Monday, June 4, 2007

Autotrol 440 Timer Rebuilding

440 timer diagram
An obvious problem that can occur is for the timer motor to fail.
The motors turn at 1 rpm, so it is quite easy to tell if it is turning.
A more common problem is for one or more of the drive gears to strip.
Removing the Tripper Arm screw, the Skipper Wheel screw and the three cover plate screws will gain you complete access to all components for careful examination.
It is easier to work on your timer housing if you remove it from the valve body.
Pull out the timer retaining pin ( 5F ), slide power cord out of it's retaining slot, unscrew Cam Shaft Bearing at rear of Cam Shaft, and then pull housing straight up.
Common Gears that Fail 1. Tripper Arm Gear # 99F ( 1031756 ) * Most common gear to break at the 2 - 3 am. position. 2. # 7 Black Gear # 420A43 ( 1031554 ) * Gear that drives the Tripper Arm Gear, and often strips out at the same times as the Tripper Arm Gear breaks. 3. Red Knob Gear # 106H ( 1001582 ) * now "Black" closely examine the "over hang" teeth of the OUT PUT GEAR, as they sometimes snap off.4. #8 Black Gear # 420A44 ( 1030844 ) * Drives the Output Gear, and if stripped, you can easily see this.
Also the "Out Put Connector" # 21E ( 1031496 ) which attaches to and drives the Cam Shaft can crack or break. Check this part at the rear of the timer assembly.
On rare occasions the Camshaft # 21F-3 ( 1031950 ) will break at one end.
Also, rare is a cracked Skipper Wheel # 14F-6 ( 1031740 ).
Close examination of both sides of the Skipper Wheel is required to detect this failure. And last, but not least, you can have a gear post break in the housing body it's self. But only the backplates for the 440i version is available and not the "box" used with the older 440 version. It is simpler and prudent to replace the Complete Timer Assembly ( with the new 440iHV ) at this point.
A complete replacement is also prudent if the unit is over 20 years old.
And now available for Models 255, 263 and 268 is the Logix 740 upgrade timer kit ( does not work with older 155, 163, or 168 valves.. sorry ).
and for Performa 263 or 268,

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