Air Compressor Repair




Introduction: Air Compressor Repair

If you are like me; and you see an air compressor like this out to the side of the road for waste pickup, you pick it up and fix it.

After I got this Campbell Hausfeld air compressor home; I plugging the compressor in to see if it worked. I found 3 things wrong with it, the vent valve is seized, and the unlevelled tank allows condensed water to pool at one end of the tank and not drain out even if you could open the valve. This caused the tank to rust and rupture.

Just to find out if the regulator works correctly; I will need to weld the leaks in the tank, and replace the seized vent valve so I can test the regulator and the automatic shutoff.

I will also MacGyver welding rod to fix the tank.

Step 1: Tools & Supplies

1 Oxy acetylene welder, my little oxy propane welder works well for small jobs like this and it is even hotter if I use Mapp gas.


Wire Brush attachment for the grinder, this comes with an adapter you can use to keep the grinder parts together.

Safety Glasses; remember use your safety gear and guards on your tools.

Wrenches; 13/16 socket or wrench, 9\16 wrench, 2, ½ wrenches and 2 adjustable wrenches.

Bronze Brazing Rod

Welding Rod

Teflon tape


Fast drying no primer needed Gray paint

4 standard ½ inch carriage bolt nuts

Vent Valve

Anti-scuff feet, I used Slideglide appliance feet.

Air Accessory Kit


Step 2: MacGyver Welding Rod

I’ve seen coat hangers used as welding rod, but I find this method works best.

Start with unplaited steel wire; unplaited is very important, galvanized, chromed, or anodized plaiting reacts badly when you try to melt the steel wire into your weld.

Heat the wire and dip it into Borax, the borax acts as a flux for an improved weld and you have welding rod.

Step 3: Prep for Welding

The metal on these tanks; is as thin as the body metal of a model T Ford, so you really don’t want to make it thinner by using a grinding disk on the tank to prep the metal. However the wire brush attachment for the grinder, cleans the paint and rust off the tank, without making the metal thinner or misshaping the metal.

Start by changing the grinder from the grinder attachment to the wire brush attachment.

Remove the vent valve.

Then power brush the metal clean for welding.

You should be able to see any holes and defects in the metal.

Step 4: Welding

Remember you can braze over a weld but you cannot weld over braze so weld first.

It is almost impossible; to weld these tanks with an arc welder or a tig welder, without blowing the tank full of holes. So I use my little oxy propane welder, it works well for small jobs like this, and it is even hotter if I use mapp gas.

Start by taping the edges of rupture of the tank with a hammer until they are aligned.

Then weld any holes and weak spots closed.

Replace the vent valve and run the compressor until the automatic shutoff turns the motor off. Watch the tank air pressure gauge as it rises to be sure the motor shuts off at the correct PSI. Adjusting the regulator and watching the outlet gauge will tell you if the regulator is working.

Check for leaks by listening and feeling for leaking air with your hand.

Step 5: Brazing

Don’t chase pinholes with welding or you will be chasing holes until the cows come home braze over your work area instead.

Remove the vent valve and clean the welds and work area with the wire brush.

Next switch to the grinder to the grinding wheel and grind just the high spots of the welds only.

Then braze over the entire work area and any suspected holes. This will make the walls of the tank thicker and stronger as well as it should stop any pin hole leaks.

Test the compressor again making sure you got all the leaks by replacing the vent valve and run the compressor until the automatic shutoff turns the motor off. Check for leaks by listening and feeling for leaking air with your hand.

Step 6: Painting

Remove the vent valve and clean the area to be painted with the wire brush.

Mask off where you are not painting; you do not want to get paint on any of the instruction labels. These labels are important and you do not want to lose any of the information on them.

I used fast drying no primer needed gray paint, then paint and let dry.

Step 7: Anti-Seize

Before you do the next part you need to know about Anti-Seize and Teflon Tape.

Anti-Seize Compound is used on threaded parts you may need to move on occasion; like break adjusters, bleeder valves, or anything you don’t want seizing up on you. There are two basic types, copper based and aluminum based.

Use the copper based Anti-Seize on aluminum and steel.

