Releasing errant cotter-pin

Ladies Raliegh Town bike. Probably about 10-12 years old. Bottom
bracket has a lot of slop in it and I was going to remove it to take a
look. Not sure if it is a sealed unit or bearings. One cotter-pin
comes out fine but the other won't budge. I've tried tapping it (and
beling it) with a hammer and pressing it out using a G-Clamp. Won't
move at all.

Any further ideas that I might try. What about heating it first?

Andrew

wrote in message
...
Ladies Raliegh Town bike. Probably about 10-12 years old. Bottom
bracket has a lot of slop in it and I was going to remove it to take a
look. Not sure if it is a sealed unit or bearings. One cotter-pin
comes out fine but the other won't budge. I've tried tapping it (and
beling it) with a hammer and pressing it out using a G-Clamp. Won't
move at all.

Any further ideas that I might try. What about heating it first?

Can't help re the cotter pin, but 10-12 y/o and still with cotter pins?
Boggle.

(bigger hammer :-) )

On Fri, 6 Mar 2009 05:32:49 -0800 (PST), wrote:

Ladies Raliegh Town bike. Probably about 10-12 years old. Bottom
bracket has a lot of slop in it and I was going to remove it to take a
look. Not sure if it is a sealed unit or bearings. One cotter-pin
comes out fine but the other won't budge. I've tried tapping it (and
beling it) with a hammer and pressing it out using a G-Clamp. Won't
move at all.

Any further ideas that I might try. What about heating it first?

Andrew

Brute force, aided by fixturing and some minor metalwork.

What tends to happen is application of a hammer mushrooms the ends of the
pin - distortion of the threaded end occurs rather than the desired motion
of the pin. Next time grease the pin on installation and when attempting
to remove it loosen the nut until it is just proud of the pin and hit the
nut.

If you are at the mushroom stage cut the threaded end of the pin flush with
the crank; than use a punch and a heavy blow. If you are in doubt as to
your ability to deliver the blow accurately, dimple the end of the pin with
a drill bit, and if possible remove the crank and arm from the frame (as
the other arm came off) and hold it in a vice.

If that fails then the pin can be drilled out. File the big end flat,
centre-punch and drill; in stages is best. Have a look at your replacement
pin when deciding where to put your punch-mark - pins vary but you probably
need to drill slightly off-centre or you may hit the axle. The pin is
softer than the axle, and if the drill bit hits it you may be able to feel
that - but it is only necessary to remove enough of the pin from the center
to allow it to be driven out from the other end, so if you do find the
drill has met the axle it is time to use the hammer. Remember, drill from
the big end - you'll be hitting the small one.

Clive George wrote:
wrote in message
...
Ladies Raliegh Town bike. Probably about 10-12 years old. Bottom
bracket has a lot of slop in it and I was going to remove it to take a
look. Not sure if it is a sealed unit or bearings. One cotter-pin
comes out fine but the other won't budge. I've tried tapping it (and
beling it) with a hammer and pressing it out using a G-Clamp. Won't
move at all.

Any further ideas that I might try. What about heating it first?

Can't help re the cotter pin, but 10-12 y/o and still with cotter pins?
Boggle.

(bigger hammer :-) )

Beat me too it... I thought they were history about 20 years ago.

The bigger hammer approach is good because if you manage to break it you
can put something decent on...

Pete.
--
Peter Clinch Medical Physics IT Officer
Tel 44 1382 660111 ext. 33637 Univ. of Dundee, Ninewells Hospital
Fax 44 1382 640177 Dundee DD1 9SY Scotland UK
net http://www.dundee.ac.uk/~pjclinch/

On Fri, 6 Mar 2009 05:32:49 -0800 (PST)
" wrote:

Ladies Raliegh Town bike. Probably about 10-12 years old. Bottom
bracket has a lot of slop in it and I was going to remove it to take a
look. Not sure if it is a sealed unit or bearings. One cotter-pin
comes out fine but the other won't budge. I've tried tapping it (and
beling it) with a hammer and pressing it out using a G-Clamp. Won't
move at all.

Any further ideas that I might try. What about heating it first?

If it had got to that stage I'd usually drill down the centre from the
threaded side, stick a punch in the hole and whack that. Make sure you
support the crank when you whack it, a thick bit of steel tubing that
sits around the cotter pin and rests on the ground is good for this.

On Mar 6, 1:32 pm, "
wrote:
Ladies Raliegh Town bike. Probably about 10-12 years old. Bottom
bracket has a lot of slop in it and I was going to remove it to take a
look. Not sure if it is a sealed unit or bearings. One cotter-pin
comes out fine but the other won't budge. I've tried tapping it (and
beling it) with a hammer and pressing it out using a G-Clamp. Won't
move at all.

Any further ideas that I might try. What about heating it first?

Andrew

Remove the nut, rotate the crank so that the threaded end is
uppermost, fill the area around the threaded section with penetrating
oil, apply some pressure with the g-clamp, walk away for 48 hrs.,
then try again. Sometime helps, sometimes doesn't, but doesn't cost
anything and can't hurt.

