hole in it so the grease just goes straight through the middle and pops the cap off. But not any more. Also, the threads are very tight so it takes a bit of effort to get the grease in to the threads.

Apart from the end cap popping off these wishbones have been great. -2.5 degrees works really well, I've not got any strange tyre wear, car corners like it's on rails. The effective wider track with the slightly longer lower arms helps too. I'll have had them on for about 5 years and there is absolutely no play in the bottom trunnions after that time (about 16000 miles, including track days and all sorts)

The reason I asked about the steel was to see if I could tack the cap on with the welder - next stage if it bursts my fix out next...
Rob Armstrong

Rob,
maybe your fulcrum pins for the Barry King wishbones are different. But the standard ones have a slot along the threads so that grease is fed to the friction surfaces of the pin. And the good ones also have a radial hole which connects the axial hole through the pin, to the groove down the side.

The main purpose of pumping grease into the assembly is to push the old contaminated grease out past the 2 kingpin cork washers, clearing any road grit with it. A design which is "grease tight" wouldn't work properly with respect to this process.
GuyW

it's been that long since I had them out I can't remember if they have a slot in them. I copied something I saw on here (might have been your idea actually Guy) and used pipe lagging instead of cork washers.
Rob Armstrong

Yes, I use slices of pipe insulation too. But they are not so close fitting that the old gritty grease doesn't get forced out
GuyW

This thread was discussed between 20/03/2017 and 27/03/2017

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