FD oil leaking into brakes

Are ya having a problem with your rig? We'll try to help. Share your tech tips and experiences here. Dr. Billy Glaser, author of the "Unofficial 750 Ural Service Manual" site myural.com, is moderating this section.
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Here is the place for you to ask questions about or share your experiences about servicing or repairing your Ural or Dnepr. Please post topics concering modifications or accesories in the "Modifications and Acessories" section. Please post oil related questions in the "Oil Threads" section.
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l3o
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FD oil leaking into brakes

Post by l3o » Mon Aug 19, 2019 11:21 am

I've got a 00 Bavarian with 1000KM on it. I just started riding it more than around town - expecting to find some bad seals. So far, there's a bad leak at the reverse lever - ordered new seal. Now, the final drive oil appears to be leaking into the rear hub/brakes, going up the spokes and coating the wheel. I have the wheel off, cleaned it out. I assume there's a seal under this flange - is that the culprit or something else? I was unable to locate it in a parts diagram - they all seem to be from the other side. So, what might be leaking?

Thanks. :bow:
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l3o
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Re: FD oil leaking into brakes

Post by l3o » Mon Aug 19, 2019 11:55 am

I took it off - seal seems to be in good shape, there appears to be a weep hole at the bottom of the flange. So, maybe it just spewed out oil by design?

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Re: FD oil leaking into brakes

Post by l3o » Mon Aug 19, 2019 12:12 pm

I think maybe there was too much fluid in there to begin with. My manual says 105mL, which when I fill it to that level, it's a bit lower than it was before it puked. It's just about to the bottom threads of the fill plug.

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Claus
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Re: FD oil leaking into brakes

Post by Claus » Mon Aug 19, 2019 12:16 pm

Yes, there´s a hole going to outside of FD and often gets blocked by brake dust and oil. Clean it out with brake cleaner/ compressed air.
When installing the seal, take good care of the seal spring! Put an thin plastic bag over the spline and oil it to beware cuts in the seal, carefully push the seal over the spline into the grove. Then take two tiny screw drivers and lift the seal to it´s seat out of the grove. Help it a bit by stabilizing with your fingers. Prior to mounting the shell, take a peep behind the seal´s collar if the spring is still in place.
If you do it the first time, it could be a PITA to get it right. But you´re getting used to it very quick...

Different to the specs in the manual you should take care to put only 90 cl (3 oz) of oil into the FD. This will help with your problem. (European manual says 115 ml (3.88 oz) and it´s too much, as well as US-manual saying 105 ml))
owned bikes: 93 Ural rig domestic model, 95 Suzuki DR 650 RSE, BMW R100GS, Suzuki GSX1100G rig, BMW R100R rig with Ural sidecar, Ural rig with BMW drivetrain under construction,

l3o
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Re: FD oil leaking into brakes

Post by l3o » Mon Aug 19, 2019 12:23 pm

That's good news. Thanks.

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Lmo
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Re: FD oil leaking into brakes

Post by Lmo » Mon Aug 19, 2019 1:42 pm

A couple of other things to consider:

Fabricate a 'vent' for the final drive > viewtopic.php?f=11&t=45551

Quick look at what's under that cover > viewtopic.php?t=46364&start=15
Lew Morris
Dnepr w/ '06 Ural Drive Train
C5 Power Arc
125/42 jets
Drilled slides/
.030" shims

1973 BMW R75/5 (original owner)
1947 HD FL (long gone, forever regretful)

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darkhorse
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Re: FD oil leaking into brakes

Post by darkhorse » Mon Aug 19, 2019 3:00 pm

I just had this problem on mine and it was the seal. Some refer to it as a pancake seal. I got the replacement from Holopaw. He had a kit with lots of seals that I have found useful to have on hand.
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