Don't go nuts with the hammer or the heat while the unit is still in
the frame.

If you need to hit it hard while it is still in the frame, support the
crank arm from below so that the shock is transmitted directly to the
floor, rather than through the BB, frame, wheels etc. This reduces the
risk of damaging the bearings, cups etc. when you hit the pin. A
breeze block,topped with a piece of wood into which you have drilled a
hole just bigger than the cotter pin can work well - place the crank
on top of the wood so that the plain end of the cotter pin in in or
just above the hole, then work away with the hammer from above. A
length of steel pipe can be used in the same way (but it's a bit more
fiddle) . Make sure that only the crank arm is supported by the wood
or pipe.

If you can get the crank off the other side, and have sufficent access
to unscrew the BB cup on the stuck side from the frame, then you may
be able to remove the remove the stuck crank and spindle as one unit.
You can then get clear access to the area to let fly with a suitable
hammer and drift and/or apply heat without risk to the frame paintwork
or the rest of the BB and bearings. You may also be able to bring the
spindle and crank to a small garage who will have a suitable bearing
press or similar which will be able to drive out the pin.

hth,

bookieb.

On Fri, 6 Mar 2009 06:07:46 -0800 (PST), bookieb wrote:

On Mar 6, 1:32 pm, "
wrote:
Ladies Raliegh Town bike. Probably about 10-12 years old. Bottom
bracket has a lot of slop in it and I was going to remove it to take a
look. Not sure if it is a sealed unit or bearings. One cotter-pin
comes out fine but the other won't budge. I've tried tapping it (and
beling it) with a hammer and pressing it out using a G-Clamp. Won't
move at all.

Any further ideas that I might try. What about heating it first?

Andrew

Remove the nut, rotate the crank so that the threaded end is
uppermost, fill the area around the threaded section with penetrating
oil, apply some pressure with the g-clamp, walk away for 48 hrs.,
then try again. Sometime helps, sometimes doesn't, but doesn't cost
anything and can't hurt.

Don't go nuts with the hammer or the heat while the unit is still in
the frame.

If you need to hit it hard while it is still in the frame, support the
crank arm from below so that the shock is transmitted directly to the
floor, rather than through the BB, frame, wheels etc. This reduces the
risk of damaging the bearings, cups etc. when you hit the pin.

This is a myth - understandable, but nevertheless untrue. The bearings,
cups, and cones are too hard to be damaged by hitting the cotter pin.

There is, however, a point to supporting the crank arm as described - it
helps make sure the blow(s) do not go awry.

In article , wrote:
Ladies Raliegh Town bike. Probably about 10-12 years old. Bottom
bracket has a lot of slop in it and I was going to remove it to take a
look. Not sure if it is a sealed unit or bearings. One cotter-pin
comes out fine but the other won't budge. I've tried tapping it (and
beling it) with a hammer and pressing it out using a G-Clamp. Won't
move at all.

I used this sort of ball joint separator as a cotter pin press, which
works a bit better than a standard G-clamp:
http://www.amazon.com/OTC-Ball-Joint.../dp/B0015PN010

On Mar 6, 2:27 pm, _
wrote:
On Fri, 6 Mar 2009 06:07:46 -0800 (PST), bookieb wrote:
On Mar 6, 1:32 pm, "
wrote:
Ladies Raliegh Town bike. Probably about 10-12 years old. Bottom
bracket has a lot of slop in it and I was going to remove it to take a
look. Not sure if it is a sealed unit or bearings. One cotter-pin
comes out fine but the other won't budge. I've tried tapping it (and
beling it) with a hammer and pressing it out using a G-Clamp. Won't
move at all.

Any further ideas that I might try. What about heating it first?

Andrew

Remove the nut, rotate the crank so that the threaded end is
uppermost, fill the area around the threaded section with penetrating
oil, apply some pressure with the g-clamp, walk away for 48 hrs.,
then try again. Sometime helps, sometimes doesn't, but doesn't cost
anything and can't hurt.

Don't go nuts with the hammer or the heat while the unit is still in
the frame.

If you need to hit it hard while it is still in the frame, support the
crank arm from below so that the shock is transmitted directly to the
floor, rather than through the BB, frame, wheels etc. This reduces the
risk of damaging the bearings, cups etc. when you hit the pin.

This is a myth - understandable, but nevertheless untrue. The bearings,
cups, and cones are too hard to be damaged by hitting the cotter pin.

There is, however, a point to supporting the crank arm as described - it
helps make sure the blow(s) do not go awry.

OK, it is in the area of an "every fule kno" well known fact, rather
than a real problem - I've never seen it happen in practice, despite
some fairly "agricultural" treatment that I've meeted out to cotter
pins over the years.
As you say though, still good practice, even if not strictly
necessary.

regards,

bookieb.

Quoting :
look. Not sure if it is a sealed unit or bearings. One cotter-pin
comes out fine but the other won't budge. I've tried tapping it (and
beling it) with a hammer and pressing it out using a G-Clamp. Won't
move at all.

http://www.sheldonbrown.com/cotters.html may help.
--
David Damerell Kill the tomato!
Today is Olethros, March - a weekend.