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MG Midget and Sprite Technical - 1275 Gearbox Teardown - Remote

Hello. It's been quite a while since I've looked for help here, but I sure need it now.

After 113,000 miles my 1971 had to come off the road. The gearbox noise which had been intermittent and tolerable now clearly indicates a problem. I was hoping to make it to the first salt on the roads, but I probably waited too long. Lots of metal flakes in the gearbox oil, and I should have been more cautious.

So the gearbox is on my bench, ready to come apart to see what I can find. I've never done this, and I'm embarrassed to say I'm stuck on step one. I've removed the nuts holding the remote housing, and it just won't lift off. I've tried hitting, prying, heating, a week of penetrating oil and regular harassment but it won't come free. I think the right side might be free based on some of my prying, but the left side won't budge a bit.

I haven't yet removed the nuts for the rear housing. Is there any chance I can just leave the remote in place and remove both together? Has anyone else encountered this?

My plan is to just follow the Haynes and Bentley instructions, along with the advice in the archives here (especially about where Haynes is misleading). If I get stuck I look for help. If I find there are serious problems in the gearbox I'll look for a replacement, but I'm hoping to do this job myself. I've read a lot about the conversion path, but I'm hoping to do the rebuild.

Thank you for any advice.
Mark 1275

The remote and rear housing can be removed together, but it makes it more awkward when reassembling.

Have you tried removing the studs by locking two nuts together? It ought to make it easier, although I've never had a problem removing the remote.
Dave O'Neill 2

I found the remote awkward to detach because of the remote shaft binding on the selector rods. I can't remember the detail now but it took a fair bit of twisting before it detached. I'm assuming the remote housing itself is free of the rear housing as only the nuts are securing it. You may need to persuade the joint to separate but that shouldn't take much, certainly not heat.
Bill Bretherton

Mark, I'm wondering now if I'm confusing the remote with the rear housing. The remote should lift off, then the rear housing will take some twisting to remove it. Maybe your PO left the gasket off between remote and rear housing causing the aluminium surfaces to stick together. But a thin blade should separate them you'd think.
Bill Bretherton

Much appreciate the responses.

All of the studs but one show no corrosion, and there's space visible around them. The one with corrosion is the one I've been soaking with penetrant, and applied heat to it as well. I tried two nuts locked together but couldn't get it to move. Seems to me it should have.

Yup, I'm actually stuck on the remote. It should just lift right up, and it's as though it's epoxied in place. There is a gasket there, or at least a black line that looks like a gasket.

I'll keep after it, and try to get a blade in there. I can understand it being reluctant to separate after 46 years, but I've brought real force to the game and so far it's winning.

It sounds like I'm not missing something obvious, like failing to detach or remove something. It will be interesting to see what the surfaces look like when I finally get them apart. I've owned the car since 88,000 miles, so I don't think the gearbox has been disturbed and had anything unusual done to it. And I didn't encounter mysteries like this in the course of the restoration.

Thank you for the answers.
Mark 1275

For what it's worth, I'm now convinced that one corroded stud is frozen, and acting like I never took the nut off. I can drive in a putty knife blade on the opposite side, and I'll just keep working my way around.


Mark 1275

Try some penetrating oil to loosen up any crud that may have formed in there between the two dis-similar metals. It also looks like the area around the stud on the remote may be slightly deformed down against the stud. See if you can gently make a gap between the two with a knife or other similar tool. That will make it easier to get the oil down there.
Martin

If you can remove the other studs, it may give you some wiggle room.
Dave O'Neill 2

Heat locally. A chef's torch with a narrow flame works well. But maybe not mention it to the chef!
GuyW

You're right that the penetrating oil just sits on top, and doesn't yet have a path down along the stud. I've tried threading a nut on top and tapping it every which way to try to open a gap, but no luck yet. Even a LOT of heat from a propane plumber's torch hasn't done the trick, and usually that works when all else fails.

That's a good idea to take out the other studs, and if I can get them to cooperate I'll do that this morning.

