Non drive side crank seal.

[Arron M]

How desperately do I need to replace this seal? Is the rubber part just a weather flap or is it part of the main sealing mechanism itself?

 

[RustyMTB]

I would do that sooner rather than later. Behind that seal you can see the yellow rubber o-ring/sub seal thing that forms part of the broken seal in your picture. Behind that in turn is a bonded seal. The whole assembly adds up to layers of protection against water penetration. @Bearing Man will sell you a kit for about £30 delivered with a tube of tacky grease that will restore the bike to how it came out of the factory.

You'll need a crank puller tool & snap ring pliers to remove the circlip that holds the broken seal in place.

Pro tip: If you diy it, the seal kit has plectrum like tools to lever out the seal. They're hit & miss as the seal can become pretty stuck on the shaft. You can use long nosed pliers to push against the inside wall of the seal & pull it off the crank shaft. It will be obvious when you see the seal. Just take care not to mar the crank threads machined into the crank spline.

 

[Mikerb]

How desperately do I need to replace this seal? Is the rubber part just a weather flap or is it part of the main sealing mechanism itself?
View attachment 102315

not something that can easily be replaced so a repair would be best. Try using some liquid gasket. Clean the area with some IPA on a cloth first, then smear some grease on the crank below the area where the black rubber seal part is missing and apply the liquid gasket. Do not disturb the crank until it has set. The grease will prevent it sticking to the cranks.

 

[Freeforester]

not something that can easily be replaced so a repair would be best. Try using some liquid gasket. Clean the area with some IPA on a cloth first, then smear some grease on the crank below the area where the black rubber seal part is missing and apply the liquid gasket. Do not disturb the crank until it has set. The grease will prevent it sticking to the cranks.

Sounds like a waste of decent beer!

 

[Spangoolies]

Depending on what motor you have:

Bosch Bearing Protection Ring Service Kit 4054289001247 | eBay

Service kit bearing protection ring BDU4xx. L1: 1x bearing ring 1.270.020.157, 1x circlip 1.270.016.112. L3: 1x bearing ring 1.270.020.156, 1x circlip 1.270.016.114, 1x tube of grease 20g.

www.ebay.co.uk

Allen key, Crank puller, a pair of circlip pliers and 30 mins of your time are all you need to fix this properly

 

[Arron M]

Thanks everyone, I have a seal on order and all the necessary tools

 

[Paulquattro]

Thanks everyone, I have a seal on order and all the necessary tools

Good glad to hear your doing it properly not botching it

 

[Freeforester]

Bodge, maybe, but don’t botch!