Diagnosing oil leak on shifter side

[anthill]

Hi all, I've read through the oil leak threads but haven't found too much detail for diagnosing oil leaks on the non-sprocket side.

I've got a 2nd-hand Rohloff I bought three years ago.  I've performed two oil changes on it, and both times only ~5ml more oil came out than cleaning oil went in.  My recollection is that it's always been somewhat oil-leaky, so I ordered some Speedhub gaskets last year.

I've partially disassembled the shifter-side twice, once to reposition the rotation of the shifting mech, once to change the anti-rotation plate.  I didn't have a torque wrench, so the screw tensions may not be perfect (I ordered a torque wrench yesterday)

So now, with gaskets and torque wrench, I'm wondering

• How bad is my leak?
• Where might it be coming from?  Uneven shifter mech mounting plate fastener torque? Shifter mech gasket? Oil seal? Flange gasket?
• Is it worth the cost / risk of disassembling anything?  I'd have to find a sprocket removal tool...

Photos attached.  I think the leak is coming from either the shifter mech mounting plate or the oil seals, since the leaking oil seems to have seeped out onto the disc rotor.  However, it's also seeped half-way across the hub, which seems a long way!  What do you think?

[anthill]

The dividing line between oily / not oily is more clear in this shot.

[expr]

Hi, there are a few places that the oil can come from on the non drive side of the rohloff. The very large paper gasket that seals both hub shells together can sweat oil (normal) but  check to see if the screws are tight (ish)

There are two more paper gaskets that are under the external shifting box which is held in place by the  flange with holes drilled all around. The large oil seal (rubber) that is pressed in to the hub is another possible area for leaks and lastly it can leak from the inside of the hollow axle shaft.

The best advice I can offer is the same with any oil leak be it car motorbike or bike, clean the entire hub carfully with a degreaser and tissue or rag making sure that everything is oil free and dry.. don't forget if oil's coming out then cleaner can go in, don't power wash it, this must be done carfully making sure that further damage isn't caused as some of the seals are delicate.

You say you have the gaskets, I'm guessing that these are the paper ones and not the rubber oil seal, if you do the (large) hub shell gasket then you will need to have the rohloff sprocket tool and a (good) chain whip to remove the sprocket. This will involve removing the hub internals (not to difficult) to slide the new gasket on to the inner face.

The oil seal can be done at home either using the rohloff oil seal remover available at thorn or using standard removal techniques the new seal will require a loctite seal compound to seal the seal in place.

If it were me I would do the full clean (inc) inside the axle and then drain and refill the hub with with correct amount of oil and run the bike as normal while checking to see for the first sight of oil to locate the area thats leaking.

[anthill]

Thanks for the thoughtful advice.  I'll do as you suggest, since Rohloff assures us the hub can leak a bit as long as the oil's anti-wear additives have had a chance to adhere to the internals.

You are correct, I've got the paper gaskets and not the rubber oil seal.  I hope it's just my uneven torquing of the screws clamping the shifter mech paper gasket, I can fix that easily once my torque wrench arrives.

[expr]

No worries,

even though you will be torquing the screws up try if you can to (pre torque) each screw in a diagonal to alleviate any offset, as you would a cylinder head on a car etc.. The screws will benefit from some loctite 243 thread lock (medium strength) on them on refit.

Not sure what the set up is on a external box but on an internal shifter there are a number of screws on the axle plate and then one remaining screw underneath to remove the changer etc, this will then expose the paper gaskets. This will now allow you to inspect the oil seal (fragile lip) be carfull when cleaning and wiping not to damage the lip, check for any splits of the seal.

It should be perfectly smooth, and fit snugly around changer mech.

Oil leaks from the hollow axle are usually down to changes in temperature, there is a silicone seal inside the hub at the end of the shifting shaft, this can allow oil past when the hub has a greater pressure in it than atmospheric also its indicative of an overfilled hub to leak oil from here.


There are also times when people have got a small obstruction such as grass or straw etc lodged between the oil seal lip which will straight away allow oil to weep out.

Just remember though that (if) you were to loose all running oil the amount left in the gearbox that adheres to the hub internal itself is sufficient to lubricate for some time, as long as you can remedy the problem as soon as possible.

using a torque driver is allways the best way to set up screws and bolts etc (but) sometimes just the feel of tightness in ones hand can also go along way to tighten up correctly which come with experience.

Carfull with the axle screws so as not to go to tight, the important factor there is the loctite which will stop them coming loose.  

[anthill]

Thanks for the encouragement, expr.  Cleaned the hub (it looks much more loved now), and did an oil change this evening.  About 5-10ml more oil came out of the hub than cleaning oil went in, so I guess the leak wasn't as bad as I had thought!

The oil seal is a 'new' type with metal ring backing, and from what I can see it looks undamaged.  I'll watch for the first sign of oil leaks like you suggest and see if I can narrow it down..

[expr]

No worries, good news on the oil seal also...  5-10ml seems good if you suspected a leak. As you said may be not as bad as it first looked, most oil leaks look alot worse than they really are due to oil migration through misting. Did you remember to also check the hollow axle for any signs of oil...

sorry if any replies are longer than normal I'm down under at the moment visiting relatives, hope it all goes ok, glad you've got the newer oil seal I forgot to say about the newer style with the steel reinforced ring.

All the best,

Dave.

[anthill]

Follow up:  It is leaking from the filler screw.  My thread locker bottle is old, perhaps it is useless.  Time to get some proper loctite as specced in the user manual.

[JimK]

Thanks for the update! Quite an outcome, after all the recent discussion on filler screws!

[expr]

Great, that's good news. Should be an easy fix then now, possibly read an earlier thread where the use or
Non use of loctite was discussed, the consensus seemed to be to go for a new locking plug with loctite on. Or be carefully to clean up any oil of the old plug and around the threads before applying the thread lock. Carefully making sure no loctite enters the hub.

Thanks for the update


Dave's.