Crank arm cap seized

[EMTBSEAN]

Right I’ve had enough of my drive side crank arm coming loose, the trouble is both caps on my crank arms are stuck solid, I’ve tried the Hope removal tool and that’s toast as well now, has anyone got any ideas, the crank arms are still removable but the caps are mullered, I’ve bought some new crank arm bolts and wanted to try these first before I pay another £180 for new crank arms, I’m disappointed with Hope as the removal tool is absolutely shite, it’s just soft aluminium and the points have just broken off anyway over to you guys please

 

[Mikerb]

Right I’ve had enough of my drive side crank arm coming loose, the trouble is both caps on my crank arms are stuck solid, I’ve tried the Hope removal tool and that’s toast as well now, has anyone got any ideas, the crank arms are still removable but the caps are mullered, I’ve bought some new crank arm bolts and wanted to try these first before I pay another £180 for new crank arms, I’m disappointed with Hope as the removal tool is absolutely shite, it’s just soft aluminium and the points have just broken off anyway over to you guys please

View attachment 147587

you are going to need new caps so i would remove the old ones by first squirting wd40 around the edge and leave for 15 minutes...then squirt some wd40..........and then use a hammer and either a screwdriver or small cold chisel to drift it off. Note it probably only needs fairly light taps with the hammer. It is the "shock" that will break the seal between the cap and the crank which is probably caused by corrosion. Tap fairly lightly using alternate opposing castellations.

 

[irie]

Agree. Must be gentle, that's all that's required to break a seal. After seal is broken should turn off OK.

 

[RustyMTB]

Little bit of heat. Heat is always good.

 

[Zed.]

Little bit of heat. Heat is always good.

^^THIS

Aluminium expands wonderfully when warm, heat will break Locktite....


heat then spray with wd type stuff as it'll soak in the threads - then fit tool and use precussive maintanance (hammer) to shock it loose

Hopefully

Rich.

 

[EMTBSEAN]

Thanks guys, I’ll try these methods and get back to you all ASAP, better get my heat gun out, I’ve just realised that I don’t have a cold chisel but I do have some straight shaft punches with nice flat ends

 

[RustyMTB]

Looking at the cap, 50nm is fairly hefty, so it'll be in tight anyway. The cap looks like you've had the wrong tool in there but either way, there's a good chance it's either got a bit much loctite on the threads or the aluminium has done a bit of electrolytic corrosion onto the steel behind. Your heat gun will break the bond, just don't set fire to it.

 

[EMTBSEAN]

Looking at the cap, 50nm is fairly hefty, so it'll be in tight anyway. The cap looks like you've had the wrong tool in there but either way, there's a good chance it's either got a bit much loctite on the threads or the aluminium has done a bit of electrolytic corrosion onto the steel behind. Your heat gun will break the bond, just don't set fire to it.

50Nm is the torque for the main crank arm bolt, the cap is a friction fit but I only nipped it up, can’t understand why it’s in there so tight, believe it or not that’s been tightened with the official Hope tool which is as handy as toothache and without Loc-tite as well

 

[steve_sordy]

Drill a couple of 3-4mm holes in the top cap. Then either push a pair of needle nose pliers in the holes and twist. Or lever the pliers with a big screwdriver. Or put the end of a steel rod into one of the holes and hit it sideways with a hammer. Then the other hole, then back to the 1st hole....... Then you can still use the top cap's original tool to fasten/remove because you haven't damaged the rounded shape.

 

[Miket775]

I know this is a weird one but I had a similar issue with my Pinnd crank - turns out the the top cap on them are reversed threaded - have you checked to see if the hopes are the same?

 

[EMTBSEAN]

Drill a couple of 3-4mm holes in the top cap. Then either push a pair of needle nose pliers in the holes and twist. Or lever the pliers with a big screwdriver. Or put the end of a steel rod into one of the holes and hit it sideways with a hammer. Then the other hole, then back to the 1st hole....... Then you can still use the top cap's original tool to fasten/remove because you haven't damaged the rounded shape.

I think the only way I’m going to get the caps off now is with a Dremmel and cutting disc attachment and try to cut the cap as deep as I can diagonally into 4 smaller sections and try a split it up and off without cutting into the crank arm cap threads, either way the caps are totally mullered now, I tried soaking them in WD40 and Plus Gas penetrating oil, and tapping them off with no luck, even heating them up had no effect, I’m not beaten though, I’ll try to drill them but in the end I know it’s going to be new crank arms and caps, I had to walk away from it earlier as the old Red Mist was descending and things get very very expensive when that happens, and as I had a hammer close by it would have possibly ended in me needing a new bike

 

[EMTBSEAN]

I know this is a weird one but I had a similar issue with my Pinnd crank - turns out the the top cap on them are reversed threaded - have you checked to see if the hopes are the same?

Yeah they’re left hand threads on Hope caps as well but I thank you for mentioning it buddy

 

[Zed.]

I had to walk away from it earlier as the old Red Mist was descending and things get very very expensive when that happens, and as I had a hammer close by it would have possibly ended in me needing a new bike

Theres no kill like OVERKILL

Rich.

 

[Hattori-Hanzo]

If you have a small enough pin spanner you can drill two blind holes in the cap that correspond to the pin spanner and try undoing it with that before getting the Dremel out.

A make shift pin spanner is easy to make if you don't have one small enough.

