ARO Diaphragm Pump Problem

[Rudy]

I've got an ARO pump that intermittently struggles to "come up to speed". This pump is on the clearcoat cycle of my automatic. 9 out of 10 times, it works just as it has for 7 years. Sometimes however, it takes about 10-12 seconds for it to start pumping. It seems to struggle. I tried putting a couple of drops of oil into the air input...but the problem intermittently arises.

When the pump hesitates, the automatic arch is halfway down the left side of the car before the polish starts getting applied...which is not good.

Ideas?

 

[Randy]

This might be a good time to think about replacing the ARO Pump and going to another pump. We had nothing but problems with ARO pumps over the years and repalced all of them years ago.

 

[Rudy]

If the problem can't be fixed, then I'll replace it with a FloJet. I was just wondering what might be causing the problem. I've even wondered if the Asco solenoid that controls the air to the pump could not be opening completely??? Is that possible? I pretty much believe that the solenoid is either open or shut....but that may not be true.....

 

[MEP001]

It's not unusual for air pumps to "stall" as they get old, in fact in my experience it's the main reason they get replaced. Seven years is a long time for one to last in daily service. Adding oil was not a good idea - it may free it up temporarily, but it'll almost surely get worse.

I have seen Asco solenoids fail to open fully, but it should be easy to test. Remove the "guts" from the solenoid and operate the pump manually from a shut-off and see if the same problem comes up with the same frequency.

 

[Waxman]

A new Flojet is $70-100.

Buy the flojet.

Had ARO's myself and now am all Flojet.

 

[I.B. Washincars]

Those things may work well for the purpose for which they were originally intended, but I'm thinking that purpose didn't have anything to do with a car wash. Most everyone has long since trashed the ARO pumps and went with something reliable. Verify the solenoid as MEP said and don't waste any more time screwing with that pump. Does any mfr. still install them as OE?

 

[Earl Weiss]

Ditto,

As time goes by all my air operated pumps, Aero, Yamada's all being replaced with Flo Jets. I use all Viton and make sure their is an air trap on the line. Don't know if they last longer than Yamadas or Aeros, but they never stall and are a lot cheaper to replace, even if you need 2 to match the needed flo rate.

 

[mac]

Maybe I've just been lucky, but I've sold probably close to a hundred ARO pumps with almost no problem. I thiunk the reason for this is that the Magic Wand systems I have them on have the solution tank ABOVE the pump. It never gets starved. The main reason I see for them to stall is that the air pressure out on the application arch is too gigh. Keep it at least 10 psi below the liquid pressure. The other thing that I do that must be helping is that I put in a 3 way solenoid that shuts off the air supply to the pump, and relieves the pressure at the pump. As these pumps age, if they sit for a few rainy days without pumping, they do tend to lock up. That being said the Flo Jets are the way to go at replacement time.