The 7 Most Likely Causes of a Stuck Walker Mower
If your mower stops working, you might assume the hydrostatic transmission is at fault, but there are actually several other potential causes.
When the hydro belt is worn, the tensioner pulley is broken, the idler arm spring is missing, the hydraulic oil level is too low or too hot, or air is trapped in the hydraulic system, a Walker mower will not move forward or backward.
Always use caution when tinkering with the hydraulics of a zero-turn or stand-on mower. Do not touch the transmission until it has cooled, and keep your distance from the hot hydraulic fluid.
Before doing any maintenance or repairs, make sure the ignition is turned off and the spark plug wires are disconnected.
Before diagnosing, repairing, or operating, be sure you’ve read and understood all of the safety recommendations in the equipment’s operator’s manual.If you are unsure of how to proceed, lack the necessary expertise, or are unable to execute the repair properly, you should seek the advice of a professional.
Table of Contents
The 7 Most Common Causes of a Stuck Walker Mower
1. Misplaced Drive Disconnect Switch
Putting the gearbox bypass levers or arms into the “bypass” position releases the hydros, allowing you to push the mower.
On each hydro, you’ll find a handle of some sort. To make the mower roll freely, you can either move the lever or extend the arm. The mower could start rolling if you’re not on a flat surface, so be careful.
If the hydro are not turned on to power the wheels, a Walker zero-turn will not move. To use the mower’s driving levers, these levers must be in the “operating” position.
2. The Belt that Drives the Pump Is Damaged, Loose, or Worn
Your zero-turn’s mobility may be impaired by a worn drive belt. Make that the Walker drive belt is still on and snugly wrapped around the machine’s pulleys.
The belt has to be replaced if it is too loose or exhibits indications of wear.
3. Tensioner Pulley Failure
Both the tensioner pulley and its bearing are susceptible to failure. Hard plastic is commonly used for tensioner pulleys, however this material can eventually wear out or shatter.
If a pulley’s bearings are bad or it’s worn out, you should replace it. Keep the tensioner arm well lubricated so it can move without sticking.
4. Idle Arm Spring Is Not Present
The pump drive belt is under tension due to the idler spring. If your Walker’s spring is broken or missing, you should replace it.
5. Low Level of Hydraulic Fluid
Walker transmissions require regular changes of hydraulic fluid to function properly. Your zero-turn may not move at all or run very weakly if the hydraulic fluid in the transmission is old or low.
Before starting the mower, make sure the oil is at the proper temperature by checking the level. Check the fluid levels by first wiping the area around the caps.
Since dirt is a common cause of a malfunctioning hydraulic system, it’s important to avoid getting any of it in there.
If the hydraulic oil in your Walker model is low, fill it up by adding more hydraulic fluid up to the maximum level indicated on the dipsticks or overflow tanks.
Walker zero-turns’ hydraulic systems perform at their optimum when the fluid is regularly replaced. Some models and suggested oils for hydraulic systems are shown below.
| Walker Zero Turn Model | Drive System | Capacity | Hydraulic Oil |
|---|---|---|---|
| ZTO | Hydro Gear ZT3400 | 5.2 Qts | SAE 20W-50 |
| ZXL | Hydro Gear ZT4400 | 8 Qts | Synthetic 15W-50 |
| ZXT | Hydro Gear 16 cc Pumps Hydro Gear 18 cu in Wheel Motors | 8 Qts | Synthetic 15W-50 |
If you notice your hydraulic oil level is low, you should also inspect for leaks. To get help fixing a leak in your hydraulic fluid, call your local Walker dealership.
6. Warm Hydraulic Oil
Bad hydraulic fluid or low fluid levels prevent the oil from properly lubricating the hydraulic system, leading to increased friction and fluid overheating when operating a Walker zero-turn.
Walker mower hydraulic fluid that is too hot may also indicate more serious problems.
If your lawn mower is leaking fluid from the hydraulic pump or starts up when cold but shuts down when hot, you should take it to a Walker dealer as soon as possible.
7. Compressed Air in a Hydraulic Pump
Walker zero-turns can become stuck or operate very slowly if air becomes caught in the hydraulic system. It is necessary to bleed the air out of the hydraulic system after changing the fluid or whenever the transmission is opened.
When the zero-turn moves, it may be noisy due to air trapped in the system. The oil may become too hot and expand out of all proportion.
Walker hydraulic system air removal and purging:
When the rear drive tires of a Walker zero-turn are lifted off the ground, air is released from the hydraulic system. If you can’t lift the drive tires, you can still do the test so long as it’s on a flat, open area with no obstacles in the way.
Before proceeding, check to see that the transmission has adequate oil.
Here are the steps required to evacuate the air from a Walker zero turn. If you need more information, look in the handbook.
- Raise the driving tires off the ground by safely supporting the zero-turn’s rear.
- Turn the key, release the parking brake, and release the bypass valves.
- Slowly advance and then reverse the drive levers about six times.
- Pull the plug on the bypass. Turn the drive levers forward and backward roughly six times while holding the throttle wide open.
- Keep doing this until the tires are no longer making an abnormal amount of noise and moving at typical rates.
- After the air has been sucked out, put on the brakes and turn off the engine. Get rid of the jacks or whatever you needed to get the drive tires flat on the ground.
- To make sure the oil in the expansion tanks is at the FULL COLD line, check the levels. If the hydraulic oil level is below this mark, add more.
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