alpha 1 gen 2 not holding pressure

Jcris

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After replacing the water pump and putting the upper and lower sections of the drive back together the drive is failing the pressure test. It will begin to drop pressure right away. With the drive assembled it's difficult to see where the leak is coming from. I've sprayed a soapy solution on the fill plug and the area around the test fitting at the bottom and get no bubbles. Same with the shift shaft assembly. The only area I can't really see is the water pump. Can I pull the lower section off and test it separate without the upper installed. At least that would allow me to see better what is leaking. When I put the water pump back together I did not use any sealant on the gasket between the pump base plate and the gear housing. That gasket is metal and not the fiber type . Was that a mistake?
Jcris
On the off chance that the gauge I'm using was leaking I decided to put a better gauge on my pressure test set-up.
I put 15 psi on it and it's holding. I rotated the prop and the moved the shift shaft around. Fingers crossed. I'll check again in a few minutes
well it's not the gauge. so I separated the gear housing from the upper to inspect
This time I pressure tested just the gear housing expecting to see some sort of leak from the water pump area and saw nothing.
I did this by holding my finger over that small hole for the oil passage and it held pressure. Could the upper portion of the drive be leaking somewhere?
Please take a look at the seal that goes on the top of the base plate
It looks rather thin of sealant especially around the mounting holes
 
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Scott Danforth

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check the prop shaft seal as well
 

Jcris

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Jcris

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The old gasket's sealant was much more uniform all the way around the gasket
If this seal were bad is a likely cause of the leak?
 
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Bt Doctur

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There is no place for a leak at the water pump except for the seal between the units and the lower driveshaft seal under the steel plate. The GEN II cannot be tested as 2 separate units ,the driveshaft goes into a seal in the upper to seal it.
 

boatguya1

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Did you put in a new quad ring to seal the oil passage between the upper and lower? (hole you put finger over to test lower unit)
 

Jcris

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Yes i did install a new quad ring
Bt,
When I did the pump I did not use any sealant on the metal gasket that lays on the housing below the base plate. Was that a mistake? All I had in the kit was the new style metal gasket. The fiber gasket apparently has been discontinued
 

Bt Doctur

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Put muffs on the lower unit and see if any water leaks out from under the plate.As for sealants, you can`t go wrong using Permatex Aviation sealant
 

boatguya1

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Sealer there won't hurt but has nothing to do with failing the pressure test. If this is new enough to have a gearlube reservoir try spraying soap on the seal/ball/spring assy that seals the passage for the gearlube to enter the upper when putting pressure in the drive.
 

Jcris

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Thanks guy's,
I've taken everything apart and inspected it again. I'm frustrated and have put it to bed for today. Tomorrow I'll reassemble the water pump and use the muffs to check for leaks. This system does have a gear lube reservoir so I'll check that seal/ball/ spring assembly.
Jcris
 

Jcris

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Well I cleaned and inspected everything and put it all back together. Sadly it has failed the pressure test once again. Only this time it is readily apparent where it's coming from. After removing the oil seal carrier below the water pump assembly I took a close look at the drive shaft. It is nicked up in a couple spots that appear to be along the path of the oil seals. I can't express how disappointing this is. I must have damaged it when I was removing the old carrier.
What do I do now? Replace the drive shaft? That's a job I may want a repair shop do, but I'm unsure. I've looked at replacement cost of the drive shaft (p/n 11140) and the cost varies quite a bit. Anywhere from $175- $550 just for the drive shaft. This gear outdrive is 21 years old. It has a partially broken and bent skeg. If I replace just the drive shaft then I'm fairly certain the entire drive should be gone through. New seals, bearings and everything else inspected, which will drive the cost up and bring it closer to buying a new lower unit. I'm seeing new lower units available through SEI with 1:81 gears for $750 -$850 plus shipping. What do you guy's suggest? Is now the time to just replace the entire outdrive?
Jcris
 

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kenny nunez

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Here is what you can do. Smooth out the high spots . Measure the shaft and get a speedy sleeve to cover the bad spot. Be sure to put a film of sealer on the shaf first. Those things work great and I have used them many times.
 

Jcris

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A sleeve seems a workable solution but imperfections on the drive shaft are very small. The sleeve would have to be paper thin to accommodate the seals. Where can you get those sleeves? Maybe a website?
Jcris
I just looked at speedi sleeve and it may work. Still checking
This really looks like it might work and would save me a ton of cash
Now I need to accurately measure that shaft
Thanks for the idea Kenny
I just pulled the upper housing and disassembled the water pump. I've got a decent digital pair of calipers but it's difficult to get an accurate measurement as that "seal area" on the shaft is recessed. The initial measurement looks like .875
Is there someplace I can get a dimension on that shaft, like an exploded view with dimensions?
 
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kenny nunez

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I must admit that I never serviced a Alpha Gen2 as they had just started to show up when I retired so I am sure someone on this site knows the measurement. You only have 1 shot when installing the sleeve. Wrap a piece of tape around the sealing surface to protect it before installation. The sleeve comes with a short piece of aluminum tubing for installation, put an open end wrench over the top of the tube so that it can be driven down to seat the sleeve. Bearing supply shops usually have them.
 

achris

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You can pressure test the lower unit when seperated from the upper. It just involves covering and sealing the oil gallery, which is that small hole next to the water pump. I use the quad ring and a smal peice of flat steel and an 'F' clamp. Works well, and allows easy testing of the lower in isolation.

Chris......
 

Jcris

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Thanks Chris,
I've done something similar and haven't gotten any leaks from the oil seal below the water pump. Which eliminates the lower carrier seal as the issue. The shaft may be ok and the leak might be coming from the oil seal on the upper portion of that shaft. Is that possible?
 

achris

More fish than mountain goat
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...The shaft may be ok and the leak might be coming from the oil seal on the upper portion of that shaft. Is that possible?

Completely possible. Just recently repair a drive with exactly those seals leaking. If you're still looking for it, put the drive back together and pressure it up. Then turn the input yoke and watch the upper part of the lower drive shaft through the exhaust cavity... You'll see a small trace of oil or if you squirt it with the soapy water, bubble.... That's how I found the one I was working on.

Chris.......
 

Jcris

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I'll be checking that tomorrow
Thanks again Chris
 

Jcris

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Apr 23, 2016
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466
I've re-tested the gear casing and it does not leak, which is really good news. But the seals in the drive shaft housing will have to replaced. I've been trying to find a kit for this s/n 0F 845543 . This is what I've found:
[FONT=Verdana,Arial,Helvetica,sans-serif][COLOR=000000]26-88397A1 OEM
GLM 87501
Sierra 18-2644
Are these correct?[/COLOR]
[/FONT]
 
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