Help! Pedal stuck in crank

by jova54   March 15, 2014  

Hi. I need some suggestions on getting a steel pedal spindle out of an aluminium crank. Looks like it was put it with no copper slip and is now to all intents seized.

I have tried the following; soaking in WD40 for a couple of days, soaking in ammonia for a couple of days; not at the same time Wink , heating the end of the crank with an electric paint stripper.

Apart from drilling the pedal spindle out does anyone have any other ideas?

Prefer not to chuck it away as it's the chainwheel spider crank.

23 user comments

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You need to shock the thread to break any adhesion, ideally a 8-10mm punch and an hammer. You don't need to go mad but a few decent taps should release it.
Don't worry about damaging the threads as that takes some doing, even fine threads will withstand the impact.

I'm a maintenance engineer in the car manufacturing industry and come across this a fair bit.

posted by Shep73 [137 posts]
15th March 2014 - 9:10

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Try locking the pedal at 4 or 8 o' clock position (depending which side) and tap the end of the crank arm lightly, repeatedly whilst torquing the pedal - either with a spanner or large Allen key. The longer the spanner - Allen key shaft the better as this gives a lever arm. Remember one pedal has a reverse thread, so make sure you're not tightening it. Should do the trick.

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posted by langfordxc [3 posts]
15th March 2014 - 9:31

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Having had this happen twice on friends bikes which ended in dead cranks, I can't wait to hear how you get on. If it's a very posh crank you can helicoil it after removal should the threads be stuffed.

This shows how to do it - $99 to buy the kit yourself, I'm guessing you won't make this mistake again so maybe a good shop is the way to go - they should have these tools/inserts about. http://thegoldenwrench.blogspot.co.uk/2010/12/repairing-stripped-pedal-t...

I was told there would be Cake. Luckily there's http://TestValleyCC.org.uk

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posted by KiwiMike [437 posts]
15th March 2014 - 9:37

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You need a solid, large, bench mounted vice, a pedal stripped to the spindle, possibly a length of pipe slipped over the other end of the crank and a lot of elbow grease and ignorance. It'll go.

posted by Nick T [752 posts]
15th March 2014 - 10:01

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Another way is to heat up a tool using a blow-torch and then putting it on/in the pedal. This works best if there is an allen key socket to put it in. The object being to heat up the spindle not the crank. Obviously do not heat up your best tools as this will not do them too much good!

posted by SideBurn [764 posts]
15th March 2014 - 11:10

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Nick T wrote:
You need a solid, large, bench mounted vice, a pedal stripped to the spindle, possibly a length of pipe slipped over the other end of the crank and a lot of elbow grease and ignorance. It'll go.

It's looking that way Nick T.

I've got some punches so going to try that but I may have to take it to the garage and use their vice.

Tried the heating trick too Sideburn but aluminium tends to become brittle if you're too indiscriminate with the heat.

Not my fault this one, just picked up a nice 1990's Marin Nail Trail to restore and the pedal is the main problem. The crankset is a Whyte Industries original so looking to preserve it if possible. When the new pedals go back on the threads will be properly protected.

Thanks for the suggestions guys.

Did Nightrider 2013 for Parkinson's UK, doing it again this year just for the fun of it and to raise more money.

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posted by jova54 [584 posts]
15th March 2014 - 11:44

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I would definitely try shep's approach first. An old engineer showed me that trick as well.

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posted by giff77 [1036 posts]
15th March 2014 - 12:06

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Try soaking it in coke for a few hours or overnight to dissolve the aluminium oxide.

Then go with KiwiMike's suggestion of stripping the pedal down and grabbing the spindle in a vice.

posted by gnarlyrider [4 posts]
15th March 2014 - 12:38

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gnarlyrider wrote:
Try soaking it in coke for a few hours or overnight to dissolve the aluminium oxide.

Then go with KiwiMike's suggestion of stripping the pedal down and grabbing the spindle in a vice.

Not come across that one so worth a try. Got some punches this morning but as my work bench is a Black & Decker Workmate it's not too easy to clamp the arm tight enough.

The pedal body is stripped off, it was a nasty plastic one so no loss, so if the coke doesn't work I'll take it to my daughter's partner's garage on Monday and put it in a proper vice.

The frustrating bit is that the other pedal came off really easily At Wits End

Did Nightrider 2013 for Parkinson's UK, doing it again this year just for the fun of it and to raise more money.

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posted by jova54 [584 posts]
15th March 2014 - 13:10

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I had exactly the same problem - a venerable PDM220 stuck in Campag Centaur crankset… what worked was to strip off the pedal body leaving the spindle only, then heat using a precise torch applied to the spindle then rapid cooling using shock'n'unlock from Halfords (about a fiver per can). Finally, overnight soaks in degreaser with a good few heat/unlock spray cycles eventually freed it off. You can heat aluminium up to about 200degC without too much bad effects and this will really help in expanding it away from the spindle.

