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

[toot77]

Update; I ordered a .060" shim and while waiting to it to arrive, I did some crude measuring and learned that the detent spring has about 0.44" travel between full length and full compressed length. Some more crude measuring gave an estimated travel for the cone of up to 0.47" to compress the balls sufficiently to lock into the detent. Didn't look encouraging for the shim idea. I did get the shim today and tried one .060". Doesn't begin to barely move into float detent before travel is stopped apparently by the bottomed out spring. I am fairly certain a .030 would not work either. I could not locate a spring with that same OD that would be any stiffer. Another thought I have is to try drilling a couple additional holes in the detent collar and add 2 more balls for a total of 4. I am not sure if that would help.

Fwiw, using a fish scale, I meaure a force of 3 lbs pulling straight horizontally at the lever knob to pop the valve out of float.

I guess I will go back to the beginning of this thread and re-read some of the other suggestions. In the meantime, I have my spare Kayaba valve installed on my T1520 and have now used it twice to clear my two driveways. The Kayaba valve, with the long handle, has not popped out of float at all, zero, none. So I will probably leave that valve on for now and see if i notice any difference when I put the loader back on in the spring.

 

[rScotty]

Ok. So now it gets a little more technical to mess with the spring and ball latch.

Here is one way to go about it...Since you already know the spring force is not enough to stay latched, the existing mechanism can become one of the data points. So I'd go ahead and measure the force per deflection - it should be linear for compression springs not moving very far. Then with that spec, you could go to McMaster and find that spring spec in a spring with a greater pitch - spring pitch is the free distance between coils in a compression spring. Greater pitch would create room for a shim at the end.

Keeping in mind that since similar spring force with a larger pitch implies a larger spring wire diameter, make sure there is room in the bore.... or perhaps over-bore it slightly.

Say, whatever happened to the idea of just using using a lighter valve handle? Did you try it? Seems like the easiest solution.

 

[90cummins]

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.

My tractor does that same thing. A slight bump & it moves out of float. My solution was to attach bungee cord to lever & give it enough tension to hold it in place.

90cummins

 

[jigs_n_fixtures]

I bought my tractor used. I was having issues getting mine into float. I took off the cap, and found a bunch of crud which had accumulated, blocking the travel. Cleaned it out, and everything worked just fine.