Been lurking over here for quite a while and finally decided to join and see if any of you guys could help me with a problem I've encountered with my 98' Bobcat 773 C-Series. I purchased this machine used about 2 years ago with only 1450 hrs on it. I have put only 300 hours on it since. One because I don't use it that often and two because I've been slowly fixing just about every dang thing on it since the previous owner took terrible care of it. So far all the problems have been minor, starter, alternator, leaking hydraulic lines, rust, bad electrical connections, traction lock problems, etc. Now I have hit a larger problem and really don't have the expertise to figure it out so here goes. About 3 months ago the left side reverse started to feel a little weak. I asked a mechanic friend about it and he said it was an "adjustment" so I didn't worry too much about it until the problem slowly got worse and left reverse was almost non-existant. Left forward was just as powerful as it always has been. I tried his "adjustment" but all that did was move the steering lever on that side. Upon further examination I found a hydraulic leak on one of the small lines on the left side drive motor. I also found that my hydraulic fluid had water in it and was milky. So we repaired the hose, changed the fluid and filter, and to my dismay the problem was still there. We checked for more leaks and turns out the hydraulic pressure sensor (next to the filter) was leaking fluid. So, we order a new one, install, and my problem is still there. That is when I found this website and read where a guy had a similar problem with a NH skidsteer. Except he had no forward or reverse. He switched his drive motors and found out that was his problem. So he had the old one rebuilt for about $800. I decide to switch my drive motors and see if it will explain my predicament. Keep in mind that I had no left reverse but everything else worked perfectly. After I switch the motors, I have no right forward but the left side works perfectly. Which makes sense to me since there are two main hydraulic ports on top of the drive motors (forward and reverse) and when you swap the drive motor from one side to the other, the ports are reversed so the problem would be reversed. I think "great this solves my problem, time to get this puppy rebuilt". So I contact a very reputable hydraulic pump repair shop, explain my predicament, and the guy tells me this all makes sense to him but I should bring in the pump, let them pull it apart and visually inspect it, and if there is no evidence of wear and tear, they will bench test it. He said rather than just sell me a new or reconditioned pump that this would be the best way to go if I could stand being down a couple more days. So of course I take it in, they tear it down and can find nothing visually wrong with it. "So on to the bench test" I think. Today, I get a call from the guy who then tells me they cannot bench test this motor because it is a "bearingless shaft" motor and really have no way of getting an accurate test on the thing. I should mention that this is an Eaton Char-Lynn Drive Motor model #114-1065-005 with the numbers 3780 below the model # (not sure what that means). This place is very reputable and the guy has been very straightforward with me so far. He has kind of walked me through this whole process as I am far from a hydraulic mechanic. He also keeps telling me he is not a bobcat mechanic (nor am I) but he "thinks" the motor is my problem since when I swapped sides with the motor that my problem swapped sides also. I just really don't know what to do from this point. Does it sound like I should just go ahead and buy another drive motor and slap it on or should I waste more money and time and try and find a place that can bench test this thing? This guy is telling me that they could rebuild this motor but there visually doesn't appear to be anything wrong with it and without an accurate bench test, they wouldn't know what to repair about it so a new one or a rebuilt one would be the best way to go. What do you guys think?
did you check the obvious, like maybe a blockage on one of the inputs on the drive motor? does it have a valve inside that could be sticking?
If there is a pressure relief valve in each pump section,id check that if possible,other than that without pressure check or bench test,you've got to take it to a bobcat dealer or make an educated guess.Its possible the relief spring is broken or stuck,if forward and reverse 'share' the releif than forget that theory.I think you diagnosed it already,so i wouldnt be afraid to go ahead and buy a new pump or rebuild the old if needed on what youve done already.
I checked for blockage the best I could and could not find any. I also failed to mention that after I swapped sides with the drive motors, the "working" motor (previously on the right side) made the left side take off like no tomorrow in forward and reverse. The "non-working" motor (previously on the left side but now on the right) made the right side have little to no forward but had full reverse.
we try that stuff all the time like on actuators or motors it sounds like its in that motor if it swapped sides with the motor if it had not swapped i would say reliefs or rotating groups but since it swapped and the steering is mechanical and you dont have loose pintle arms is what i first thought but if one dirrection works fine then its not that because it affects both i would say buy a new motor because it lies in there since it stays with the side the motor is on
bite the bullet and buy the new drive motor. You sound pretty competent and doing it yourself should save you a few bucks. I know that around here, the bobcat dealer has nothing but a bunch of inexperienced 20 year old apprentices that dont know s#it. They would just waste a bunch of time that costs you money.