Persevere!

Also make sure you do this work in a well ventilated area - the ignition of fumes could kill you.

posted by Trull [55 posts]
15th March 2014 - 15:11

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One last tip, if you want to apply maximum torque, braze the spindle to the middle of a bar then turn with both hands so when you apply the force it will be pure torque rather than torque plus shear force. The shear force will simply ratchet up the friction and will stop you from undoing the spindle.

posted by Trull [55 posts]
15th March 2014 - 15:14

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Lots of complicated suggestions flying about but the simple answer is indeed that the pedal spindle needs to go in an engineering vice bolted to an imovable bench, the other way is to take a large pedal spanner or normal spanner and clamp that in the vice edge ways on and then put the pedal flat into the spanner. You dont need a punch, you dont need a claw hammer or ball peen hammer, you dont need amonia and you most likely wont need a heat gun either. If it's the non drive side crank clamp the pedal flat in a girt big engineering vice or clamp a pedal spanner or heavy duty spanner of the same size into the vice edge on as suggested. Wrap the crank in a rag to stop it marking, slide length of cold rolled steel tube about a meter long over it (round or box section either will do if it fits) and it will make short work of getting the pedal un stuck. If it's the drive side with the spider a rubber mallet will do the same job instead. A bit of WD/GT85/Plusgas etc etc will help as they are all mostly petrol but you should not need any truly nasty chemicals. The pedal probably was greased but it was probably greased with white lithium grease which bonds steel to ally through galvanic corrosion. Cheap and cheerfull answer rather than copper slip for future use is plain old vasaline (fnar fnar).

posted by MKultra [196 posts]
15th March 2014 - 19:44

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But there's an easier way that involves a banana, 2 goldfish, strawberry flavour jelly cubes and a 2litre pudding bowl to try first.

posted by Nick T [752 posts]
15th March 2014 - 20:07

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my last one was an Allen key fit so I could use an impact driver on it ....

still on the 3rd switch-back of Bwlch !

posted by therevokid [679 posts]
15th March 2014 - 20:11

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Nick T wrote:
But there's an easier way that involves a banana, 2 goldfish, strawberry flavour jelly cubes and a 2litre pudding bowl to try first.
You left out the blood of a virgin drawn under a full moon.

posted by MKultra [196 posts]
15th March 2014 - 20:25

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MKultra wrote:
Nick T wrote:
But there's an easier way that involves a banana, 2 goldfish, strawberry flavour jelly cubes and a 2litre pudding bowl to try first.
You left out the blood of a virgin drawn under a full moon.

I'm in Guildford. Where am I going to find a virgin? Big Grin

Did Nightrider 2013 for Parkinson's UK, doing it again this year just for the fun of it and to raise more money.

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posted by jova54 [584 posts]
15th March 2014 - 20:29

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jova54 wrote:
MKultra wrote:
Nick T wrote:
But there's an easier way that involves a banana, 2 goldfish, strawberry flavour jelly cubes and a 2litre pudding bowl to try first.
You left out the blood of a virgin drawn under a full moon.

I'm in Guildford. Where am I going to find a virgin? Big Grin

You must have a Games Workshop in town?

posted by MKultra [196 posts]
15th March 2014 - 20:33

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I have had an issue like that in the past, got any TF2 spray lying around? Spray it around both sides, then take a lighter. It gives a nice quick blast of heat without doing any damage and should free it.

Failing that, it is a vice job.

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posted by Gkam84 [8685 posts]
15th March 2014 - 20:38

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Think I'm going for the nuclear option.
Tried Coke over the weekend and it still wont budge so off down the garage or LBS depending which has an engineer's vice this morning.

Did Nightrider 2013 for Parkinson's UK, doing it again this year just for the fun of it and to raise more money.

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posted by jova54 [584 posts]
17th March 2014 - 10:03

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I bet it's looking spotless after the coke though, it does wonders on the toilet bowl Big Grin

posted by Nick T [752 posts]
17th March 2014 - 10:34

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This is better than Sherlock. We want photos!

I was told there would be Cake. Luckily there's http://TestValleyCC.org.uk

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posted by KiwiMike [437 posts]
17th March 2014 - 11:08

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Off to the LBS

Did Nightrider 2013 for Parkinson's UK, doing it again this year just for the fun of it and to raise more money.

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posted by jova54 [584 posts]
17th March 2014 - 11:20

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Sorted.

The thread had got crossed at some point in time. Managed to get it out with a bit of damage to the thread in the crank. LBS re-tapped the thread and there appears to be enough to keep the pedal in place but I'm going to have a look at having it heli-coiled just to be safe.

Did Nightrider 2013 for Parkinson's UK, doing it again this year just for the fun of it and to raise more money.

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posted by jova54 [584 posts]
17th March 2014 - 13:24

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