Seized axle plate torx screws

[bike_the_planet]

Hi Folks,

I have a three-year old Rohloff that seems to work well. I use it for regular commuting and some touring (not as much as I would like!).

Last week, I indulged in a spot of preventative maintenance and tried to undo the five Tork screws that hold the axle plate on. Even though I had undone, and redone them up about 1 year ago, three of them were now locked solid. Trying to undo them with a quality Torx drive resulted in the heads being chewed - not good.

I have since tried to remove them using tools including a counter-clockwise fluted bit that grips the head, but they seem to be locked solid. The heads are now well chewed

My next option is to drill them out but this is risky. The screws are a narrow gauge and any mis-allignment could damage the threads they screw into, not to mention getting swarf into the hub itself. If I could obtain a counter-clockwise drill bit, then that might just give them the impetous they need - or snap the heads which would be a problem also.

I suppose I could leave them and do nothing - the hub is working ok at the moment. But having anything seized gives me a sense of unease - it shouldn't be like this.

Has anyone had this before and what did they do to loosen the damn things?

Cheers

[Cambirder]

Sounds like the "preventative" maintenance you carried out a year ago may be the cause of your problem. Did you use a torque wrench to do them up and apply some anti-seize grease? if not you probably over tightened them and the lack of grease has caused some to seize.

If I was you I would not take any further action for now,  get it fixed professionally if you need any other work done to the hub in the future.

[Fred A-M]

In your situation, I'd contact Rohloff and try to appeal to their well-documented good nature in sorting these things to maintain their reputation rather than attempting anything further yourself - they may charge I guess but it's bound to be much much less than buying a new hub.  My tact would to be charmingly honest and hope they respond accordingly.

[JimK]

use a torque wrench to do them up

Looks like 3 Nm is the specified torque, from p. 112 in the service manual. That's pretty gentle!

[bike_the_planet]

Sounds like the "preventative" maintenance you carried out a year ago may be the cause of your problem. Did you use a torque wrench to do them up and apply some anti-seize grease? if not you probably over tightened them and the lack of grease has caused some to seize.

If I was you I would not take any further action for now,  get it fixed professionally if you need any other work done to the hub in the future.

Thanks for all the replies.

With the greatest respect, I am an electrical engineer by trade and I am very familiar with torque and torque settings. 3 Nm is around 0.3kgF at a 1 m radius. Using a standard 'shaft' type torx driver, it is not easy to accidentally over-torque.

I set these a year ago on my wife's Rohloff also, and hers are fine. I suspect the problem maybe due to the fact that I cycle near salt water on a regular basis and some corrosion may have occured

I will be sending it back to Rohloff to fix as I don't have a jig that would allow me to align a drill accurately to drill these screws out.

Thans again for your replies.

[expr]

Hi you would only need to drill the heads off using a 6mm bit this will then allow the axle plate to be removed of which 1 remaining screw will need to be removed the leftover threads sticking out can then be gripped by mole grips to remove.

[bike_the_planet]

Hi you would only need to drill the heads off using a 6mm bit this will then allow the axle plate to be removed of which 1 remaining screw will need to be removed the leftover threads sticking out can then be gripped by mole grips to remove.

Thanks expr - yes I thought of that one too. Can I assume that you have had to do this yourself before now? 6mm sounds about right and I assume that there would be a few mm of shank protruding when the plate is removed which would allow adequate purchase of a pair of vice grips.

Given that there is an approved Rohloff service agent in Perth I might just get them to do it.

Cheers

[Andre Jute]

Forgive me being stupid, but why should anyone want to take off the axle plate, unless they are changing from internal to external switching? If your Rohloff box already has the more desirable external klickbox, there seems to me zero reason for taking off the plate, except by Rohloff themselves if you should ever have occasion to return the gearbox to them for them to work their magic. Rohloff are clear the people best equipped to deal with removing the screws.

