I have a 19Z 943 loader that I am planning to sell pretty soon and it has been a great loader but it has a problem that I can't figure out. It has always taken a while before it will move when you shift it to travel for the first time after starting it up . I think it is a charge flow issue but I don't know enough about these hydrostats to know where to begin to check. I have had it about 3 years and it has always done this. I have put a couple hundred hours on it I guess but it has never gotten any better or worse. I have serviced the transmission filter 2 or 3 times since I have had it and they always look good but do not have any affect on the way it acts. I have tried to find some good discussion about this on the forum but I have not had any luck. I have seen a few people talking about making sure that the transmission shifter and pedal linkages are adjusted out properly but I can't find any information on how to perform this procedure to be sure that's not the culprit. The machine has plenty of power and performs flawlessly after it does start traveling so I'm assuming the linkages are pretty close to right. Any information would be greatly appreciated! Thanks in advance:notworthy!
we have had the same problem with ours. if you jack the cab up you can see the hydrstat. at this point pressure clean the crap out of it cause you don't want and dirt falling when you do the next step. there is a valve cover on top of the hydrostat. take all those bolts out and lift the top off. there are 3-5 hard lines inside. they either need to just be tightened or need new seals. we tightened ours. this will help alot. just keep in mind it must be really clean when you pull that cover. any dirt in there could be really bad.
Thanks lgammon. I pulled the cover a few days ago to make sure that the 4 rubber hoses were not leaking and tried to wiggle the steel lines to see if any were obviously loose but they looked good. I should've put a wrench on them I guess:Banghead. Time to raise the cab back up and pull the cover again. I assumed the steel lines were flared and did not think they would have seals. I will try to get a part # and go ahead and replace the seals while I'm back in there to totally eliminate that as a possible cause or hopefully fix the problem. Thanks for the advise! I will give you an update when we get a chance to open her back up!
Did u run machine with the cover off ? Make shure u cap off the brake line !
Yes. Only for a minute though. I had the tracks up off of the ground to keep it from crawling. I felt uneasy about bringing the machine to full throttle with the cab up and it will only begin to travel after bringing the engine to full throttle and the travel lever to full stroke so I closed it all back up. I hope to get it opened back up this weekend. Can you please give more info on capping the brake lines. I'm not sure which lines they are. Any information on what I should do and what I should look for would be great. Sorry I did not respond sooner! For some reason I missed seeing your reply!
Still no luck with the drive problem improving. I pulled the cover back off the hydrostat, replaced all of the seals on the tube lines. capped the brake line off and started it up to see if I could spot any leaks. Everything looks good. Unfortunately it still takes the machine from 10 seconds to as much as a minute to move for the first time after starting. I've had a few heavy equipment mechanics in the area come by to see if they could do anything with it and they are not sure what's happening either. Can't afford to get a Cat dealer out and I have been burned on doing that in the past. Like I said, when it starts traveling you can run all day with out missing a lick but shut it down then come back to go again and it won't move until it's ready. Any help would be great.
What about preasure build and vent not clean, or torke coniverter low on fluid, Or smothing is sticking?? just guessing. Please post what you do, thanks.
Hi there basicequipment did you ever figure out that problem on the 943 where it don’t move at first time moving after starting ? Mine has same issue but fine after that ? Any info is appreciated thanks
What oil are you using in the hydrostat.? If the machine runs fine when it has warmed up maybe the oil is a little on the heavy side. Hydrostats appear to be quite sensitive to oil viscosity, especially in cold weather.
It's a hydrostat, no torque converter.
my oil came from cat it was just for the hydro-stat i think it was a 10 weight i would have to go look but for around here he said it would work down to -10 he also said don't use motor oil that was why i went there to it i think cmark also told me that. i also found a leak somewhere up in the middle of trans on the front but cant see where it is coming from i have belly pans off now trying to find that leak. its not a big leak i just don't like it leaking .
Oh and my # 19Z0250
10W oil is correct for the hydrostat. CMark may well have more suggestions.
