94' Case 1845C drive problems, please help

[cldunivan]

Hello, i am new here and i am glad i found this awesome place. i just purchased a 94 case 1845C with only 1540 hours. it sat most of its life and is in really good shape. I used it about 3 hours when i noticed a faint stream of oil on the ground as i was backing up where i was working. turns out the right hand top hose going to the drive motor had been rubbing against a bolt on the opposite side and wore a hold in the line. I parked the machine and went and got a new hose made up and the local NAPA store. put that on and fired it up. Here's where the problem starts. I didn't have harldy any power at all on the right side. It would move but really slow. I replaced the filter and checked the fluid level, added about 2.5 gallons to bring it up to full. Still dont have much power going to the right side. I tried cracking the lines and bleeding them, and some of the plugs on the tandem pump that control that side. Nothing has helped it yet. I even switched all 4 hoses at the drive pumps to the opposite sides and the problem switched sides, meaning the drive motors are good. I am lost here. I was hoping to have a great machine here. Before i noticed the leak i had tons of power and now hardly any on the right side. Also if i push the right lever all the way forward, and then try to operate the left side it makes the left side loose power, but as soon as i let off the right side lever the power comes back instantly to the left side as normal. Also when putting it under a load backing up using the right lever sometimes there is a really loud whining sound. also the motor doesn't pull down hardly and using the right side. Any suggestions? help? simple fixes/things to check. i am lost here.......... thanks

 

[melben]

I hope that you were very clean when you changed that hose. Hydrostats will tolerate NO dirt as the commutator plates in the drive pumps are brass and score very easily. If ANY abrasive was allowed to enter the hose as you fed it into position you will be doing a rebuild on the piston pump. Sadly it sounds as if that may be the case as you said it worked before you changed the hose. The plate and the piston barrel mating face and slippers on the pistons shoud all be checked for scoring . The systems are self bleeding so that is not an issue. A good mechanic and a precision flat surface that cannot flex with 400 grit wet or dry with some oil as a lube and some patience can get them working again. I have done it many times. mel

 

[cldunivan]

Where is that piston pump your talking about located and is this sumthing that can be done without tearing the whole thing apart? I have rebuild many automotive engines and restored a couple cars, doing all the work myself, but i am lost at how these machines operate. Any info on this would be great and is this an easy fix? how bout cost? i have plenty of tools and even more time if this is something you can point me in the direction of and a little how-to would be great. thanks again

 

[melben]

T
he tandem pumps are bolted directly to the plate on the bell housing and have all the drive hoses fastened to it. The cab should be rolled ahead to gain access, you really need a service manual to even start this project. The tandem pump has two drive sections, one right, one left. following the hoses will tell you which section serves the right and which the left. rereading the first post, are you sure the hose from NAPA meets the pressure ratings of the 45C's drive pressures, many auto parts stores do not have the hose specs required. Not to question your abilities as a mechanic but hydrostatic pumps are simple in theory but somewhat complicated to get back together, getting the swash plate in right can be a bit tedious due to the design. You may consider having a pro do it or just learn your way through it. Mel

 

[Glen Bell]

If the problem follows that new hose from side to side, I would suspect that hose or fitting is restricting something. I know nothing of this machine but that only makes sense to me....didn't have the problem before the new hose, problem follows the hose from one side to the other......must be the hose, no?

 

[cldunivan]

Thanks again for the response. Yeah the hose is rated at 4000psi so that should be good. The problem is in the front part of the tandem pump, the side closest to the motor. I have a thick parts manual with the breakdown of all the parts that go into this thing. I was just curious as to weather i would need any speacial specific tools to tear this thing apart and reasemble. I guess worse case scenario i could pull the tandem pump myself and save the price of labor there and just let a professional rebuild it.

 

[alrman]

I would be checking a few pressures before ripping it apart - charge pressure at least.

 

[cldunivan]

I have a couple pressure guages, on goes to 600 and the other to 5000. Anybody got any pictures or diagrams where i can tap in to to check some pressures?

 

[dporter]

Have a new hose made at a hydraulic shop. If the problem followed the hose it must be the hose. Something is wrong with the new hose!

 

[dporter]

Taje the original hose with the hole to the Hydraulic shop so they can match it.

