Hi. I need some expertise.
I’ve bought an old postal bike (cargo bike) that I’m going to have sandblasted and painted.
The last thing I need to remove to fully strip it down is the bottom bracket. Unfortunately, my impact wrench destroyed all the splines in the bottom bracket, so now I don’t know how to get it out.
I should probably mention that it’s made of plastic.
Can it be drilled out and removed that way?
I’ve tried using pliers to turn it from the outside, but without success.
by Ok-Doctor-2622
17 Comments
Heat it up really good with a torch, and hit the axle with a hammer real hard. So if you heat up the right drive side cup, hit the left side of the axle towards the right. Repeat for the other side, you might need a big nut for the other side. Lay down the frame and put a piece of wood beneath the frame, so you don’t damage the frame when hitting.
For the next time: Do not use an impact for brittle plastic cups, secure the tool by basically screwing it into the axle with a washer and then use a long wrench. (They also make tools for this.) Soak in lubricant beforehand. For very brittle plastic cups this doesn’t always work, but it‘s worth a shot before absolute brute force.
Edit: also are you sure this is not entirely rusted through?
Bike has bigger problems than the bottom bracket.
U shouldnt use an impact wrench U should use a ratchet/breaker bar/normal wrench. Did U turn it the right way non drive side counter clock wise the drive side clockwise. Usually the non drive side can come off with a good amount of elbow grease
Since both cups are on u cant really remove the spindle to use a hacksaw
U should probably drill the cup out away from the outer shell of the BB or try what the other comment I just saw as I wrote this said
Bit of rust there on the frame as well.
genuine question, is there any metal under that rust?
i’ve had a bike in a similar conditions and when i wire-wheeled the rust i just dug straight through the frame, perhaps it’s not that bad, but the chain stays are pretty critical and they might be weak.
Give it a month and you’ll be able to just pick the steel away from around it
You paid money for that shitheap?
This poster and the gacked drivetrain poster need to meet
So first of all, try to remove the left side cup by using a bolt to secure the bb removal tool. It will help if you can do it, but in any case the removal process is simpler that it looks. What you want is to hammer out the metal spindle, then use a saw to cut the plastic, taking care to not damage the threads. This is made easier by removing the left side cup.
Unless you own the sandblaster take a wire wheel or even a wire brush and explore those chainstays. You’ll find out if they’re solid and you’ll save money time and anguish if they aren’t.
It came out at last.
https://preview.redd.it/8882z5z3v8mg1.jpeg?width=3024&format=pjpg&auto=webp&s=fe673336a49147f3ffbe684f5d2a5ba0df7fd411
There is a German YouTuber called nlz.fahrrad who makes videos about these problems, he has one for this exact one, too. Check it out, I think it will help you!
“festes Tretlager ausschmelzen | Plastik Tretlager ausschlagen & ausschmelzen”
In this case…. Take a gas torch and burn it out!
That frame is toast.
In regards to the BB, I find that tapping it out with a hammer works best.
Hit the spindle with a hammer until the BB flies out, then you can attack the cups.
next time use a qr skewer to clamp the bb tool on then turn w wrench…
but no chance I’d spend the time w that kind of rust. even if it looks ok after sandblasting it will be thinned enough to fatigue crack if used as intended
Has this bike been stored under the sea?
I am sad these photos came with a story. Because i could actually tell what bike i was looking at. I have fixed these thousands of times. Feel free to have a personal AMA in my inbox if you need help