Just purchased an older Bobcat Model 742. Everything works good except the main lift arms do not hold a position. Any thoughts on the cause/correction? There was a major line leak which has been corrected and fluid replaced.
Welcome to the forum Pops502. If you do not have anymore leaks my guess would be either: A: One or both of your lift cylinders are bypassing fluid internally via faulty piston seal. B: The main control valve has a problem with that particular valve section. Hopefully it'll be the rams that just need rebuilding. That'll be much easier than removing the valve body. Good Luck.:thumbsup
This should be your "4" series system.
:notworthy Jeff D. puting out info we all can use Thank You.
Well, I figure I'd better contibute something "pertinent" every once in a while. If I only picked on Digger and Squizzy, and posted old family pictures, Steve would be chasing me off with a stick.:bouncegri
tear the cylinders down and look at the seals and the nut on the end of the rod they are known for comming loose and the seals get old and brittle after a while
Got an 02 773 with a service code 5-14 popping up on the display - beeping for 10 secs before shutting down automatically, the code means extremely low on hydraulic charge pressure ? The hydraulic oil level is all good in the view finder ????? anyone know what i need to do to get her goin again ??????
Jeff D. Great schematic. How might I obtain a full image of that so I can get all the wording on the right hand side. I am a newbie at this site and with a 741 I just acquired. Thank you, Jim
lift cylinders I agree with the problem is the lift cylinders. What I have found, that you need to repack both of them, if one fails. I didnt listen to someone tell me this and I ended up repacking the other one. I guess the new one puts more strain on the old one. The cylinder I had fail, would get hotter quicker, under a load, than the other one. Good Luck
Likely piston seals, but first you need to pressure test them to verify this is the problem. Disconect your hoses and conect the cylinder(s)to your air compressor on one side and see if air bubbles out the other cylinder port under pressure. If it passes this test, then install a 3000 psi pressure guage on the the uphose and cap the hose to the other up cylinder and pressure up the line. Theguage should show the pressure beingheld constant. If it leaks down,you either have a leaking hose or the valve body is leaking back. Ken
would anyone know why the red button on the under the seat leaks hyd.oil?
I'm having a similar issue with a 743B, but I am pretty sure that the issue is because of a leak in the flexible line that runs to the upper part of the lift cylinder on the right side. I was told by bobcat they didn't have the part in stock, but I could have one made. Can someone tell me the dimensions of this line? I just haven't had an opportunity to remove the line yet. But I wanted to see if I could get the line made before the weekend. Thanks! JT
bobcat 743 has anyone had the tank leaking fluid? I cant find any leak while running machine but keep loosing fluid
I got a problem with a bobcat S220 my auxillary control valve sticks when you close the grapples and you have to shut off the machine. I used to flip the switch back to open and it would release, now it just sticks open or close. any ideas
If the red manuall lowering valve is leaking it can allow the arms to drift back down.
Raise the cab and check to see if you find your oil in the belly of the machine. If it has a leak but the machine is dirty inside it could conceal the leak. If it is dry there check your chain case oil. If it is way over full your drive moror could be dumping it in the chain case. JJ
the charge pump is bad.It mounts to end of drive pumps!
I have the same problem. Did you get an answer yet?
one of aux solenoid valves is sticking, causing pilot oil to be directed to the aux spool. 50/50 chance it'll work again if you pull them out and clean. usually once they start sticking open, it's time to replace. :drinkup
check your drive belt
Ok, first I am a newbie to site but a mechanic most of my life. Thanks for the site and response I have a 753G about a 2003 model, I am chasing a leak , seems to be around the lift or tilt cylinder line that connects to the block. I removed a line looking for a sealing issue but saw nothing unusual. I cannot see the actual leak because my seat is up, bar is up and it only leaks when in use. I did have to replace a blown line to Hydro motor on right, but it seems unrelated unless it’s a pressure issue. Have not notice position change in tilt or lift but I have only operated this machine about an hour, which equals 5 gal hyro fluid, 1 replaced line, and still have one leak. Is this schematic shown in this thread also same as the 753? I ordered a manual but haven’t received it yet. Any ideas where to look or how to find this leak?
Hello, We have a Bobcat 743 that seems to have the valve spool stuck for the bucket lift function. We removed the valve linkage and the linkage is free but we cannot move the spool. Quick note. The machine was accidentally run with the aux shifted over to the left. Not sure if that damaged anything or not??? Any help on how to rectify that would be appreciated. thanks
Sorry......it was run with aux shifted to the right.