The Stovebolt Site Forums The Shop Area General Truck Talk Ranco heater valve questions

I purchased a used Ranco heater valve complete with functioning bellows/capillary tube. The problem is that the temperature adjustment cam/off latch will not "grab" the spring tensioner screw. It is a pressed on, knurled fit that has been stripped. So, I am going to attempt a repair (not sure how right now), but my main question is how was the spring/cam adjusted when new.

The cam will only turn about 7/8 of a turn from "off" to warmest setting. The spring tension adjustment screw has much more travel. I noticed in Denny's photos of his heater valve that the spring looks compressed about half way through it travel in the warmest setting. If this is the case, then the spring is never relaxed when the valve is off and the latch in the off position would have a much harder time "grabbing" the pin/boss. Here are Denny's photos. Hope you dont mind me using your photos

In the photos you can see the cam in the warmest position hitting the pin/boss that stops its travel. you can also see the spring cap plate halfway in the slot keeping it in position...this represents half its travel from rest or significantly more than one turn of the adjusting screw/cam.

After studying the Ranco valve, I can understand why they continue to function with a broken bellows. The bellows job is to override the spring and close the valve if the temperature climbs too high, thereby providing some sense of automated control. Without the bellows, the driver/passenger has to maintain temperature control by turning the temperature knob.

Full travel on my plunger fails to seal off coolant flow- there is always some degree of flow regardless of full range movement. When I learned this, I realized the valve provides very little adjustment and I no longer worry about tweaking its operation.

Bill

That may be true, but I would like to get it the best I can initially. The valve, if working properly should significantly reduce coolant flow to the point of providing little heat. I would surmise that a valve that has no temperature control is not working properly or the valve and seat have deposits preventing it from closing.

The valve has four little prongs on it,they get bent then don't close all the way.To get to it,heat the solder until it melts and pry the end cap off.This will allow you to remove the valve and bend the prongs back into place. control valve
Reinstall the valve,use your propane torch and solder and sweat the cap and body back together.Be careful not to use too much solder.


Tim

Tim is dead on. Although this pic is a little blurred you can see a prong bent just as I took it apart.
http://i140.photobucket.com/albums/r19/LutherParris/52Panel/000_0200.jpg

In my photo bucket is also a pic inside the body. that little valve is "metal to metal" but if its right it will shut the water flow off pretty dang good.
With a prong bent it will restrict how much the valve closes.
Hope this helps some to.

When I rebuild them,I bend them like in my picture posted.They shut off nice and tight.The end is like a swivel,I let the end soak in pb blaster for a couple days,they do get seized over the years.I assume that is why the prongs get bent.

Tim

I inspected the water valve and the prongs are not bent nor have deposits or excessive corrosion. My issue is the spring tension adjustment. Can someone look at their valve and let me know if the spring is completely relaxed when the valve is off. Better yet snap a photo of the spring when the valve is latched in the off position. Thanks.

Here's my related question.........is it common for the end facing the engine to leak? Mine has begun to leak even when cold and it appears to be coming from the end. Looks like solder there. Is more solder at that seam the answer?

No, generally they leak around the stem seal.

DG

Thanks Denny.