Allis Chalmers D272 Hydraulic pressure

[Mic736]

Hi

Does anyone know the hydraulic pressure of the lift on the Allis Chalmers D272 tractor, built in England?

I could not find this pressure to check my hydraulic pump

Any help would be appreciated

 

[Jim.ME]

Hi

Does anyone know the hydraulic pressure of the lift on the Allis Chalmers D272 tractor, built in England?

I could not find this pressure to check my hydraulic pump

Any help would be appreciated

Check your pressure and post what you have for pressure. You don't need to know the spec to see what you have currently.

 

[Mic736]

The relief spring was broken. Put a new one and i have 220 bars ( 3200 PSI) . But may be it is to high. The cylinder bore diameter is 3". So the power is 9.6 Tons on the cylinder. It is very high for this small tractor. I don't want to broke the cylinder frame.
It is why i would like to know the spec.

 

[Bob Bancroft]

The relief spring was broken. Put a new one and i have 220 bars ( 3200 PSI) . But may be it is to high. The cylinder bore diameter is 3". So the power is 9.6 Tons on the cylinder. It is very high for this small tractor. I don't want to broke the cylinder frame.
It is why i would like to know the spec.

That sounds like a good number for the piston pump system common for AC at the time, but if it's a gear pump, that is high. I don't know if this tractor design is related to the ED40. I've read that the ED40 did indeed have serious issues with catastrophic breaking of the lift mechanism.

 

[Mic736]

It is a 2 pistons pump system , like model B and C .
Lift mechanism is similar than the ED40 one

 

[Bob Bancroft]

That sounds like a good number for the piston pump system common for AC at the time, but if it's a gear pump, that is high. I don't know if this tractor design is related to the ED40. I've read that the ED40 did indeed have serious issues with catastrophic breaking of the lift mechanism.

Norm Swinford's book makes no mention of the D272, at least that I could find. He does state that the ED40 had a crankshaft driven hydraulic pump with a system pressure of 2650 PSI. He further states that a valve was the repair for the hydraulic problem. But I don't know if the operating pressure was lowered, or if the original valve was sticking and exceeding the system design pressure.

 

[Bob Bancroft]

It is a 2 pistons pump system , like model B and C .
Lift mechanism is similar than the ED40 one

I don't know what to tell you. The cylinders used on the high pressure system were typically a lot smaller than 3 inch. With your figures I come up with 11.3 tons. I think I'd do something different with the relief spring to back the pressure down to the 2000 PSI range.

 

[4wdtom]

Hi

Does anyone know the hydraulic pressure of the lift on the Allis Chalmers D272 tractor, built in England?

I could not find this pressure to check my hydraulic pump

Any help would be appreciated

You have little to loose if you try a weaker spring. If things don't work as they should, that is the hydraulics don't lift what they should that is a sign you need more pressure but it won't hurt to try the system with less pressure.