Crank axle keeps working loose
 

I've taken the bottom bracket apart and put it back together 3 times. I've adjusted
the adjustable cup 3 times and locked it tight. I ride 2 blocks and the axle wobbles.
Any suggestions?

well, I guess the question is "what part is coming loose?".

The candidates are:
1. adjustable cup
2. fixed cup
3. crank arm is coming loose on the axle, which gives the impression that the bearings aren't adjusted properly.

I'm guessing that you have to adjust the left cup to tighten things up, which wouldn't point to the crank arm coming loose.
Is the lock ring loose, or do you have to loosen it first before adjusting the left cup? If it is still tight, that suggests that the right cup might be backing out.

Photos would help, as always.
A video of you checking on the looseness and tightening things up might not hurt either.

Steve in Peoria
(I'm betting on the right cup coming loose, just in case it wasn't obvious :) )

[QUOTE=steelbikeguy;22162006]well, I guess the question is "what part is coming loose?".

The candidates are:
1. adjustable cup
2. fixed cup
3. crank arm is coming loose on the axle, which gives the impression that the bearings aren't adjusted properly.

I'm guessing that you have to adjust the left cup to tighten things up, which wouldn't point to the crank arm coming loose.
Is the lock ring loose, or do you have to loosen it first before adjusting the left cup? If it is still tight, that suggests that the right cup might be backing out.

Photos would help, as always.
A video of you checking on the looseness and tightening things up might not hurt either.

Steve in Peoria
(I'm betting on the right cup coming loose, just in case it wasn't obvious :) )[/QUOTE
I don’t think it’s the right side cup because I couldn’t get it off the first time so I serviced the bearings through the left side. I did notice that the caged bearings fit pretty tight against the cone

Is this the '86 Panasonic you've been messing with?

Nope it’s the 85 Univega Gran Comp

can I change my guess to "the caged bearings are installed the wrong way around"? i.e. might try flipping them over.
Of course, that should mean that the axle doesn't turn freely, I think (I don't recall ever doing this myself)

Photos would be helpful, of course.

I wonder if Park Tool or RJ the Bike Guy have videos explaining about caged bearings?

edit: so you're saying that nothing came loose after each adjustment? i.e. the lock ring wasn't loose and the fixed cup wasn't loose? And the axle turned freely each time you adjusted the bearings?

Steve in Peoria

Unless they are the opposite of every other caged bottom bracket bearing I've done they are
the right way. O(pen end of cage towards cup closed end towards cone.

Unless it's a Campy retainer that accepts 11 balls, I will guess the great majority of c&vers here prefer to toss 9-ball retainers in the trash.

I'll have to double check but I believe I replaced 11 balls. I think my next step will be to remove the cage
and putt the bearings in loose.

As @SurferRosa implies, there are BB that need caged bearing sets the other way around, like this Campy that needed the closed end toward the cup.

https://photos.smugmug.com/photos/i-...-kpLNhzf-M.jpg

Let's assume that the cages and balls are installed properly. Let's assume that everything is adjusted properly. Let's assume that the non-drive side lock nut is locking the non-drive side cup properly. That would leave only one thing, in my mind...

Are the bottom bracket threads or the cup threads in good shape? If not, under use, it is possible that the entire cup is slipping on or jumping over the threads. A cracked bottom bracket shell would also contribute to the problem. Other than that, what else is there to consider?

Again, this thought assumes that installation and adjustment is done properly.

Bearing cage in backwards if they have 11 in the cage.

Open side of caged bearings faces spindle bearing race.

There is one possibility that hasn't been mentioned.

If the faces of the bb shell are not parallel, the lock ring has a pretty good chance of loosening up.

"Facing" or milling the faces of the shell removes the paint and excess metal. It allows the lock ring a
smooth surface to rest against.

Tools are expensive for this, but it is truly the best way to get top performance out of
any bb or headset- especially precision versions.

rusty

This could be it. I was under the impression from the RJ video that all bottom bracket bearings fit with the open end of the cage towards the cup. I will check it today

@robertj298 - Assemble the bearings on the spindle before installing to test the ease of rotation of the caged bearings. The cage should not touch the spindle at all. Then check by adding the NDS cup and apply pressure to the bearing while you turn it. Flip the cage and do it again. One configuration will be much smoother than the other.

More ideas here https://www.bikeforums.net/bicycle-m...sening-up.html and https://www.bikeforums.net/bicycle-m...direction.html

And remember, RJ is a hack. He's mostly effective, but a hack nonetheless...

With cup and cone BBs, you want the adjustment to be a bit on the tight side.

The other suggestions here are good and you'll have to work your way through them.

True for 9-ball retainers, but not 11-ball retainers, as @Dfrost notes above.

Hats off to SurferRosa From videos and all my other bikes I have done I
just assumed the bearing cage went in with the open side facing the
cup not the other way around. Guess I'll know the next time

^ we have all made that mistake once.

Maybe make a mark on the BB aligned with one of the holes in the adjustable cup once you've got it tightened down, and see whether the hole moves?

Not me, no sir, uh-uh.

More than once...:innocent:

Only once then came up with the process in my previous post. Works every time, but I usually replace with loose balls.