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D5G Cat, parking brake won't release.

Mark250

Senior Member
Joined
Aug 30, 2015
Messages
1,267
Location
victoria,Australia
Occupation
heavy equipment technician
Hi D5GDevo A couple of things to look at .The ECM controls the park brake solenoid and the override solenoid according to inputs to the ECM
d5g park brake logic.jpgD5G park brake logic 2.jpg
Any of the items listed above can cause your park brake to stay applied. one that may not show a fault is the service brake limit switch
also you said that you had no faults in the dash did yo check the LED fault light in the fuse panel?
D5G Fault LED.jpg
you can check your codes without ET by this method
D5G fault code access.jpgd5g fault code access 2.jpg
you may have a broken drive plate which is some type of nylon, the rear pump supplies charge pressure to release your park brake. to check your charge pressures use the test ports shown
 

Mark250

Senior Member
Joined
Aug 30, 2015
Messages
1,267
Location
victoria,Australia
Occupation
heavy equipment technician
using the implements wont give an indication of drive condition because the implement pump is driven of the right hand side of the engine

D5G coupling.jpgD5g test ports.jpg
 

D5GDevo

Well-Known Member
Joined
Sep 8, 2012
Messages
70
Location
Kentucky
Just to let everyone know what was wrong with my machine. I had to pull the engine and replace the nylon flange and hub that drives the hydrostatic pumps, it was stripped out. No electrical problem at all. Thanks for everyone advise and help.
 

truecountry

Senior Member
Joined
Sep 24, 2007
Messages
412
Location
clarksville va
Occupation
Shop Manager and Tech
Just to let everyone know what was wrong with my machine. I had to pull the engine and replace the nylon flange and hub that drives the hydrostatic pumps, it was stripped out. No electrical problem at all. Thanks for everyone advise and help.

These guys here are the best ............Hats off to all
 

Brady06!

Member
Joined
Sep 23, 2024
Messages
11
Location
Mississippi
Define "the same thing" please. Do you mean the park brake won't release.?
Always good to start with a Serial Number.

Question: Do you know how to access Diagnostic Codes on the machine.?
Sorry about that the break want release and we have no pressure on either hydraulic filter just trying to find a way to test the drive plate before we pull the motor
 

CM1995

Administrator
Joined
Jan 21, 2007
Messages
15,950
Location
Alabama
Occupation
Running what I brung and taking what I win
Brady I would suggest you follow Niges advice and post of a serial #.

You are in good hands following his advice.
 

Nige

Senior Member
Joined
Jun 22, 2011
Messages
38,491
Location
G..G..G..Granville.........!! Fetch your cloth.
So here is the coupling. The hystat drive pump is mounted on the back side of the Plate #3 and the coupling is on the front side. The two eyes on the back side of Plate #3 are the rear engine mountings.

This is why the engine has to come out, even with the drive pump removed in the machine there is no access to get at the coupling #1. I suggest while everything is disassembled that you check the Coupling Hub #2 is tight on the shaft. I seem to recall at least one case where the hub had slipped along the shaft and as a result the splines had disengaged from the coupling. It's a split hub that clamps to the shaft with an Allen bolt.

1727282336886.png
1727282392565.png
 
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