300 Utility Hydraulic system

Fri Aug 21, 2009 7:33 pm

For the last few years, the raising/lowering cylinder on my bush~hog has had seals leaking. I finally ran the 300 out of hyd. fluid and the cylinder wouldn't raise. I quit raising and lowering it but kept mowing. The hydraulic system growled a little whilst the engine was running, cavitating.

Finally, I took the cylinder off, disassembled it and ordered some o-rings and seals from Baum Hydraulics in Omaha to repair it with. If you haven't got their catalog, get it. They have stuff you didn't even know you needed til you see it in there! Phone salesmen are very knowledgeable.

Back to tractor..... Repaired and replaced the cylinder. Filled basically empty system full with hydraulic fluid of some sort from farm store. Absentmindedly filled past full mark on dipstick. Started tractor. Hydraulic system on my 300 has two control valves. One for remote (mower~one way) cylinder, and one for the 3pt lift (2 way) on the tractor.

Now, engine running [idling] and lever pulled, it'll raise the mower or 3 point- barely. The thing makes a cavitation growl and acts like the suction is blocked.

It'll raise the mower or 3 point- barely. The oil flow comes in spurts.

I disconnected the hose from the mower cylinder, removed the reservoir filler plug under the seat and aimed the hose end into the resevoir. Pulled the lever for this hose and like I said, the oil flow came in spurts to match the growling of the system.

If I throttle up the engine, whine increases and the pump will not put out any oil to speak of. It only makes flow when near idle speed. Too bad I didn't have my digital camera out there to make a little movie clip so you could see and hear what it is doing.. maybe next trip.

Makes me think something is clogging the pump intake and starving the pump. I first suspected an air bubble in the pump cavity, but that seems doubtful.

I don't think I ruined the pump by running it low on oil, because it will move the cylinders, but only at idle. Not much, but some.

Worse comes to worse, I'll remove the pump and look inside it and see if it has worn itself too much being oil-starved, and that ought to show me if I have a restriction in the suction side or not...........

Re: 300 Utility Hydraulic system

Sun Aug 23, 2009 5:38 am

I don't know the particulars of the 300 system, but I suspect there's a filter screen somewhere on the suction side, probably in the reservoir. Running the system low on fluid may have stirred up enough sediment to plug it.

Re: 300 Utility Hydraulic system

Sun Aug 23, 2009 7:47 am

Thanks for replying. I was hoping someone would chime in. In the service manual there is no exploded view of this particular system.

I hope I can drain the new oil out without losing any or making a mess. I'll bring it home to the shop and disassemble it and see what I can find.

Anyone feel that by running the system so low I coulda' ruined the hydraulic pump? I'd think that with any oil in there at all, lubrication is happening.

Re: 300 Utility Hydraulic system

Tue Aug 25, 2009 9:22 pm

Runnin low even for a few mins. can smoke a pump on an IH (dont ask how I know!!)---back trace thru your system to the filter,--if like the 404 the filter has a screen over it on the outside and will get clogged with slime from the condensed moisture that the fluid collects from the system! ----remove it and clean it real good, then change the filter and put in NEW fluid, then comes the fun part!---Priming the pump/system!---takes a lot of messin but should finally hit solid,--unless pump is gone! thanks; sonny

Re: 300 Utility Hydraulic system

Fri Sep 04, 2009 10:54 am

SONNY wrote:-back trace thru your system to the filter,-

Well, I've got the pump off, the steel lines from the pump to the resevoir, and haven't taken the pump apart yet.

-if like the 404 the filter has a screen over it on the outside and will get clogged with slime from the condensed moisture that the fluid collects from the system!

There is no screen on anything I have apart. The resevoir on these tractors is what your seat sets on. A cast iron part of the tractor frame. I shone a lite into the innards where the suction line feeds from, and nothing in there.

-Priming the pump/system!-

I was hoping that this may have been my problem all along. Air in the system.

Now that I took the pump assembly off, I may have to remove the front of the tractor to be able to get the timing mark on the driven gear back in the correct position to keep the ignition in time.

Plus, when I got the pump off- the nut that holds the driven gear on the shaft has spun nearly off the end of the shaft, but luckily the housing it sets in kept it from coming clear off. The lock washer failed to hold it in place.

What I would REALLY like to find is a service manual for this particular tractor that has detailed vies of the hydraulic system. If there is some sort of filter system on it, it is in the resevoir area, but I can't tell where it is.

Re: 300 Utility Hydraulic system

Sat Sep 05, 2009 10:03 pm

Thinking out loud here.

I took the hydraulic pump apart today. Nothing out of the ordinary. There is a bit of scoring on the outside diameter of the aluminum housing where the "gear" teeth of the pump travel- but just on the outlet side right at the outlet. I don't see it as serious, though. Nothing on the side faces of the gears where they rub on the brass side plates. The brass was smooth, also. No wear.

Nothing else was scored or worn.

I saw a small slotted screw in the top of the pump and took it out. A spring loaded ball check valve! I didn't really notice any gunk or other substance in there that could've been holding the ball off its' seat, but it may have gotten washed out previously.

I wish I had gotten that check valve screw out when the pump was on the engine, but there wasn't any room for a screwdriver and my hand at the same time to where I could get it loose- it was at too awkward of an angle.

I think maybe that ~ 1) something was holding the check valve off its' seat and not letting the pump build pressure, or 2) that was an orfice I could've bled air out of and maybe got the system back in operating condition cause I don't think the pump was harmed by the low oil situation.

