SAME Explorer 85 special 4wd

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It was still running smoothly with a blown head gasket on number 2; I don't know how that's even possible.

The tin is looking pretty bad, OH insists I fix that.

 

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Engine reassembly is stopped while I wait for the last little gasket.

So here is some of the hydraulic system upgrades I made, which could be of general interest. I did these over some years, but I'll start at the front end.

The European version of the Mercury 85 shipped with a 14cc pump, the US version had a 19cc pump.

I changed my 14cc for a 22.5cc that I found online.

Just in case anyone wants to know, I spent a long time figuring out the hydraulic pumps.

Same Mercury hydraulic pump info;

Pump gear is 1.27/1 over crankshaft speed; the repair book gives wrong numbers.

Pump has a 9 spline shaft, and “Euro 2” mounting flange with centering collar.

14cc pump [European versions, including “Special Export”] sdf part number; 2.4539.410.0 Bosch number 04394801

19cc pump [US versions] sdf part number 2.4539.430.0 Bosch part number; 0510625332

22.5cc Bosch / Rexroth number 0510725348 [will bolt on].

I wanted to be able to run the engine slower while using my hydraulic hedge cutter, and it works much better now. However, the original SAME auxilery hydraulic block behind the seat can barely even handle the EU pump volume. It's just really small, I believe it was held over from previous models that had lower oil volume. More on that later.

 

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The hydraulic pump feeds a long steel tube that runs to the rear valve block; I rerouted it to run to a 3 lever valve block near the steering wheel for the front end loader and hedgecutter (and whatever comes later).

First, I made a tubing bender that mounts on my workbench for the heavy hydraulic tubing.
I made replacement fitting where the old tube joins, with a 1/4" side port for a dashboard gauge.
The SAME used 18mm tube but I could only source 16mm, so I made an adaptor sock to braze on.
The tube is a bit squirrely to get around the clutch pedal movement.
The outlet of the new valve block feeds the original one at the rear; later on I changed to a steel tube and added a priority flow valve to solve the restriction problem.

 

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After I added the system pressure gauge on my instrument panel, I saw that pressure would go really high when RPM was up. It rose in a linear pattern, clearly a flow restriction. I did some testing to find out where the problem was; disconnecting the lines and running the oil into a bucket.

Unfortunately, I can't find my notes at the moment with the actual numbers; but the results were clear. most or the restriction was the original SAME auxiliary valve block behind the seat, and the 3-point lift was restrictive as well. With my new pump and increased volume, it was really robbing power. At full engine speed, back pressure was almost 50 bar 700psi!

the flow is too tight for even the 14cc EU pump, and the US pump is 19cc. As stated above, I've put a 22,5cc pump on my tractor.

So I went to my workshop and made the fittings, bolted my bender to the bench and bent the tubes, then brazed it up.

 

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With the priority flow valve installed, no-work pressure tops at 20 bar; still quite a lot of wasted energy, but much better than before.

The next thing I did was swap out the many different flexible tubes that had built up over many years, to a common fitting. I put in steel tube wherever possible, in a way that all the flexible hoses are now all alike and interchangeable; so I can keep a couple of spares.
Before, when a hose would give way the whole tractor might have to stop until I had a replacement made. Usually, this would happen on a Saturday afternoon so I'd be stuck until Monday.
Especially tricky was the 4 hoses to the FEL, that all had to curve one inside the other. I made some diabolical adaptors for the valve block to make it work. All hoses are 1/2", 1 meter long, straight at one end with a 90 degree elbow at the other.
I did this a year or two ago and it's all been working well.