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Lapping hydrostatic pump plates

gmark1

Plastic
Joined
Mar 7, 2020
I’ve got some Eaton 5.4 hydrostat pumps that are a little low on pressure, and want to take the seal plates, and slippers out to try lapping them, hoping to up the pressure. From my research, I haven’t found the steps involved, I.e., kind of grit used, and grit sizes when doing hydrostatic pumps like these. I assume silicon carbide for the hardened steel plates, and aluminum oxide for the brass. Have no clue what grit sizes, and such. Any advice is appreciated.
 
Been there,done that.....dont waste your time ....the "brass" is bronze sinter coating.....once scored its cactus....Eaton (and others) are very cunning and the cost of one part is more than a new pump......
 
I had some Monarch hydraulic pumps for my snow plow on a pickup years ago and I tried to grind and lap the plates and gear to no avail. I ended up buying a new pump.
 
I used to do hydraulic repairs and rebuilds.....the only thing can be done is to lap the rotor (hard steel) on a Lapmaster ....any attempt on a surface grinder will heat check the surface .....the valve plates are sinter ,and very thin coating as well.....any scores will be through the critical spots where the leakage path is shortest.......and as I mentioned ,spare parts are more costly than a new pump.
 








 
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