Leaking main seal again/Dead ring?

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Kamikazz
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Leaking main seal again/Dead ring?

Post by Kamikazz » Mon Sep 24, 2018 11:22 am

Hello guys,

I have a Patrol 2006. Two years back (20k KM), I change piston, rings, oil pump, gasket, flywheel, clutch and all bearing after the bearing's crankshaft exploded.
I changed the carbs's needle around 26k KM.

I am now at 28k Km and since this summer, I changed twice the main seal. I found out the new pad's on the new clutch is broken too... I am running with Old disk clutch and One new disks for now...

Soo, yes, I changed the main seal twice this summer because that was leaking inside the clutch. And still leaking even with new seal...

I try to understand what could be the problem. I suspect the ring, because the oil dipstick start to pop this summer. I pass a pipe in the oil's hole to keep the crankcase at nearly zero pressure at that still leaking after a ride...(That was only a test)

I got 115/120PSi on Left and Right cylinder. I don't feel low power and there numbers are the same after my rebuild. They didn't changed.

What test can I try to find out the problem? If the is the ring, can I simply order new pistons or I will need cylinder too (that will be the second hone they will receive!)?

Thanks guys!

PS: Yvan's idea to get nearly zero pressure in the crankcase case.
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Ural Patrol 2006
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VWK75S
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Re: Leaking main seal again/Dead ring?

Post by VWK75S » Tue Sep 25, 2018 4:27 am

Kamikazz wrote:
Mon Sep 24, 2018 11:22 am
because the oil dipstick start to pop
Please explain?
John
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Re: Leaking main seal again/Dead ring?

Post by Kamikazz » Tue Sep 25, 2018 8:41 am

The dipstick uncrew himself and pop out from his hole.
Ural Patrol 2006
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Re: Leaking main seal again/Dead ring?

Post by hotflash44 » Tue Sep 25, 2018 9:17 am

check this video on the rear seal might help there is a right way and a wrong way to install, also check your crank case breather might be in bad shape sound like a pressure issue to me. link lemoto.info/c4%3A-engine also myural.com/crankcase&covers.htm :cheers:
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Re: Leaking main seal again/Dead ring?

Post by stagewex » Tue Sep 25, 2018 10:41 am

I don't understand the picture. Your dipstick unscrews itself and pops out so you did this?
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Re: Leaking main seal again/Dead ring?

Post by hotflash44 » Tue Sep 25, 2018 11:27 am

stagewex wrote:
Tue Sep 25, 2018 10:41 am
I don't understand the picture. Your dipstick unscrews itself and pops out so you did this?
not talking for Kamikazz, but i think he was trying to re route excessive crank case pressure. he said it was a test. anyway if the CC pressure can make the dipstick unscrew itself i would be amazed, anyway as the beat goes on :lurker:
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Re: Leaking main seal again/Dead ring?

Post by jaybird » Tue Sep 25, 2018 1:37 pm

hotflash44 wrote:
Tue Sep 25, 2018 11:27 am
stagewex wrote:
Tue Sep 25, 2018 10:41 am
I don't understand the picture. Your dipstick unscrews itself and pops out so you did this?
not talking for Kamikazz, but i think he was trying to re route excessive crank case pressure. he said it was a test. anyway if the CC pressure can make the dipstick unscrew itself i would be amazed, anyway as the beat goes on :lurker:
The older metal dipsticks do sometimes loosen up and come out when the engine is running, not so much with the newer plastic ones.
Why don't you two go unscrew your dipsticks while the engine is running and report back, it would probably benefit the OP to know what you find.

Happy trails,
Jaybird
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Re: Leaking main seal again/Dead ring?

Post by hotflash44 » Tue Sep 25, 2018 2:32 pm

jaybird wrote:
Tue Sep 25, 2018 1:37 pm
hotflash44 wrote:
Tue Sep 25, 2018 11:27 am
stagewex wrote:
Tue Sep 25, 2018 10:41 am
I don't understand the picture. Your dipstick unscrews itself and pops out so you did this?
not talking for Kamikazz, but i think he was trying to re route excessive crank case pressure. he said it was a test. anyway if the CC pressure can make the dipstick unscrew itself i would be amazed, anyway as the beat goes on :lurker:
The older metal dipsticks do sometimes loosen up and come out when the engine is running, not so much with the newer plastic ones.
Why don't you two go unscrew your dipsticks while the engine is running and report back, it would probably benefit the OP to know what you find.

