Gday, The front lifting arm spool valve on my 1982 Case 580D backhoe is not working properly. With the lever in neutral the hydraulic pump is loaded up so much that the starter can't turn the engine to start. To start the engine it is necessary to put the lifting arm lever just slightly into the down position by about 10 lb force which is an inch or so forward. If the engine is running with the lifting arm lever in the neutral position the load is almost enough to stall the engine at idle. There is no lever position where the lifting arm is stationary and there is no load on the engine. Lowering the lifting arm seems to be normal. Raising the lifting arm seems normal and actually unloads the engine compared to the neutral position. The issue seems to be isolated to the lifting arm spool valve. Is anyone able to held diagnose this issue for me?
Welcome to HEF David OZ: Have you tried taking the linkage loose from loader lift spool and see what happens?
Thanks for responding. Yep the leaver and linkage has nothing to do with the problem. It’s all about the position of the spool valve. I think there must be something wrong in the valve.
Make sure your disconnects didn't come loose or a kink in the hose or lines going to the rear backhoe. A restriction in those lines will cause the same symptoms. TGP
Remove spool and check return spring and detent for float position.
Thank you. The backhoe clamp pistons leak so I disconnected the hoe so I could use the machine as a loader. I’ll fix the clamp pistons and reconnect the hoe. Thank you for the diagnosis. I thought I had a stuffed spool valve. I’ll let you know how I go. It will be a while, I’m currently on Cape York which is a very remote area and I’m not expecting to be back home for a while.
I’ve had the valve apart and it’s all OK but does need some love. Water has got in but it’s all retrievable.
You can't just unhook the rear backhoe. The Hyd. oil will dead head and stall the engine. You must hook the hoses together to complete the oil flow. TGP
Thanks. I picked that up above. When I get back to it I’ll reconnect the backhoe and try it out. Prior to this the front arms used to slowly raise. Am I right in assuming that this would be caused by the “up” side of the spool valve allowing some bypass?
I reconnected the hoe and the FEL works perfectly. Thanks for the advice. Now to replace the 4 piston clamp seals and a few hoses and I should have a decent machine.
I'd like to use field serviceable fittings and hoses can you tell me are the fittings JIC and what size hoses are on the machine it looks like 3/8" and 1/2" on the front? What size are the larger ones on the hoe Please.
On my E they are mostly 1/2” and 5/8” JIC, there are 2 ORBS to JIC 5/8” also.
Thanks for the response.
Thanks everyone for helping getting the valves and the fittings sorted. I've got it in a thousand bits replacing locking pistons and hoses. On a related matter, how does the locking valve work for the backhoe slider. I see that it is plumbed into the dipper valve. I have the locking pistons out for replacement and can't play with the controls but it looks like the locking pistons are pressurised when the dipper valve is operated in the close/dig direction. Have I got that right?
Can anyone tell me what year this is please. I thought it was 1982 but the 1982 shop manual has an older 3 point linkage backhoe shown.
Hey David, It likely could be 1982. Problem with the service manual is that it written for the more popular US centremount model. Your side shift was built in Australia for the market here. It uses the US valve & cylinders. There was a printed Australian supplement in the parts book to cover the side shift frame & carrier. I'm guessing you need part numbers for the sideshift lock cylinder seals?
I've got the seals and I am getting new pistons made, but thanks anyway. I'm still looking to understand the operation of the sideshift lock and its interaction with the dipper arm.
The s/s lock valve allows pressure to the 4 x s/s cylinders. When you raise the lever, (if adjusted correctly) it should release the pressure at the 4 x cylinders. When the lever is lowered, it allows pressure from the dipper circuit to pressurize the 4 x cylinders. The pressure to the 4 x cylinders only happens when you are pulling the dipper towards you - when you reach main relief pressure the 4 x cylinders will be fully pressurized to stop the side shift frame from sliding. There is a check valve in the circuit which helps to keep pressure locked in the cylinders. To slide the frame, release the pressure at the valve by raising the lever & push (using dipper) the side shift frame to where you wish it to be. By pulling the frame, with the dipper, you send pressure to the cylinders & it will be harder to slide. SO pushing is more effective than pulling. I often roll the back of the bucket to move the frame. You obviously need to feather the boom as you slide, to keep the s/s frame level as you move the dipper or bucket, otherwise the s/s frame just jams up. A little grease on the top rail will help it to slide as well. Not too much, as excess will drop down into the cylinder clamping area & reduce the locking ability. If the frame has not been slid for a number of years .... you will blow some older hoses as they move from areas where they have sat for that time. Takes a little practice at first but is easily mastered. I see you have the frame slid off the end to service the cylinders, so you already may be proficient, just thought I would give a full operational description to help others in the future.
Thanks Alrman. That is exactly what I needed to know. Its great to get the right info form someone who knows what they are talking about. Very much appreciated. Regards, David.