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500 Hour Service Interval Guide for a Yanmar C50R Crawler Carrier – Part 2
Written by Luis Montes Updated On February 24, 2025
We previously replaced the engine air and fuel filters on a Yanmar C50R crawler carrier as part of the 500 hour service interval.
In this post, we’ll cover how to change the hydraulic filters (case drain and main filters) and fill the hydraulic oil.
You can also see the whole process on our Tekamo HD YouTube channel. Check it out.
PPE Recommendations for Working Under Heavy Equipment
For situations where you need to work underneath a piece of heavy equipment, Shawn recommends the following:
- A coverall (mostly to protect your clothing).
- Safety glasses to prevent debris, chemicals, or oils from coming into contact with your eyes.
- Gloves or PR88 cream to protect your hands (and forearms) from oil, gasoline, grease, etc.—our article “Komatsu PC200LC 1000 hour service part 2” offers more info about PR88 cream.
- There are several falling and bumping hazards underneath a machine. A hard hat is highly recommended, but you can also opt for a bump hat, which is more compact.
Safety Measures Before Doing the Tasks
To access the hydraulic tank on the Yanmar C50R, you must turn the dump bed sideways and remove a panel.
Photo source: www.ritchielist.com.
We “neutralized” the dump box with a lock bar to prevent it from coming down accidentally.
As an extra safety measure, we placed lock-out tags and disconnected the battery from the Yanmar C50R to ensure nobody would start it. To prevent sparks, start by disconnecting the negative terminal. We’ll get back to this topic toward the end of this post.
Install the Hydraulic Oil Return Filter
Be careful when removing belly pans. They are quite heavy. By eyeballing the image above, the belly pan (50 in x 20 in x 1/32 in) for the Yanmar C50R could weigh approximately 65 lbs. In addition, dirt sometimes builds up on top of the pans.
Lubricate the rubber seal. A dry seal would stick when installing the filter. Oil helps it to slide a bit on the mounting surface and compress, thus giving you a better seal.
Unlike the engine oil filter for the Komatsu PC200LC, Shawn didn’t prime the hydraulic oil filters for the Yanmar C50R. Why?
The first reason is that the filters protect different systems.
Many people prime engine oil filters for fear of excessive wear, while others don’t for fear of contaminating the engine system. However, as our Komatsu PC200LC 1000-hour service article discusses, even manufacturers don’t entirely agree on this topic in their equipment manuals.
In this case, the filter is in the return line, no sensitive pieces are in the reservoir tank, and the oil will go through the main filter further down the line.
Install the filter by hand, turning it clockwise. As we encourage and recommend in most articles, don’t install spin-on filters using a filter wrench.
Install the Hydraulic Oil Main Filter
Turn the housing counterclockwise to remove it.
Check the condition of the O-ring on the housing base (see the image below).
An O-ring in good condition is pliable and has a rounded cross-section, while a worn-out O-ring is hard and brittle, with a D-shaped cross-section.
Check also for cuts and cracks in the O-ring. They significantly reduce its sealing ability.
Push the filter and thread back on the housing.
You can use a ratchet to reinstall the main filter housing. There’s no need to tighten the crap out of it. Turn the housing until it’s properly seated and snug.
Fill the Hydraulic Oil
To unscrew the vent cap on this machine, you’ll need a 1 1/2″ wrench.
We like using one of those funnels with a screen to prevent contaminants from entering the hydraulic system.
The Yanmar C50R’s hydraulic tank capacity is 9.2 gallons (35 liters). We top it up with Tekamo brand AW 46 (anti-wear with a moderate viscosity). Aim the oil level between the top and bottom marks of the sight glass.
The vent cap of this Yanmar C50R had thread tape on its vent cap. Shawn, who has more than 25 years of experience as a heavy-duty mechanic, says it’s a good practice to put thread sealant to guarantee that incoming air passes only through the screen filter and not through the threads as well.
The correct way to apply the sealant tape is to do so clockwise to the direction the threads face you. Doing so will keep the sealant from bunching up or peeling off.
Tidying Everything Up
To wrap up the service on this crawler carrier, we reinstalled the battery and the cover on the hydraulic oil tank.
The Yanmar C50R is 24 volts. For such starting systems, the proper sequence is to connect the 12 volts batteries in series, as the image below shows.
Since the negative terminal is connected to the machine’s body, the whole machine is essentially the negative terminal. Connecting the positive terminal last and touching the machine’s body with your wrench will create sparks.
So when reinstalling the batteries, reconnect the ground cable last to leave the circuit ungrounded (open) and avoid creating sparks—the same thing when you’re boosting a machine, as Cam explains while recharging a drained battery on a John Deere 135G.
The last step is to turn the dump box sideways to install the top panel. You can watch the process on YouTube.
All in All
Visit the Fortis HD blog for more service interval posts.
Be sure to read the previous post, which covers other tasks for the Yanmar C50R 500 hour service interval. In it, we explain how to change the engine air and fuel filters.