 

[Goose]

I hear this same story over and over after guys have hydrostat hoses made and usually what has happened is when they cut the hose to length they do not blow out the debris and then when the hose is installed the debris goes right into the pump and damages the port plate and the rotating group. I usually pull the pump group apart and end up resealing it, replacing the port plates and lapping the rotating group if it is not damage very bad. Then the motors need to be resealed at least and cleaned good if no damage is found and all of the hoses flushed out. The hose builders do not relize the damage the debris can do in a closed loop hydro system. The good hose shops will at least blow out the hose good before and after crimping on the fittings. The real good shops will blow a few cleaning spuds through the hose to get it good and clean.

 

[melben]

It would not hurt to check the charge pressure but from the original post the fact that the good side drive is affected when the other side is actuated tells me that the charge presure is being dumped through the damaged side when actuated. That the system worked before the hose was changed is very significant. I redid the same machine twice in a row within several days from a dirty drive hose installation while the Federal Prison near Lewisburg Penna. was being built. They didn't learn anyting the first time!!!!!!!!. They put lower pressure rating hose from NAPA than the system called for and blew it and then repeated a dirty hose installation a second time. If there is any dirt in the belly the hoses MUST be plugged with secure JIC pulgs and once in position the plugs cleaned with brake and parts cleaner, the male fittings cleaned absolutely clean and only after there is absolutely no kind of abrasives in the system can the hoses be attached and tightened. In fact the hoses must be cleansed internally as most hose shops cut the hose with an abrasive wheel and pieces of the hose reinforcing wires and carborundum bits off the cutoff wheel can be inside the hose from the hose making. process. Keep us posted as to what your pressure readings show. Mel

 

[maytag]

Sorry bout your bad luck. Its quite possible as already mentioned you introduce contamination into the system with the hose change-not only from the grit and grime on the machine but also from the hose itself if a foam pig was not used to clean the hose before installation. My money would be on contamination fouling a set of check valves in your right piston pump or the high pressure reliefs for the right side if they are located in the right side pump(most will be located with the motors though). Just my $.02-don't believe it has run long enough for "3 body abrasion" to wipe out a piston pump and not affect the motor on that side. If you could post a schematic I could maybe be of more help.

Good luck,
Maytag

 

[melben]

Thanks Goose, I was typing my response as you posted yours, you are so correct and add that to the dirt that can be introduced while fishing unplugged hose through the lower parts of the pan and you have a recipe for disaster. The damage that occours will be almost instantaneous as the contaminant is trapped in the closed loop and just keeps circulating and the results will be an immediate loss of power, the right way to repair it would be to have all components in that loop disassembled and cleaned including all hoses. I also have lapped the pieces back to usable condition including the port or commutator plate, you get a bit of minor rounding at the very edge but nothing where the actual sealing takes place. I have restored many to like new performance with a thick flat glass, 400 grit wet or dry and some elbow grease with a consistant figure eight motion while sanding it with a light lubricant or a parts cleaner to carry away the removed material from the piston shoes, commutator plate and piston barrel mating surfaces.

 

[alrman]

This may help to confirm your problem.....

 

[cldunivan]

So here is where i stand at this point. I was off work today so i ended up pulling the tandem pump. took it to a local reputable shop that deals with case stuff. the guy is going to pull it apart and see whats the deal and we can go from there. i was unable to check pressure reading cause i didn't have the right fittings. do you really think the drive motors need to be pulled apart and cleaned? i pulled the belly pan and all the drive motor hoses. everything is getting a good cleaning for sure! i did plug off the fittings on the drive motors so nothing can get into them. I should hear something by friday on the pump...... lets hope for the best:Banghead

 

[melben]

As goose stated and myself also, that is the only way to ensure that your system is completely free of contaminants. ONE-(1)- particle of sand can undo all the rebuild that you are underway with. I cannot stress hard enough that once something is inside the closed loop system the only way out is to remove it or wait till it creates a big enough path to get out on its own (severe damage). The only thing worse than doing these jobs is doing them over. Mel

 

[stovein]

I think a lot of people don't know that the only filtered oil the hydrostatic system gets after the initial charge is makeup oil thru the charge system to compensate for case loss in the motors. So if dirt enters the system it will never go through the filter and will recirculate.

 

[cldunivan]

Is there anyway i could put a filter on each drive side? does anybody make a filter that would work in both directions. you would thing as big and tough as these machines are that they would built the pump system alot better so that it could take a little abuse. Its kinda like building a monsterous bridge and then making its main support beam a toothpick.

 

[stovein]

I don't know if there is a filter that would work under that high a pressure and amount of flow. Really if it is all assembled clean and the initial fill is with filtered oil from charge pump all new oil entering the system is filtered so it should be good for a long time.