I have a 420 as a daily runner, but with the cold weather arriving I have found that the heater control cable (or what it is attached to) has seized.

Is there any "simpler" way to get to the business end of the cable without removing bonnet, box, and seemingly everything else within a few feet of the heater box?

Or am I just being naively optomistic?

Many thanks in advance....

Neil

 

my heater control cable (1967 Mk2 so may not be applicable) is attached to a common heater valve in the engine compartment that is used in many british cars of the 50's and 60's. they are readily available for purchase online, relatively inexpensive and simple to replace. they can, in conjunction or separately, with the cable that controls them, as you've found, offer an annoying resistance upon reaching maturity.

 

I think I may have reached maturity.
many thanks
Neil

 

In the 420, if you remove the chromed grille located above the radio on the under dash shelf, you can see where the cable begins and attaches to the Temp lever that moves left to right. It is the same as in the S type.

to remove that chromed grille, you pry it up carefully as it is held in place by 4 plastic pins or " buttons".
Use a "fork" type of trim removal tool by sliding it under the grille and each pin, the type of tool that also removes the clips behind door cards.

then you can inject a spray lubricant up the cable sheath to see if it becomes easier to operate.
In the S type and 420 it is a very simple system.
The other end of the cable connects to another lever, but not to the Heater tap / valve. You may be able to inject lubricant through the left side of the box where the lever and cable end are somewhat visible.
​​

 

The S-Type and 420 have a vacuum operated valve I believe, the cable just moves the flap in the heater box.

I would start by disconnecting the cable at the heater box end and see whether its the cable or heater box that is siezed.

If its the heater box then spraying the pivot points at each end and working it with some pliers or mole grips might help.

 

yes.

 

 

I have recently solved multiple cable problems by taking the inner cables out, cleaning and lubricating. One was "in-situ" so I squirted with WD40 down the cable at one end as best I could. Time after time, with much wiggling!!!

 

Bowden cables should react well to this treatment as long as the airbox flap hinge has not seized.

 

For less than £10 you can buy a cable lubricator. Used on motor bike cables. From my experience of stripping down the heater box I think you will find it is more likely to be the hinge for the flap that is either seized or very stiff.
https://www.ebay.co.uk/itm/154395374457?epid=9029697350&hash=item23f2ae7379:g bcAAOSw18Zdj3zB&amdata=enc%3AAQAIAAAAwAnH7hV6uxJ sfVl%2FZP1WGoPO6DsF%2BuRNFobtmoo2rbngsnj2WwFJq8CGu Pk%2FaCwQ4mcT%2FxzGUcAJJJw%2BbOTokTdmWzAKp6Oya7Rpl zymqMLuI2LYYpxLPujy6gdOAznLuZFpA9Pw8deb9SH204k1%2B Jb9wBW7KUPpz%2Fq8qAul6kxy3fJU%2Fuqvf4SOXNyWYFUWp5Z 1Ik0cXjpZV5YYBf%2Fe69IXp2QImrtwumTo3gPw3BfUE69S5R1 Hng8n2%2BozDUomZw%3D%3D%7Ctkp%3ABk9SR_63rMaGYw

 

That's a neat tool!!

 

Maybe the cables should have had grease nipples? I was recently under a Mercedes 300SL and was amazed to see grease nipples on the parking brake cables. Never seen that before.

 

I had a Mk7 Jag back in the 1960s and it had grease nipples on the handbrake cable.

 

Thanks to all for their help and comments

I have ordered a cable lubricator and will let you know how I get on.....

I think I will need to get to the flaps so will be dismantling from the front...

Happy days!

 

I solved a seemingly insurmoutable under-dash flap using copius amounts of WD40 and gently wiggling the flap. It was completely stuck. Took patience and a lot of swearing whilst upside down and breathing in WD40 fumes!!!