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Case 621D

Tinkerer

Senior Member
Joined
May 21, 2009
Messages
9,367
Location
The shore of the illinois river USA
It could be a seized caliper. You can open the bleeder valve and release any fluid pressure that may be holding it . If the caliper doesn't release, then it will need servicing. Be sure the machine cannot move when you are trying to release the parking brake. If this thread was in the wheel loader forum you would have a better chance of having someone with 621D experience read this.
 

gggraham

Senior Member
Joined
Feb 13, 2009
Messages
588
Location
London Ontario Canada
Occupation
Licensed Heavy Duty Equipment Mechanic
What are your brake pressures? The test ports are on the LH side of the machine under the plastic cover just behind steps. Seen lots of bad brake charging valves on these things.
 

Vetech63

Senior Member
Joined
Aug 10, 2016
Messages
6,420
Location
Oklahoma
i am checking a 621D and the parking brake on the dash is on it will not go forward or reverse. any suggestions on that
I would check your brake pressure first. Remove the small cover attached to the lower right of your cab. There should be a test port for your brakes. I don't remember exactly but I believe it should be between 1800- 2000 psi. If you have the brake pressure, then its more than likely a electrical problem. There is also an accumulator valve that the brake pump output line goes into first, that's where the pressure switch is. I had one of those valves grenade on a 621.
 

Coy Lancaster

Senior Member
Joined
Dec 19, 2014
Messages
1,985
Location
Arkansas
Occupation
service tech
There is a serial number break on the 621D which do you have early or late s/n?
The brake accumulator control valve is built into the pedal valve on the D series and the accumulators are under the cab. Do you have any warning lights on in the cab? Make sure that your brake light is going out before you try and disengage park brake, always hold brake pedal down before you turn park brake off and leave shifter in neutral and if you have the FnR switch on the loader control handle make sure it's in neutral position. I'm sure you know all this but just some issues to check.
 
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