Door Latch/Lock Mechanism

Lotus Excel Door Handles, connecting rods, locks, latches and central locking

A collection of hints, tips and photos.

One of the Excel's main weakspots is the exterior door handles. They're Toyota parts, only used on the Celica Supra Mk II for about a year from 1982-83. Lotus being Lotus, they inverted the Toyota handles and used them on the opposite sides of the car. As a result, it isn't possible to fit later Toyota "pull up" handles without a complete redesign of the actuating mechanism.

That said, if you get the connecting rods and everything else properly aligned, the stress on the handles can be minimised and they shouldn't fail. 

If you find that you have locking problems, and that your exterior handle is pulling away from the door, then the plastic that holds the insert for the clamping bolt has probably failed. Epoxy resin, a longer insert and careful readjustment of the whole mechanism is a temporary answer - but you might also consider this option. Similarly, if your central locking is misbehaving you may have a loose connecting/pivot lever, fractured wire near the hinge, or a problem with the door handles. Tightening the pivot point for the actuator connecting lever is easy.

If you door flies open on corners, your latch has probably failed - which  can be a major problem because 100% compatible latches are in short supply. We're working on an alternative solution.

The system shown below is from a later car with central locking. Early cars didn't have the electric actuators and extra connecting rods, but the basic system changed very little over the years.

There's not a huge amount to say about the process of getting the mechanism aligned, except that it takes time and patience and helps to be able to visualise things based on the components off the car.

The latch mechanism is held onto the beam by 4 allen-head setscrews. On later cars, there are 3 spacers (1plate at the top and two thick washers at the bottom) between the latch and the beam. Watch out for the lengths of the setscrews. One is shorter than the others - probably best to put it back in the same place.

The next two photos show the whole latch and rod assembly, including the pivot lever for the central locking, once they're been removed from the car. All that is required to get to this stage is to pop the rod ends out of the plastic clips on the door handles and the actuator and to unbolt the lever from the inner door skin.

This is the infamous plate with the "Z" slot that "protects" the exterior door handle from over-stress (in theory, when the door is locked, the flap can still operate). Note that the ends of the rods are threaded so they can be screwed in or out to adjust length. This Z plate has a mounting problem - it should sit at the bottom of the slot on the lower (door opening) latch lever, but this one has slid up. Lotus tack-welded the pin to the latch to keep it in place, originally. If it sits too high, the geometry is "off" when the door is locked, and the rod to open the door won't slide in a way that protects the handle from breaking.

Check these connecting points carefully. The E/C clips do corrode and/or fall out, which leads to all sorts of problems - including strange central-locking cycling, and complete failure to open the door, eventually. If your door doesn't open nicely from outside, please DON'T try to force it by pulling harder on the handle (see note above about handle breakage). Use the interior handle and apply an outward force from inside the car.

And this is the other side of the latch where the rods from the inner handle connect to release and lock the door. Again these are threaded so length can be adjusted - BUT if you have central locking, you'll need to play around with the point at which they attach to the pivot lever too.

The rods are clamped to the CL actuating lever, inside the door skin, with grub screws. A small allen key is required to release them. The internal release rod (i.e. from the interior handle to the latch) does go where the parts manual shows it - it needs to be on the outer skin side of the lock pivot rod or there's too much friction in the system. (i.e. not where it appears to want to run naturally).

Note: When putting the lock and rod assembly back into the door, make sure that the two rods for the exterior handle come up through the beam. The big hole in the inner face of the beam means you can get fingers in to guide them. If they aren't projecting up before you attach the latch to the beam, you'll have to unbolt the latch again.

And finally, a couple of shots of the door handle from inside.

This is the latest of the version of handle - it has a single piece clamp bracket (early models have two - one at each end) and a hole drilled through the handle and bracket to take a reinforcing pin which completely fails to solve the breaking screw hole problem. It was worth a try, I guess.

And finally