Author Topic: Removing alloy post from alloy frame (Read 3698 times)

Hmoon27 · « **on:** March 26, 2013, 01:51 PM »

Whats the best way?
I've got a mid school gt pro xl alloy frame and a gt alloy micro adjust stuck in it!
I've had it in the vice but the post just bends.
Any ideas?

ozone · « **Reply #1 on:** March 26, 2013, 02:17 PM »

Quote from: hmoon27 on March 26, 2013, 01:51 PM

Whats the best way?
I've got a mid school gt pro xl alloy frame and a gt alloy micro adjust stuck in it!
I've had it in the vice but the post just bends.
Any ideas?

How deep is the post inserted down the tube? When an alloy post/frame corrodes, it's almost as if it's welded together.

After trying all methods available to me, I chopped the top off the post and cut the rest of it out using a hacksaw blade whilst wearing a suede builders glove.

It took a while mind so only consider doing this as a last option.

Drilling would work if you get access to a pillar drill or similar.

MartyC · « **Reply #2 on:** March 26, 2013, 03:22 PM »

belt the top of the seat post with a very large hammer to break the seal that has formed, if that fails then fill the seat tube with diesel and leave for a day or so before trying again.

GavinDavis · « **Reply #3 on:** March 26, 2013, 03:25 PM »

Tighten and old stem around it and use a tube for a bit of leverage on the quill.....worked for me

southern andy · « **Reply #4 on:** March 26, 2013, 04:44 PM »

Quote from: gavindavis on March 26, 2013, 03:25 PM

Tighten and old stem around it and use a tube for a bit of leverage on the quill.....worked for me

Doing this ^^^^^ on an ali post with an ali frame $:-\$ $:-\$ $:-\$

Like Ozone said, a pillar drill. I'm sure you have a metal workers place near where you live. Go through the drills in sizes using each one as a pilot drill but make sure it's straight with the frame. Slowly does it is the best way.

Rabdul06 · « **Reply #5 on:** March 26, 2013, 05:11 PM »

Soak it over night in penetrating oil, diesel etc put a solid bar down the middle of the post prevent it crushing then fix a stem/forks to it and give it some.

ozone · « **Reply #6 on:** March 26, 2013, 09:23 PM »

Quote from: Rabdul06 on March 26, 2013, 05:11 PM

Soak it over night in penetrating oil, diesel etc put a solid bar down the middle of the post prevent it crushing then fix a stem/forks to it and give it some.

^^^^^
None of these methods seem to work on aluminium oxide as they do on rusty steel.

I tried the lot, turning in vice, Tw@tting with hammer, WD40, Plusgas, Coca Cola

before I took matters into my own hands.

senzo milano · « **Reply #7 on:** March 26, 2013, 10:32 PM »

Heat the seat tube with a paintstripper or gastorch... and try to wrick the seatpost out while its heated...

but no overheating...

bobbbbsy · « **Reply #8 on:** March 26, 2013, 10:38 PM »

allys soft.. drill a big hole in it enough for a screwy , insert and twist

Discostu · « **Reply #9 on:** March 26, 2013, 10:57 PM »

You say it's a pivotal post. It isn't one of the types that has a wedge/quill type of bottom, like the bottom of a quill stem?
As some pivotals came like that. If so you will need to screw a threaded rod or bolt into the wedge and belt it down to free the post.

If it is a standard alloy pivotal post which has degraded along with the frame it could be a right bu66er to remove,
Did you clamp the post in the vice and use the frame as the lever to twist it round? I would probably go for this option after a bit heat has been applied with a blow torch to the frame seat tube to expand it.

jT Racing · « **Reply #10 on:** March 26, 2013, 11:12 PM »

vice trick works, but you need something to put in the top of the post to stop it crushing and help it bite.

oldschoolace · « **Reply #11 on:** March 26, 2013, 11:24 PM »

My favourite trick is to drill a hole in the seatpost big enough to put a decent sized allen key through. Drop the seatpost in a vice so the frame is upsidedown and the allen key runs parallel to the jaws. Then tighten the vice til its snug on the tube. When you turn the frame the tube usually wants to slip but the allen key prevents this and gives you better torque.
Never tried it on a ali frameset yet but its worked on all the steel frames i have had

ozone · « **Reply #12 on:** March 27, 2013, 07:42 AM »

Check out Sheldon Brown for advice on posts stuck because of galvanic corrosion. He reckoned (RIP Sheldon) ammonia will dissolve it if you're looking for a chemical solution.

http://sheldonbrown.com/stuck-seatposts.html

The tried and trusted methods for steel on steel used above just don't cut it when two lumps of aluminium have fused together.

