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A Simple Guide to a Compressor Valve Rebuild

Compressor Valve Rebuild | KB Delta

Compressor failure is no laughing matter, the cost can definitely damper one’s day. The first thing on most people’s minds is to throw it away and buy a new one. This is actually pretty costly in itself, because there is not always the need to actually throw it away when you can rebuild it. Compressor valves are made up of multiple parts that work together to create the valve, and if one of those components go bad then the valve is considered failed. However, often by replacing certain parts, you can complete a compressor valve rebuild and avoid having to replace the valve altogether. If your valve has failed, instead of spending money on a completely new valve, use this article as a guide to walk you through the process of a compressor valve rebuild.


Diagnose the Problem

Any number of problems can occur when a compressor fails. However, when a compressor valve fails there are different symptoms you can check out immediately. To make sure it is in fact the valve that has failed, ask yourself the following questions:

  • Is the refrigerant not moving properly within the compressor?
  • Is there sludge within the system?
  • Is there oil or lubrication loss?
  • Is the compressor overheating?

If the answer to these questions is yes, it’s likely that the compressor valve is the problem. But before the compressor valve rebuild, check the rest of the compressor to make sure the valve is the culprit.


Parts of a Compressor Valve

It will be helpful to familiarize yourself with the difference parts of a compressor valve.


These are the pieces of the valve that make sure that the oil and the coolant stay in the compressor. Typically two different surfaces cannot be machined absolutely perfectly, this is why a gasket is so important. It buffers the gap between the two surfaces, making them watertight. If one of these fails, you will likely see oil, lubrication, or refrigerant leaking. However, in some instances, the gasket could fail resulting in mixing of liquids within the compressor. This will most likely showcase itself through oil, lubricant, or refrigerant loss without the actual sight of these on the ground or on the compressor.


O-rings serve a similar purpose as a gasket. It is typically used between two surfaces on a valve, there is an indentation where the o-ring will sit. The reason for the indentation is to make sure you use the correct size of o-ring, while making sure the o-ring is in the perfect location, making human error near impossible. If there is an o-ring failure, you will typically see a leak from a fitting, or just a loss of oil, lubricant, or refrigerant.

Guide Pins

Guide pins typically do not fail unless handled outside of their general application.  However, if a guide pin does fail you can count on leaks, as well as over heating. The guide pins make sure that each piece is aligned properly so that there is an extremely small margin for error when the compressor valve is assembled, or reassembled. The guide pins seat in a component, and the alignment holes allow for perfect fitment when assembling the other components on top.

Spring Plates

The spring plates are typically used to buffer the operation of the compressor. If a spring plate fails you can expect noise, as well as possible leaks coming from the compressor. The spring plates “bounce” with the movement of the internals of the compressor, giving to the stress of the machine, protecting the other components of the valve.


These can include:

  • bolts
  • studs
  • lift washers
  • lock nuts

Each piece of hardware serves its own specific purpose. The hardware that is on the old valve should be replaced when it is rebuilt, a good rule of thumb is if you don’t know, do it anyway.  When there is force applied to metal, it can deform the hardware. Even a slight deformity can cause structural weakness in the hardware that can break sooner than you think. The most common issue with hardware is thread galling.


When to Start a Compressor Valve Rebuild

With all of the essentials now known to you, the ability to understand when you should rebuild your compressor valve is of vital important. If you notice anything out of the ordinary, such as the symptoms stated above, then you should look into rebuilding what is damaged. The valves can cause a plethora of problems if you leave it unchecked, not just to itself, but to surrounding components.  The result of the “Domino Effect” from not keeping a check on the valves could lead to complete compressor failure due to excess heat. The reason for the heat is because the compressor may not circulate the oil or lubricants properly, or just the lack of the two due to a leak.


How to Remove Your Valve Plate

Typically, you can find the compressor valve seated below the cylinder head on the compressor itself.

  1. Make sure the compressor is drained of all air pressure.
  2. Disconnect the lines coming from the tank to the cylinder head.
  3. Carefully take out the bolts of the cylinder head.
  4. Remove the cylinder head from the valve plate.
  5. Removing the valve plate.

Make sure to be careful when removing parts so that you don’t damage anything during disassembly.

To reassemble the compressor, follow the instructions backwards, making absolutely sure you do no cross thread any bolts.


In Conclusion

The compressor valve assembly is extremely important to the compressor. Not only does it regulate the air, oil, lubrication, and the refrigerant within the compressor, it also serves as its own noise dampener. The spring plates take some of the vibration out of the compressor during normal working conditions. The spring plates, gaskets, o-rings, guide pins, and hardware work in conjunction with each other to make a functional part.  If any of these things go bad during the compressor valve rebuild, you will have a valve failure. Also remember, replace the hardware whenever you rebuild your valves. If you choose to use old hardware, make sure you look toward the future at problems that may occur if you do. Rebuilding a compressor valve is a great choice, but you should not have to rebuild it prematurely due to hardware failure.

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