Use the aluminum based Anti-Seize on copper, brass, and steel.

Anti-seize is easy to use, just paint it into the threads with the applicator brush under the lid.

Step 8: Teflon Tape

Teflon Tape is used to stop leaks in threaded parts like gas lines and air lines. It also acts like Anti-Seize but it is not meant to be moved on occasion. It is not sticky like masking tape, so there is a right way to use it and a wrong way to use it.

Hold the tape in your left hand and the part in your right hand with the thread of the part you want to apply the tape pointed away from you.

Turn the part clockwise until the Teflon tape goes completely around the part.

Then tare the tape off.

Step 9: The Vent Valve

Replacing and installing the new vent valve is quite easy on these compressors; remove the vent valve with a 9/16 wrench.

Go to your local auto parts store, it is the same valve used to drain car radiators.

Open and close the valve as you apply Anti-Seize to the threads of the valve screw to get the Anti-Seize in the threads of the valve screw.

Then apply the Teflon tape to the valve thread and thread the valve into the tank vent.

Don’t over tighten the valve screw or the valve thread or you may end up replacing them in short order.

Step 10: Replacing a Wheel

These air compressors use ordinary lawn mower wheels you can get at your local hardware. They use the same nut and bolt used to mount a lawn mower wheel to a lawn mower, these you can get at your local hardware also. You will need a 13/16 wrench or socket and a 9/16 wrench to change the wheels. There is not enough room in the wheel frame to use a 9/16 socket.

Unfortunately for me changing the wheels would not level the tank, so I had to add feet to the front frame.

Step 11: Anti-Scuff Feet

This compressor is missing the two rubber feet in the front frame.

I used Slideglide appliance Anti-scuff feet for replacement feet; to level the tank, I picked them up at my local Home Hardware along with 4 standard ½ inch carriage bolt nuts.

Place the first nut on the feet and put the feet in the holes in the front frame.

Adjust the lower nut on the feet until the tank is level.

Put the top nut on the feet and tighten with the two ½ inch wrenches, like the wheels there isn’t enough space for a socket inside the frame.

Now that the tank is level test the compressor again and make sure it drains the condensed water out of the tank when you open the vent valve.

Step 12: Accessories

Now that you have a good air compressor you need attachments. Not all quick disconnects are made the same so I got an accessory kit with a female connector. However I was in luck the male connectors fit the female connector on the hose I had.

1 blow gun, 1 safety nozzle, 1 inflation adapter, 1 tapered inflation nozzle, 1 inflation needle, 1 dual foot tire air chuck, 1 tire gauge, 2 male couplers, 1 female coupler, 4 male quick connectors male thread, 2 male quick connectors female thread, 1 female quick connector female thread.

You really don’t want to be reefing on these parts so all you need are a couple adjustable wrenches and Teflon tape to assemble the accessories.

Step 13: Tire Chuck

Ok this real simple put Teflon tape on a male quick connector with the male thread as I instructed in step 8 and thread it into the dual foot tire air chuck.

The tire chuck is done and you are ready to inflate tires.

Step 14: Blow Gun

The blow guns parts are the blow gun, safety nozzle, inflation adapter, tapered inflation nozzle, and inflation needle.

Just like the tire chuck; put Teflon tape on a male quick connector with the male thread as I instructed in step 8 and thread it into the blow gun.

The blow gun works with the inflation adapter, and the inflation needle for filling things like footballs.

The inflation adapter and the tapered inflation nozzle is used for filling air mattresses or clearing water out of your RV.

Last the blow gun works with the safety nozzle, this can be used for clearing dust out of your computer or shavings out of your lath.

Step 15: The Last Tweak

The weakest point on your air lines is right here where the flexible hose meats the regulator coupling. Every hose fails at this point because it goes from free to move to fixed in place and this creates stress at this point. Especially if the hose gets bumped a lot when moving the compressor about. The only way to relieve this stress point is to make the hose detachable.

Start by detaching the hose; this is a flare coupling and you need both halves of the flair coupling attached to the hose. So take the other half of the flare coupling out of the regulator and reattach it to the hose.

