TR4 Door Release

[ianc]

TR4 DOOR RELEASE

Of late, I had found that depressing the button on the passenger’s door sometimes failed to release the door, so I would have to get inside and give the door a thump whilst pulling back the internal handle.  Over the last weekend, when, at Brian Culcheth’s invitation, Maddy and I drove 4VC to Sherborne for the Rally Car display at the Classic Car Show, this problem occurred 3 times, so something needed to be done.

I was aware that some sort of adjustment was incorporated into the release mechanism, so consulted the Workshop Manual, which showed a screw and locknut on the end of the plunger, inside the door.  Clearly, access to this adjustment would mean removing the door cladding and dismantling the mechanism – something to be avoided!

To investigate the problem, I removed the screw at the left end (near B post) of the door pocket and released the cladding at top, side and bottom of the left half of the door, which, with the window raised and easing the cladding away from the door, permitted me to get my right hand inside and touch the release mechanism.

The obvious fix would be to reduce by a small amount the gap between the head of the adjusting screw and the lock contactor, and Maddy suggested that one of the plastic packings, which we have used to align furniture, might fit the bill.  I had purchased a pack of these last year from Wickes (code 214866, Broadfix 28mm Flatpackers), which are colour-coded in 1mm steps  from 1mm to 6mm thick.  Taking the thinnest (green, 1mm), I found that it would fit into the gap, but I didn’t require the full 10cm length.  Cutting off about 30mm, I applied double-sided tape, and managed to get the tape to stick to the lock contactor, which is flat where the screw’s head meets it.

The passenger door can now be opened with ease, and, as long as the packing piece remains stuck in position, should do so for at least another 50 years!

Ian Cornish

Note: In the WSM and Parts Book, the items mentioned are not separately identified as each is part of an assembly.  In the WSM, Figures 50 and 52 show what goes on!  The mechanism seems to have been altered somewhat for TR4A/5/6, and I cannot say whether a similar fix might work.

[RogerH]

Hi Ian,

the 4 and 4A are the same.

Here is an expolded view of the lock.

The screw and lock nut go through the base casting and into the plunger 

 

Roger

 

[RogerH]

Here is a better view of the adjuster screw and plunger

The screw and lock nut can be adjusted so as to have a small gap between the screw head and the lever on the door lock mechanism

 

Roger

 

Edited July 24, 2019 by RogerH

[stuart]

Dont make the gap too small or it makes the release hard work.

Stuart.

[ianc]

Thanks, Roger - very helpful shot.  And I think it illustrates why I decided not to dismantle all the inside of my passenger door in order to try and get at the locking nut and the screw.

My "fix" was comparatively easy to achieve, and, although I note that Stuart advises caution, I can say only that Maddy and I agree that I have overcome the problem on 4VC''s passenger door using a piece of plastic just 1mm thick.  It suggests to me that over 50+ years of use, that amount of wear has occurred in the system.  Oddly enough, I don't (yet!) have the problem with the driver's door, even though it gets much more use.

Had I found the 1mm sheet difficult to insert, I would have looked for something thinner (my garage is full of useful odds & ends - things which Alex thinks I ought to consign to the dump!).

Ian Cornish