Ride-On Scraper Wheels, Casters and Wheel Motors

On a battery ride-on, the drive wheels, wheel motors and front caster take more abuse than anything except the blade. Carpet fiber and glue wrap the wheel motor shafts, the caster stops swiveling, and the machine starts fighting you. This guide follows the National 5700 and 5000 manuals, which use the same rear wheel and caster parts.^[1][2] Always check the manual for your model and serial range.^[3]

How the drive and caster are put together

Each rear wheel is driven by its own hydraulic wheel motor. The front of the machine rides on a single swivel caster. These part numbers come from the 5700 and 5000 parts lists.^[1][2]

Other models use different wheels. The 5600, 5625 and 7700 take the 5600-300 wheel, and the 8000 takes the 401697 wheel. Older casters (which are no longer available) that run two wheels on a center spoke take two 5200-194A wheels (4" x 2-1/4"). The current plate-mount caster takes the 403352 - all models use this caster. 

Every day: clean the build-up

The daily checklist includes inspecting the wheels, caster and wheel motors for build-up and cleaning them.^[1] Debris wrapped around the wheel motor shaft is the most common cause of a wheel problem.

1. From the back of the machine, look at the wheel motor and the wheel motor hub.
2. Pull out any carpet strands. Blow out dust and glue with compressed air at low pressure, not high pressure.
3. If that doesn't clear it, pull the wheel and clean the build-up off the wheel motor shaft.

Every month: grease the caster

Grease the caster fitting once a month so it keeps moving freely.^[1] Keep the caster clean so it swivels freely. A caster that still binds after cleaning and greasing should be replaced.

What it's telling you

Start with these checks before you order parts.

Pulling a wheel to clean the shaft

This is the manual procedure for build-up that compressed air won't clear.^[1]

1. Raise the front by lowering the cutting head all the way, or with a 2-ton jack. Place blocks under the forklift cup.
2. Slowly raise the cutting head until the machine rests on the blocks and the wheel on that side is off the ground.
3. Remove the cotter pin and loosen the center wheel hub nut.
4. If the wheel is stuck on the shaft, hit the steel rim from the inside with a rubber mallet.
5. Remove the wheel and clean the build-up off the wheel motor shaft.
6. Re-mount the hub so the keyway lines up with the key on the motor shaft. Tighten the hub nut to press-fit the hub.
7. Put the cotter pin back in, then lower the cutting head to lift the machine off the blocks. Repeat on the other side if needed.

Changing a rear wheel

The cutting head does the lifting, and blocks hold the machine while the wheel is off.

1. Push the cylinder lift lever forward. This lowers the cutting head and tips it to jack up the machine.
2. Place blocks under the forklift cups on the side you're working on.
3. Let the cylinder down so the machine rests on the blocks and the wheel is off the floor.
4. Remove the five 1/2" lug nuts with an extended-arm wrench and remove the wheel.
5. Mount the new wheel and tighten the lug nuts very firmly.^[1]
6. Raise the cylinder to lift the machine off the blocks, remove the blocks, and lower the machine.^[1]

Changing a wheel motor

Block the machine up as for a wheel change, and have a container ready for oil.

1. Disconnect the machine from power.
2. Block up the machine and remove the wheel.
3. Remove the oil lines from the wheel motor. A small amount of oil will run out; catch it in a container and wipe up spills right away.
4. Remove the four 1/2" wheel motor nuts and pull the motor out.
5. Install the new motor and reconnect the lines. Check the hydraulic oil level before you run the machine.^[1]

Never check for leaks with your hand. Use cardboard, because pressurized fluid can inject through skin. Fluid spec and change intervals are in Ride-on scraper daily and weekly maintenance.

Changing the caster

The front lifts on the cutting head, the same way the rear does.

1. Push the cylinder lift lever forward to jack up the front of the machine on the cutting head, then block it with a wooden block.
2. Remove the four bolts and pull the caster. Clean or replace it as needed.
3. Install the caster, pull it toward the rear of the machine, and tighten the four bolts.
4. Lower the machine.^[1]

Moving the machine without wrecking the wheels

Protect the wheels and caster whenever the machine is moved.

• Use the front transport wheel assembly. Raise the slide plate so its bottom is even with or above the guide channels (6" to 8" is ideal). Raise the cylinder, insert the assembly into the cutting head, and pin it. The casters should swivel freely, with the plate parallel to the floor.^[1]
• Tape the wheels with wide masking tape for move-in and move-out through finished areas.
• For transport, lower the cutting head to lift the machine off the swivel caster, chock the wheels, and strap it down. See Loading and transporting floor machines safely.

References

1. National 5700 operating and service manual (401809 Rev P)
2. National 5000 operating and service manual (403706 Rev F)
3. National Flooring Equipment manuals by model and serial range
4. OSHA: Control of Hazardous Energy (Lockout/Tagout)
5. OSHA 29 CFR 1926.417

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