Let’s start by quoting a Service Bulletin from Meyer Products talking about the elimination of couplers on hydraulic units dated April 2008;
“…reducing hydraulic problems caused by leaking, inoperative or restricted hose couplers.” We wholeheartedly agree. Now, couplers are a necessary evil if you are running a Custom Classic or EZ Classic. What can you do to prevent “hydraulic problems caused by leaking, inoperative or restricted hose couplers”? Well for the leaks all you can do is keep an eye on your couplers and change them if they are leaking. Inoperative is often hard to tell. It may surface as the plow getting stuck angled to one side, or it could be as simple as rust build up making it hard to couple and uncouple them. Couplers are critical to proper plow operation. They are not a place to take the cheap route. If they are rusty, replace them. If they are leaking, don’t watch the drips, replace them. Remember where oil leaks out water can get sucked in.
Let’s look at couplers:
On the left are “Ball Type” Couplers. By far these are the most common we see on pumps that come into our shop. They are also the most unreliable in our experience. In fact, we do not even sell them. If they are so unreliable then why do so many people use them?
1. They are cheap.
2. They are what came on many units for many years.
3. They are available from many sources.
4. They are cheap.
5. The person selling them says they work fine, or they are what you need. (Bad advice)
6. They are cheap.
We often have them come in on units, and they are aftermarket, and often rated at 3000psi or less working pressure. The E-47 that first used them, has a pump pressure of around 1650psi. Ok, great, they are rated at 3000psi. Now, the Crossover Relief Valve on the E-47 opens when the pressure in one of the hoses reaches about 3800psi. That doesn’t necessarily mean that the pressure in the hose is 3800psi, it means that is when the valve pops open. The pressure in the hose can easily reach 17,000psi, depending on how fast the vehicle was moving when it hit an immovable object. Scary, huh? Sometimes it only takes exceeding that 3000psi rating once to cause a ball type coupler to fail, and only allow fluid to pass through it in one direction after that. When fluid tries to flow in the other direction, the damaged coupler acts like a check valve. That is why in the Troubleshooting Guides from Meyer they often suggest to “replace the Couplers” when there is an angling problem.
On the right are “Pin Type” Couplers. These are what we sell. We use both Genuine Meyer and aftermarket with excellent success. It is not that they never fail, it is that they are more reliable and fail a lot less than the old cheap Ball Type couplers. They are typically more than twice the price of the Ball Type couplers, but they are 10 times more reliable. We use Pin Type Couplers rated at 4000psi working pressure with great success. You can only go so high when it is 1/4″ pipe thread.
When the E-57 came out, it had a newly designed Power Angle (PA) Block. It used the Pin Type Couplers that you see on the far left, and far right on the PA Block in the above photo. Around this time Meyer also switched to Pin Type Couplers on the E-47 and E-60 units as well. The E-47 and early E-60 units used the two (hose End) in the center of the photo on the hose ends, and on the PA Block as the PA Block has Pipe Threads like the hoses.
The E-58H and others listed above used the couplers pictured above. They have been eliminated on all production units as of April 2008.