Rebuilding A Hydreco Gear Oil Pump

[CapetaniosG]

Need to rebuilt a Hydreco oil pump. The pump is for an M20 Allison gear. Talked to Hydreco service people but no much help from them. The guy I talked to may had a fight with his wife that morning.

If I buy all the parts from DD how difficult would it be for me to rebuilt the pump using the Allison manual as a guide? Is there a shop that can do the repairs for me?

Thanks

capetaniosG

 

[wndsr]

I had a local hydraulic shop go over mine due to leaking oil. At the time he told me if it needed actually rebuilt with gears or if the housing was too badly scored, the cost to rebuild would be cost prohibitive. That is assuming I was getting the straight story. I have used this shop in Pa many times and have trusted them in the past.
Ben

 

[SereneWarrior]

I rebuilt one last year and found that it was not too difficult. The pump is operating just fine, so I guess I didn't do too badly. The rebuild kit is comprised mostly of seals and gaskets. It came with all the instructions I needed for the job which took me only one evening. I'd rate my mechanic's skills at average, so I'd bet you can do it yourself.

 

[Nonchalant1]

I rebuilt both of my Hydreco gear oil pumps for my 1978 Allison M20s on 8V71TIs. It's an extremely simple pump and easy to rebuild. They come off the drive easy, but on mine I had to remove the intercoolers to get the pump off. Intercoolers come off easily too (just hoses and 2 bolts). It's an eccentric cam pump (envision an old Mazda Wankel engine) directly driven off the blower shaft. It is a single milled body with 2 end plates and the cam drive. The pressure regs, etc. are all exterior mounted on the pump body and the pump itself is pretty bulletproof. About the only thing that goes wrong is the 2 big seals wear out or break. They're just bid O rings, which I ordered from Detroit Diesel. One is used as an O and one is bent into a rounded four point star by a channel in the pump body. Put in new seals, reassemble and you're good to go.

Doug Shuman