Need help with Piston / Gear pump seal leak?

[joshlee]

I'm trying to understand why the paper gasket in-between the Piston and Gear pump leaks? What I mean is, where is the oil exactly coming from, because after looking at pictures on these pumps, it looks like there should be no oil where they connect at.

Thanks for reading and any advise will be helpful.

Josh

 

[MossRoad]

You sure its coming from there and not migrating from a fitting?

 

[joshlee]

Yep, its definitely coming from that paper gasket. My 425 and 1430 both have small leak there. I'm taking the 425 one apart tomorrow and putting a new gasket in. I don't think it will fix the problem, but that's what Terry told me to do. He obviously knows way more about these machines than I do.

 

[MossRoad]

Best of luck.

 

[joshlee]

After seperating the two pumps, I was amazed to see a big rubber O-ring in there. Knowing that fluid doesn't get past a rubber O-ring, I noticed that the one side of the O-ring was up against the steel housing on the Piston Pump, and the other side was against the paper type gasket, which had no type of sealant on it. I'm used to the O-rings being between metal or plastic parts, so I talked to a guy down at the New Holland/ Yanmar dealer, and he said they are big fans of this gasket material for something like that. So, I have the O-ring stopping the oil, and this as a gap filler and a back up (with no paper type gasket) incase something were to get past the ring. The oil was coming from the Tram. While having the pumps separated, there was a very, very small amount of oil coming out. I'm thinking its suppose to be there for lubricating the spline shaft on the gear pump. Also, seeing that O-ring tells me that there is suppose to be oil in there. I won't change the one on my 1430; the reason for doing this to the 425 is because I was curious to what and how it was leaking.
The stock gasket on this oil tank was a paper one and it leaked, until I fitted it up with a cork/rubber on and some silicon.