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Air Compressor Quick-Connect Leaks – Why & How to Fix

Published Categorized as Compressed Air Plumbing, How To Guides No Comments on Air Compressor Quick-Connect Leaks – Why & How to Fix

Quick-connect fittings are reliable and very popular connections used on possibly every air compressor system. Air leaks, possible in any part of the compressed air system, are commonly found at or around quick connections.

This page will provide you with information on why your quick connect may be leaking, how to fix it and replacements readily available!

Table of Contents

Air Compressor Quick-Connect Leak Impacts

So what are the consequences of having an air leak at your quick connect? First of all, the cost of energy is going to increase leaving you with an overly inflated electricity bill. Air compressor quick connect leaks will cause a loss of pressure within the compressed air system.

These losses in pressure will thereafter reduce the performance of the air tools or other attached pneumatic devices. The inconsistency of the air pressure will cause an increase in production time and also have a poor effect on the quality of the results.

When your air pressure drops below the optimal PSI for your air tools you may immediately think “I’ll just increase the pressure at the air compressor”, not considering whether you have a leak or not.

If you were to do this (which by the way is absolutely not recommended), your air compressor will need to cycle more frequently which will lead to greater costs and a potential decrease in the compressor’s lifespan due to premature failure.

When I say cycle, I’m referring to duty cycle which is an ever-so-important feature of any air compressor. If you’re unsure what this is, please visit our Air Compressor Duty Cycle guide!

Why Does My Air Compressor Quick-Connect Leak?

The end of almost any line coming from an air compressor is fitted with quick connect couplers. These couplers are connected and disconnected an unbelievable amount of times, dragged across shop floors or garages, and dropped on hard concrete or other surfaces.

Therefore, it becomes quite easy for them to become damaged and begin to leak. On top of this, if you do not install the quick connect properly or it is an incorrect size to your needs then pressurized air will be able to leak out.

Air compressor quick connect leaks can also occur due to a problem with the fittings sealing. The majority are designed to seal internally using O-rings hence there typically is no need to use PTFE tape or dope on the threads. Damaged O-rings, whether they’re scratched, chipped, or broken will allow air pressure to escape.

As there are so many types of quick-connect airline couplers available, from industrial to automotive types, it’s highly likely that you have two incompatible types connected to one another, resulting in a leak. This is a very common reason for air compressor quick connect leaks.

Industrial-type couplers are Type D and are 1/4″, whilst automotive couplers are Type C or Type G and can be of sizes 1/4″ and 3/8″ respectively.

How to Fix My Air Compressor Quick-Connect Leak

First of all, check your compressed air system thoroughly to ensure the quick connection is the cause of the leak. If it is, there are a number of ways to go about fixing the issue.

I would advise that if there’s any evident damage or no issue with the seal then replace your quick connect with a new one! They’re typically not that expensive and it’ll be far more worthwhile. I will provide some replacements further down the page.

How to Replace a Damaged Quick-Connect O-Ring?

If you have a damaged O-ring, the process to replace it is generally very simple and will only cost around $0.20-$0.50 per O-ring. Follow these steps:

  • Remove the collet from the mouth of the quick-connect fitting
  • Use a thin flat tool (tweezers or a toothpick will suffice) to loosen it and then pull the O-ring out of its well
  • Use a tool or tubing to push the replacement O-ring into place (ensuring it’s flat)
  • Place the collet back into the fitting

I previously mentioned that it was possible you have two incompatible types connected to one another, if this is the case you could purchase an O-ring and place it inside the socket to stop the leak between the two. This will allow you to use an industrial-type end with an automotive quick-connect socket!

Replacement Air Compressor Quick Connects on Amazon

Before purchasing a replacement quick connect for your air compressor it’s important that you check your manual and find out exactly what type of fitting you have. Though the two main types are industrial and automotive, these also possess subtypes!

If you can’t find the right information, contact your manufacturer directly, and hopefully, they’ll be able to help. I will provide a few replacements below that could be suitable for your air compressor!

Individual Replacements

Let’s start with individual quick-connect replacements. Below are a few suitable replacements for almost any compressor. First is a 1/4″ female durable brass fitting provided by Milton.

Milton also offers a 1/4″ male brass body fitting if a male thread is what you require!

Don’t worry, other sizes are available! You will be able to find a quick-connect fitting that matches your size requirements. Below is a Milton Type G 3/8″ male brass coupler.

Set Replacements

It may be more worthwhile if you buy a whole set of couplers and plugs, readying yourself with additional replacements for any future problems you may face or compressed air system expansion.

The first set is a La Lematec 15-piece female coupling set. These heavy-duty air tool accessories are compatible with any air compressor configurations in different work settings and are manufactured to the highest quality to ensure no air leaks.

The WYNNsky 1/4”NPT Air Coupler and Plug Kit is a #1 bestseller, ideal for general purpose applications with the durable anodized color coating having a high scratch resistance.

The Tanya Hardware Type D coupler and 14-piece plug kit offer both male and female couplers. The high-quality durable brass fittings are interchangeable/compatible with most manufacturers.

The Jaco Type D 12-piece quick connect fitting set provides high-protection leak-proof male and female couplers.

FAQs (Frequently Asked Questions)

Why is my quick connect leaking?

Your quick connect can be leaking for the following reasons:
1. It’s possible that the O-ring is damaged and needs replacing
2. It’s likely that you have two incompatible types connected to one another
3. You may not have installed the coupling correctly
4. It may be the wrong size coupling for your compressed air system

Why do my air compressor fittings leak?

Leaks can occur in air compressor fittings due to the parts being damaged, oversized or undersized, and even incorrect installation. It’s therefore important to ensure you have the correctly sized fittings, ones that are compatible with one another and not damaged.

What is the best sealant for air fittings?

The best sealant is PTFE tape or PTFE dope. Some recommended products include the following; Mill-Rose 70885 Blue Monster Thread Sealant Tape, Rectorseal 23631 1/4 T Plus 2 Pipe Thread Sealant, and Dixon Valve TTB75 PTFE Industrial Sealant Tape.

How do you seal air fittings?

Though applying PTFE tape seems like such a simple task, if not done correctly it can cause significant issues down the line. The first important step is wrapping the tape clockwise in the direction of the fitting’s thread. This will help tighten the tap onto the fitting as you tighten the fitting into your part. The second important step is to leave one or two threadings free of tape at the end of the fitting. This is to allow the tape to be squeezed into the open threads as it is being tightened.

If you have any questions regarding air compressor quick connect leaks, please leave a comment below, with a photo if applicable, so that someone may help you!

By Aidan Weeks

A passionate Mechanical Engineer with endless enthusiasm for fluid power - building off the back of over 18 years of high quality contribution and discussion stimulated by Bill Wade here at About Air Compressors. With both practical and theoretical experience in pneumatics and hydraulics, I'm putting my knowledge to work - and working my grey-matter through my research, assistance and publishing work here at About Air Compressors. Feel free to reach out any time! P.S. A HUGE shout out to Doug who really offers such great value to all visitors to About Air Compressors - once again, feeling like I'm standing on the shoulders of GIANTS by getting to work alongside such a great community

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