Allis Chalmers 715D Backhoe

rfazio · Oct 14, 2014

I was using the backhoe this weekend really for the first time. I got it cheap at auction and am realizing why. The hydraulics seem weak. It's a shame the unit looks pretty good everything works well otherwise. The backhoe bucket which should be the strongest thing on the machine is just weak. I would like to check the hydraulic pressure before I buy a new pump for the thing. I'm thinking to put a pressure gauge on it near the line that goes into the piston and read it when it stops under load and I have full open valve. Does anyone know what kind of pressure I should get from the pump? Supposidly Allis Chalmers used the Cummins motor in these backhoes from 1983 to 86? My engine was built 12/18/88. Makes me think it is an 89.

Bob Bancroft · Oct 15, 2014

My information shows the 715C used the AC engine 1982-1984. Prior 715 series used the Perkins. Anything after 1984 wasn't AC, as it had died, but the backhoes lived on.

There should be any number of spots around that machine where you can place a gauge. I assume it's a fixed displacement pump, with pressure regulated by a relief valve. I imagine 2000-2500 PSI would be the maximum.

Allis Chalmers 715D Backhoe

rfazio

Member

Bob Bancroft

Well-known Member

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