Massey 135 hydraulic pump?

tessiers · Apr 25, 2015

I have a 1970 MF135 Perkins diesel. Last year my hydraulic pressure was at about 300 psi give or take, I bought a rebuilt pump and installed it and everything worked great PSI over 2000. Over the course of the year, maybe 200 hrs. the pressure has slowly dropped to 500 psi again. Is there anything else could be causing my troubles? I have checked the filter several times. Pressure relief?

J_J · Apr 25, 2015

You probably need a flow and pressure check on your hyd system.

It will tell you the pumps condition.

If your pump is good, then check for valve leakage or cyl leakage.

A pressure gauge might help you troubleshoot the hyd system.

tessiers · Apr 25, 2015

I have a pressure gauge, plugged into my hyd outlet it reads 500psi currently. That is the outlet to the lift cylinder on the mower conditioner. There is a valve, but there is no cylinder in the system. Not sure how to check flow, I really don't care about that, I only use a 2x10 cylinder to lift the mower. All my other tractors lift it with no trouble.

J_J · Apr 25, 2015

draulics:
Capacity: 8 gal [30.3 L]
Pressure: 2800 psi [193.1 bar]
Pump flow: 4.5 gpm [17.0 lpm]
Total flow: 4.8 gpm [18.2 lpm]
Oil type:
MF-1129

When you max out any cyl, if the pump is good, you should show 2800 psi on the hyd gauge.

If not, then something is leaking. Relief valve, valve spools or cyl seals.

So if you only see 500 psi max, then you need to start looking for the cause.

Take a 5 gal bucket and mark it in 1 gal increments.

Run engine to max and pump flow into bucket.

If you can pump 1 gal in 13.33 sec, then your pump is pumping the correct flow.

tessiers · Apr 27, 2015

I'll try the flow test, simple as that is I never thought of it. I hate to think of it but I think I got a bad pump, called the shop they say they will go good for it, just sucks having to tear it down again. Plus I wish there were a way to test the pump once its out of the tractor. The tech told me he has very few pumps get returned but it is possible, he has no way of testing without tearing down.

J_J · Apr 27, 2015

You say are using a hyd shop that can not test a pump.

All one has to do to test a pump is to install a flow meter, a pressure gauge, a relief valve and a needle valve .

If you know the pumps rated GPM, and pressure, you can seethe results by turning the pump and adding a load by turning the needle valve closed, if the pump is pumping at 75% or above, you have a usable pump.

tessiers · Apr 28, 2015

The pump does not have an inlet outlet they can connect to, it requires the pump to be submerged in the tractor housing and the top cover to hold the stand pipe into the pump. I am sure they could figure something out, but how accurate and to what end. This is an internal pump, no threaded connections.