I don't see anywhere in the manual where it says, "Take the screws in the axle plate out every so often and grease them." On the contrary, the Rohloff is sold as an ultra-low maintenance gearbox, and the only service the user should perform is changing the oil in the gearbox, and adding a little grease to the cable guides (internal switching) or the klickbox pulley (external switching).

If it ain't broke, don't fix it.

***

I'll admit though that, when I first heard about these screws corroding in, I was hot to trot, and bought some Witte (best German quality) T20 bits. But on second thoughts all I did was check that the screws are torqued in right. BBB sells a torque wrench in a box with some bits (not including T20 or 2.5mm or 2.0mm Allen, which are also required) which goes down to 2Nm. Cyclo sells exactly the same thing cheaper, if you can find one.

***

All of that said, I agree with the OP. Those mangled screw head would bother me too. Get Rohloff in Perth to fix it. Whatever they charge will be less than the pain every time you look at those screw heads.

Good luck and good riding.

Andre Jute
Wish I were back in Adelaide!

[bike_the_planet]

Forgive me being stupid, but why should anyone want to take off the axle plate, unless they are changing from internal to external switching? (etc etc...)

If it ain't broke, don't fix it.

That's a fair question.

I guess I prefer to make sure things don't get seized up.

I'm a little paranoid given that, after the first 5000 km (most in a tour of Europe) I lost the seven lowest gears to slippage. I just couldn't use them. I sent the unit off to Rohloff in Brisbane. All they could find was a small amount of what appeared to be congealed loctite in the gearbox. I hadn't done anything to the unit except a couple of oil changes.

All of that said, I agree with the OP. Those mangled screw head would bother me too. Get Rohloff in Perth to fix it. Whatever they charge will be less than the pain every time you look at those screw heads.

Good luck and good riding.

Andre Jute
Wish I were back in Adelaide!

Thanks. Oz is a great place...

Cheers

[expr]

sorry for long delay in getting back!

No I haven't had to do this to a hub but have done it many times at work, you wouldn't need to bother to much about any misalignment as the allready c/sunk drilled hole will guide the drill bit in, hobbes the reason that you would need to take off the axle plate is to reach the internal changer mech to replace the cable etc, the other option would have been to get a very sharp metal chisel around 8mm wide and gently tap into the head creating a slotted head screw in to which you could put a slotted screwdriver for much more leverage.

underneath the axle plate is one remaining screw which allows the gear change mech to be taken out and replaced etc...

[Andre Jute]

hobbes the reason that you would need to take off the axle plate is to reach the internal changer mech to replace the cable etc,

Thanks for that, expr. I have the EXT gearchange mech, so I guess my torx can corrode all they like; any work on the gearchange gubbins behind the EXT klickbox will be done by Rohloff, who will no doubt be happy to hear the customer left it to them.

I'm surprised that Rohloff hasn't fixed this weak spot.

[Danneaux]

If it is not too late, have you tried soaking the affected bolts in a penetrating co-polymer spray?  When faced with similar situations, I've used such products ( http://www.blasterchemical.com/pb_blaster.html  describes one I've had good luck with; there are many on the market) and -- if the heads were already buggered -- used a Dremel Moto-Tool and emery cutoff wheel to carve slots across their faces to take a screwdriver after the penetrating spray had gone to work.  I employed a similar method to remove some corroded fuel-tank fittings to replace an in-tank pump assembly a year or two ago.  It worked when all other methods appeared utterly hopeless.  Works great also for removing galvanically-corroded aluminum quill stems and seatposts from their contact with steel tubes. 

Easy-outs (broken-bolt extractors with reverse threads) can do a remarkably nice job when other attempts fail.  Be sure to use a tap handle on the extractor for best results, as the extractors themselves are very hard and therefore can be quite brittle.

I know it sounds silly, but when faced with such dilemmas in the field, I've had great luck dousing the frozen fittings with the contents of a fresh can of Coca-Cola, tapping lightly, redousing, waiting, then having a go with the proper tool.  This surely can save the day while on-tour, when ordinary maintenance often needs to be deferred, leading to problems with seizing.

So sorry you're having trouble.

Best of luck,

Dan.