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MG MGA - Is my gearbox front cover cracked?

Hi guys,

I recently dropped my gearbox front cover and 1st motion shaft specs off at an engineering workshop to have a centalising tool made. The tool is perfect, however I have just noticed what appears to be a crack in the cover (looks like its been thumped with a mallet!)

I know its very hard to see the crack in the attached picture, but if we take this as given, does this now mean that my front cover is junk?

Cheers

Steven


S HILL

Steven,

It is not clear if the crack is only inside the circle or is also that line that extends to the left.
It should be easily fixed by welding, but you may not wish to apply welding temperatures to the cover. There is always a slight chance of distortion. This cover takes no load and so you could always use a "cold weld". One of those products that is a mixture of fine metal particles and epoxy resins.

Another alternative is to find a front cover off a 3 bearing MGB and fit an MGB diaphragm clutch. Makes an MGA feel like a new car.

Mick
Mick Anderson

I am getting my gearboxes confused. The MGA front gearbox cover does have load on it, but I still think that it is repairable.

Mick
Mick Anderson

Steven
Are you sure it is a crack as it looks a bit like a casting defect to me? There are quite often small defects in the casting as air gets trapped between the rapidly cooling metal, these are usually evaluated in the casting final inspection and either approved, repaired or rejected.
As this part of the gearbox should not be stressed I think there is no big problem. A creeping adhesive will probably do the job if the surfaces are clean inside. I think my gearbox is however covered in oil residue from the engine so it may be that glue will not bond very well.
Welding is an option but go to a specialist.

Neil
Neil Purves

The gearbox front cover does take the mechanical thrust load the helical input gear as well as the force of the clutch release lever. The "crack" appears to be a casting flaw. This is in a non-critical no-load-bearing location within the seal neck of the cover. You can seal it up (if if actually leaks) with any epoxy (like JB Weld for instance) or any gasket sealer (after washing it in lacquer thinner to be very clean).
Barney Gaylord

Or if it really is a crack I can let you have a new front cover as I have switched to a B clutch
dominic clancy

Steven,

Just a question about your centralizer tool. The tapered section seems very long, as though it would go into the seal.
The tool should fit only against the bore in the cover. It should be able to fit against the metal of the cover, with the seal fitted in the cover, but without passing into the seal.

Not being able to compare to any scale in the photo, your tool may correctly only fit into the cover bore.

Mick
Mick Anderson

There is one way of finding out for sure:

http://www.grainger.com/Grainger/items/3WU63
Del Rawlins

I tried my own link and it doesn't seem to be working.. . Anyway, it was a dye penetrant testing kit, Grainger part number 3WU63, which sells for $53.

Del Rawlins

Del,
The link worked fine for me!
Neil McGurk

Huh. It said my session had expired, so I figured it was a temporary link created by the search I did. Apparently, it just meant that only *my* session had expired... 8^/
Del Rawlins


Thanks for you comments and kind offers guys. I have a spare 1600 gearbox which I think I will 'rob' the front cover from for my own peace of mind.

Mick, the centraliser tool is tapered so will not go into the seal. However after a couple of trial fits on the weekend I think I will take it back to the engineering workshop to have the end milled down so that it can be pressed up flush with the front cover. It would certainly work fine as is, but I want to make sure it's perfect.

With the number of A's still on our roads it surpises me that no supplier has taken to re-producing what would appear to be an essential tool. Which has me thinking. Would there be any interest from forum members if I got the workshop to turn up a few more? This would of course be a purely not-for-profit exercise.

I was charged Aus$135 but this may go down if I get enough interest.

Let me know if your interested and I'll investigate.

Cheers

Steven
S HILL


Thanks for you comments and kind offers guys. I have a spare 1600 gearbox which I think I will 'rob' the front cover from for my own peace of mind.

Mick, the centraliser tool is tapered so will not go into the seal. However after a couple of trial fits on the weekend I think I will take it back to the engineering workshop to have the end milled down so that it can be pressed up flush with the front cover. It would certainly work fine as is, but I want to make sure it's perfect.

With the number of A's still on our roads it surpises me that no supplier has taken to re-producing what would appear to be an essential tool. Which has me thinking. Would there be any interest from forum members if I got the workshop to turn up a few more? This would of course be a purely not-for-profit exercise.

I was charged Aus$135 but this may go down if I get enough interest.

Let me know if your interested and I'll investigate.

Cheers

Steven
S HILL

Steven,

I don't think you need to mill it to make it fit against the face of the front cover.
I think that it is better for the taper to fit into the bore of the cover, as long as it does not go into the seal.

I do not have an original tool, but the BMC sketch indicates that it has a taper.
Also, if you read para. 7 of the BMC instruction it says that the tool is pushed into the bore "until it is tight".
This must mean that the tapered part is pressed into the bore.

See image, and the image on next post.

Mick


Mick Anderson

Page 2 of the BMC instruction is attached.

Mick


Mick Anderson

I'll take a tool if it's not too expensive
dominic clancy

This thread was discussed between 07/12/2007 and 10/12/2007

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This thread is from the archive. The Live MG MGA BBS is active now.