New Holland (Prince) Loader Valve Will Not Stay In the Float Detent Position

[the old grind]

I have an idea if @rScotty's fix #2 doesn't work. Almost certainly the cap on that spool is a soft alloy, not steel. If so, over time, the balls could easily have worn away the "sharp edge" on the detent groove. Perhaps all you need is a new cap.

My T1520 has had this issue since I bought it new off the lot. I've always had to hold the stick in float and the detent is barely detectable when going into it. Stiffening 17 by shimming is kinda obvious isn't it?

Anyway, don't remove the cap by itself, lest the balls fall out. Loosen the two long bolts and remove the cap and outer sleeve to bench the sub-assembly. Be sure that 16 slides out with the the cap, sleeve, & outer spring all together.

 

[rScotty]

My T1520 has had this issue since I bought it new off the lot. I've always had to hold the stick in float and the detent is barely detectable when going into it. Stiffening 17 by shimming is kinda obvious isn't it?

Anyway, don't remove the cap by itself, lest the balls fall out. Loosen the two long bolts and remove the cap and outer sleeve to bench the sub-assembly. Be sure that 16 slides out with the the cap, sleeve, & outer spring all together.

Thanks for the check valve explanation. Looking at designs in detail is always fun.

Back to the detent and a possible stiffening shim, you have the advantage of me with the manual. Details of #17 and #18 are not shown. And as I look, it makes me curious about something else,,,,Why do you think that the cone, spring, and balls are also used in the bucket spool valve that does not have the ridge and and annular space that make a detent? For centering?

Shimming the spring is certainly an answer, but may not be the only one. The detent works because the balls are forced over a ridge. How many balls are there? How are they constrained? Can the number be changed? If so, would changing the number of balls accomplish anything?

rScotty

 

[the old grind]

Cone and four balls are also in the curl spool w/o a lip so that quick dump must be held vs detent to a fixed position. The cap sleeves are different between spools and could be switched with functions/connections but there's also an orifice to move over too. It's under a plug on the top of the valve by the capped end.

16, 17 & 18 are kinda crowded into the top B&W pic in post #4 with numbering arrows pointing to them. Here's another pic from the manual. 16, 17, & 18 are then shown as 13, 21, and 22 with 24/25 being the outer sleeves with groove or not. I call 22 the cone, and it's 21 that's weak and can be shimmed to hold the balls into the groove/lip more securely.

 

[toot77]

First of all, Thank You for the comments and input to my questions here. Much Appreciated!!

I only see 2 balls on each spool in the diagrams for the Prince valve. I also have been trying to understand why the bucket curl spool also has the cone & balls. On this Prince valve the bucket dump function is described as a 2 stage function with the second stage adding regen (I assume that means first stage is without regen). The older 1520's Kayaba valve (according to the description in the 1520 service manual) also has regen on the bucket dump function, but it is not described as a two stage thing.
The information below is for the Kayaba valve, not Prince.

Is it a safe assumption that regen is a pretty standard thing on loader valves for the bucket dump function on compact tractors? I am curious because should shim(s) not help the Prince valve (or I loose the balls in my garage), I do have a spare nos Kayaba valve as a result of an ebay bargain some 16 years ago.

My 1520 has never had a loader on it. It has the 7108 loader valve as part of the front snowblower, so i do not know how well that valve actually works with a loader. Looks like New Holland switched to the Prince valve for the 7308 and 110TL loaders. According to New Holland, the Prince and Kayaba valves are interchangeable although both are listed as obsolete.

Is there any real functional difference between these valves?

 

[the old grind]

Net functions are the same for both valves, just different ways of achieving them mechanically. btw, I had a 7308 FEL on my 98 1520, traded in on the T1520 & never saw which valve was on the former.

The KYB valve/info might only confuse us, & the old SB is in regards to that one. But in both cases it's the force keeping the balls seated that is lacking and the simple cure is to increase it with more spring pressure. That's our only and common issue.

Four balls in the Prince valve but only two show in cross section views, and what looks like a wedge is really cone-shaped. The balls on the curl valve don't have a detented position that stays, but must be held by the operator for rapid dump. Pretty basic and easy to overthink all this, but we'll get there.

 

[jmc]

In case no one mentioned it, Kubota had a rash of loader valve malfunctions that sound like yours and there were several good threads on fixing it if you can search for them.

