Hi, I’m new to here, and must admit my mechanical knowledge is very limited. I have a 2008 Cat 312C, one track travels slowly in one direction. At first I assumed swivel joint seals, however noticed quite a bit of play in the problem side track lever until there was any resistance. So I started to investigate the pilot valve. Once I took off the rubber covers I noticed on the problem side, there were small pools of oil where I assume both pistons are. Ive attached a photo for reference, although it may not be that clear. You can easily move this side with your finger while the correctly working side is stiff, so I assume this is where the problem lies. I’m just enquiring if it is possible to work and fix these valves rather than replacing the whole valve? Or would I be biting off more than I can chew. And would the problem seem to be the seals within the valve? The part number is 158-8250 Thanks for your help (hopefully) Peter
I takes them apart and freshen them quite often. It's better off the machine, but can be done on the machine. Outer boot damage not only scuffs the seals, but also allows excess wear in the plunger top and mating bolt.
Yup, fluff and buff, back to work.
Thanks for the replies. So take valve off the machine, change seals, plunger tops and mating bolts if needed. I’ve found this attached breakdown of the valve. I suppose I’ll strip the valve down and then order what I think I need. Thanks
Just seals on the stems and boots over the rockers to stop new dirt usually stops the leaking. And, grease at the rocker Allen to stem tops.
I dont see a serial number, and 312c look to be much earlier than 2008. I'll give part numbers if you post a serial number.
Please find serial number on photo attached.
You'll need: 4 @ #8 6V8400 Seal-O-Ring 4 @ #10 1195389 Packing 2 @ #14 0875709 Bellows Relieve hydraulic tank pressure by removing fill plug. If you don't remove valve from machine, at least disconnect the supply and case drain hosing, and plug, before disassembly. Unbolt pedals. Remove bellow. Loosen center Allen set screw in middle of rocker. Push pivot pin out. Remove #34 Allen head bolts. Lift off #33 cover. Pry out each #17 cap. Remove and replace packing and Seal-O-Ring. Clean #11 pushrods. Reverse to assemble.
Oh, and it is a 2008.