Clean and apply Teflon tape to the thread before attaching a male quick connector with a female thread.

Step 16: The Female Quick Connector

The female quick connector has a female thread so you will need a male coupler.

Coat both of the threads on the male coupler with Teflon tape.

Screw the male coupler into the female quick connector by hand.

Then using an adjustable screw the female quick connector assembly into the regulator outlet and you are done the last tweak.

Step 17: A Job Well Done

Now you can inflate a tire or a ball at home or in the shop, and you have a few connectors left over to add tools to your compressor.

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    Question 2 years ago on Introduction

    Have a pancale style compressor that cuts out at 50psi. It is set at 110.constantly have to reset ot.why


    3 years ago

    Neat repair .. I would have probably attempted to save it as well .. build a cheap cage enclosure in case it ever does actually fail although I really doubt it if you never let it pass 100 psi .. maybe a 100psi safety release valve as well

    Stay Safe

    Josehf Murchison
    Josehf Murchison

    Reply 3 years ago

    I am glade you liked it.

    It has a safety valve and an automatic shutoff that is adjustable if you know how. Most of what I do; will not need over 40 psi, so I could adjust it or the shutoff to the value I wanted. These air compressors do not hold as much pressure as oxy or asset tanks, (2500 psi and up.) In fact they hold less psi than an 18 wheeler steering tire. So the metal is just thin sheet steel, my repair is over twice the thickness of the original steel.


    3 years ago

    I am using the .Central Pneumatic 21 gallon air compressor from three months ago. It is quite durable thanks to its oiled pump system, long-lasting motor, and reduced vibration through foot stabilizers. As a new user till I don't face any problem to run it. I can transport it to any place as I want. Its two wheels and one handle help me to easily carry. But I can't replace any parts of it. This article really helps me to get some knowledge about the parts of this compressor machine and replacement.
    Thank you for this article

    Josehf Murchison
    Josehf Murchison

    Reply 3 years ago

    You are welcome.
    That looks like a nice compressor.


    Reply 3 years ago

    Thank you, Josehf Murchison,


    4 years ago

    Excellent write up with lots of good pictures and description, but I would seriously have it hydrotested before bringing it up to full (normal) pressure. I watched a couple youtube videos of exploding air tanks and I am intimidated. I too would stop and pick it up, but I would remove the rusted metal completely and flange weld more new metal in to repair it. The cost of a professional hydrotest is cost prohibitive, but I saw some do it yourself hydrotesting. I know that sounds crazy, but since water does not compress, there is very little stored energy, so if it does give out, it will not explode, it will just "break" open. I recently picked up a 4HP 20Gal Sears compressor with a rusted tank, for $40. I was drawn to the 7.7CFM rating and planned to use the motor and compressor on a sturdier larger tank I have. I like the idea of repurposing a propane tank for compressed air because the working pressure is so much lower for compressed air. Thanks for sharing.


    4 years ago

    you should be able to tig weld that metal.

    Josehf Murchison
    Josehf Murchison

    Reply 4 years ago

    I tried a tig welder in the past you just end up chasing pin holes forever.


    4 years ago

    fyi ,its never a good idea to weld a pressure cylinder, if they are rusted through they need to be replaced, or they will explode!

    Josehf Murchison
    Josehf Murchison

    Reply 4 years ago

    Well I've done it 5 times.

    It is not a good idea to do it on tanks rated higher than these or larger than these like a propane tank 600 PSI or an oxygen tank 2200 PSI.

    But as I mentioned in the Instructable, the steel on this tank is as thin as the body metal of a model T Ford.

    These tanks are not pressurize as high as a truck tire.

    Tank 100 PSI

    Truck tire 150 PSI


    4 years ago

    Nice repair project. But where is the final painted picture? The gray you used after welding and brazing isn't the same as the final picture you shown...or is it?

    Josehf Murchison
    Josehf Murchison

    Reply 4 years ago

    The picture in the last step is the finished product. The inability to see the repair is one of the reasons I did not bother to make the repair perfectly smooth. You cant see it unless you put your nose right up to it.