Can I reuse my drain screw...?

[mickeg]

...
EVERY drain plug, that I have ever got involved with is a simple thing. A steel/alloy plug with a replaceable washer. ...

So…..Why didn’t they simply design a drain plug with a replaceable washer ??……

I guess someone would then ask…... ‘Can I reuse the washer’ ??……….

I was not supposed to re-use the same washer?  I do not think I ever replaced the washer.

...
Wonder if you could reuse the oil.

That did not even occur to me, as if you could, then why take out the drain screw in the first place.

I do have a small piece of tape over the drain screw, but that is only intended to keep the muck out of it so I can insert the wrench into the screw without having to clean it first.

It is very important that you don't insert the drain screw too deep into the Rohloff hub shell, because it may interfere in the operation of the gearbox.

One-half to one millimeter of the drain screw should ideally stand proud of the surface of the hub shell, and its top must never be any deeper than level with the surface of the hub shell.

Seems strange that they would design it so that it is possible to over insert the screw to the extent that it can interfere with the internals!
Why not build a limit of some sort into the design?

Mine always stopped, so I think there is a stop built in.  Perhaps someone turned the screw too hard and broke the stop loose?  Another reason to renew the blue loctite on the screw, so it will stay there without trying to turn the screw too hard.

[Andre Jute]

It is very important that you don't insert the drain screw too deep into the Rohloff hub shell, because it may interfere in the operation of the gearbox.

One-half to one millimeter of the drain screw should ideally stand proud of the surface of the hub shell, and its top must never be any deeper than level with the surface of the hub shell.

Seems strange that they would design it so that it is possible to over insert the screw to the extent that it can interfere with the internals!
Why not build a limit of some sort into the design?

Cost, weight, casting capability, though difficult to tell which for those of us not in the room when the design was made. The cost of ordering a shell with extra thickness and machining away the entire surface except a ridge around the drain plug hole doesn't bear thinking about. The weight of leaving the entire shell thick would cause a racer like Herr Rohloff to come out in boils. It may be possible to cast the shell locally thicker at the drain plug but that would probably preclude the nice machining now on the shells. Altogether it may have seemed that the best answer was to tell mechanics to take care screwing in the stud.

[Matt2matt2002]

I've used the same drain screw plug x3 times over 3+ years but this month tagged on a new one from a SJS order.
Just saying......
😉

[Danneaux]

I was not supposed to re-use the same washer?  I do not think I ever replaced the washer.

It depends on the designer's aim.

When I had my own Honda car service center back in another life long ago, it was standard procedure to replace the crushable aluminum washer on the oil pan drain bolt. At the specified torque, the bolt head actually embedded slightly into the washer and the washer itself deformed slightly into the oil pan's threaded socket opening; all this ensured a tight seal.

I didn't believe it at first, so I conducted some experiments on my own car where I drained the oil, cleaned all traces of oil off the outside of the pan, and then torqued the bolt in place reusing the washer. When I checked back in 20 minutes and wiped the pan with a light colored cloth, there was a slight "mist" of oil 'round the used washer. Overnight, a drop formed at the edge. This happened three times, so I figured Honda knew what they were talking about and always used a fresh crushable aluminum washer with each oil change onmy car as well as all others I serviced. No leaks between changes!

Other makes I've seen used copper, nylon, and even bronze crush washers as well as non-deformible steel.

My family owned Honda cars for about 40 years. Our other vehicles (light trucks and SUVs of various sorts) used V6 and V8 engines with reusable (steel) drain bolt washers. We kept those vehicles a long time also and they never developed leaks 'round their plugs. They did however require use of a sealant. Honda's transmission drain bolts used crushable washers, but their coolant gallery plugs used sealant. The difference depended on how the interface was engineered.

