Equipment Care & Repair

Ride-On Scraper Hydraulic Leaks and Weak Lift

Hydraulic fluid, levels, filter intervals and the usual causes of leaks and slow or weak lift on National ride-on scrapers.

Updated · 2 min read

Most hydraulic problems on a ride-on scraper are low fluid, old fluid or a leaking fitting. Pumps and valves do fail, but check the simple things first. Figures below come from the National ride-on manuals.[1][2][3] Use the manual for your model and serial range.

Safety

Lower the head, shut the machine off and disconnect the battery before working on hydraulics. Never check for leaks with your hand. Use cardboard; pressurized fluid can inject through skin.[1]

Fluid and level

Low or wrong fluid causes most slow and weak lift. Use Texaco Rando 46 hydraulic oil, or a compatible ISO or AW 46.[1] The 5000 and 5700 hold 6 gallons, and a change takes about 5.5.[1][2] Check the level at the fill hole; the oil should show 1" below it.[1]

Service intervals

This is the schedule for the 5000 and 5700.[1][2]

When What
First 100 hours Replace the filter
Every 200 hours after Replace the filter
500 hours Change the fluid

More in Ride-on scraper daily and weekly maintenance.

Leaks

The troubleshooting guide points to four causes.[1] Tighten loose fittings with the correct wrench, without over-tightening. Coupling leaks usually mean missing or damaged O-rings, and a pinhole in a hose means replacing the hose. Replace old oil and the filter yearly if the hours don't come up sooner.

Slow, weak or jerky lift

The manuals don't have a single entry for weak lift, so work through the likely causes in order.

  1. Check the fluid level and condition, and top up or change it.
  2. Check the filter, since a clogged filter starves the pump.
  3. Look for leaks at hoses, fittings and cylinders.
  4. Make sure the battery is charged; low voltage slows the pump motor.
  5. If the movement is jerky, slow down on the levers. Moving them too quickly causes it.[1]
  6. On the 5700, check the dual lift adjustment.[4]
  7. If all of that checks out, the pump or valve may be worn; there's a video on replacing the pump and motor.[5]

Don't adjust the relief valve to fix weak lift. On the 5280, it's set at the factory and shouldn't be touched.[3]

Common mistakes

These make hydraulic problems worse.

  • Mixing fluids. Stick with ISO/AW 46 or a compatible oil.
  • Overfilling. Fill only to the level at the fill hole.
  • Reusing O-rings. Replace them whenever you open a fitting.
  • Turning up the relief valve. It's factory-set and shouldn't be adjusted.[3]

Parts we carry

These are common hydraulic parts for National ride-ons.

References

  1. National 5700 operating and service manual
  2. National 5000 operating manual
  3. National 5280 operating manual
  4. National Flooring Equipment video: 5700 adjusting the dual lift
  5. National Flooring Equipment video: Replace the hydraulic pump and motor

Linked PDF documents are archived copies saved by PreFloor Tools so they stay available if the publisher moves or removes them. Check the publisher's website for the latest revision.

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