Reverse Engineering, 424 Hydraulics

I've done some studying of the manual. It seems 90% of the technology in the cylinder block of components is dedicated to moving the arms to a select position in relation to the shift quadrant and holding it there (draft).

After my conversion, what I will have remaining is the standard up/down by spool alone, similar to the old external proprietary MH cylinder. I intend to purchase an external in line relief valve, either in the spool or in-line because I don't want to go in and fool around with any F*&*&^%-up relief valve in the lift housing again. Besides I would have to block off more orifices to make use of it. All the trinkets and linkage I can say goodbye too and I'll junk. The disadvatage is resale value
as anyone looking for position control won't have it, neither will they have draft control. But most around here are just happy to have it lift and working. Might even be a plus, as less probability for mech failure.

Down will be under dead weight. Expected problems will be tweaking for no cavitation, but with a 7GPM pump I don't expect much of a problem. Also is thread tapping without getting the filings in the works. Brazing and welding is out for fear of cylinder distortion and there isn't much room for error. I was thinking of using an external in line filter for the suction side. Why? Funny that you should ask, the price is .... get this... 300$
for the filter and tube assembly from CASE.!!!! It's filtering OK now but if ever I need one, I'll convert.

I'll need a single 3 way single spool to lock in up position, neutral and down. Down is simply a return to the reservoir by unseating the ball for position 2. All this set to 2400 lbs on the relief valve.

Input line to the cylinder will be accessed thru the accessory outlet port screw, but I'm not restricted to that. Hopefully I can aways drill and tap a new orifice.

I'll use the quarant shaft housing on the right side of the driver seat to mount the spool. The double spool aux valve will stay where it is on the rh fender.

The only reason all this is possible is because it appears it is possible to isolate the piston by blocking off the position control orifice, which leads further into the regulator.
I can do that I think by taping in a NF bolt in the PC housing. I may have to ground down the cylinder head at that spot to accept the head of the bolt.

Anyway I'll know more if I can do it when I take the assembly off myself.

Starting soon, will keep you posted and maybe post some blueprints if it works.

I see you emailed me about the manual for the 424.
The email spam filter caught it, and I happened to notice it in the qaurantined items tonight when I was searching for another email someone sent.

It sounds like you have one of the manuals I have, but I think I have 2 more that pertain to that tractor. There is lots of troublehooting information. I am at home tonight, 24 miles from my shop, but will look tomorrow to see just how much info. I have.

It's your tractor, and it's not for me to tell you what to do with it, but I can't understand why you'd want to butcher the 3-point system. These little tractors are somewhat rare, and becoming collectable, and cobbling up the hitch hydraulics would sure knock the heck out of it's value. If I recall from your earlier post, the hitch was working, and quit suddenly. I'm sure it's something quite simple, if you take the time to go through the troubleshooting procedure, and narrow the problem down to the offending component. As I stated before, I have a 424. We have worked the heck out of the three point with a 2 bottom plow and a 6 foot Bush Hog for years, and have never had a lick of trouble with the three point. I also own an old Ford, and the three point on the 424 works like a Swiss watch compared to that tractor.

I gather the fact the valve system is so complicated frustrates you, but it really is a sophisticated system, and probably should be considered advanced for the year of manufacture. With a little patience, it can be made to work again. Email me again if you are interested in the additional info. for this system.

If I recall correctly, the hydraulic filter on this tractor is in the pressure line coming OUT of the pump, which is a bit unusual, but should be good, for the fact it would catch any filings from the system before they get to the 3-point hitch valve. The fact that the filter is rather unusual, and probably specific to this series of tractors explains it's high price.

Good luck, however you decide to procede.

On the filter, it has a suction filter in the line that goes to the pump. It's a 1.5 X 7in jobbie, and costs a fortune. There is another small screw type filter that's just before the regulator on the pressure line. That's the one your talking about I think.

(On the subject of filters the stainless coffee filters you get for a few dollars might be useful, and they seem to be a few microns finer than on the tractors. Might be a good last resort if you can't find one. You'd have to make it fit somehow and use a larger sq. in. area of mesh to make up for the finer mesh).

While I'm doing a tear down, I'll be on the lookout for the problem and if I can fix it I will, but the conversion is a last resort.

Thanks.

Les see, no lift at all. I assume your hyd motor isn't under load, evident by a working engine. That means your getting flow thru. Your other system also works which tells me your flow and pressure is OK. It could be the linkage at the position plunger. I'd turn off the engine and drain the reservoir and remove the top plate. It's a good idea to have one of those 1.5in swivel mirrors on a stick that they use for finding small screws that fall in the engine compartment on occasion. You can get em at a dollar store I think. Shine a small pen light in the reservoir and slowly pull the position lever to lift. The manual continues.... "the linkage moves the roller away from the rockshaft cam. This allows the position control plunger to move out under spring pressure opening the regulator bleed port" .... and so on.

So watch the position plunger to see if it is being activated by the linkage, if not the problem is in the linkage. My tractor has a small short chain that I assume was replaced by a solid arm in later models. Yours is a 444, so it could be a later make. I discovered my chain was disconnected, that would cause the problem.

If it's working OK, the problem I figure is internal and you may be a candidate for conversion too, or else clean off that work bench and put a nice clean sheet on it, have a compressor for blowing out orifices and start cleaning and disassembling. Some of the other guys here may have a better idea of the problem.

Let us know what you find.