Many drain plugs (both NPT and metric) are subtly tapered (sometimes referred to as a "pipe taper") so when the drain bolt or plug is fully home, an interference fit prevents leakage. I have not yet checked my Rohloff drain plugs during my oil changes (I use a new one each time), but it is likely they are tapered. If it is indeed tapered and is over-torqued, then not only would the plug extend into the hub's interior, the threads could well be enlarged to the largest plug diameter, affecting future sealing.

I eventually fitted oil drain actuator valves (Fram, Femco, Fumoto) to all my vehicles so I never had to remove the drain bolts again. Rohloff's current solution is appropriate to need.

Best,

Dan.

[John Saxby]

it was standard procedure to replace the crushable aluminum washer on the oil pan drain bolt

Similar drill on the drain-plus washer on Hans, my '86 BMW airhead.  I always replaced the washer.

I've never changed the drain screw on Osi, my Raven, in the three seasons I've ridden it. No leaks--I do use blue threadlocker, and cover the screw with a tab of electricians' tape to keep it clean.

[StuntPilot]

I re-used my first drain plug 4 times. On each re-use the plug sat lower and lower in relation to the Rohloff shell (tightened each time with the same torque). When the drain plug was level with the shell, I used a brand new one. Tightened with the same torque again, the new plug now sits 0.5 - 1.0 mm above the Rohloff shell.

My conclusion would be to replace the drain plug when it becomes level with the Rohloff hub shell.

[John Saxby]

Useful tip, Stunt -- thanks.  My drain screw is still slightly proud of the hub shell -- good for another year, I expect.

[Andre Jute]

I re-used my first drain plug 4 times. On each re-use the plug sat lower and lower in relation to the Rohloff shell (tightened each time with the same torque). When the drain plug was level with the shell, I used a brand new one. Tightened with the same torque again, the new plug now sits 0.5 - 1.0 mm above the Rohloff shell.

My conclusion would be to replace the drain plug when it becomes level with the Rohloff hub shell.

This makes sense, especially if you reuse the Loctite on the screw. It would compress a little more each time you use the screw, and the screw would sink deeper.

Lovely visual control you've spotted, Stunt. No expensive tools required, just to use your eyes and your noggin.

[Dave Whittle Thorn Workshop]

Mk1 Rohloff drain pugs are infact an M6 grub screw coated in oil proof Loctite, Rohloff by hand punch the Allen key end of each plug to flare it.  This stops the plug traveling too far into the hub and damaging the internal. If you keep trying to reuse this plug the flare will eventually be reduced.

Mk2 Rohloff drain plugs appeared on hubs shipped after their summer break late August 2016, these are parallel M6 grub screws but all importantly incorporating a stopped thread meaning there isn't a chance they can wind into the hub.  Eventually all the spare and oil change kit plugs will also be of this design (when Rohloff's/Distributors/Retailers stocks clear through of the Mk1 style)

For what they cost I would never not use a new one even with the Mk2 version, oil proof Loctite is expensive and doesn't store well so I don't see that as a solution and using blue Loctite 243 etc. causes issues, I probably get 1-2 hubs a moth back with rounded drain screws where people have used it or been re-using the plug. 

But its up to the individual, I also fix cars at weekends and generally go much further than most garages when it comes to replacing fixings / studs / bolts / washers / seals /gaskets etc. but I've never had a job come back on me yet...  you pay your money you take your choice.

[bobs]

+1

[John Saxby]

Dang!  So there's likely no market for used Rohloff drain screws  :-(  But maybe...polished, they'd serve as industrial-strength sequins, things for the Harley guys to wear on their jackets, time capsule components, etc.

[Javier]

Unfortunately the "can I reuse my drain screw?" thread was losing momentum... but there it comes David Whittle Thorn Workshop's message to refuel the issue 

[Matt2matt2002]

Always good to hear from Dave.

What were the Hub numbers issued after August 2016?

[Tiberius]

Unfortunately the "can I reuse my drain screw?" thread was losing momentum... but there it comes David Whittle Thorn Workshop's message to refuel the issue 

........with a fairly convincing reply.........

[bobs]

If anyone should  know its Dave.