Contact me HERE if you have any questions


Hydraulic Circuit Modifications

As shown in my previous post (shown HERE), I needed to modify the hydraulic system to meet my needs. Basically, I'm taking out the extra pump and valve sections that were use for the three reels. I only need 3 pump sections (out of the five) and 2 valve sections (out of the five).

Here is what the valve sections looked like originally.

From left to right,
  • Drive control valve
  • Reel valve
  • Reel valve
  • Reel valve
  • Lift/lower cylinder valve
  • Relief valve
The lift/lower cylinder and the right most reel valve are fed from one pump section. This enters the relief valve on the right and is passed through the lift/lower cylinder valve to the reel valve. This is very important because the left most reel valve also passes through to the drive control valve. This provides the second speed (additional flow) when actuated. Since I'm removing that valve, I'm glad that the lift/lower valve that is staying will have the same function.

This is what it looks like after removing the three unneeded valve sections.

Next up is the pump. As discussed in the previous post, there are 5 pump sections. I plan to cut out 2 of them. What will remain is the larger pump section for the main drive, and two smaller sections (one for the lift cylinders and the other for the hydro steering). 

Here is what the pump looked like originally.

The first two sections share a shaft and the remaining three sections share a shaft. Both of those are joined by a splined dowel. Since I will be removing two sections, I needed to cut down the shafts. 
First up was disassembly. The four sections shown below will be removed. 

I then mounted each shaft in the lathe and used a cut off wheel to cut the hardened shafts.

I used my wife's nail polish to mark the mesh as it is recommended in the manual to do so (all of my paint pens were dried up). After I was done, everything was cleaned in the parts washer and reassembled and the pump was reinstalled. 

After reassembly, everything works as intended. I didn't doubt that since I had access to the Jacobsen manuals that provided a ton of detail. Now that this step is out of the way, I can begin disassembly of the entire mower. The next step is going to be getting a decent model of the engine so I can finish the design. I have a lot to fit in a small space and I'd really like to know how the engine is going to fit. I'm either going to try photogrammetry, or find someone to 3D scan the engine for me.