IIRC, the consensus was that the earlier ones didn't have the weep hole so condensation would rust the detent assembly or freeze up in the winter. Members reported drilling their own weep hole. I ordered the new subassembly and the replacement had a weep hole, so, a design upgrade.

 

[macdoesit]

I have a 2010 New Holland T1520 with the 110TL loader. The OE loader valve is a Prince valve. My problem is that the valve will not stay in the float detent position when using my front snowblower. I have owned this tractor for the past 2 years.

I also have a 1995 New Holland 1520 (which is what I have used the snowblower for the previous 27, or so, years. The OE loader valve on the 1520 is a KYB Kayaba valve. While it has worked fine, i.e. usually stays in float, I do have a 1993 service bulletin for the Kayaba valve that my dealer gave me in 1997 that describes adding a 0.075” shim to the detent spring to improve keeping the valve in float detent by adding 8 lbs force to it. I must have questioned it once way back. I do not recall if I made the service bulletin mod.

My question is; is there a comparable mod that can be made to the Prince valve to make it stay in float detent? The Prince's detent does not look like the Kayaba service bulletin diagram.

The prince valve casting number looks to be C-689 Rev G, but is hard to read.

Mine did the same thing, it would not stay in float. Mine is exactly like yours, I took the blue cover off and noticed it would stay in float position. When I put the cover back on I noticed the joystick was hitting the cover, I took a round rasp and filed the cover down a smidge where the joystick rod was hitting the cover and it now works as it should.

 

[toot77]

Regarding the handle clearance with the cover, I don't think that is an issue. Here are a couple photos of the valve with a cover minus the boot and handle. First is with valve in neutral position

Next is with the valve in the float position

A thought that did pop into my head a bit ago, is whether the length & weight of the valve handle extension is helping to knock the valve out of float. The float detent feels pretty firm when operating the valve without the handle extension. The T1520 valve handle is about 19" long which is 5-1/2" to 6" longer than the handle on my old 1520 (with Kayaba valve fwiw). I know that it is enough longer that it is more in the way when getting on and off the tractor.

 

[toot77]

I jumped into it today and disassembled the float detent. I did remove the valve so I could do it on the bench (at least for first time). It did come apart easily, as I was told on here several times in past few days. (Thanks again for all the input). This is what I found

The balls, cone, and spring were well covered in grease. There as no rust, dirt, grime, scale. There are only 2 balls. Maybe saving the cost of 2 extra balls helped Prince get the New Holland bid from Kayaba??
For anyone else who tries this, I noted dimensions needed to select the shim(s). The 'G' dimension is the size of the largest drill bit that I could easily slide into the bore where the spring sits, so the ideal, or max, shim OD looks to be about .260". I do not think it is necessary for a shim to have a center hole to clear the rod on the back side of the cone. I am thinking to start with .060"-.075" for thickness mainly because that was the recommended shim thickness on the old SB (I know it's different valve but it is a starting guess). If I don't find something around here, I will probably order shims from McMaster.

Also, taking it apart is easy. After removing the rear detent cap and its 2 screws, I just wrapped a rag around the detent collar, including the end, and slid the collar back. Between the rag and the existing grease, nothing acted like it wanted to take flight. Getting it back together, maybe not so easy. The axis of the bore where the balls set is rotated at an angle that I don't have anything to safely pinch them into place while sliding the collar back on. I haven't quite figured that out yet, but thinking of making a plate that I can fasten to the valve base plate with a bolt to function as a jack screw to push and hold the cone in.

 

[rScotty]

Regarding the handle clearance with the cover, I don't think that is an issue. Here are a couple photos of the valve with a cover minus the boot and handle. First is with valve in neutral position
View attachment 2123902
Next is with the valve in the float position
View attachment 2123903

A thought that did pop into my head a bit ago, is whether the length & weight of the valve handle extension is helping to knock the valve out of float. The float detent feels pretty firm when operating the valve without the handle extension. The T1520 valve handle is about 19" long which is 5-1/2" to 6" longer than the handle on my old 1520 (with Kayaba valve fwiw). I know that it is enough longer that it is more in the way when getting on and off the tractor.
View attachment 2123904

Nice idea. Will you be making up a lighter handle just to check?