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Kevin, Technician
Category: Agriculture and Farm Equipment
Satisfied Customers: 732
Experience:  Over ten years of expirence in Ag Electronics and Hydraulics
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I have a Deere 8100 TWD row crop tractor. After refueling,I

Customer Question

I have a John Deere 8100 TWD row crop tractor. After refueling,I tried to go backward to get away from the fuel supply however the brakes were locked.Transmission was working fine but tractor would not move just lug engine down in forword and reverse. Any idea what is happening?
Submitted: 1 year ago.
Category: Agriculture and Farm Equipment
Expert:  Kevin replied 1 year ago.

Hello, my name is ***** ***** I can help you with your question.

The problem you describe is most commonly caused by the brake valve pistons getting stuck down. This happens due to the rubber boot on the top of the valve rotting out allowing dirt and moisture to sit on top of the brake valve pistons. The below link will take you to a diagram showing the brake valve with the boot shown as #5.


Because the valve is mounted vertical once the boot fails and dirt starts to sit on the brake valve pistons it can cause them to bind in the down position. I have seen people bring tractors in asking for a transmission overhaul or rear axle rebuild only to find that the brake valve needed to be cleaned and re-sealed. As a temporary fix you can often spray a light lube oil in around the top of the brake pistons and hit the brake pedals a handful of times to free up the valve. Ultimately the valve will need to be removed and resealed. Removing the brake valve is easiest if the exhaust pipe is first removed. Once the exhaust pipe is out of the way the brake valve is easily accessible for removal. The below diagram shows a breakdown of the brake valve itself.


Please let me know if I can be of any further assistance as I will gladly assist you with further diagnostics as needed.