RV8NOTE128, solving RV8 heater control problem, V8 Register, MG Car Club

128
Solving a problem with the RV8 heater control cable
John Hornabrook (Woodcote Green 1781) from Queensland in Australia has sent in this useful note on a difficulty which a number of members downunder have faced with their RV8s. John had the help of his chum, Greg Tunstall, who describes how the problem was fixed. (Apr 02)

Our problem was an inoperative heater control. The knob turned but did not turn on the hot water valve in the engine bay. You could see the cable trying to push the tap but it would not operate the valve properly. With the cable disconnected (at the tap), the tap could be operated manually without much effort but the cable was not doing its job. We had made a decision to fit a remote cable and a suitable tap to overcome the problem. But after investigating the lack of accessibility to do this and the availability of the parts, we decided to try and fix the existing set up.

First we needed to get access to the control in the dash to see if it could be repaired or replaced. After stripping out some of the centre console and dismantling the dash and woodwork around the controls, we were left with a large plastic control box that has three controls on it. The far right hand was the heater. We could see the cable from the heater tap entering a groove in the box. The cable outer had come out and was just moving along the wire inner every time you moved the control knob. Closer examination proved that this was the only problem with the box and it seemed that re-securing the cable

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would cure the problem. The cable was supposed to be secured to the box with a plastic U shaped clip. We prized it off with a screwdriver, relocated the cable and attached the clip.

This seemed to do the job perfectly but we were concerned that it might push the cable off again after refitting it. The best way to secure it was to undo the clip and put some polyurethane glue/sealer on the cable at the clip and reattach the clip. Polyurethane is really rubbery and strong w hen it sets so it should bond it in place securely. We did all this without removing the box from the dash, just manoeuvring it to gain access where needed. This is a bit fiddly but works well. We then screwed the box in place in the dash and went into the engine bay to the heater tap assembly. Minor adjustment here to the outer cable clamp had the tap working perfectly.

We would have liked to remove the cable completely to lubricate it but it would have been almost impossible because the end of the inner wire is bent in loops to attach to the tap. I am not sure at the box end because it is internal and you cannot see it unless you dismantle it ( if you can ). The last thing to do was to refit the woodwork and console section etc. This proved to be very fiddly, just getting the woodwork straight seemed impossible but it all came together well.With the job completed the last minute test proved it worked well, maybe a little stiff but not difficult to use and we did not have to buy a new control box or fit a remote tap and cable.