If these ideas don't do it by the end of the week, my last resort will be to drill the stud out. I have a small drill press, but it will be a challenge to stay straight, so I hope it doesn't come to that.

I've been using WD40, and the rust version of WD40. I have Liquid Wrench on the shelf and will try that. Are there any other brands you've found more effective for this sort of thing? I wonder if aluminum being in the mix means another product would be better.

Thank you for the ideas. I hope I can post they're separated soon.

And I thought keeping track of all those shafts and gears was going to be the hard part...
Mark 1275

I'll say it before Nigel. PlusGas beats WD40 hands down.
Strangely, brake fluid is sometimes effective when other potions don't help.

Good luck Mark.
Greybeard

You can make your own, there's a recipe on the internet for stuff called Ed's red, one here http://www.arrse.co.uk/community/threads/homebrew-gun-solvent.217058/ , and there is or was a comparison online of its performance as a penetrating oil and IIRC it was one of the best even against commercial offerings tried.
David Billington

I've seen various recommendations for ATF/acetone mixture as a penetrating fluid, so I tried it. Didn't seem that effective.

I might try adding paraffin and white spirit, but I don't have any lanolin in the garage.
Dave O'Neill 2

Seized studs are always fun. It is always one stud, nut, bolt or whatever when something is being dismantled. WD-40 though is not a true penetrating fluid although many will disagree.

Have you tried heating then rapid cooling of the part along with penetrating fluid? Sometimes that does the trick. If you can get some fluid between the stud and housing and letting it soak for a few days with daily spraying and shocking the part with a hammer works too, that will help. When reassembling a coating of anti-seize will help prevent this again far down the road.

You probably know all of this anyway but good luck!

Clare
Clare Ravenwood

Mark, don't you have "PB Blaster" in Mass? That stuff is supposed to shift most stuck parts as I understand it.
Bill Bretherton

Weld a big nut on top. The heat helps, and you'll hopefully then be able to get enough purchase to turn the stud. As soon as it moves a little bit apply your choice of penetrating oil and work back and forth until it rotates enough to unscrew.



AdrianR

Much appreciate the ideas. I agree WD40 isn't the premium stuff, but I didn't realize it wasn't a penetrating oil. I'm using Liquid Wrench now, and will have to look at the label. I've not seen PlusGas here, but definitely have seen PB Blaster. Sounds like I should have a can on the shelf, and just might get one tomorrow. That Ed's Red looks interesting, and I think I've got all the ingredients.

But at this point I think I'm winning.

I tried removing the neighboring studs, and the first one came out easily, but the second didn't budge. There's just not enough threads showing for me to get good purchase with the standard nuts. If I had a good jam nut and a thin wrench, might be better. I ruined the top threads of the corroded stud early on, and don't want to ruin more.

But - by midday today I could see a sliver of daylight under the whole housing. It's evening now and the gap is up to about 3/16". I thought I would be able to easily drive the housing back together, and then work the oil into more of the stud. But it only reluctantly closed up.

I started with a heavy duty putty knife, driving it in at the gasket line away from the corroded stud, then a small screwdriver, walking the putty knife around. So I'd say I'm winning, but it's definitely a war of attrition.

Didn't think of welding the nut on. If this process goes off the tracks, that sounds a great deal better than drilling.

I'd like to think tomorrow evening I'll have it done, and it will be interesting to see just how these metals reacted to cause such a bond.

Thank you for the continuing encouragement.
Mark 1275

Success!

Thought I'd give it one more effort before the end of the day, and it's now off.

Only took me a week, but I'm now up to the point that takes others 5 minutes.

That's one unhappy looking stud.

Thank you for all the responses. I'm sure I'll be back here when I'm stuck again. Hopefully it will be past step 2.

Mark 1275

Well done. Perhaps put some copaslip or similar anti-sieze compund on the replacements, someone may thank you in 45 years time.
AdrianR

I had the same problem, this is the way it was solved as the extractor had not enough grip

Flip Brühl

This thread was discussed between 09/09/2017 and 12/09/2017

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