400 Loader Spool Valves

krumenacker · Feb 22, 2019

I have an Allis 400 loader on my 5050. New pump and rebuilt cylinders.

Both the up and tilt on the bucket drop immediately.

The problem appears to be in the spool check valves. Looking for parts, hard to find springs,etc. should I rebuild?

Cross, etc have cheap replacements.

Suggestions?

Traditional Farmer · Feb 23, 2019

I'm getting ready to add a separate value to the loader on my Oliver 1550 so I'm going to mount the new valve on the right fender and at the same time I figure I'll add a couple
extra remotes for the rear so it'll need a 4 valve unit.Getting it from Surplus Center will be a little less than $400.If you need extra remotes now is a good time to add them.

krumenacker · Feb 23, 2019

Thanks, saw surplus suggested in other threads, will check them out.

Joe(TX) · Mar 15, 2019

I don't think the valve has check valves. Most don't. It is more likely the cylinder seals on the pistons leaking

krumenacker · Mar 15, 2019

(quoted from post at 08:29:30 03/15/19) I don't think the valve has check valves. Most don't. It is more likely the cylinder seals on the pistons leaking

As stated in original post,
cylinders are newly rebuilt, don't leak, and new pump.

All four cylinders have no hold in either direction, and appear to drop evenly. I cannot use the tractor because I have to have my hand on the lift spool at all times.

The problem has gotten worse even as I have fixed these other issues. The other fixes resolved many problems, but it still has no hold.

19 74996403 2 PLUNGER, lift check
20 74996404 2 SPRING, lift check plunger
21 2 O-RING, lift check plug (Not serviced; use O-RING KIT 70346304)
22 70344011 2 PLUG ASY., lift check (Incl. O-RING)

So I believe the problem is in 19 and 20.

These may not be the problem and it may not have a check valve. Please give more information so that I may solve this problem.

Thanks,

DrAllis · Mar 15, 2019

I think those valves do have load checks in them. I have a question for you. Are you sure you don't have the hoses to the cylinders hooked up bass-ackwards??? You should have to PUSH forward on the hydraulic levers to raise the boom and roll back the bucket. If you are wrong the load checks can't work.

Jim.ME · Mar 16, 2019

DrAllis,

Are those valves backwards of "normal"? Most loaders, I am familiar with, you pull back on the lever to raise the boom. Push forward and it should lower, and go/lock into float (if valve has it) when the lever is fully forward. The bucket curls back when the lever is pulled back and dumps when pushed forward.

DrAllis · Mar 16, 2019

Use the "float" position to prove me right or wrong. It's been 20+ yrs since I've ran one but I'm sure the levers are BACKWARDS. if FLOAT IS REARWARD, THEN RAISE IS FORWARDS.

DrAllis · Mar 20, 2019

Waiting for a verdict on this loader problem...………….

krumenacker · Mar 26, 2019

(quoted from post at 05:21:36 03/20/19) Waiting for a verdict on this loader problem...………….

Thanks to the good Dr. for noticing.

This is my Dad's loader tractor. I've operated it since I was a kid.

The cylinders and hoses are correct and working correctly. It just keeps getting weaker.

I tried using springs from the hardware store in the check valve last summer, it worked about an hour until the oil got hot.

Jim.ME · Mar 27, 2019

Just trying to think of things it might be. It seems strange both the boom and bucket circuits are having the same issue at the same time. I don't have anything to look at and can't find that parts book on line for reference.

What is the history that lead you to replace the pump? Did you pack the cylinders or have a shop do it? Cylinders can leak internally and you can't see that. Packings have been damaged during cylinder assembly at times. Two levers or joystick? Can you make it hold if you get the valve just right? If so that could be the centering springs. Just curious. Does it have a float position for the boom lift and is it way ahead or way back? Do you push or pull the lever(s) to lift the boom and dump the bucket?

Have you checked to see if the OEM parts are available from an AGCO dealer? A new aftermarket valve may be a better option than rebuilding your valve.

Aaron SEIA · Mar 28, 2019

www.agcopartsbooks.com Log in as a guest and search "loader". The All Loaders book is there and has the 400/500 valve spool in it.
AaronSEIA

Jim.ME · Mar 28, 2019

Thanks AaronSEIA. My mistake, I was looking for a 400 book.

krumenacker · Apr 27, 2019

It is in the spools. When I say other things are newly fixed, I mean in the last few years.

If asking why other repairs, it was running on a pulley off the pto when I purchased.

The weather has improved and I've had a chance to work in above freezing temps.

AGCO doesn't support. Parts are unavailable.

I sanded the old brass valves, replaced the springs with springs from a WD pump, and will test.

Next step is after market spools.

400 Loader Spool Valves

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