Heating and Ventilation

NB. On my 1969 Mk1 FF there are no rear electric demister fans. The car has an electrically heated rear window

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Two photographs of the new “ranco valve that I bought from Cropredy Bridge Garage. Comparing it to the old valve it is very similar except that there is no mounting braket for the operating cable. I asked the List about my leaking heater valve(“Ranco valve”):
“My Ranco valve leaks through the exposed rubber bellows. I’ve bought another for £53 (2004). It is located on the left hand side in the engine bay and is the same as the late CV8’s. Having part removed the unit in the engine bay and having part dismantled the dash I can’t see how to remove the thin copper tube? that acts as a sensor to provide thermostatic control of the unit. I do not just want to yank it out as it probably goes round a bend that I can’t see and/or may damage the heat exchanger.
My questions are: 1. how is it removed and 2 is it possible to cut the tube in the engine bay and solder the new tube ( also cut down to size) to it, so that I don’t have to remove it. I don’t actually know how the tube or is it a solid copper wire works other than it obviously conducts heat/cold to the unit which suitably responds. Maybe I’ll just cut it off altogether?

Later I also asked:
A couple of people on the list have suggested that it isn’t really worth fixing/installing the temp. sensing device on the Ranco valve just replace the valve and cut off the sensor. Depending on what else turns up, this may be the route I’ll go down. I’d rather not do any more dash dismantling. It was a shame I didn’t think about all this and perhaps ask the list before buying the new valve. I could have probably sourced a much more reliable alternative heater valve. Further since my posting it has also become apparent that on the new valve assembly there is no bracket to attach the operating cable so I will have to do some butchery work anyway.

The responses were:
1.You may be able to repair the old valve using parts off the new valve. I would not cut off the thermocouple on either old or new. 30+ years between servicing is not bad for a valve! All the old one needs is a service and seal. I think that it is possible to dismantle the valve in situ, and if you don’t have a new valve for spares, turn some brass to hold an appropriate modern seal, solder this onto the rod, fit the seal, and fit the old valve to the bulkhead without having to remove the dash. A reliable bodge is to get a 13mm in line isolating valve with compression fittings from a plumber, fit copper tubing to it and (possibly) rig a lever to the head of the slot on the valve. The tubing pushes nicely in to the heater pipes. For 2.5 pounds you get a reliable solution, that (IMHO) looks better than a butchered ranco valve. You can leave the original in place but unconnected. When you next have the dash out (eg, to fit air con), you can fit the ranco valve back properly. Given that new ones are scarce, it seems a shame to butcher one. Your proposal involves butchering two! (old and new!) There is a place on the web that repairs the old ranco valves, though I have not used them myself, as this entails removing the valve and thermocouple to send it off.

2.I find this on the Web http://HeaterControlValve.com/page6.html

3.http://www.heatercontrolvalve.com/ this place rebuilds the Ranco’s, but are somewhat expensive. They don’t do the vacuum actuated Interceptor III valves. I inquired a year ago or so.

4. Bremar the thermocouple goes through the bulkhead and the turns through 90 degrees( if I remember right) so you can’t “yank” it out. You need to access it from within the engine compartment not the interior. Jensen never did consider the problems of repairing anything. Wait until you do a major refit and fit a valve off another car?