Good morning, I have a Bobcat 743 which is leaking oil from somewhere on the control valve but for the life of me I can't see where it is leaking from. Is there one area of the valve that leaks more frequently than other areas? Can the seals in the valve be replaced with the valve still in the machine or does the whole thing have to be removed? If it has to be removed is there a seal kit to be had, and would I replace all the seals in the valve while it's out or let well enough alone and just repair the leak? Machine has 4000 hours and a four spool valve.
I've replaced seals on mine a couple of times without removing it. It's not fun at all..... Ed
I don't imagine it's any fun at all, I can't even get my fingers on the front of the valve. Now I'm really perplexed, I pressure washed it and dug out all the dirt, sticks and sawdust [I use it to support my sawmill operation] then started it while on the jack stands. I cycled the lift and tilt cylinders a few times and ran the wheels in revers and forward for about five minutes, no leak! I don't get it. I had to add two quarts of oil twice in three days and had oil dripping from the bottom of the machine when I was working it. The floor of the machine had oil pooling under the control valve. Is it possible the spools will only leak when I am lifting a heavy load? I may have to put it all back together and take it back to work and lift a few heavy logs, it's in my home garage at the moment. Ed, that image above your user name is about 3/4" square on my screen and I can't figure out how to enlarge it, looks like a Stihl with about a five foot bar, what spiecies tree is that?
While it's opened up, check the hose clamps on the suction hose, it's the big one that crosses over everything......that was my last leak. The forum software isn't friendly to a tall pic. It's a Stihl 084 & 5' bar. Tree was a White Oak, lightening had hit it years ago, was dying slowly, needed to be removed while it was still safe. Ed
Thanks, I checked those already. They were a little loose but not leaking. Fixed a few more snags on it this morning and going to take a fir down next door and see if it leaks lifting the logs. Weird. I would like to have that on my mill, people pay big bucks for slabs of oak for tables, mantles etc.
Well that oil leak started up again big time. I removed the engine along with the muffler, rad, oil cooler, and fan shroud. Man what a mess in there, oil soaked sawdust everywhere. There was so much dirt and crud between the pump and the fan shroud it distorted the front of the shroud rearward enough for the fan to grind a hole in the shroud. I still cannot see where the oil is coming from. I put a mirror under the valve and can see some oil on the bottom but cannot see where it's leaking down from. I will reseal all spools. There is a little oil around the pump input shaft, not much but I may as well reseal that as well. Anyone done that in the past? Can it be done with the pump in the machine? Thanks.
Its been a while since anybody added to this subject so here I go. About a month ago my 743 developed the dreaded spool leak. I've repaired it once before through the rear however decided to do it properly this time by removing the unit for a rebuild. To get the spool block out I had to remove the main hydraulic pump, not a difficult job but a little heavy although not impossible. Out and in took me two weekends, probably about 20 hours. I ordered a seal kit for the 4 spools from Clark Equipment Australia and was sent enough for one spool. First problem as I needed the Bobcat the following week. I purchased seals from my local hydraulic supply store and fitted them front and back on all spools. The unit still leaks after re-assembly I think the rear seals are incorrect so I'll now do the job again. That's the reason for this post. I'm going to cut an access opening, maybe two in the side of the Bobcat, something I should have done years ago. I will report the procedure with images over the next few days.
What a mess... what a fire hazard. Be glad you only have a leak. Oil soaked saw dust sounds like what you want to start a fire.
Hi I am trying to repair an older 743 bobcat that had oil leaks on the spools in the control valve. I got it seal kit from the dealer and it had several different spool seals in the kit (for different applications I guess). There are black, orange and green. I have resealed it x2 but still have a leak on at least 1 spool. Any ideas?
The spool itself could be worn. I had a spool for the steering valve on my track loader leak. It had to be rechromed. It's possible the seal got damaged on the install too. Did you put a little oil on the O-rings when you installed them?
I think the o ring is ok, but you may be correct about the spool. Any idea how to evaluate the spool?
Measure it with a caliper on different sides and see if there is much difference. Technically it should be round within a couple thou. all the way around. It may be worn where it slides as well.
I will, but I think it may have the wrong stem seals in it according to a service bulletin I just became aware of from Bobcat.gonna try measuring and replacing the seals.