HOLDING TANK 3/4 FULL LIGHT

[BEC53]

MY OLD HOLDING TANK LIGHTS ON MY 1985 53 DON'T WORK. ARE THEY WORTH TRYING TO FIX? I THINK THEY ARE HOOKED UP TO SOME TYPE OF AIR SWITCH. MAY BE OLD JABSCO SWITCH. ANYONE WORKED WITH THESE?

[Genesis]

They're an air diaphram switch that goes through a pipe to the tank.

The most likely causes of failure are either that the pipe is clogged or it is leaking; in either event it won't trip the switch. The diaphram could also be punctured.

The trick is finding the switch. On my 45C, it is in the forward bilge area right near the shower sump.

[spartonboat1]

That is a fairly straightforward repair. What I like is that although you term it "old" they are a simple system and you could replace all the parts for under $70-100 or so, and I am including the brass pipe on top of the holding tank, which extends down into the tank 6"'s or so.

Usually if the air diaphram switch is original it can go bad i.e. the electrical connections get corroded, or the internal points that make up go bad. In any event the easy check is to pull the flex line (usually flexible) off the holding tank pipe and push it down into the bottom of a bucket of water. The depth of the bucket should exceed the pressure necessary to activate the switch. Put an ohm meter on the switch and it should read, when the sw makes up. If it doesn't make up, then the switch is bad I would think, since 6" of depth will trip it. Jabsco makes them, e.g. Hydro-air switch for bilge apps, etc. All the same, just diff packaging.

The indicator light at the head may be bad- check with a meter, or maybe the bulb holder has gone bad.

Sam's is your friend for that stuff- easiest to ask them and you just get what you need without much fuss.

However, if you have a 53' then you might consider a gauge, such as the Hart Tank Tender that is not too expensive; anything under $900 meets that criteria today, it seems. You can read the levels of your holding tanks, water tank(s), and fuel tanks from one gauge. Very simple and no electrical components.

43' Hatt owner...

[BEC53]

I currently have a tank tender on the fuel and water, but was unsure how well they would work if added to a waste tank. I'll check the diapham switch out first. Also, has anyone completely mapped out the calibration chart for tanks on a 53MY in inches?

[garyd]

There is a seperate white fuse in the dc fuse area. Check to make sure that is good. Take off the red cover on the vacuum switch and rock the switch closed. AT this point the 3/4 light should be on. If not check voltage along the line, at fuse, at swicth, at light.

Boat US and Sam's have the vacuum switch replacement. Sams has the brass plug/tube.

[dshuman]

I want to get tank tenders, but all my water and fuel tanks have the same large 2 3/8 inch hex caps on them and I can't get them off to replace with the tank tender dip tubes. Pipe wrench won't do it and I afraid to hit the pipe wrench with a sledge for frae of breaking something. Tried WD40 and Liquid Wrench. Any ideas?

[garyd]

use a 1/2" breaker bar with a 3/4" adapter and a 3/4" 2 3/8 socket. Get your back against something use your legs and she will turn. You may need a 1/2" extension. You can get all of this stuff at sears.

[mikep996]

A useful trick that often works to free a stubborn bolt/nut/fitting, whatever, is to first TIGHTEN the bolt. You only need the tiniest fraction of a turn to break the corrosion/rust and, for reasons I do not understand, It is easier to break the corrosion by tightening slightly first.

I know it seems counter intuitive but it really works well.

[dshuman]

Thanks. To "MikeP996" I did try that when you recommended before. No go. But thanks. I have been spraying them with a small amount of WD40 every weekend and I'll try it again. I have the tools mentioned except the socket. I was just afraid I'd break the bronze out of the fiberglass with too much pressure.

[Dshuman]

Did the trick, plus MikeP's "tighten first". I got the fuel tank and holding tanksenders loose. The extra pressure moved the epoxy around the sender on the water tank so I'll just have to leave it and replace the Rochester sending unit with the new type from Rochester. Thanks for your help.

Doug