Gearbox drain plug weep

[Fanum]

I decided to order the proper type of plug to use a sealing washer (type on the left). The parts fiche suggested these part numbers were correct

drain plug 23107651450
washer A14X18-AL

But what arrived looked like the plug on the left (ordinary hex head not socket cap), but with no taper to centre a sealing washer like the plug on the right!

I suspect that what plug you use will be irrelevant, if the facing surface on the GB side is damaged.

I think I'd be looking in my box of dremel sanding discs to find one the same diameter as the face of the GB side of the interface, then nailing it to the end of a very similar sized bit of dowel (the nail will be inside the hole mouth so it won't matter) then spinning it gently on the surface, like a boy scout spinning a stick to make a fire

If you can flatten the surface properly, the washer type plug, with either a soft copper or a fibre washer plus maybe a fine smear of RTV on it should seal it nicely

EDIT....just seen your last post .Fibre washers sometimes split radially out from the inner ring when used with a tapered bolt......They seem to work better with a non tapered (or minimally tapered at least) bolt.

 

[Dr Bones]

Thanks Fanum,

I already have a plan for dressing the sealing surface. I have an M14 x1.5 bolt with a plain shank, which I'm going to cut the head off. I also have a piece of thick walled pipe with a 14mm I/D, which has been faced off in a lathe. the plan is to screw the bolt into the drain hole, then use some valve grinding paste on the end of the pipe to dress and level the sealing surface. The bolt should keep everything square. Before I take the bolt out, I'll flush all the grinding paste out with brake cleaner and then compressed air.

Original advrider post here

http://www.advrider.com/forums/showthread.php?t=739594

 

[Trullion]

According to Haynes bikes made after late 1996 did not have a washer and should be torqued to 30NM. The earlier bikes had a washer and should be torqued to 23NM. This accords with my own experience of having owned both a late 1995 and a 2000 oilhead. Maybe a previous owner has over-tightened a drain plug that should only be tightened to 24NM. Without taking the one out of my late 1995 RS I can't be sure whether it is tapered or not, but it does have a washer.

 

[Dr Bones]

According to Haynes bikes made after late 1996 did not have a washer and should be torqued to 30NM. The earlier bikes had a washer and should be torqued to 23NM.

That would fit with my 97 bike, and I think you are right, some gorilla overtightened the drain plug without a washer fitted, then tried to add one to fix the now chewed mating surface. Like I said, I have a plan to reface the mating surface, depending on how that turns out, I'll decide what to do next.

 

[warmshed]

Sounds like a good plan but be prepared for a long session, grinding, even on alloy will take quite a time. keep changing the grinding compound.

If you can get someone to turn down the end of your your slave M14 bolt to fit a tap seat cutter, As it will be hardened it wont be easy to open out the threaded hole of the cutter to go over the 14mm bolt unless you anneal then re harden it again.

Progress will be quicker and should be easier to keep square. various sizes are available. You can araldite the cutter to the end of a tube or drilled rod, tube to give you a grip to turn it.
http://www.ebay.co.uk/itm/Tap-Resea...nd_Tools_Equipment&hash=item19d3243871&_uhb=1

 

[Dr Bones]

Ok, hopefully this is all sorted now. I cut the head off a M14x1.5 bolt to seal the gearbox and centre the 14mm ID, 20mm OD pipe I'd had faced off in a lathe. I used valve grinding paste (coarse first then fine) to carefully resurface the damaged mating surface, with the pipe. It took about two hours of grinding, with regular changes of paste to get the mating surface to a 'respectable, but not perfect' condition. Everything was then flushed out with brake cleaner and compressed air several times to get rid of all the grinding paste before I took the guide bolt / plug out.

I had no success in trying to locate a drain plug designed for a washer, BMW have deleted that part now, only supplying the washerless version, and none of the breakers had one either.

So I fitted a Ford Mondeo sump plug washer (24mm O/D, M14 Dowty seal), on the washerless plug and torqued it up to 23nm (torque for Mondeo sump plug is 21-28nm).

So far so good, only time will tell.