 

[RustyIron]

can’t understand why it’s in there so tight, believe it or not that’s been tightened with the official Hope tool which is as handy as toothache and without Loc-tite as well

Dude! What have I been saying about assembling aluminum fasteners?
You can lead a horse to water, but... sometimes you have to hold their head under.

Just pony up the ten quid for a tube. Pony? Horse? See what I did there? Join the ranks of elite craftsmen, and reduce the frequency, cost, and labor related to damaged fasteners.

 

[steve_sordy]

If you have a small enough pin spanner you can drill two blind holes in the cap that correspond to the pin spanner and try undoing it with that before getting the Dremel out.

A make shift pin spanner is easy to make if you don't have one small enough.

"Pin Spanner" that was the name of the tool I was trying to recall! (see post No #9)

 

[EMTBSEAN]

Dude! What have I been saying about assembling aluminum fasteners?
You can lead a horse to water, but... sometimes you have to hold their head under.

Just pony up the ten quid for a tube. Pony? Horse? See what I did there? Join the ranks of elite craftsmen, and reduce the frequency, cost, and labor related to damaged fasteners.

View attachment 147623

Many thanks buddy, I can’t get any in that size tube in this country, it’s £20+ in this country for what looks like a big tub however I do have some excellent quality copper grease designed for vehicle brakes, would that be ok to use on my aluminium caps.

 

[EMTBSEAN]

Many thanks for the suggestion of the pin spanner, I’ve done a Google search and Bob’s your uncle, Fanny’s your aunt, Screwfix has one for £2.99, my order is in and I’ll pick it up on Friday, I’ve never heard of one of these before so thanks for bringing it to my attention guys, every day is a school day if it works it’ll be a cheap fix

 

[RustyIron]

Many thanks buddy, I can’t get any in that size tube in this country, it’s £20+ in this country for what looks like a big tub however I do have some excellent quality copper grease designed for vehicle brakes, would that be ok to use on my aluminium caps.

I think your copper brake grease will be fine. After all, we're working on mountain bikes, not Space Shuttles. I'll let you in on a little secret. My tubs of anti-seize are all nickel based. Nickel is not as good as copper on aluminum. But it's better than regular grease, which is better than oil, which is about a thousand times better than nothing at all. Your copper brake grease will have good high-temp stability. It's not necessary on a mountain bike, but it doesn't hurt anything.

 

[Hattori-Hanzo]

Thinking about this, are we sure the cap actually unscrews, or is it a press fit into the crank?

Hope crank arms are self extracting, so it would defeat the purpose if the cap unscrews

 

[Weeksy]

Thinking about this, are we sure the cap actually unscrews, or is it a press fit into the crank?

Hope crank arms are self extracting, so it would defeat the purpose if the cap unscrews

I'm confused as to why he wants to remove the cap anyway. Like with Raceface etc, i don't know what the secondary one is for, it doesn't seem to have an actual purpose as you only use the 8mm allen on these usually anyway. But i admit, i've never used Hope cranks.

 

[RustyMTB]

Opening post explains the chaps problem.

 

[Weeksy]

Opening post explains the chaps problem.

So removing the flowery bit allows the user to remove the main center part and replace ? Without that you can't remove the main tensioning bolt ?

 

[RustyMTB]

I dunno, guy says his cranks rattle loose & he's got a problem taking the end cap off. That's all I can tell you. Maybe Sean will be along later to expand on things.

 

[Hattori-Hanzo]

I believe he wants to replace the worn bolt which is trapped underneath the cap.

The cap must be independent of the bolt. As the bolt is undone it's head pushes against the cap which forces the crack arm off the spindle shaft.

I don't know for sure but guessing this is how it works.

It would make sense that the cap is screwed in place with a reverse thread.

I think it's been said, but applying some heat from a small torch should help in removing it. A heat gun might not be sufficient.

As for the cranks constantly coming loose, I had a similar issue and found in the end that the Isis splines inside the crank arm were worn which was causing it to keep coming loose.

 

[Weeksy]

It would make sense that the cap is screwed in place with a reverse thread.

He has been trying to get it off the right way ?

 

[EMTBSEAN]

Let me explain my issue, my drive side crank arm has been coming loose despite torquing it the specified 50Nm, the (extraction) caps are seized in place, I’ve applied heat with no success, I’ve also tried WD40 and penetrating oil which was also unsuccessful, I’ve tried lightly tapping it, also unsuccessful, I am wanting to remove the crank arm bolts to renew them before I pay out for new crank arms, the crank arms are threaded on and are left hand thread, next attempt will be with the pin spanner suggestion, I appreciate your input guys and hope this explains everything

 

[EMTBSEAN]

I think your copper brake grease will be fine. After all, we're working on mountain bikes, not Space Shuttles. I'll let you in on a little secret. My tubs of anti-seize are all nickel based. Nickel is not as good as copper on aluminum. But it's better than regular grease, which is better than oil, which is about a thousand times better than nothing at all. Your copper brake grease will have good high-temp stability. It's not necessary on a mountain bike, but it doesn't hurt anything.

Thanks buddy, and thanks for your patience with me if I ever get the bloody caps off and fit my new caps, I’ll be sure to never not use copper grease on them ever again, just one last thing, do you use copper grease on the actual splines of the motor too, I’m talking about the splines that the crank arms fit onto or just normal grease, thanks

 

[Hattori-Hanzo]

I’ve applied heat with no success

More heat! It can't be stuck if it liquid

 

[EMTBSEAN]

More heat! It can't be stuck if it liquid

Now you’re just being silly