dbuzz77 Posted March 6, 2010 Report Share Posted March 6, 2010 can someone tell me how the knob on the heater box is supposed to operate? it says heat or off. does it spin or pull out? thanks Quote Link to comment
DanielC Posted March 7, 2010 Report Share Posted March 7, 2010 It should turn about a 1/4 turn. On a 40 year old truck, there is a good chance it is stuck. Quote Link to comment
Hyphy Posted March 8, 2010 Report Share Posted March 8, 2010 if it is stuck, dont try to force it with the knob. They can be difficult to come by and using vise grips is much easier. Example: i have 3 cores.... ONE knob Quote Link to comment
dat521gatherer Posted March 8, 2010 Report Share Posted March 8, 2010 yeah they all get stuck if not moved often enough. take the screw out and the knob off they use some vise grips and slowly move the valve stem clockwise/counter clockwise. if this doesn't work the only way to get it to move and work properly is to take the heater core out and put a wooden dowel through the pipe and hammer it till it comes out. them clean it and reinstall. careful not to twist that white knob off. they go for $20-30 when they come up on ebay once or twice a year. considered a rare 521 part these days. Quote Link to comment
mklotz70 Posted March 8, 2010 Report Share Posted March 8, 2010 there's a small retaining screw holding the valve in. If you take that out first, you can turn it more than a 1/4 turn to work it out. You'll want it out of the rig unless you like the smell of antifreeze on your carpet :) Somewhere in my Mend project thread, there's some decent pics of taking the valve out. Quote Link to comment
patd Posted March 8, 2010 Report Share Posted March 8, 2010 yeah they all get stuck if not moved often enough. take the screw out and the knob off they use some vise grips and slowly move the valve stem clockwise/counter clockwise. if this doesn't work the only way to get it to move and work properly is to take the heater core out and put a wooden dowel through the pipe and hammer it till it comes out. them clean it and reinstall. careful not to twist that white knob off. they go for $20-30 when they come up on ebay once or twice a year. considered a rare 521 part these days. This was in the glove compartment when I bought my truck, I am still looking for one. :blink: 1 Quote Link to comment
pl521sss Posted March 9, 2010 Report Share Posted March 9, 2010 This was in the glove compartment when I bought my truck, I am still looking for one. :blink: I have 3 of those knobs Might sell one or 2 Quote Link to comment
patd Posted March 9, 2010 Report Share Posted March 9, 2010 I have 3 of those knobs Might sell one or 2 If you decide to sell one let me know how much you want and if you have a paypal acct. I will send you the payment plus mailing and will add some for the paypal fees. :) :) :) :) Quote Link to comment
dbuzz77 Posted March 9, 2010 Author Report Share Posted March 9, 2010 thanks , guys. my knob is almost round, there is no lever on it. i'll try loosening it with spray first. Quote Link to comment
zed1 Posted June 7, 2013 Report Share Posted June 7, 2013 Has anyone reproduced the decal for the heater control? http://www.flickr.com/photos/53116286@N07/8981078234/in/set-72157625809569365 Keith Quote Link to comment
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