I purchase this 1960s Case 340 with a model 22 loader and backhoe. Oil was pouring out some of the hydraulic cylinders on backhoe. I replaced seals on several cylinders. Crowd cylinder piston seal was blown. I assumed my problem was blown piston seal particles have lodged in control valves or secondary relief valves causing no hydraulic pressure to boom cylinder. Swing only works in one direction from day one but I could still use hoe some what by tilting machine with stabilizer pads and gravity would swing boom back. After about an hour of use boom started to have no power and could barely raise it and would fall to ground in a matter of seconds. By the time I parked in shed boom would not raise at all. I purchase a service manual and pulled crowd-boom-bucket spools in hydraulic control valve. I found as I suspected some thing that looked like plastic debris about the size of a quarter lodged in a poppet valve in boom spool. I also inspected boom secondary relief valve and it look fine. I did not pull crowd and bucket secondary relief valve as crowd and bucket are working fine and it is on bottom of control valve. I happily put everything back together thinking surely that my boom problems will be solved. To my dismay was absolutely no different in boom lifting or down pressure. I did read in manual that swing have a relief valve in different location and assume that is not related to boom problem. Front loader works fine....stabilizer, crowd, bucket works fine. since can't lift boom don't know what status of swing is now. I don't have access to hydraulic flow meters or hand pressure pump as service manual advises to do some checks. To take to a service shop will probably cost double what old hoe is worth. Does anyone have advice on what to try next? Thanks for any input, I am at a loss as to what to try next.
Welcome to HEF, Steven ! Reseal the boom cylinder. Your description indicates a worn out piston packing. Same with BOTH swing cylinders. One of them may even have a loose piston in it.
I never even thought of that......I could remove one of hoses to boom and hook pressure gauge to valve side of cylinder and plug hose to cylinder and check for operating pressure? I do have a hydraulic gauge.
If the piston seal is leaking badly you will not be able to get a high pressure reading due to the oil going around said piston. Will the boom stay up with the control valve in neutral ?
Is hard to tell. hydraulics will not lift it and had to jack it up and chain it to haul to shop. Seem like when I jack up again in shop to unhook chain that is sank slowly taking 10 sec to drop 2' to floor. This is what was under poppet valve in boom spool.
Have you changed the hydraulic filter and cut it open to see what is in it ?
Case 340 ??? Skid steer ? I have never heard of a Model 22 backhoe. Model 22 loaders on a 420 or 430 tractor I have. Can you post a picture of the unit ?
You are correct it is 430. I must be dyslexic. LOL
Have you changed the hydraulic filter and cut it open to see what is in it ?
You don't make it easy for someone to help you. Isn't the backhoe a Model 23 ??
I apologize for mis information. It is an model 22 serial # 4083100. I unhooked the top hose of boom spool an capped the hose and connected a hydraulic gauge to boom spool outlet. With engine running and activating boom spool, engine would bog down and gauge would register around 1500 psi. This leads me to think that your first suggestion that piston seal is blown was correct. looks like it will be a real bear to get boom cylinder out to overhaul. It is in an enclosed box of the boom arm. I have already rebuilt crowd and bucket and stabilizer cylinders. Maybe as you also suggested swing cylinders need rebuilt to correct swing problems. Thank you Tinkerer for all your input so far.
Just a recap I rebuilt boom cylinder and that fixed that problem. It was a blown piston seal. I also rebuild swing cylinders while I was at it and that made no difference with the swing to the right problem. As I erroneously titled this thread as a 340 case back hoe with model 22 back hoe when in fact it was a 430 case back hoe with model 22 back hoe. I will start a new thread for the swing problems. Thank you Tinkerer for helping me with this.