Author Topic: Removing stubborn pedals  (Read 16836 times)

fruitcake

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Re: Removing stubborn pedals
« Reply #100 on: June 07, 2020, 01:36:24 pm »
For what it's worth, I've found that stepping on the spanner is easier than trying to lever it using my hands. This requires a spanner with a handle thick and long enough that it can take a foot pressing down on it. Sometimes a 12" adjustable will fit the pedal flats, other times it needs the pedal spanner with a piece of pipe covering the handle.

Setting for this job is what makes it safe. I keep the wheels on the bike and place the bike in a place where it won't move, facing into the corner of the room is good - make sure you're prepared to support your own weight for the moment when the pedal comes free.

Edit: Similar idea is shown upthread in Feanor's excellent post.

Re: Removing stubborn pedals
« Reply #101 on: June 07, 2020, 02:40:36 pm »
Thanks, but as above leverage on the spanner is limited, by rounding of the flats on the pedals from attempts so far, to less than I can achieve with arm strength alone. Hence the last few messages.

Re: Removing stubborn pedals
« Reply #102 on: June 08, 2020, 09:24:30 am »
It's often easier with the crank off. Boiling water on the end of the crank has never failed me.  Sticking the crank and pedal in the freezer for an hour THEN pouring boiling water over the crank is the next step.  You have to be quick...the crank expands more, and faster, than the pedal spindle.
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Re: Removing stubborn pedals
« Reply #103 on: June 08, 2020, 10:33:27 am »
the worst cases I have encountered have only succumbed to ;

- pedal spindle in the bench vice
- length of something added to the crank for extra leverage
- multiple hot/cold cycles using blowtorch or heat gun
- using ATF instead of penetrating oil on the hot crank

Most oils become very fluid at high temperatures and penetrate well. Once the part is hot, solvent-based penetrating fluids just boil and are of little value.
ATF starts to burn (char) at slightly over 200C which means that you ought to see if you overheat the crank or not (the metal  will quickly  change irrevocably at higher temperatures than this).  At lower temperatures the water tied up in the oxide will bubble out through the oil, and you know you are doing some good. Alternating hold/cold cycles cause (net) the oxide in the thread to lose water and gain oil. 

Even with the best and most thorough treatment there is always a fair chance that when the crank starts to move, it will have torn the threads in part of the threaded length. When this happens the threads in the crank will be damaged, depending on where the tear starts. If it is near the back of the crank then the crank thread may be totally destroyed and a helicoil is necessary. If it is near the front of the crank then you may lose one or two threads only in which case the crank is still usable.

IME the threads are most likely to bind near the front of the crank especially when pedal spindles without a full shoulder are used (these let the grot into the threads and help the grease/copper-ease to be washed out). The undercut in the spindle threads can either harbour copper-ease or corrosive grot; the choice is yours.   However during removal the damage to the crank is severe should the threads be torn starting from the back, so it makes most sense to have the pedal spindle in the bench vice so that the back of the crank is uppermost, and to introduce penetrant from there, heat/cold cycle assisted.

When you have got the pedal out, the spindle threads may be full of aluminium etc. Under no circumstances should you screw such pedals back into a nice set of cranks; you will wreck the crank threads.  The spindle ought to be hard, too hard to address with a file (if you want the file not to go blunt very quickly). You can appear to clean the threads out with a wire brush, but IME the only 100% safe and effective method of cleaning the threads is to scrape the grot out using a pointed tool. I usually employ the point of a Stanley knife blade, and examine the result using about x10 magnification. If you want to 'test' a pedal spindle then there is something to be said for screwing it into an old steel crank.

IME if you adopt the above approach then the pedal spindle can always be saved (*), and the crank (if the seizure was bad enough to start with) is more likely than not to be damaged. However it is never so badly damaged that it cannot be repaired using a thread insert.

(*) the exception to this may be stupid pedals with allen-key-only spindle fittings; 6mm sockets round out too easily, and 8mm sockets tend to split lengthwise when high torque is used.

hth

cheers

Re: Removing stubborn pedals
« Reply #104 on: June 08, 2020, 01:17:49 pm »
... IME the only 100% safe and effective method of cleaning the threads is to scrape the grot out using a pointed tool.
I have a small screwdriver that I use for the purpose, though I've never gone as far as checking with a magnifying glass. Generally, the aluminium comes out in chunks. I've already done the other three pedals that I mentioned.

Re: Removing stubborn pedals
« Reply #105 on: June 08, 2020, 02:03:50 pm »
Coca-Cola is also on my list, as in this thread.

Reminds me of a similar story (stuck BB not pedal), I'm sure I've posted it here before. Ah yes:-

Had a similar problem when changing the BB after the axle on my commuter hackbike snapped (http://www.greenbank.org/misc/IMG_4637.JPG) thanks to my RAW POWER.

It snapped on the way in to work after 3 miles so I collected the bits off the road and cycled the remaining 5 miles one legged. Nipped to Evans at lunch to buy a new BB, BB-tool and crank extractor. Got a friend to bring a long handled socket wrench in. Intention was to go to the pub after playing 5-a-side football and swap it over sitting outside the pub in nice sunshine with a pint (or several) in my hand.

Pedals off, cranks off but just couldn't get either side of the BB undone. No amount of brute force was helping. The nearby garage had closed and, unsurprisingly, the bar didn't have any WD-40.

Got another pint and sat there thinking what to do. Friends now sniggering at my predicament and half disassembled bike.

But then I remembered exactly what to do.

Inside to the bar and ordered a coke with no ice. Bike on its side and tipped some of the coke onto the BB so that it pooled there nicely. Left it for 15 minutes and it undid with only a reasonable bit of force. Turned the bike over, bathed that side in coke, waited and that too undid with no hassle. New BB in and all working again within 10 minutes after that. Mix of stunned amazement and annoyance from friends.


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Re: Removing stubborn pedals
« Reply #106 on: February 19, 2021, 04:41:58 pm »
Blimey !  I got one of these yesterday



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