/ Pilot Control Spring Mod #1  

Jay Flay

New member
Joined
May 17, 2025
Messages
2
Tractor
AGT KU-18e
Hello - new to this forum. I ran this by a longtime member first and he suggested I post to the group. So here you go...

What is everyone's experience with the Pilot Control Spring Mod, if any? Any thoughts, questions or concerns about the mod? The following is what I know about the mod and I do not profess to know it all, so always open to hear from others.

FULL DISCLOSURE: First, I own about 1.5 acres, own an old (but awesome) Case 1840 skid loader, own an AGT KU-18e mini-ex and I also happen to work for a spring manufacturer here in Oregon. I designed a custom spring kit for my mini and about 6 weeks ago decided to offer the kits for sale. For details... WWW.PILOTSPRINGMOD.COM

WHAT IS THE MOD? If you are not familiar with the mod, the goal of the spring mod is to "help" people settle down jerkiness in the hydraulic controls. I was exposed to the mod on Facebook Groups where guys were buying cheap springs on Amazon, using dykes to cut them down, and sliding the cut spring over the pilot pistons to add "resistance" to the joysticks. From what I can tell, this early cut spring mod was hit-n-miss as far as performance. Some guys felt a difference while others did not. Many of the guys who tried the cut spring mod and did not notice a difference are trying my kits and becoming raving fans.

MY KIT - Bottom line, I wasn't willing to have sharp steel wire flexing in my pilot control assemblies and I wanted maximum "resistance" within the small pocket available. So I went to work. The amount of material, number of coils, wire diameter, tensile stresses, solid height, and end finish all contribute to function, performance and cycle life. Prototyping resulted in my GEN1 and GEN2 kits. NOTE: I did an experiment where I used a digital fish scale to measure push-pull force with and without the kits installed if anyone is interested in that data let me know.

MY OPINION - WHY THE MOD IS SO POPULAR The way I describe the spring mod...when done correctly, the springs safely deliver a more tangible connection of the operator (joysticks) and the machine hydraulic functions. This is especially helpful for inexperienced operators (probably 80% of people who purchase these inexpensive machines). The incremental improvement in joystick feel makes a big difference and enables guys like me to enjoy the process of acclimating myself to my machine controls, find and stay in the sweet spot for controlling hydraulic functions on my machine and more importantly get the required seat time it takes to truly smooth out operation of my machine.

PRIMARY CONCERN SO FAR - The primary concern people have had regarding the mod is scoring/scratching on the surface of the pistons, especially in the "piston stroke" zone (bottom .300") let's call it. I addressed this concern on my GEN2 kit springs using a coiling feature where both cut wire ends of the spring are flared out (.010" - .020") away from the ID of the part. The subsequent coil above the cuts, makes it impossible for the cut wire ends to reach the piston surface. One of the attached images shows the feature circled.

NOTE: I do not believe the spring mod is a cure. Seat time and technique are the real cure. But after six (6) weeks, selling almost 500 kits in 6 countries, working really hard to find (I cannot find any so far...knock on wood) issues and unhappy customers, and piling up almost 60 5-star reviews, I am a believer in the spring mod. It makes a difference and across the board guys are enjoying their machines. Seat time and productivity are up.

All feedback welcome. Thanks everyone!

James
 

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   / Pilot Control Spring Mod
  • Thread Starter
#2  
SOME NUMBERS - I recently attempted to try and quantify the difference my custom pilot control spring kits are making. 5-star reviews are huge, and very important to me, but WHY are owners raving about the kits? So I used a very rough but relatively repeatable data collection process to measure how much pull force is required to pull a joystick close (but not all the way) to full stroke. I measured factory (no kit) first, and then I measured the pilot controls with both my GEN1 and GEN2 kits installed. I collected five (5) measurements for each setup, then I averaged the measurements to arrive at the numbers below. Here is the data...

FACTORY: 13.2 oz (0.83 lb)
GEN1 SpringPilot Kit: 30.4 oz (1.90 lb)
GEN2 SpringPilot Kit: 36.6 oz (2.29 lb)
 

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