Husqvarna hydrostatic drive or often referred to simply as hydros, hydro-drives, or HSTs — constantly have variable drives. A pump affects hydraulic fluid inside a closed system and reduces gearing that responds to changes in that hydraulic pressure.
However, failure of any one of these components will prevent the lawnmower from moving.
A leak from the hoses or any of the other components will also stop the hydrostatic transmission from working.
So, let’s see the Husqvarna hydrostatic drive problems and its solutions.
Husqvarna Hydrostatic Drive Problems and its Solutions
1. Hydraulic Fuel Leak
One of the customers mentioned that a leak of the oil that powers the hydraulic pump hindered the mower’s movement. You will get to know whether the lines are leaked by observing the following symptoms –
- If there is any leak in the line, there won’t be optimum pressure in the lines, and the Husqvarna mower won’t run smoothly.
- There will be a burning smell which indicates a leak in the line.
Fixing The Leaks:
You need to change the lines if you find any leaks. When the rubber parts get worn and cracked and oil comes out from the seal, you should replace them.
The crankcase can also eventually get cracked or broken off the immense pressure. So, you may have to replace it if it is out of work.
2. Doesn’t respond to the shifting
Sometimes, the mower doesn’t have the power it had previously or doesn’t respond to your shifting. It can happen if the transmission control arm may be out of adjustment.
If the wheels continue to move when the machine is in neutral, it’s time to access and adjust the adjustment bolt.
There is a possibility of activating the manual bypass lever when there is no response to your movement of the shift control arm.
First of all, you have to ensure you’ve released the parking brake before shifting the machine, as the mower will not respond to your adjustment of the control lever to move forward or backward.
And always disengage the cruise control before attempting to shift.
3. Air in the Lines
Air can get into the lines when your hydrostatic mower idles all winter. And it doesn’t have enough pressure to deliver the same results as normal.
Removing Air from the Lines
It is recommended to empty your mower of hydraulic oil at the end of every season before putting it away for the winter. Again, when it comes to flushing air out of the lines, you can follow these steps:
- Put the mower in place by locking the rear wheels with objects. Engage the parking brake.
- Disengage the transmission according to your owner’s manual.
- After turning the lawnmower on, you should put it in neutral and let go of the brakes.
- Push the throttle all the way forward for about five seconds.
- Wait five seconds in the forward position, pull the throttle into reverse and hold for another five seconds. Repeat this process three times. Doing this will expel air from the hydraulic transmission.
- Shut Off the Mower
- Re-engage the transmission
After the transmission is re-engaged, drive forward for about five seconds and then do the same in reverse.
I hope after this process, there will be no air. This process costs a lot less than taking your mower to a professional.
4. Mower not going forward and backward
One of the reasons why a Husqvarna hydrostatic lawn mower won’t move is the old hydraulic fluid.
Worn drive belts or air in the lines can be the other causes.
So, you have to be cautious about the long period of non-active transmission drive.
5. Mower not starting
Sometimes the mower won’t start up or has issues while starting.
Don’t worry! Some easy steps can eliminate this problem.
You have to follow the given steps –
- Make sure that your mower has fuel in the tank
- Check the neutral control level.
- Double-check all the settings before choking the engine or starting the ignition.
Husqvarna Hydrostatic Transmission Repairs
Since the Husqvarna hydrostatic mowers are completely sealed, it is hard for the user to repair them. So, you should seek out an authorized service representative to perform diagnostics or make repairs.
For an average homeowner, it is tough to troubleshoot and repair a hydrostatic transmission for the lack of appropriate tools, training, or knowledge for the job.
Now, you know the husqvarna hydrostatic drive problems and how to solve those.
Since your hydrostatic mower can fail to move for several reasons, you need to figure out the cause. Then, it will be easy to find the solution.
Null the valve if possible. If the system is overheating, check the oil level in the tank, inspect the heat exchanger, check the inline pressure filters, inspect the crossport relief valves, and check the pump and motor case drains for excessive bypassing.
Let us know about your experience!