JD 450C Steering issue

[klmahnke]

Good morning all, new to this forum. I have a JD 450C with 3600+ hours, 1978 model. This is a new machine to me and the first machine I have owned. The other day while using the machine (machine worked as intended) the right stick for steering became harder and harder to move machine in intended direction until it finally stopped machine completely when pulling back. A few weeks ago I broke a hydraulic line on the backhoe, fixed it and filled reviser with fluid. I am wondering if this may have anything to do with the issue at hand. Looking under the seat I find two hydraulic valves which I am assuming are the brake adjusters? I am also assuming that pulling back on the track steering applies pressure to the brakes to turn? (Remember, I am new to tractors) Can someone give me some help in trouble shooting this issue? The machine drives straight right now but, when pulling back on the right stick, machine stops. When you let go of the stick it holds fast for a few seconds then releases and will travel forward again. Also, are there any fluid filters to change on this machine? I do not have a service manual for this machine! Man are they expensive! Any one have one for sale or know where I can get one? PDF version is fine.

Thanks in advance, Kaelin

 

[Tx Jim]

You're correct in that steering clutches on 450C are hydraulic. I would guess faulty control valve, low pressure or worn clutch discs.

 

[klmahnke]

Thank you for the reply and the diagrams. Here is what I can tell you. Referring the the second diagram. 1) how do you remove the valves and do you by chance have a part number. 2) right valve when line is removed from top will shoot fluid to the top of the cab with engine running, with valve open it stops. 3) left valve when line is removed from the top only shoots fluid about 18 inches high, with valve open it stops. Which valve is operating properly?

Again, thanks in advance for any help, Kaelin

 

[Tx Jim]

IMHO right valve is operating correctly BUT my JD industrial equipment knowledge is very limited as I was employed yrs back by an "ag only" JD dealership plus I have no access to a 450C tech manual.

 

[klmahnke]

Thank you, Tx Jim. If anyone else out there has a manual and could give me a part number and tell me if the valve can be changed from the top or if I need to remove the top plate to change it, I would appreciate it.

Kaelin

 

[gghb]

youv'e probably over adjusted the brake by too

much jerking on the lever common problem if i remember my thousands of hrs on 450's. look up how to back off the brakes and quit jerking the levers pull them .you will find a large threaded plug with a 1/2drive hole over the adjuster on the top face of each final don't remember the procedure to adj [CRS]

Greg

 

[Tx Jim]

If spool valve requires replacement then housing will also need replaced as they come in a matched set.

 

[klmahnke]

Ordered and replaced spool valve. Pretty straight forward, disconnect the linkage and pull out valve. Same problem exists though. Now, I am pretty sure that the problem is still related to pressure but I am not sure where to go from here. I changed the filter for the hydraulic fluid (pretty dirty) so I am leaning towards a fouled line somewhere. What confuses me is that I have high pressure to one valve and low pressure to the other. Since they both take fluid from the same place it doesn't make since that this would be the case unless a valve was bad. I suppose it could be bad clutches but right up to the time it quit steering there was no issue, no hesitation, no jerking, nothing. Does anyone have the procedure to adjust the brakes?

 

[J_J]

You have an open center hyd system.

Hydraulic System
Pump type Open Center
Relief Valve Pressure 2250 psi


The hyd system is open center, and the pump fluid flows through all valves to tank.

Can you install a pressure gauge in the first valve In port and check the pressure.

It should be low with all valves in neutral.

 

[klmahnke]

Don't have a pressure gauge but I replace the spool valves. Today I adjusted the brakes looking at the simple stuff first. Then, reading on another forum one gave instructions to test the drive clutches by pushing up against something stopping the tractor. Giving it throttle, only the right track turns. If this is the case it tells me that the left drive clutch either needs to be adjusted or replace. My question then is; does my left drive clutch need to be replaced? Is there a way without tearing half the machine apart to adjust the clutch pack? Now for the zinger. I am rural Alaska where the closest mechanic is hundreds of miles away. Besides any travel time hourly rate is $160 to $200. And being the left track doesn't drive, I can't get it loaded onto the trailer to move it from my property.