Technical Tech: Ranco Heater Valve repair

It's getting warm out, so now is the time to get the heater working, for that trip into the mountains. Many cars from the 50s used a Ranco heater water valve, with thermostatic control. They always leak, there is a rubber seal that deteriorates over the decades. I decided to try to fix the valve in my 51 Hudson. I fiddled with it quite a bit and decided the thermostat gizmo was working fine, so it would be neat to get it all working as it should, and leak free.

First you need to find the parts. I researched quite a bit, and discovered that NAPA still lists the part. It's a Balkamp 6601000, and I was able to get one from the local dealer, after asking them to order it. They got a box with several of them, and they box looked pretty old. Maybe it's time to stock up? $10 a piece, not a bad price if you only need one.

Edit September 2023: There is a seal kit available from a company in Michigan that sells parts for Mopars, it's on ebay listed as "Mopar RANCO Heater Water Control Valve Repair Kit Seal Set"



The valve assembly has several parts with bent tabs holding it together. If your valve has already been rebuilt in the past, the odds are you will break off most of the tabs when you open it back up, or try to put it back together. In that case, good luck. I was fortunate, my valve was a virgin.

First thing is to get the valve out of the car, and perhaps test the thermostat by putting the capillary tube into a pan of hot water, and running the mechanism, and see if the end of the valve mechanism moves in and out a bit under different conditions of heat, cool, lever pulled, lever pushed. Also test that water can flow through the tubes when it's open, and not when it's closed. If this stuff is not working now, it probably still won't work after you replace the seal, so it's a good idea to get it all figured out ahead of time.

When you are ready to take it apart, first set the temperature lever so the flat spring at the red arrow is close to the main mounting plate. Then pull that flat spring out, off the end of the valve shaft. Be patient and careful. After you do this, you can remove the coil spring, yellow arrow. Leaving the coil spring on will help hold the valve where it needs to be to remove the flat spring.



once the springs are off, you can remove the main housing from the mounting plate. There are six bent tabs holding it on. It's spring loaded, so be careful.



Now you can see the four tabs that hold the valve assembly together. On this valve, the thermostat disk is in the way of the bending those four big tabs, so you have to remove the disk. It's held on by three small tangs on the other side, carefully bend them and remove it. You should be taking pictures of YOUR valve as you do all these steps, because they are not all built the same--some have the capillary going out at a different angle than mine does, for example. After you remove the thermostat disk, you will be at the difficult part--bending those four big tabs straight



I ground down an old flat blade screw drive so the blade was more like a chisel, and used it to carefully pry the tabs up a bit. Then I used pliers to bend them almost straight. You don't want to bend them any more than necessary, because they will want to break off. Once the tabs are straight enough to remove the mounting plate, do so. Disassemble the valve, and clean all the parts as appropriate for your particular car (mine did not want any cosmetic work, but many cars will want to have this stuff glass bead blasted, and repainted to look pretty).

Put the valve poppet back in place, then put the new seal in. To get the whole assembly staked back together tightly, you need to compress it. I made a special tool from a piece of 1" 16 gauge steel tubing, that supports the valve just under the tabs.



The tool goes under the valve, then a socket fits on top of the steel plate, just enough pressure to force it together. I used a screw drive and hammer to tap the tabs back down at about 45 degrees--enough to hold it, but not enough to break them off.





It's not as pretty as it used to be, but it should hold OK.



Also make sure the copper and steel parts remain fully pressed together after you release the press. This tight fit is what keeps the rubber seal from leaking.



When assembling the two large pieces, they are spring loaded, and will not want to stay put while you attempt to bend the tabs over. Put the thing in a vise, one end or one corner at a time, and tap that tab over with a hammer, then clamp another corner, etc. Once the main assembly is done, get the springs back on, put it in the car, hook up the hoses and control cable, and see how you did.

 

I just ordered the part. Thanks for the info.

 

Thanks Jim, I have a couple to order now while they are still available.
Great technical information lots of us can use!
KK

 

Great tech.

 

I have been working on cars for over 55 years, and have never rebuilt a heater control valve. Just bought new ones. Thanks for the tech run through, never too old to learn something new.

 

Awesome. I am working on a friend's Chrysler, and this is one of the things that needs attention. Thanks Jim.

 

You will enjoy that heater. It will roast you. You rarely have to use the heater fan unless you need defrost (which is pretty poor) because all you need to do is open the cowl vent.

 

yeah, it's a neat system. I test it today, it's working fine.