Mtce tip: horn compressor

[reidyyz]

Well, it's not that I'm cheap (maybe a little) but it's in my nature when I encounter a component that fails, I have a strong need to know why. Be it a washing machine pump, cordless drill or in this case, the horn compressor on the car. It worked enough when I test drove the car a month back, but now it had some grinding noise with no appreciable 'honk' to it. I did add some oil, got slightly better, so I still ripped it apart and here are my findings.

First, I knew it was getting good power and ground as it was a good strong grinding noise. I removed it and put it out it on a bench. There is always concern when opening up any unit that springs, ball bearings and the like pop out and fly away, not in this case. Three small slotted screws open up the top. Inside there is a rotor spinning about the elex motor shaft with four plastic/phenolic fins riding in four slots in the rotor. The fins are free floating and move in and out freely, no springs. The rotor sits in an offset bore where as the rotor spins (CCW) the fins ride the outer wall of the bore in and out. I found my fins had some abrasion on one side, the side that gets pushed from the rotor slot wall. I cleaned and touched them up with 400 grit s/paper then turned them around as the other undamaged side still had a smooth finish. I oiled all the parts lightly and dropped about 10 drops of light oil in it before closing it up and reinstalling it. Do not bother adding any more oil as it will spill out the air inlet channel. With a strong, charged battery, the horns worked beautifully. I also cleaned the power and ground studs/spade connectors, replaced the plastic tubing and even repainted the horns.

But in the end my joy and pride in solving this was briefy extinguished when I saw you can get a new horn/compressor kit from autoricambi for $46. However, that's $46US ($58Can) still in my pocket, a compressor assy not off to a dump, a beautiful summer day playing with my new toy and an interesting lesson learned.

[18Fiatsandcounting]

Well done Henry! I tend to find the older components to be of higher quality than the new stuff, so I rebuild old parts if I can. There are certainly things that wear out (belts, hoses, bearings, etc), but many electrical gizmos just need to be taken apart and cleaned.

-Bryan

[dinghyguy]

Henry,
I have done exactly the same thing, clean lube and enjoy. Oh and you forgot the shipping to Canada, which will add at least 25$ to your 58$. Oh and Lordco here in BC had a special a while ago on the air horn kit for 45$can. Likely not the original Italian sound but i bet no one will actually know since us Canadians are to polite to use our horns.

cheers
dinghyguy

[dinghyguy]

Henry,
I have done exactly the same thing, clean lube and enjoy. Oh and you forgot the shipping to Canada, which will add at least 25$ to your 58$. Oh and Lordco here in BC had a special a while ago on the air horn kit for 45$can. Likely not the original Italian sound but i bet no one will actually know since us Canadians are to polite to use our horns.

cheers
dinghyguy

[Tcamp]

Thanks Henry. I have my compressor out and will do just as you did. What a valuable community of knowledge. Mine works but I took it out to polish it and paint the bracket and clean connections, etc. Sounds crazy but looks great. Never thought i would have to service my horn lol

Honk if you're happy.

Todd.

[18Fiatsandcounting]

There's a locknut at the base of the trumpet on the original air-driven horns. It takes some experimentation, but you can adjust the insertion depth of the trumpet to get that classic "pig squeal when someone stepped on its toes" Italian horn sound. Once that is achieved, tighten up the locknut. If you're really good, you can adjust each trumpet individually so that, when both are blowing, it sounds like you mean business. Or you're in Italy where it's normal.

-Bryan