I am fretting over how to put the pump back on the motor and getting the ignition back in time without pulling the front cover off the engine (which looks like it entails removing the front axle, radiator and all sheet metal) so I can see the timing marks at the gear teeth!!Maybe I can just get number 1 on TDC compression, put the pump in, put the distributor on and see where the rotor is pointing.

There has got to be an easy way.........

Re: 300 Utility Hydraulic system

Sat Sep 12, 2009 9:09 am

Reading your post, The only thought that comes to my head is that screen is shot. You have to take the seat off and the cover. Clean the crap out of the resevoir. Sorry! After 50 years it's time. I think the screen is available from CNH. Has to be over $100 now. Remember everything has to be clean and flowing. Its like running your oil system for your home burner out of oil on a cold winter night. :censored: You sucked the crap on the bottom of the tank. Hey and please do not I repeat, do not have a Joe Kansas moment on that cover of the resevoir! :twisted:

300 Utility Hydraulic system

Mon Sep 14, 2009 9:14 pm

Well, I didn't really think there was anything inside that resevoir. I am glad you posted. I would have hated to have filled the thing back up with new oil and have to drain it all out again to disassemble the resevoir!

I will be pleased if there is a wad of crud clogging things up. What does this screen amount to that it costs so much, and surely there is some way to make one from scratch.

I have the pump apart and am going to replace the shaft seal. The one that is in it isn't shot, but is scored on its' face to where I can't read the number. I didn't try calling the Case/IH dealer locally to see if they have a reference number. I ordered what I thought was correct from the Baum Hydraulics company. In there catalog they list about 5 varieties of seals. Some are grease seals only, some are grease and oil, and one is a pump shaft seal. Problem with it is it is about 7/16" thick and there is only room for a 5/16" wide seal body.

As for getting the pump/distributor back in time, I think I have been making a mountain out of a molehill and should not be worrying about that timing mark.

I think I should be able to just get the engines' number 1 cylinder on TDC, mate the distributor to the hydraulic pump. Then, with the rotor pointing at number one cylinder on the cap attempt to install the assembly as a whole onto the engine. The gears that will be meshing are, I think, Helical spur gears. Not straight teeth. When I mesh the gears the pump shaft will be forced to rotate a bit, so if it does I'll just pull it back out of mesh and turn the rotor a bit the opposite direction and try it again until the rotor is pointing at the number one cylinder position on the cap when the pump body is seated in the block. Viola! :{_}:

Anyway, again thanks for posting that tidbit. I will take the seat off and take the top off that resevoir and go exploring.

I think I found my problem......

Fri Sep 18, 2009 10:30 pm

Put the pump back together with a new shaft seal in place, put the pump back on the engine, then put the distributor back on the pump. I still don't think my pump was ruined from lack of oil.

Decided to delve into the reservoir, which is located under the seat and on top of the transmission. A big cast iron housing. About 18" by 22" and a total of about 6 inches thick.

Got all the bolts out, took off the control valves, and lifted the top half of the housing off. It is a two part casting. The bottom half is the top of the transmission.

Anyhoo- I lift the top half off and what comes into view but a cylindrical screen filter- attached to the top half of the resevoir with a pipe nipple- and it is collapsed on itself. About an inch and a half in diameter and nine inches long. Two layers of screen- inside layer looks like 1/8th" square hail screen which is covered with real fine brass mesh. Two caps soldered on the ends, with a piece of one inch pipe protruding out the side in the middle- soldered. Couldn't see light thru it real well.

The brass mesh was basically clogged up with varnish and moisture laden gunk and the odd bit of solids. I soaked it in diesel fuel for a while and scraped off most of the exterior gunk.

It wasn't collapsed flat, just badly misshapen. Sucked shut. I unsoldered the end caps and rounded the thing back out and then set the whole screen assembly in a pan full of "Superclean" degreaser to hopefully eat all the varnish and solids off the brash mesh and end up with a new filter screen.

Now, I ruined the gasket taking the housing apart so I am gonna try some form-a-gasket (black silicone oil resistant) and make it work.

I am thinking that this was my problem all along and nothing was wrong with the pump. Before I took the housing apart, I called the local Case-IH shop and asked if there was a screen or filter down in this housing. He couldn't even find a drawing or anything for a 300 of the utility variety- all he could find was ones for the row crop tractors.........

Now I can call him back and say for sure that there is one in there!

Re: 300 Utility Hydraulic system

Sun Sep 20, 2009 3:49 pm

Outstanding! Hey CNH has that gasket! I bought mine a couple years back from Carter and Gruenwald out of Brooklyn, WI -not New Yawk, Got the screen there too. There is no farm place here :roll: just talk to The man behind the curtain, Ken Updike :lol: :lol:
Or should I say " Pay no attention to the man behind the curtain".He gave my cub ,the heart ,the brain ,the nerve.... Ok Ok I'll stop!
Must be that the Jets beat new England today :{_}:


Wed Sep 23, 2009 10:05 pm

Filled the resevoir with hydraulic fluid and started the tractor!

I had been concerned about it being out of time, but it started easy and ran fine. No way to put it under load to see how it acts- I will have to go back out and hook the bush hog and do some mowing to test it out.

No whining from the hydraulic system. I didn't bleed anything. Oil oozed out at the junction of the steel line and the resevoir! Forgot to tighten those three mounting bolts- rats!

Ran the control valve in the up and down positions and everything works smooth- and lots quicker than it used to. That collapsed filter screen must've been starving this system for a long time and I never knew any better.

Now that there is a free flowing supply to the pump- it's like a new system. I haven't got anything to put on the 3 point to put a load on it yet, so I just stood on it and it didn't hesitate to lift me and let me down.

Now, I wonder what is going to go wrong next?