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Posted by: blitZ Apr 20 2007, 08:24 PM

I've been attempting to find a good used AAR, as others have, and have had no luck. So, I decided to fix the darn thing. It's actually a simple device. I believe typically two things go wrong.

1) The insulation between the housing breaks causing a short. This causes the fuse it shares with the fuel pump to blow, which causes the car to come to a discouraging halt.

2) The tube with the slot port gets stuck and won't close.

If your insulation is still good, but the port won't close, you may be able to free it by removing the pipe, squirting in your favorite solvent: PB Blaster, WD-40, vodka, etc. Work the tube back and forth to free it up. I was unable to do this and needed to repair the wire, so I opened it up by grinding off the lip of the bottom housing with my Dremel.




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Posted by: blitZ Apr 20 2007, 08:26 PM

Once, the top is off you can see the inards. Basically a ceramic base with a simple heating coil on the bottom.




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Posted by: blitZ Apr 20 2007, 08:28 PM

The top has a spring like piece attached to the tube which expands when heated and gradually closes the port.




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Posted by: blitZ Apr 20 2007, 08:30 PM

Next, drill out the rivets on the bottom. The center one holds the ceramic base to the housing, the other is the ground. The wire piece can be clipped off with wire cutters.


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Posted by: blitZ Apr 20 2007, 08:31 PM

Under the ceramic base is a heat shield and a nub of the remaining hot lead.


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Posted by: blitZ Apr 20 2007, 08:34 PM

The wire repair involved tinning the wires back together and covering with some shrink tubing. I added a little sillycon around the shrink tubing and the ceramic base to prevent any possible short.


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Posted by: Pat Garvey Apr 20 2007, 08:35 PM

Looks cool so far. More to follow?

Posted by: blitZ Apr 20 2007, 08:37 PM

Place the ceramic base back into the bottom, lining the holes up. I used a pop rivet to secure it. Some solder was melted into the ground hole to secure the ground pole to the casing.


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Posted by: blitZ Apr 20 2007, 08:39 PM

I have a portable compressor with a 12v supply I used to test. You should be able to feel the base heat up and watch the port gradually close. I secured the top back on with a little wire. It will be easier to get back into if another repair is required. It's working fine so far. I think it's possible the heating coil could break, however it could be easily replace with a little solder work.

Hope this helps someone.


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Posted by: smooth_eddy Apr 20 2007, 10:02 PM

Nice work

I have wondered about my AAR valve. I pulled mine off and bench tested it with a 12V battery charger. I noticed that the valve only closed about 3/4 of the way. I blasted it several times with PB Blaster lubricant but no change. I even let is soak overnight with still no change. Is a 2.0 liter AAR supposed to close 100% when warm?

Eddy

Posted by: computers4kids Apr 20 2007, 10:27 PM

Thanks for the tutorial...I vote for "classic thread status!" Actually, looks pretty staight forward...let us know how it holds up.
Mark

Posted by: McMark Apr 20 2007, 10:45 PM

Not just a classic, a new tech article.

Posted by: Air_Cooled_Nut Apr 20 2007, 11:21 PM

Good info. Goes good with what has already been seen:
http://www.914world.com/bbs2/index.php?act=ST&f=2&t=39113

Posted by: smooth_eddy Apr 21 2007, 04:53 PM

Posted by: pbanders Apr 21 2007, 05:38 PM

Since you already pulled off the side port, I suggest removing the top port, too. This lets you remove the rotating cylinder, enabling you to clean the bore completely. Make sure when you're removing the bimetallic coil that you mark the position - this determines the "calibration" of the AAR.

Posted by: blitZ Apr 21 2007, 08:20 PM

I actually played around with the calibration as to how long I wanted the high idle to last. Things change after 30 years. The heat coil doesn't heat up as fast as it used to and the bi-metal coil has been through umpteen heat cycles. YMMV

I was just glad to get a working unit, again.

Posted by: Brian_Boss Apr 21 2007, 08:39 PM

Be ready to catch the innards, including the fragile ceramic insulator, when you drill this rivet. Otherwise, the insulator will fall to the concrete shop floor and shatter into countless tiny pieces, or so I hear.

Posted by: Travis Neff May 17 2007, 06:31 PM

Bump for Shaggy.

Posted by: shaggy May 17 2007, 06:37 PM

thanks

ill be atempting this later with both of mine.

Posted by: tdgray May 17 2007, 06:53 PM

Missed this one.... excellent tech tip. Bravo my man.