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Dan, Technician
Category: Agriculture and Farm Equipment
Satisfied Customers: 5570
Experience:  17+ yrs. shop and field experience with all major brands of heavy equipment, trucks and farm equipment - 1995 WyoTech graduate.
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Deere 304J wheel loader I'm experiencing a couple of

Customer Question

John Deere 304J wheel loader
I'm experiencing a couple of problems that all started at the same time after I changed a couple of hydraulic hoses and topped off the reservoir. The hydraulics are operating slowly, the engine only runs up to 2600 RPM, and there is an error code e2002, which is related to the parking brake.
Submitted: 1 year ago.
Category: Agriculture and Farm Equipment
Expert:  Dan replied 1 year ago.

Hi my name is***** will be glad to try to help. Check your hydraulic filter for fine metal and the oil for fine metallic glitter that would indicate a pump or component failure occurring. What is your serial number? Let me know.

Customer: replied 1 year ago.
The oil checked out ok, serial # ***** *****
The error code as it reads in the manual:
-no park brake pressure when park brake release solenoid activated
Expert:  Dan replied 1 year ago.

Thanks for the update. Check that the solenoid is getting power and functioning mechanically with no debris inside or leaks at the valve. If ok pressure test the park brake release piston seals for leakage. Let me know

Expert:  Dan replied 1 year ago.

Park Brake Manifold, Accumulator, Hosesand Fittings


1 AT324738Manifold1

2 AT218853Fitting1

3 AT334955Switch1Brake Pressure SUB FOR AT312156

4 AT187618Seal1

5 AT325426Cap Screw2

6 14M7517Lock Nut2M10

7 24M7213Washer210.500 X 25 X 4 mm

8 AT324963Valve2

9 AT324958Solenoid Hydraulic Valve2

10 AT310372Hydraulic Hose1


11 XEL10LCFFitting1SUB FOR LW247242302 AND AT218872

51M7106O-Ring17.500 X 1.500 mm

12 XET10LOMDCFAdapter Fitting1SUB FOR AT218873

51M7106O-Ring17.500 X 1.500 mm

13 XEW10LOMDCFAdapter Fitting1SUB FOR AT218871

51M7106O-Ring17.500 X 1.500 mm

14 XEW18LOMDCFAdapter Fitting1SUB FOR AT274831 AND LW247108302

51M7109O-Ring115 X 2 mm

15 AT274522Fitting1

16 AT324735Hydraulic Hose1


25 AT274522Fitting1

31 AT218853Fitting1

40 AT313797Hydraulic Accumulator1

Expert:  Dan replied 1 year ago.

Check for a possible faulty accumulator as well. Click the link for the diagram to go with the descriptions

Expert:  Dan replied 1 year ago.



1 AT317615Spacer6

2 AT313931Disk Spring4

3 AT313933Piston2

4 AT313844O-Ring2

5 AT313845O-Ring4

6 AT313934Ring4

7 AT313935Cover2

8 AT313846O-Ring2

9 AT313936Ring2

10 AT313937Piston2


11 AT313938Plate2

12 AT313939Compression Spring6

13 AT313940Screw6

14 LW10663168Brake Disk6(SUB FOR AT317617 OR AT313836)

15 AT313837Brake Disk6(SUB FOR AT317618)

16 AT313874Spacer2

17 LW11124013Cap Screw4SUB FOR AT313941

18 LW10353979Screw6(SUB FOR AT313942)

19 AT313939Compression Spring6

20 14M7275Nut4M12


21 AT313944Washer4

22 AT313304Screw4

23 AT313253Drain Plug4

24 AT313883Shim2



25 AT313265O-Ring1

26 LW11340098Seal4SUB FOR AT313239

Customer: replied 1 year ago.
I did replace 2 houses going into that manifold, would the accumulator be affected by that?
Expert:  Dan replied 1 year ago.

Were they under high pressure? The accumulator stores standby pressure. It is possible the accumulator discharged or failed.

Customer: replied 1 year ago.
This is my first experience with an accumulator, but the y didn't seem to be under high pressure. Is there a way to tell if they have discharged?
Expert:  Dan replied 1 year ago.

I do not recommend working on an accumulator unless you have the proper tooling and training as it can be dangerous but there is a nitrogen charge that fills a bladder if a bladder style and that is at a specified pressure. When you then force hydraulic pressure to counteract that pressure on the opposite side of the bladder the pressure increases and becomes stored energy in the accumulator. The top cap will have a charge fitting..... There should be no oil at that fitting, it is the nitrogen side. If there is, the bladder has ruptured and the accumulator is no good

Expert:  Dan replied 1 year ago.

Also a charge kit is needed to check the accumulator charge pressure. They are relatively inexpensive.

Customer: replied 1 year ago.
I'll do some more checking tomorrow, as I'm out of the shop now. Thanks for the help so far.
Expert:  Dan replied 1 year ago.

Sounds good. Id verify the electrical and other components in the circuit are ok first.