Picked this up from a buddy to rebuild and I have never had a seatpost so damn seized up. Tried the normal WD, PB, and Kroil. Tried gentle and less gentle heat and a big fucking wrench, cooling seatpost and heating frame. Obviously I don’t care about the seatpost but I am hoping to save the paint. before I go at it with a hacksaw blade from the inside I was hopeful so one would have a trick.
by SR-02-D_CJ_CD
12 Comments
When I worked in the shop we would clamp the seat post in the bike stand so the frame hung free. Then we would use the frame itself as the lever arm. This made it so we didn’t have risk clamping or damaging the frame. You may be able to accomplish similar with a workbench vise.
I will say, we did not win on every frame. Sometimes they are too far gone.
tons of pb blaster from the bottom, kept upside down. keep doing that for like a week
if it really wont budge you’ll have to meticulously saw it into halves or even pieces from inside. Thats how i saved my paint
I prob should have mentioned it’s an aluminum seatpost in a steel frame.
It’s had the penetration oil soak for a few days and no sign of budging. I sadly I have done the using a hacksaw blade from the I.D to saw it out on other jobs. I was just hoping for a new tip or trick I haven’t run across yet
Is the post itself garbage? Clamp the post in to a vise hard. Like to the point that it deforms (not at the frame though. That’s important). And then use the frame itself as your breaker bar by turning the frame around the post
Ice the post. Dry ice if you can get some. The constriction of the aluminum alloy can break it loose from the seat tube. I assume you doused it with liquid wrench or as we like to use in the shop, a mixture of transmission fluid and acetone. The combo broke loose posts that had been assumed fused for years.
When all chemicals fail, take a hacksaw and cut the post off with about 1″ showing above the frame.
Then cut multiple vertical slots in the post as deep as you can without cutting into the frame.
Hammer and punch the pieces.
Drinking a tallboy of Rain-Dog will help.
Step 1 PB blaster soak for several days. Spray it into the seat tube from the BB and set bike upside down
Step 2 clap seat post in vice as mentioned above. Use bike as lever.
If the seat post fails, cut it off near the frame and use hacksaw blades clamped in vice grips to cut the seat post vertically then brake it apart. This is the last ditch effort prior to the torch which will wreck the paint.
RJ has a playlist on YouTube, the slide hammer one is awesome.
https://www.youtube.com/playlist?list=PLxO5aF0sensiVdiClC_JH6OboqFl5Dvay
Then there is Sheldon
https://www.sheldonbrown.com/stuck-seatposts.html
I would remove the water bottle bolts in the seat tube and spray a ton of PB blaster in the seat tube and let it sit upside down.
Have you soaked it inverted with the fluid above the level of the bottom of the seatpost inside the frame? Also remove the clamp bolt completely. If nothing works and it’s worth the money to you then send it to the seatpost guy, who will get it out no question.
I recently went through this with an aluminum dropper post in a carbon frame. I tried soaking with all parts of penetration fluid for weeks. I ended up destroying the seat post by drilling a hole through it and put a long bolt. Turned everything upside down and put in a bench vise and twisted using the frame as leverage.
Turn frame upside down with the bb out, spray pb blaster inside the seat tube, come back tomorrow and put the seatpost in a bench vise and carefully use the frame as leverage turning back and forth.
(Alternatively to removing the bb, you can pray the penetrating fluid through one of the bottle cage mounting points)