An 80s racer frame I had this problem with was bending when I had clamped in a vice as the bond is that strong. The frame would either have cracked at the lugs or bent in half if I kept trying to turn it out that way.

http://sheldonbrown.com/stuck-seatposts.html

Discostu · « **Reply #13 on:** March 27, 2013, 08:09 AM »

You can't use that method as it will also eat away the alloy frame.

leehunt1 · « **Reply #14 on:** March 27, 2013, 08:40 AM »

Quote from: gavindavis on March 26, 2013, 03:25 PM

Tighten and old stem around it and use a tube for a bit of leverage on the quill.....worked for me

You shouldnt drink in the afternoon Gavin..

ozone · « **Reply #15 on:** March 27, 2013, 08:46 AM »

Quote from: discostu on March 27, 2013, 08:09 AM

You can't use that method as it will also eat away the alloy frame.

Caustic soda would knack the frame - he's on about using ammonia to dissolve the aluminium oxide - not the entire seat post. $:-\$

not johndub71 · « **Reply #16 on:** March 27, 2013, 10:05 AM »

Piss has ammonia in it... saves money..

adenough · « **Reply #17 on:** March 27, 2013, 10:14 AM »

With ally, id get a nice sharp screw driver, prize the seat tube open a bit, then fill with WD40, leave for a bit then id whack the seat post (with a mallet) downwards, yes, as ramming it further in, sounds odd, but if the post moves you can then twist it out

if it doesn't go down any further, then you've lost nothing

jT Racing · « **Reply #18 on:** March 27, 2013, 07:52 PM »

Using a hair dryer or careful with a heat gun can crack the bond. Also freezing with one of those pipe freezing gizmos can help. It is a tough bond to break but I've done it a few times.
Putting a steel bar or small steel 'something' in the seat tube to stop it crushing in the vice, get it gripped up nice. Get your heat gun, apply tension(twist) and apply heat, don't cook the fook out of one spot. Two people make it easier, but be patient, keep good tension on the tube and keep it hot. It will crack the bond eventually, might take a few goes over a few days but it's always worked with some fortitude and methodology.

animal · « **Reply #19 on:** March 27, 2013, 07:52 PM »

What size post is it ? 22.5mm ? or larger ? Where u based ?

jT Racing · « **Reply #20 on:** March 27, 2013, 08:00 PM »

I had one once that was cut off level with the seat mast. I had to use a boomerang hack saw and chop through it on opposite sides and chisel it out.

adenough · « **Reply #21 on:** March 27, 2013, 08:42 PM »

try a thermic lance,

senzo milano · « **Reply #22 on:** March 28, 2013, 09:51 PM »

Quote from: adenough on March 27, 2013, 08:42 PM

try a thermic lance,

Hmm it was alloy i believe

Rabdul06 · « **Reply #23 on:** March 29, 2013, 09:36 PM »

Weld the post to the front bucket of a JCB. Wedge the bike sideways in a doorway and pull the fooker out.....oh and make sure you soak it in something first..er...washing up liquid, pish, fanta, porridge etc...

senzo milano · « **Reply #24 on:** March 29, 2013, 09:39 PM »

Quote from: Rabdul06 on March 29, 2013, 09:36 PM

Weld the post to the front bucket of a JCB. Wedge the bike sideways in a doorway and pull the fooker out.....oh and make sure you soak it in something first..er...washing up liquid, pish, fanta, porridge etc...

Yes ..... put it in the wasing machine at a temparature of 100 gr celsius

Author Topic: Removing alloy post from alloy frame (Read 3698 times)

ozone

Rabdul06

ozone

ozone

leehunt1

ozone

Rabdul06