I recently picked up a rough shape 91 stumpjumper that i want to turn into a commuter.

The sealed cartridge BB is stuck.....and i mean stuck. I have been soaking it for a few days now in PB. I have a m8x1 sae bolt running through my bb tool into the spindle to keep things nice and lined up and tight as those spines dont seem to like to stay seated. I have been on it with a 12 inch adjustable wrench and no dice. I have even take a 2 foot 1/2 inch drive breaker bar and 1 inch socket to it and used a cheater bar but still no dice moving things on either side.

My next thing is going to be trying to soak it longer and use a impact gun on it. This may sound extreme.....and it is but this thing is STUCK. IT appears to be steel cups and a steel frame. I am not sure how it got so tight.

Anyone know of any place that rents electric impact guns?

I dont want to put a torch to the frame and i am 99.9% sure cola and lemon juice and all that wont work at this point. I have time on my side and am going to let it soak for a few weeks while i either source an impact gun or come up with another way.

soak it heavily with pb blaster & let sit for a couple of hours while spraying it periodically in-between.

You probably already know, but just mentioning it to be absolutely certain... You're aware that the non-drive-side is left-hand (reverse) threaded, right? Turn it clockwise to remove.

You could potentially try other penetrants, too. A 50/50 mix of acetone and ATF is a pretty well-regarded homebrew version.

Assuming you are turning it the right way, as noted above, an impact gun might be your next best choice. A 2.5' breaker bar can easily generate 400 ft-lbs. of torque, so you'll need to get an impact gun that generates MORE than that to do any good. Most 1/2" drive electric impact guns are less than that. A 3/4" drive electric might do the job but you'll have to get the right adapter to connect to your BB driver. Check the specs before you buy or rent one.

An air impact wrench will probably get you more. I have a 1/2" drive that is rated at 700 ft-lbs. and a 3/4" that is good to 1500 ft-lbs. If you don't have a compressor you'll need to rent one of those too.

You've got that backwards. The drive-side is reverse threaded.

There are a tool holders for the proper fixed cup wrench, so it wont come off like your adjustable wrench will

and bike shops may have them, I do being an old worker in them...



yea righty loosey in left hand threaded fixed cups [(except Italian & French) both sides RH thread on them.]

Cartridge BB ? which one?





...

D'oh! I know that... just somehow managed to type it wrong. Thanks for the catch.

Put the cartridge tool in a bench vice vertically and the bike on top laying on its side. Use the whole frame as a lever.

If the tool keeps popping out, run a bolt from the spindle through the tool with a washer to keep it in place.

i have run the bolt and washer. Frame wont be enough leverage. My breaker bar is longer than the tubes on the bike at this point. I will give it a few more days soak in pb. I am in no rush but i it is bugging me that it wont budge. I hvae had stuck ones and finally got them. This one so far is a different story. I kind of which i had one of those magnet oil pan heaters. Warming it up might help and that wouldnt scorch the heck out of the finish.

Sometimes they need a little more persuasion.

here we go again... see thread Counter clockwise, clockwise, what?? Andy

I have broken a number of BB cup tools over the years. Some were on "classic" cup and cone BBs and some on modern "cartridge" ones. After high torque or impact don't do the job more destructive (to the BB and frame) methods are next. Heat or grinding. One sure way is to slot the shell across the threaded portions it to open up the ID of the shell. Then weld/braze the slot closed and retap/chase. I've never had to do that because the cost to the customer was never agreeable, no doubt. Andy

I'm not sure of your location but around here you could walk into the service bay of any tire store and one of the guys would throw an impact wrench on it if your socket is 1/2" drive.

It got so tight because that's what it's designed to do. BB threads are oriented so that the epicyclic motion of the ball bearings does not loosen the cups, but tighten them. And 24tpi is a really fine pitch for that diameter a fastener, so it can get really tight.

That, and corrosion. (This is why I tell people to use anti-seize instead of grease on threads. Much better at resisting corrosion.)

I assume you're trying to remove the LH cup first. Almost all cartridge BBs have a "fixed" RH and a "free" LH cup It's easier to remove the LH cup first, then go after the RH cup.

You don't need a torch, or probably even an impact gun. Even with steel cups, an impact gun will probably strip the splines on the tool and/or the cup. They're really not designed for that. If it's a steel cup, a heat gun will get it hotter than it needs to be. It can burn the paint off, so keep it far enough away to prevent that, and keep it moving around. Be ready to strike while the iron is hot, literally.