Happy trails,
Jaybird
or better yet you do it and send pictures :cheers:
2016 gear up asphalt grey, name Seryy Medved ,Air America CIA circa 1967/8 Vung Tau Viet Nam USS Tutuila ARG-4 (AND JUST A TOUCH OF AGENT ORANGE!)

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Re: Leaking main seal again/Dead ring?

Post by Msblu79 » Tue Sep 25, 2018 3:28 pm

A leakdown test of the rings would tell you if they are working or worn badly. Put the cylinder at TDC, valves closed and pressurize the chamber with comressed air and see if it holds for at least a minute or so, if it bleeds down quickly they may be worn enough to cause the pressure blowby at the breather & seals.
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Re: Leaking main seal again/Dead ring?

Post by Snakeoil » Wed Sep 26, 2018 11:45 am

I agree that pressure did not unscrew your dipstick. If you want to keep it in place, replace any metallic sealing ring with a properly sized Viton O-ring and it will stay put.

Your linked breather probably did not accomplish much if the ability to breath was limited by the ID of the breather hose. You would have been better off running two separate hoses, both running to atmosphere to increase crankcase pressure reduction.

The leak might be caused by seal placement. It took a while to pry the answer out of the experts here. Gobium likes to challenge folks to figure it out on their own. But, the length of the sealing surface on the flywheel is somewhat short which means if you drive the rear seal into the bearing carrier too far, it will not fully engage the sealing surface on the flywheel and hence leak. My 650 did not leak a drop until I rode it in very cold weather and then started to drip. I actually remembered installing that seal and there being no step to drive it against. I did install mine a tad deep and think that is why it leaks a bit.

If you replace the seal again, I would suggest you install the seal to be flush with the face of the bearing carrier surface. So install it with a flat piece of wood or metal so that the it stops at that surface.

Take pics if you go back in to replace that seal again. I think photos would be helpful to others in the future. I probably should check BillyG's site for such photos. They may already be there.
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Re: Leaking main seal again/Dead ring?

Post by jaybird » Wed Sep 26, 2018 12:36 pm

The base pressure and the seal leaking are likely unrelated, as Snakeoil said, the seal may be improperly installed or, it may be the incorrect seal.
Inviting hotspam and stagewex to remove their dipstick while the engine is running was not a trick question, it was instructional, and was meant to offer some useful feedback from other members to provide a base line to help the OP solve his problem.
I would urge all Ural owners to remove their dipsticks with the engine running just once, so they know what is normal and to avoid any extra drama and creative plumbing exercises later.

Happy trails,
Jaybird
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Re: Leaking main seal again/Dead ring?

Post by stagewex » Wed Sep 26, 2018 6:53 pm

Sure, I'll try it. It's never come loose or unscrewed itself ever before, and it is the old type original metal dipstick.
At idle of course.
Stagewex

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Re: Leaking main seal again/Dead ring?

Post by stagewex » Wed Sep 26, 2018 6:54 pm

Sure, I'll try it. It's never come loose or unscrewed itself ever before, and it is the old type original metal dipstick.
At idle of course.
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Re: Leaking main seal again/Dead ring?

Post by Kamikazz » Fri Sep 28, 2018 6:46 pm

Hello everyone,

The ghetto yvan's installation with the pipe in the dipstick was only a test... My idea was, if the ring leak and pressurize the crankcase, that may be why the seal leak... If I remove all the presure, may be I will confirm that is the ring. I try something and that doesn't work. In same time, I tested if the breather was the problem...

I received my leakdown test from Amazon today. I loose the intake pushrods to prevent the rotation of the engine.
That is hard to do over 75psi anyway... But the result are clear AND the engine was dead cold.

*** Result ***
Left Cylinder:
75psi In /69PSI Out +/- 8%
Right Cylinders:
75psi IN / 70PSI Out +/-7%

Left:
Image
Right:
Image

Mobil talk about 5 to 10% for a good working engine. Soo that is a perfect engine for Ural! I guess! :)
https://mobiloil.com/en/article/car-mai ... kdown-test
Last edited by Kamikazz on Fri Sep 28, 2018 7:27 pm, edited 1 time in total.
Ural Patrol 2006
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Re: Leaking main seal again/Dead ring?

Post by Kamikazz » Fri Sep 28, 2018 7:14 pm

For the placing of the seal, when I installed it for the second time. I use a piece of wood and gently push it to be flush with the bearing plate.

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Ural Patrol 2006
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Vespa V5B3T 1974

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