This discussion has come up several times in the past on other forums but has never been resolved to my satisfaction. In my opinion, there is only one way to come up with a definitive answer and that is for someone to try one of those valves out on their tractor and compare the operation of the valve to another tractor of the same model that has the OEM holding valve kit on it. Jump from one tractor to the other and put them through identical testing.
I am nominating case448 for this experiment. All those in favor, post your affirmative vote in this thread. :sidelaugh:
So...... all of the above aside, let's talk about the practicality of using an aftermarket valve such as the one referred to in this thread. For argument's sake, let's say that valve works. That's only half the problem. The other half is the mounting and connecting of that valve to the tractor. Take a look under your tractor and tell me where there is space to place that valve where it will not impact on ground clearance? It's bad enough on a Hi-Wheel model but on a Lo-Pro series, you will constantly be concerned about snagging things if you take the tractor off-road into rough terrain. On top of the clearance issue, you will be faced with purchasing several hydraulic fittings and custom hoses so that you can connect this valve. Once you add those costs to the price of this aftermarket valve, it doesn't look like such a bargain any more. The price gap narrows to the point where you have to ask yourself if all the aggravation is actually worth the few bucks being saved?
While you dislike the idea of paying $200.00 for an OEM holding valve kit, the fact remains that you can install the correct kit on your tractor in about one hour's time and you are good to go. There is no engineering involved or running around to chase parts. The valve kit you buy today will likely never go down in value and most likely will increase in value as time continues to pass. I can't say that an aftermarket valve and a bunch of hoses will do the same thing ten years from now because hoses have a limited life expectancy.
The other day I read some advice on another forum by someone who believes himself to be knowledgeable about these tractors. He told the person who was asking about holding valve kits that he should TRY to buy a valve that had all the lines with it. That was just another piece of bad advice in a long list of bad advice that comes from this person. Case produced several Holding Valve Kits and if you buy the WRONG kit, it will come with the wrong lines and you won't be able to hook it up. Secondly, if you do not get a complete kit, then you are screwed again because almost all of the steel lines are NLA (no longer available) from Eastman. Perhaps........................you may get lucky by phoning every Ingersoll dealer to see if they happen to have the line or lines you seek gathering dust on a parts shelf but the odds are not in your favour.
We have a FAQ's section here that has a document that speaks about holding valves. You may find it to be an interesting read.