Thanks guys for all the replies. Looks like I will be investing in a new motor. Can anyone tell me if I have to bleed the air out of the motor/hydraulic lines upon installation of the new one or is it just self bleeding?
just start it and let it idle for a few minutes then as you drive it it will work the air out
Thanks. Supposed to pick up the new motor in the next day or two.
Similar problem I have a 753 that has a hydralic leak from one of the drive motors i believe. The hydralic fluid that is leaking is going into the drive chain case. Is this a common problem? I have removed one of the drive motors and the output shaft seems very loose?(normal not normal??) Any help would be appreciated
the shaft will be loose it kinda floats in there when its apart and when its put together its splinnned into the carrier shaft as for the oil problem look at the motor and make sure all the bolts are tight on the hydralic motor next pull the seal on the carrier and replace drill a hole in the seal you have room behind the seal so don;t worry about not felling it punch throught the seal metal then put a screw in the hole a little bigger than the hole use a pry bar and remove then put the new seal in the side that is leaking look for the snap ring on the carrier to be broken and look for any play int he shaft in and out and up and down to much can take out that seal also if the motor is leaking drive pressure buy in the motor it can blow that seal out also
773 hydralic problem I have a 763 that is filling the chain case full of oil in about 10-15 mins. I have removed both drive motors and looked at both carrriers and seals but do not see a problem with them. Complete carriers were replaced not long ago on both sides. After inspecting both sides i pulled both sides of the drive motor hoses up were i could connect the drive motors while laying on the frame. so now i have both motors connected but where i can watch the motors actually run. When i start the machine one of the motors at the small hose that attaches to the motor is pushing fluid out , the other motor at the small hose is not doing this.. I'm thinking that the oil that is coming down the small hose is building pressure in the carrier and blowing by the seal into the chain case. I have been told that the small hose going to the drive motors are to return the fluid that has leaked from the drive motors.. ANY HELP WOULD BE GREATLY APPRECIATED... THANKS CHRIS
thats right on the small hose they are case drain lines that take the excess oil away from the motor that leaks by internally if you have one that is putting alot of oil out you need to resal that one there should be just a little oil that comes out of the small line have you pulled the case drain filter off and seen if there are any metal shavings in it? the presssure is blowing out the seals in the carrier so pull that motor apart and see if the seals are blown or internal damage to the metal parts inside get a seal kit for the motor and the timing instructions for putting the motor back together from your local hyd shop or your local bobcat dealer would be better
Hydralic Problems I Have Taken Both Motors Off And Pulled The Hoses Up So I Can Attach The Motors Back And Watch Them While They Are Running. When I Start The Machine Up One Of The Small Hoses Has Oil Pumping Out Of It And The Other One Does Not. Should Oil Be Coming Out Of These Small Hoses At All? My Main Problem Is The Chain Case Is Filling Up With Oil... Any Help Would Be Appreciated Thanks Chris
pull the motor apart and look at the seals and internal metal parts for scoring and pitting and put a new seal kit in don't reuses the old seals that is unless you see damage on the geroler in the motor then it is often easier to replace the motor as far as cost is concerned
773 Actuator Issue??? I have an older (8-10 years) 773 with advnaced hand controls. After running the unit for 5-6 hours (moving snow and back draggin most of that time) the error lights on the tilt/lift handle will flash 5 times and I am dead in the water. If I let it sit for 20-30 minutes I may get 15 minutes of work out of it. I took the unit to my local dealer and the diags. they ran said both actuators are bad. Any advice or assitance would be greatly appracited.
How do I get help with my '98 bobcat 763 that won't allow both foot pedals to function unless I activate option on hand controls?
I have a 1978 bobcat 753 and after cleaning battery cables it will not start. Has power at starter but when you turn switch on nothing happens
Make sure you got all the wires at the cable connectors back on. Some of the machines had a smaller wire 12ga or so that fed current to the entire system. The large wire was for the starter only. Also check the connections at the starter as you may have knocked something loose cleaning the cables. The starter stud was also a point for the main harness power wire connection. The thing that really throws me is you say its a 1978 753; that year doesn't jive with that series.
Thanks I will check that tomorrow. I was told this is a 78. I have the serial # 508613880.