I was wondering if anyone might know something about a ride control on a 420? The ride control only slightly works, to the point where you can barely tell if it is on. It has been leaking at the "pressure control switch" for quite some time and I pulled it out today and could not get the plunger to extend like a regular soleniod when I hooked it up to a car battery. I noticed the pressure switch was located on the line that lowers the boom, and not the line that raises it. When I first crank the machine up in the morning with the ride control off, the front bucket will lower slowly for about 6 inches or so. During the time that it is lowering slowly, if I flip the ride control switch, it will settle faster. I can turn the ride control off and raise my front tires up about 8-10 inches off the ground with no problem, then flip the switch and the tires will settle to the ground, which is what is supposed to happen I think. I guess the solenoid in the house is working, but not the pressure control switch. Just was wondering if anyone had ever had a problem with a ride control or not. The local dealer will charge an arm and a leg to fix what I think is a simple problem and I am trying to tackle it myself. Any tips or suggestions would be greatly appreciated. Thanks.
ride control is there any way to maybe get the solenoid/pressure control switch un-stuck since it appears to be hung in the fully retracted position?
whats your serial? Actually the pressure switch you mention is supposed to prevent the machine dropping when it is raised up on the bucket, when there is pressure on the rod end it should close and prevent the ride control to activate. Measure and see if it is open when you have the bucket up and closes when you lift the machine. It sounds as your valve is working as it should also since you get a slow drop in the morning when the oil charges the accumulator slowly through an orifice and then faster when you activate the ride control and the valve opens. I'd suggest you get the pressure checked in the accumulator, it should be right around 270 psi. if the charge is wrong it won't provide the right dampening.
How should I measure to see if the value is open or closed? If I raise the bucket or the front of the machine with the bucket, won't fluid pour out of when I remove the switch? Should the valve visibly open or move in some way if power is turned on and it hanging down under the machine or if connected to a car battery? The valve is is fully retracted into its housing where the wires connect. I had no idea the pressure in the accumulator should be 270psi, I was assuming 2700psi at least. Never knew!
Another bit of info that might help is when I bought the machine, the ride control completely would not work. When I investigated further, the plug supplying power to the pressure switch was not plugged in completely, i guess hydrualic fluid leaking on it and vibration caused it work lose. When I plugged it up snugg, it made a sort of quick spewing noise, then the ride control worked at roughly 50% according to the previous owner who was comparing it to when it was new. over time it has gotten worse and worse. My initial thought was low pressure in the accumulater thinking that some of the nitrogen might have leaked out with the hydraulic fluid at the pressure control switch, but now I am not so sure. As far as the serial number goes, I can only remember the first 3 letter which are FDP.....
The pressure control switch probably is working correctly. I just remembered that I can turn the ride control on, raise the front tires off the ground. It wont lift of the ground for a second or two and then it kicks in and raises the tires completely off of the ground as long as i continue to push foward on the lever, but soon as I release the lever, the tires settle to the ground. A local mechanic said the pressure switch should be magnitized slightly when activated. Havent had a chance to check that out yet. But just cant figure out why the ride control worked better after I plugged the pressure control switch up several months ago if it is only meant to help with maintaining down pressure? Where would be the most likely place for the nitrogen to leak out? The entire valve is covered with oil and dirt from the leaking pressure control valve, but the point where nitrogen is added, is clean as a whistle. Just racking my brain trying to diagnose and fix a problem with something that is completely new to me.
You mean the solenoid on the valve? that creates a magnetic field when energized. The accumulator is basically a cylinder with a piston inside that separates the gas from the oil and over time the piston may leak some allowing gas the escape out into the oil or letting oil in to the gas, when checking for the correct pressure you can let some gas out and it should be dry without any oil large amounts of oil. the gasfitting can leak as well but since it only should come dry nitrogen gas there a leak is hard to spot. I think most equipment shops can check the accumulator pressure for you, the fittings are standard. The switch can be checked without removing it, take a multimeter or test light. Pin A is ground Pin B not used Pin C should be grounded when the switch senses pressure. But as you say, it doesn't affect the operation of ride control, it only can shut it off completely but then the dashboard light should turn off as well so it can easily be seen if thats the case.
thanks for the information. I have a better understanding of how the system works now. I will have the pressure checked as soon as possible. the only thing that is still confusing me is why the ride control started working better after I plugged the switch up snug. who knows?