Bicycle Mechanics - Hi, how do you fix the cap that covers the ball bearings on the front wheel?

I recently bought a used 1999 cannondale m400.
The only thing I see wrong with it at this time is the front wheel. There is a flat cover and isn't tight onto the hub that covers the ball bearings and I believe it's getting dirty inside there.
I tried plugging the cap back inside but it won't stay. Does anyone know how to fix this problem on my own?
Do I need a new wheel or do I need a new hub?

Sorry I'm new to mountain biking and want to learn what I can so I don't have to take it to a bike shop. Thanks.

I recently bought a used 1999 cannondale m400.
The only thing I see wrong with it at this time is the front wheel. There is a flat cover and isn't tight onto the hub that covers the ball bearings and I believe it's getting dirty inside there.
I tried plugging the cap back inside but it won't stay. Does anyone know how to fix this problem on my own?
Do I need a new wheel or do I need a new hub?

Sorry I'm new to mountain biking and want to learn what I can so I don't have to take it to a bike shop. Thanks.

Is it a steel or rubber seal? If it's steel, try gently bending the edge of the cover outward so that it's a tighter fit. It won't need much. Then use a rubber mallet to put it back in place. Don't go caveman on it. You should just tap it into place.

It it's a rubber seal, it's probably decayed and you'll need a new one. Try a local shop.

Is it a steel or rubber seal? If it's steel, try gently bending the edge of the cover outward so that it's a tighter fit. It won't need much. Then use a rubber mallet to put it back in place. Don't go caveman on it. You should just tap it into place.

It it's a rubber seal, it's probably decayed and you'll need a new one. Try a local shop.


Its steel. I'll try what you said but should I first clean out the bearings and then relube it? What do I use to relube the bearings? Will any heavy lubricant work like lithium grease perhapS?

The cone should hold this in place... ideally the cone should go through it and the sheild then jam on the smooth edge of the cone. If it is working lose the hole in the sheild (that the axel fits through) is probably worn, it should not fit over the cone... but jam on it. In short as the wheel turns, the axel, cone and sheild should not... the cup turns around the sheild.

Lithium grease is fine, but a marine grease is better.. it is more water resistant.

Lithium grease is fine
:eek: Lithium grease?!?!:eek:
I always read on here that Lithium grease was very baaad!:D

The cone should hold this in place... ideally the cone should go through it and the sheild then jam on the smooth edge of the cone. If it is working lose the hole in the sheild (that the axel fits through) is probably worn, it should not fit over the cone... but jam on it. In short as the wheel turns, the axel, cone and sheild should not... the cup turns around the sheild.

Lithium grease is fine, but a marine grease is better.. it is more water resistant.

The type of seal he's talking about is a metal ring that is press fit into the hub and doesn't really make contact with the cone or axle nuts. It's not meant to turn with the axle but just to shield the bearings from spray. It's not really a seal, per say.

As for grease, buy a tube of Phil's grease or Park. It'll last for years. A tub of marine grease is okay but it will last for several lifetimes:D

The type of seal he's talking about is a metal ring that is press fit into the hub and doesn't really make contact with the cone or axle nuts. It's not meant to turn with the axle but just to shield the bearings from spray. It's not really a seal, per say.

As for grease, buy a tube of Phil's grease or Park. It'll last for years. A tub of marine grease is okay but it will last for several lifetimes:D
Yes, that is what I thought he meant too. I will add that some hubs have that setup with an actual neoprene seal that is fitted into the hole in the pressed in metal piece. I am not sure how common this is, but I have a nice set of early 80's Nashbar hubs like that.

:eek: Lithium grease?!?!:eek:
I always read on here that Lithium grease was very baaad!:D

Oh give over! :D :lol:

If like me you relube every 6 weeks there is nothing wrong with Lithium Grease! It could even last longer! :D

But... use a real water resistant grease (like marine grease) and it will last ... um... a year even! ;)

Anyway, as regards the bearing sheild. I fess up, I got the wrong end of the stick. I have never seen that type of sheild... all of my bikes have had the fixed sheild, but most of my bikes are cheap! :D