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500 Hour Service Interval Guide for a Ditch Witch SK755 – Part 5
Written by Luis Montes Updated On February 6, 2025
In the fourth post of this series, we serviced the engine air filter.
In this final post, we’ll change the hydraulic oil filter and top up the oil level on the Ditch Witch SK755 to complete the 500-hour service interval.
You can also watch Keith doing both services on the Tekamo HD YouTube channel of Keith:
The Usual Suspects
To unscrew a spin-on filter, you can use a strap wrench, filter pliers, or channellock pliers. Part 1 of this series explains the differences between each tool.
The SK755 hydraulic oil filter is lower than the hydraulic tank. Because of this level difference, plenty of oil will come out once you remove the filter.
The tight design of mini skid steers doesn’t leave space for a catch container or absorbent pads. In this case, the most you can do to minimize the inevitable, abundant mess is to have the new filter ready. Take the packaging off and lubricate the seal with a thin oil film (preferably fresh). Lubricating the seal will:
- Prevent it from biting as the filter tightens so it doesn’t rip or tear.
- Make it much easier to remove the filter on the next service.
Although we always recommend against using a tool to tighten spin-on filters in our blogs, we had to make an exception here because all the hoses in the hydraulic compartment were pressing against the filter, and hydraulic oil was leaking around it.
Close the hood, lift the safety bars, and lower the bucket.
Change/Top Off the Hydraulic Oil
The SK755 hydraulic oil capacity is 9.2 gal (35 L) of AW 46 (“AW” stands for “Anti-Wear,” and “46” indicates the oil’s viscosity grade according to the ISO standard).
The 20 L bucket of Tekamo oil we had for this service was hard to manipulate on this tiny machine, even with a funnel. For controlled pouring, 1 L containers or a pour jug (which we had) are better options.
Whatever your option, as you pour, keep an eye on the sight glass so you don’t overfill the tank.
The hydraulic oil sight glass is under the rear hatch (which you should have left open when you changed the inline fuel filter). It has a red floating ball to help you check the proper oil level. Add fluid until the level is halfway on the sight glass.
As Keith explains, overfilling the tank will cause excessive positive pressure and cause seal damage. On the other hand, a tank with a low oil level won’t have enough positive air pressure. Thus, the pumps must pull the oil, which makes them work harder.
Conclusion
Visit the Fortis HD blog for more service interval posts.
Be sure to check out the other posts we have in this series to cover every task for your Ditch Witch 500 hour service interval:
