Heater control cable wont push the control valve shut .

[Keith Scarfe]

On the early cars (mine is an S3) the heater control cable works by pushing the heater control valve shut using a solid wire inner cable. On mine, when I push it, it gets so far, to the point of the valve clicking shut and wont push any more it seems like the inner is just flexing and straining within the outer part. It is a relatively new cable (reproduction one I think - cant remember where I got it from now) but I think the problem is that it is cut too short. I cant work out if the outer needs to be put nearer or further away from the valve in the clamp or if it has no bearing on how the inner works. Anyone any ideas how you adjust this to make it push the valve shut rather than the cable just straining within itself? I assume I need to make the inner longer but am not sure.
Ta.
Keith.

[rodlittle]

Keith
If you loosen the clamp that holds the cable outer to the valve and then push the knob in as far as it will go that should close the valve. If it doesnt then the valve is faulty. if it does retighten the clamp on the outer in this position and see if you can then pull the knob to fully open. If not then you need to shorten the outer a bit. Im assuming theres no way you can lengthen the inner
rod

[prezoom]

Keith,

I have the same problem, but somewhat self induced. The control wire was too short to completely shut off the valve. Must have been broken off where the screw clamps the wire at some point. The outer housing was already extremely short, so I could not trim off a small portion to effectively make the wire longer. So, I purchased an aftermarket choke cable, hecho de China, and cut off the wire. I removed the original knob and wire, and removed the offending wire from the solid portion of the control knob. Then drilled the hole deeper in the solid portion and soldered in the new wire. TA DA....... Then discovered the wire was made from butter or something else equally as soft and the wire would bend where it came out of the cable housing, when trying to push the valve closed. Checked and I was only missing one toe. So, I have now bought a piece of music wire of the appropriate diameter and when I get a round tuitt, will remove the apparatus, un-solder the offending wire and try the much stiffer music wire. It should work, if I can get it though the outer housing.

As an aside, I just hooked up the control wire to the same sort of valve on my other restoration and made sure it would shut off the water valve. It does and I am happy.

Remind ones self, don't by cheap crap from China........makes for twice the cost and work.

Rob Walker
26-4889

[ericbushby]

keith
Check if the route taken by the cable is direct.
On my S3 I could pull the valve open although with some difficulty but it would not close fully.
I have had a return spring from the valve to the alternator bracket for some time.
However I have just realised that there is an unused grommet almost in line between the valve and the heater knob and the cable had been fitted through the wrong hole, way out of line.
I shortened the cable and refitted it and now the operation of the valve is smooth.
Yet another mistake that was easily corrected once I spotted it.
Best of luck
Eric in Burnley
1967 S3SE Type 45, Back on its wheels and ready to go, But it has been raining for three days.

[simonknee]

I had the same issue. My problem was that the cable outer (bike brake like) would flex rather than overcome the extra little snick to get the valve to lock off. I got around this issue by setting up the system as follows.

Undo the lock-screw on the cable at the valve.
Close the valve completely
Pull the cable out by 10mm (or whatever works)
Tighten the lock-screw.

You'll now find that you have enough gumption left in cable travel to get the valve to snick off shut.
I also found that the 10mm closes up a bit more after a few uses.

My problem my all stem from an old cable. However perhaps a new cable may still suffer from flexing of the sheath.

[simonknee]

I second the post from Eric about taking the direct route. Extra bends and length in the cable not only make it difficult to move but exacerbate the flex problem. I too made the run as short and straight as possible.

[Keith Scarfe]

Thanks all for the pointers. I will have a 'play' again this weekend. I think however it is because the cable is too short. Dunno how that happened. Anyway, If I can sus it I'll post back.

[Keith Scarfe]

I just thought I would post a follow up to this.
I have got it working quite well now.
First of all I did as suggested and re routed the cable to make the run as straight as possible. This simply meant in my case swapping it to the lower hole through the bulkhead (where I had put the washer tube as it is slightly bigger). This made it slightly better but still wouldn?t work. It did however have the added advantage of making the length of the overall cable longer so I had a bit more to play with.
Next I examined the valve itself. When operating it by hand (with the cable detached) it was noticeably stiff and notchy at the point of it snapping shut. This is a brand new valve. The click shut is achieved by the driving bar riding over an edge of the metal housing. So basically what I did was just file the edges of the track guide in the metal housing all smooth with a needle file (lost all the nice electro plating unfortunately) and this seems to be the fix. Sprayed it all liberally with WD40 and it all moves much smoother now. Latches shut so I haven?t filed too much off that?s ok. Connected the cable up and all is good.
Thanks for the pointers.
Keith.

[ericbushby]

Thankyou for posting the end of the story Kieth.
If we all did that we would all learn a little bit more each time.

Eric in Burnley
1967 S3SE Type 45 ( Running rough)!

[skelteanema]

Hi Keith,

thanks for ending the story. I am having the same problem with my heater valve and also came to the concludion that it was the area where the driving bar goes over the small edge on the metal housing. Mine valve is also relatively new so maybe it is something that is slightly tight on the newer valves. I was going to attack it with a file, but didn't get around to it yet. Now that you have had success I will have a go as well.

[mark030358]

I just used the information in this thread to fix the exact same issue with my Sprint.

A top post!!

Many thanks

Mark

[Keith Scarfe]

I just used the information in this thread to fix the exact same issue with my Sprint.

A top post!!

Many thanks

Mark

[simonknee]

Glad you guys got a fix but I would caution that you might find the valve will open up by itself now. When I want to set the heater at 50% I invariably find that it creeps out to 100%. The edge you have filed away acts a lock in the off position. The cable is also supposed to twist and lock at the knob end - hence the groove - but this never seems very good on my (prob orig) cable.

If it wasn't for the "edge" allowing it to lock in the off position I would be getting rather warm!

Simon

[mark030358]

Simon,
Nope.. works perfectly

cheers

[Keith Scarfe]

I think Simon is right to a degree. Yes this edge does indeed keep it shut once it 'clicks' over it so if you file too much away it wont hold shut. You just need to file a little off to make the pathway smooth. i.e. just enough to allow the cable to push it over the lip but not too much that it falls back and re opens.