Hi! I have a compressor that leaks air on the bottom of the tank. I neglected to drain it during it's life time, so it got rusty at one spot and, when I pump air, it leaks. Is it repairable? Could any patch be welded, or something else?

A hose connection, such as a hose end coupler for
your tools,etc They get rusty inside & only last about a year

Next would be any threaded connection,mostly hose & regulator or filter related

Then you have the air tank check valve leaking or the drain valve
on bottom of the tank

No you need to simple tighten the bleeder valve on the bottom of the tank. Its there to release moisture and manual says to drain after each use. I drain mine weekly if I've been using it. It prolongs tank life by preventing rust.

Josh:
Your compressor shouldn't run more than ten to fifteen minutes before shutting off. The pressure should be posted on the machine somewhere ( a decal usually says xxxpsi). You evidently have an air leak somewhere. On the bottom of the air tank there is a valve for draining the tank of air and any moisture. Make sure to close that valve by hand only (Screw it in all the way by hand and remember, you are working upside down, so don't get confused as to which way to turn it). If the valve will not unscrew to drain the tank, you can use a pliers to loosen the valve to let the air out, but be sure you are turning it in the correct direction or you'll break the drain valve!! Now that you have the drain valve closed, turn the compressor on and watch the pressure gauge. When the pressure gauge reads the pressure on the decal, the machine should turn off. If the pressure gauge stops climbing before it reaches the specified pressure, you have an air leak somewhere. You can either feel for the leak at the air line connectors by hand or mix a dish soap and water solution the pour on the air line connectors to look for the leak. Keep the soap solution away from the motor!! When you find the leak, drain the tank using the drain valve at the bottom of the tank, disconnect the hose coupling that is leaking and wrap Teflon tape around the threaded portion of the male end of the fitting (3 wraps should do it) and reconnect the coupling ( tighten it well). Close the drain valve and start the compressor again. and check all fittings for leaks again.

Check that the drain cock on bottom of tank is shut off,or leaking.?

Check if air intake is clogged.
Check if drain valve on tank bottom is open or closed.
Look at pressure gauge and see if pressure is zero.
Adjust pressure so tank will hold 80-120 psi.
Check air lines between compressor and tank to see if they are leaking. Listen for leaking air while motor is running.

If you need further help, I’m available over the phone at https://www.6ya.com/expert/gene_9f0ef4df2f9897e7

check air tank drain valve located on bottom of tank, if it is not leaking try adjusting air pres regulator (large black knob close to air hose connection.) the knob when turned in will increase the tank air pressure, if knob wont turn check that lock ring on bottom of knob to make sure it is disengaged. also check for air leaks in all lines and connections

Check for a fitting on the bottom or end of the tank. This fitting is used to drain air when not using the compressor for long periods, and should be left open most of the time. The biggest reason is that compressed air contains moisture...which will eventually rust your tank. Opening the fitting allows the water to drain out.

Since you have 1 bar, it's probably on, but loose.

Otherwise, feel for air leaks.You may try brushing on some water and dish soap...the leak will cause bubbles.

Good luck.

The brown liquid you are getting out of the compressor is water with rust in it from the inside the air tank. Somewhere on the bottom of your air tank there is a valve you need to open from time to time to drain the water from your tank. If you are getting rusty water from the air outlets you probably have a lot of water in the tank. If you can take the compressor outside, with pressure in the tank, where the water won't stain anything and slowly open the valve to drain the tank.

Hi, my name is John. Welcome to FixYa. You are loosing pressure somewhere. Check for air leaks in the lines, check the line coming from the pump to the tank, check the drain valve at the bottom of tank. Thanks for choosing FixYa....John

When you compress air the moisture in the air condenses and pools in the tank, all compressors do this whether new or old. If there is water built up in your the tank it will come out when you release the air. There is a valve on the bottom of the tank you have to open from time to time to drain this water from the tank. Take the compressor outside if possible or have something under the valve to catch the water as it comes out. Open the valve slowly or it will blow the dirty/rusty water all over. Campbell Hausfeld and some other companies make filter/driers to put on your supply line if the air needs to be dry for your use. Most box stores (Home Dept, Lowe's, etc.) carry these driers or can order them for you.