Hi folks,
could i please have a consensus of opinion on stopping the inner race of a crank bearing from rotating on the shaft. the new bearing is reasonable fit but there are signs of rotation on the crankshaft (polishing of the surface) where the bearing sits.
any ideas that dont include buying another crankshaft would be great!
cheers
les.
they make shaft/sleeve loctite, green, but not sure how that would hold up. worth a shot. its #640
m in sc,
i was thinking of using that as a last resort, problem is that they list an "oil resistant" variety and it is hugely expensive and makes me think that the 640 would not stand up to oil.
les.
i can say that it will hold up to oil. ive used it on the lathe gearbox at work. but... on a crank bearing.. :huh:
Yeah, i know.
i was wondering if anyone had tried "roughing up" the crank, or drilling for a pin etc.
i was even thinking of applying some water locally and rusting it up a little!!
les.
I cant believe i'm suggesting this, but you -could- set the bearing on the shaft and heat up the bearing and crank end and braze it, let it leech in. it sounds like the crank end is toast already, so really nothing to lose. i guess. Now i feel dirty. :devil: :dawg:
npw were getting somewhere!!
the only reason i don't say tack weld it, is it will pull the bearing one way or the other when it cools.
im wondering whether a hard solder run in there would hold it
i mean, maybe. i'll be honest, its all a bad idea but i also get the gist of why you are doing it. silver solder would be worth trying.
+1 for silver solder
another way, which i think is what i will try, is to touch a small weld "pip" on the crank up against the web and then dremel a small slot in the inner race so that it cannot rotate.
what could possibly go wrong
I would go with the green Loctite. That's what it was made for, "restoring fits to worn assemblies" and the spec sheet says it is not affected by gas or oil.
What about building up the shaft using thermal powder coating, or hard Chrome, then grind it to correct press fit?
J-B Weld Cold Weld formula? Package says rated 5021 PSI, Fuel & Chemical resistant. I've had success with JB securing rear wheel bearings that fit too loose in the hub.
Quote from: RDnuTZ on April 30, 2024, 09:41:52 AMJ-B Weld Cold Weld formula? Package says rated 5021 PSI, Fuel & Chemical resistant. I've had success with JB securing rear wheel bearings that fit too loose in the hub.
we did that to a very old CR500 once, it lasted like 3 years. still.. it did work.
i think i have sussed it, bearing in mind (no pun intended) that the race is a reasonable fit on the shaft (light tapping with a soft hammer will put it on).
i have managed to drill a 2mm hole into the flywheel in the corner up against the shaft, and then dremel a small slot into the inner race that will fit over a roll pin in the drilled hole.
no more rotation and the pin cannot come out while the bearing is in place. might help someone else out in a similar situation.
thanks for all suggestions.
cheers
les.
Don't know what kind of bike - but do be careful with heroics; a seized crank bearing can destroy a case in short order. I would be hesitant to apply any 'soft' fixes that involved heat or chemicals. Many 2T cranks can have the outer flywheels replaced easily; a lot cheaper than fixing something like this:
(https://i.imgur.com/Wc5aSjb.jpg)
Warren
bike is a dt250mx.
i agree, but i dont think drilling slightly for a roll pin is a soft fix, replacement bearings for certain cranks have a drilling and a roll pin in the outer race, so its a variation of that really.
nasty mess of that crankcase - ouch!
les
well, that will def fix it.