Secondary drive drain plug cracked casing

[Christopher]

Hello Folks can this be repaired? GS850 1980
Cracked secondary drive drain plug casing. I was replacing the gear oil and somehow did this. Anyhow please help

[salty_monk]

It could be welded & re-tapped I guess....

[dpep]

Can you carefully screw the bolt back in? That would keep the threads lined up while you attempted any repairs.

It is not under pressure. The lubricant it holds is very thick. And it is very rarely opened.

If I found myself in that situation I would screw the bolt in and then cover the outside crack with a wide coat of JB Weld or other preferred metal epoxy/glue. I would probably give it at least two coats.

After giving it a lot of time to cure I would then try to find a thin rubber washer to use under the bolt head when I screwed it back in. That should help to keep the lube in with less torque applied against the stem and the repair.

You can go light on the torque initially and check for drips. If there are any tighten and recheck until there are none.

Be careful on your test rides as any lubricant that does leak could go on your tire. It will get thinner as it heats up so you do need to ride for an accurate test. You could tape an absorbent rag around the stem and keep testing until one comes back clean.

You've got nothing to loose.

[bwringer]

Agreed -- the gear oil back there is not under pressure, so this is a case where a careful JB Weld repair could actually do the trick just fine. The gear oil does get pretty warm in operation and a bit thinner, but not nearly as hot as engine oil.

If the drain bolt will screw in, then Don's instructions should work pretty well. Clean the area very carefully, removing every last possible molecule of gear oil.

It would probably be a good idea to give the bolt a coat of wax (shoe polish or carnauba car wax, or similar) as a release agent so that the epoxy won't bond it into place.

Or, allow it to bond into place, but drill and tap the drain plug first with an M6 thread and add an M6 screw; basically create your own "piggyback" drain plug so you'll never have to remove it again. For future gear oil changes, you'll remove the smaller screw and wait somewhat longer for the oil to drain from the smaller hole.

Installing a thread insert would not work here; you'd have to remove far too much of the weakened material and put a lot of stress on it.

[eil]

I would be tempted to go the JB Weld route as well. Consider drilling a hole where the crack ends to prevent it spreading. If it was mine, I would probably try digging out a fair amount of the metal so that the JB Weld can be sanded flush. With JB weld sealing it, the threads may not be able to take the normal amount of torque to bite down on a crush washer without opening up the crack again, so it would not surprise me if a silicone washer is required after the repair.

Or just take it to someone who's good at welding aluminum and get it fixed right.

Just some random thoughts, take with grain of salt, etc.