Not familiar with this machine but reasonably familiar with stationary industrial hydrostatics. A hydraulic schematic from some kind soul would be a huge help, as well as pressure check locations and expected pressures at each location. Since the system works after a time, my guess is that for some reason oil is draining out of that hystat loop and takes some time to refill the loop. If you shut it down after it is working correctly, is the startup wait the same if you restart in 20 seconds or 2, 5, 10 minutes? It does sound like the hystat loop is low on oil and for some reason it's taking a long time to refill. Are there 2 charge pumps or just one? If there are two charge pumps the one feeding that side could be sick. If one pump, could be a stuck shuttle valve or charge pressure relief pressure too low or stuck open. The other thing to check is that there is a free flow of oil to the charge pump from the oil reservoir. This is where pressure test points can be very helpful, since these charge pumps and main pumps are usually pretty tightly integrated, making it hard to tell what is happening. I'm hoping we can find someone with a schematic that may show test points. We could dig a little deeper with that. Jon.
Here you go.
Hi Cmark do you now by chance the part number of this tube I can’t find it in the parts book ? Here are some picks of the hydrostatic that l have in my 943 I’m not even sure what it goes to or coming from ?
Sorry here’s the pics
The one in the photo is, I think 4T9945, callout #12 below, however this is just a photo off the internet, right? To correctly identify yours we would need your transmission serial number as these lines did change over the years and the serial number can't be found through SIS.
Chris, did you mean to say callout #13 on the illustration rather than #12..? #13 is the 4T-9945 Tube, #12 is called out as an O-Ring.
It's a good job somebody's not hung over...
You current physical state bears some resemblance to your avatar I take it..? I'm all right, on break until a week after New Year. So I don't have to worry. Merry Xmas mate.
Oh is that a O-ring seal on that pipe ? I didn’t pull it off yet but it’s leaking right at the fitting ? I thought it might be flared or something and it was cracked I will pull it off tomorrow
It may be a JIC fitting or it may have a seal. Like I said, it depends on your transmission serial number.
Thanks, Cmark, for providing the Cat info...but the Cat people who dreamed up that abortion of a drawing should be shot with balls of their own shzt!!! Its a half a schematic and half a pictorial drawing and makes it hard as h*ck to follow and understand. Do you have any information on what the pressure taps should read and at what engine rpm? There are some gems of info that we can glean from what we have for documents right now. Basicequipment, one of the pages mentions "Pressure taps" and it looks like they suggest they are on quick disconnects....I'm hoping they are lined up on a little panel somewhere, marked "A" to "Q". Are you able to do some pressure checks on some of those points? If you can, please let us know what you read at: B: Charge pressure. C: Servo supply pressure. M: Charge pump pressure. As I've noted to Cmark, the pressure readings really should be at some known engine rpm. But the charge pressure should be something over 345psi, the servo pressure should be 345psi +/-15 psi and the charge pressure should be 175psi +/-15psi. Jon.
Here's a copy of the troubleshooting data sheet. It gives you the essential points. The important one for initial troubleshooting is the venturi differential pressure as that determines engine RPM which in turn determines pump output. There hystats are marvels of engineering IMO and there's a lot going on at the same time.
Keep it simple I'd try and get three gauges set up start cold and see what's what. I'd suspect charge pressure is coming on slow at first thought. Could be scored charge pump having issue pulling prime.
Hi Cmark and Nige thank you for info I fixed that leak with adding a small o-ring on both ends of pipe looked like age has hardened the rubber in fitting .another question do you have a electrical schematic I’m trying to install new water temp and hystat temp gauges it’s driving me crazy some on cut some of the wires where the gauges go . I was tracing them out with a tracer but it don’t seem right . I just like seeing what’s going on before it’s to late I was going to run radiator over flow hose out in front of windshield so I could see it push water like nascar hahaha.
This is about the best I can do with a wiring schematic for the gauges.
Hi Cmark me again I have a host at line that is bad it goes to the drive motor the top line on the trans that has the steel tube on it to keep it bent ? When I change this do I have to bleed anything ? Or just add more trans oil ? Thanks
Hydrostatic line
Nothing to bleed. Just keep the oil level up and run at idle for a couple of minutes. And be very careful not to let ANY dirt get into the open ports. Time spent cleaning before you remove the hose will be time well spent.
Thanks Cmark