Harbor Freight 21 Gallon (red) Broke on Ring

by Neil Cunningham
(Charlotte NC)

I have a HF 21 Gallon 3HP the older RED model. It blew a head gasket and in trying to repair it with gasket material from Auto Zone the Piston came out of the head.

In trying to put it back in I broke the top ring (top of the piston) =.

I went ahead and replaced all 3 gaskets (I made them from sheet of gasket material) I reassembled the unit and it wont build pressure.

I have air coming out of the intake.

So my questions are these, would this broken ring keep this from building pressure, like is air leaking by the piston etc? If I by the rebuild kit others have talked about will that probably fix this....

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Jun 13, 2016
I fixed Harbor Freight compressor
by: Bill

Thank you so much for taking the time to update us on your success in repairing the compressor.

Good job!

Jun 13, 2016
FIXED my Compressor
by: Anonymous

I wanted to post that I was able to fix this compressor. Thanks for all the help! Just to help anybody else with one of these I will post my details.

First the compressor blew a head gasket and was leaking air from between the valve plate and the cylinder.

So I took it apart and by mistake pulled the piston from the cylinder. Tried to reinstall the piston (which I had never done before) I broke the top ring.

So I bought the Valve Plate kit which has the gaskets and need valve plate and reed valve.

Also bought Piston Ring kit.

I got the parts installed everything and reassembled. Fired it up and still blowing air from intake.

So I took it apart and realized that I had put the head on backwards. There are 2 pins that hold the reed valve in.. I did not align those pins with holes in the head. After looking further I had cracked the cylinder because of this. So I ordered a cylinder head and reassembled. Now all works great.

Couple of things I found, parts are available eReplacement has them as well as Jacks Small engine.

The parts for a Campbell Hausfeld HL4000 will fit this. Same motor and pump seem to be the same.

I was able to make the gasket for the bottom of the cylinder from gasket material I bought at auto parts store.

This is not that hard to work on....

May 24, 2016
by: Doug in s.d.ca

..came out of the head? You mean cylinder? And had you disengaged it from the crank? If not, then that's be at least part of the problem.

May 24, 2016
Harbor Freight 21 Gallon Compressor
by: Neil

I had one of the rings break, would this also cause this issue. I found new rings and valve and gaskets do I need to replace all of this?

May 23, 2016
Harbor Freight intake valve
by: Bill

"I have air coming out of the intake. "

That's commonly a problem with the intake valve failing.

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