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Stuck pedals cranks

Posted: 25 May 2018, 1:12pm
by matt2matt2002
Aluminium cranks
Steel MTB pedals
Stuck
Cannot remove
Any ideas

Re: Stuck pedals cranks

Posted: 25 May 2018, 1:25pm
by Brucey
I'd suggest that you try the following things in order

1) double check that you are turning them in the correct directions; LH pedal has a LH thread, and RH pedal has a RH thread.

2) Penetrating oil, leave to soak (might do some good, won't do any harm)

3) heat, repeatedly, alternating with more oil. Note that more than ~100C will damage a black finish on the cranks and more than 200C could start to alter the condition of the aluminium cranks. If they are bad, it can take over 300C to shift them.

FWIW it is normal for well-seized pedals to finally come out, but they often take the crank threads out with them, which effectively scraps the cranks (thread repairs are possible but cost about the same as cheap new cranks do, and probably your chainrings are worn anyway, so.....)

To get more purchase on the pedal spindle than a spanner affords, you can strip the pedal down and put the pedal flats in a bench vice, with packing if necessary.

The pedals themselves are more likely to survive all this than the cranks are, in fact. Even if the pedals pull the crank threads out, some careful scraping (use a magnifying glass to inspect the threads carefully) usually removes the crud from the pedal threads.

If the pedals are bad but are not coming out, consider rebuilding the pedals (using parts from an identical new pair), around the old spindles. When the chainrings wear out, bin the lot.

cheers

Re: Stuck pedals cranks

Posted: 25 May 2018, 4:38pm
by Airsporter1st
The only thing I would add to the comprehensive answer above, is don't underestimate the power of percussion. A well fitting spanner, tapped sharply with e.g a heavy wooden mallet can often be more effective than the application of sustained torque.

Re: Stuck pedals cranks

Posted: 25 May 2018, 6:08pm
by matt2matt2002
Many thanks

Re: Stuck pedals cranks

Posted: 25 May 2018, 6:17pm
by RickH
I have length of square section steel pipe (one end is shaped for an unrelated, non-cycling function) about 85cm/33" long that fits over the handle of my pedal spanner. This auxiliary handle hasn't failed to shift a pedal yet! :D

Re: Stuck pedals cranks

Posted: 25 May 2018, 7:44pm
by drossall
And how big, and how good, is your pedal spanner in the first place?

Re: Stuck pedals cranks

Posted: 25 May 2018, 7:55pm
by RickH
drossall wrote:And how big, and how good, is your pedal spanner in the first place?

It was a freebie with a cycling magazine with about a 6" handle. 8)

Re: Stuck pedals cranks

Posted: 25 May 2018, 10:08pm
by drossall
First thing I'd try is a proper one. Points above about possible thread damage apply, but quite likely not.

Re: Stuck pedals cranks

Posted: 26 May 2018, 1:14pm
by Steve
Much harder with pedals that have no spanner flats and must be removed with an Allen key....

Re: Stuck pedals cranks

Posted: 26 May 2018, 4:00pm
by gxaustin
Much harder with pedals that have no spanner flats and must be removed with an Allen key....


Best use a socket Allen key and heat (as suggested by Brucey). Ally expands more than steel so a good hot air blower may help + add penetrating oil. If you don't have one check out your hair dryer - my daughter in law has a 2kW hair dryer. Great for paint stripping too :D
I put the widest spanner that fits on the pedal and stand on it.

Re: Stuck pedals cranks

Posted: 26 May 2018, 4:28pm
by Airsporter1st
Steve wrote:Much harder with pedals that have no spanner flats and must be removed with an Allen key....


.......but easier to use an impact gun.

Re: Stuck pedals cranks

Posted: 26 May 2018, 5:43pm
by robgul
Try Finish Line Chill Zone (same concept as applying heat with differing metals) - I seem to have a lot of success with it on seized pedals in the shop.

Rob