If your cups are aluminum, heat will make things worse, and the impact gun will definitely strip the cup splines. If that's the case, you might want to try a freezing spray/penetrant. I've had pretty good success with them.

My suggestion for heat was without a full description. One heats the shell best possible, not the cups. Then when cool the cup is again tried to be removed. Heating or cooling the cup is hard to do without also involving the shell. Heating the shell is easier to control as it has far better access. But at this point things are approaching last resort state anyways. I have only done this a very few times and always with the understanding that paint will suffer as the amount of heat is fairly high. Still, whatever works is what works. Andy

Do you have a shorter socket? That extended length is hurting your effort.

still soaking....but thats ok ....it is still cold and wet outside. Still no luck has of yesterday. I hope i can get it out so i can use the frame or i am out that money i spent. Not alot but still.......and it is a neat older frame despite its scraches and wear. Id still make a great rig and clean up nice.

still nothing. I think i am going to cut into the fixed cup lip enough to make a slot in a few spots and then use a flat punch to try and "shock" it into start turning. This might be a lost cause and i might just need to face that i am out the money spend on the frame. I will let it sit another week and soak. I was able to get the bottom cable guide bolt out and it did drip penetrating fluid as i would expect. There is plenty of it in there.

and still nothing. I think my 1/2 inch breaker bar is going to break before it breaks free. Time for the chisel and hammer method to give it a couple of shocks to see if it brakes free that way. IF it doesnt.......its likely a lost cause. One last attempt after that might be to weld a large nut on the steel part of the fixed cup and try it that way but im not holding out much hope with that method. Wish me luck.

Good news and bad news.

The fixed cup and shell is out. I did like i said...cut grooves with dremel in 2 spots and smacked the grooves with a flat chisel. it still took tremendous force but with my breaker bar and cheater pipe the came free.

The nonfixed cup is still stuck.

I cleaned out the bb of debris and threaded in the fixed side to have the spindle for guidance with my bolt holding the tool in place. No dice. I guess i keep on soaking. I would figure the fixed cup might be a bit looser than the nonfixed side and i got lucky. I am afraid now i wont be able to get the nonfixed side out. IF those teeth/splines get eaten up by the tool and strip.....i am likely screwed.

i will give it another good soak and some light heat.

This frame is an ugly toilet of a frame cosmetically but is great otherwise......and after all this....i want to ride it. Sure i could go purchase a different one and even a full bike for about $250 of the same model and way way better shape......but why?

My trick is to chuck my BB tool vertically in a sturdy bench vise. Thread your whole bike frame onto that. Then think for a minute about which way I need to rotate the bike frame to loosen the BB (Important).

That's the only trick that I know because it has never failed me. Honestly, it has surprised me how little torque on the frame is required.

and.......its out. Soaking for 2 weeks and letting it sit in the sun today while soaking and taping.......plus a 24 inch breaker bar and a 24 inch cheater pipe.....various bolts, spacers and a lot of patience paid off. It was IN THERE. Corosion and likely some strong thread locker by the looks of things. It jolted out turn by turn on each side. Both sides i thought it broke the tool l or the breaker bar when it started to come free.......or i was skipping teeth on the tooth but it was turning.


I won.

Thanks all.

oh...and if anyone knows a good place to get a Shimano UN71 or its equivalent as it doesn't appear to be made any more......pls let me know.

Congrats!

the original shimano un71 was 73mm x 113mm.

Its dead.

i am thinking of running a modest 1x9 drivetrain here for city and some light trail.


Would 113mm still be the right spindle length for this type of thing. I have a sram x5 front with a x9 rear i am thinking of running. IF anyone can make a recommendation here for bottom brackets that would be great. I could probably even go more modern and use a hollowtech style bb and try to source a proper length crankset i suppose. The hollowtech bbs are cheap. I am thinking of a 36 - 40 chain ring up front.

Spindle length is determined by the crankset chosen. Choose the crank first and then buy the spindle length/BB type it requires. External Hollowtech BB is for hollowtech cranks only. Until you decide on a crank the only thing you know is you have a 73mm shell width with BSA (English) threading. The direct replacement would be a UN54 (plastic NDS cup) or UN55 (Al NDS cup)