Road Master Air Horn

When I got the 330, the air horn compressor was missing.  At the time I just bought a Fiamm air horn kit from a local auto supply place.

Recently, I got a used Fiamm Road Master.  I  installed it a while ago, but it didn't work well.  Since I also have a 'city' horn (a switch selects which is used), I didn't worry about it until I had another reason to have the grille out.  The usual solution is a little light weight oil in the oil hole.  That didn't solve the problem as the motor just drew current but didn't turn.  So I ended up having to remove the horn and take it apart.  This picture is with the top taken off.

The horn compressor works by having the shaft off center to the chamber.  As the metal cylinder in the middle turns, the vanes slide out and contact the chamber wall.  The inlet is in the area at the lower left with the most space.  Air is picked up and pushed around to the other side.  As the space narrows, the preceding vane goes past the outlet so the air gets pushed out to the horns (red hose on the right).  Everything has to be really clean for the compressor to work correctly.

The usual problem is just crud and rust keeping the vanes stuck in the center (the motor will run, but no air is expelled) or keeping the motor from turning at all.  A good cleaning with a little wire brush on the Dremel helped the chamber.  The cylinder, slots and vanes were cleaned too.  Then a light coating of oil had everything working correctly.

I got a pleasant surprise.  When I was working on the horn, I noticed that the name plate looked like it had tape over it.  The whole thing had been painted wrinkle black as some point so I thought that they had just painted over the plate too.  But I was able to peel off the years old masking tape and clean up the residue, leaving a nice Road Master name plate.  You can also see the green plastic cap for the oil hole.

The instructions say to 'Lubricate every 3 to 4 weeks with Fiamm special oil'.  Of course, this should be done using the oil bottle that came with the toolkit.  Instead, I just use the same pneumatic oil that is for air tools.

Skip forward about 5 years.  The compressor described above seemed to always stop working when unused for a couple of months.  I took it apart, cleaned and re-oiled it several times and finally gave up.  I got another Road Master compressor that actually came with the PF coupe, but wasn't correct for that car.  So when I got the correct Marchal compressor, that compressor became a spare.

I sand blasted and wrinkle painted the spare compressor at the same time as I was doing the valve covers for the PF coupe.

Well, I finally got tired of not having an air horn and the 330 was on the lift, making it easy to remove the grille to access the compressor.  Here's the old compressor, easily accessible with the grille removed.

I also had the bracket cadmium plated with the last batch of oil filter wrenches.

I used a heat gun to soften the red air line to remove it from the old compressor and again to re-install it on the new one.  Here's the replacement compressor ready to go.

Since this compressor has been sitting around for several years and has always worked every time I've tested it, the next time I need the horn, I shouldn't be left in the lurch.