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Curtis B.
Curtis B., Technician
Category: Agriculture and Farm Equipment
Satisfied Customers: 26033
Experience:  Technican turned service manager on multiple lines of equipment and rental equipment.
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I have a 1996 John Deere 300d backhoe. The rear brakes are

Customer Question

I have a 1996 John Deere 300d backhoe. The rear brakes are locked so it won't move. When I flip the parking brake switch it tries to move but the rear breaks are both locked down. How do I get the brake to release??
JA: Sometimes things that you think will be really complicated end up being easy to fix. The Heavy Equipment Mechanic I'm going to connect you with knows all the tricks and shortcuts. Is there anything else important you think the Heavy Equipment Mechanic should know?
Customer: I have always had to flip the parking brake switch on and off a couple times before the machine would go into gear and move.
Submitted: 3 months ago.
Category: Agriculture and Farm Equipment
Expert:  Curtis B. replied 3 months ago.

If the service brakes are locked, the usual problem is the foot valve , not returning all the way, either from pedal sticking or the internal valve not returning. To check, when brakes are locked, go th the brake line at the rear axle and loosen the line to see if it has pressure on it. If it does, brake valve or brake pedal not returning.

Expert:  Curtis B. replied 3 months ago.

See brake diagram above.

Customer: replied 3 months ago.
It's the parking brake that is locked!!!
Customer: replied 3 months ago.
I'm sorry. Let me go to the machine in the next few days and I'll get back to you.
Expert:  Curtis B. replied 3 months ago.

You said the rear brakes are locked. On 300D, the parking brake is drive line brake. The park brake has electric solenoid and a hydraulic actuator that has to release it. Does it get voltage to the solenoid? Does the actuator solenoid move the actuator? See attached.

Expert:  Curtis B. replied 3 months ago.

Controls.

Customer: replied 3 months ago.
Curtis,
I don't see an actuator on the last schematic?? Was that the one you meant to send me?
Expert:  Curtis B. replied 3 months ago.

# 13 is the actuator. Hydraulic cylinder activated by the solenoid valve # 51/52 .

Expert:  Curtis B. replied 3 months ago.

I see question is still open , did you find the problem?