Brake Light switch fix-all C900's

The brake light switch has a "ratchet cylinder" on the plunger which very often collapses, making the switch close the circuit permanently and making adjustment difficult to impossible. This tutorial explains how to fix this problem once and for all.

Difficulty:2/10

Parts needed: brake switch and super glue

Tools: 13mm wrench and socket, tiny screwdriver/feeler gauge/ sharp knife, glue, wd-40 or any mild lubricant

Time: 15 minutes

The brake switch is located on an assembly just next to the steering column shaft. If you crawl underneath the dash with a flashlight, it's easily visible, regardless of whether your 900 is equipped with the large or small knee bolster. The function of this switch is to close the circuit for the brake lights whenever the brake pedal is depressed. It's spring loaded an works opposite of a push button switch.
If the plunger on yours has collapsed, your brake lights will be on all the time.
The removal is straightforward. Undo the the bolt holding the switch assembly in place and undo the connectors. If you have cruise control, there will be other switches which needn't be touched. Use pliers to compress the neck of the switch and pull it out.

Now you end up with something like this:

Attachment 13881

This is what it looks like when the plunger has collapsed.

Now using your sharp tool, remove the guts of the switch:

Attachment 13882

Attachment 13883

Attachment 13884

You don't need to do anything to this part, other than maybe adding some sort of lubricant to the moving parts.

Now remove the plunger from it's cylinder:

Attachment 13885

You can see the silly ratcheting mechanism which we will now glue permanently. This causes the plunger to collapse when it's pushed backwards and causes the brake pedal plate to lose contact with it.

Extend the plunger until it looks like this:

Attachment 13886

Obviously, you shouldn't use elmer's glue, but any super glue will do:

Attachment 13887

Let dry.
Make sure the plunger is smooth and that blobs of dried glue will not interfere with its movement in the cylinder.

Put the plunger back, making sure the small pin is facing up:

Attachment 13888

Carefully press the assembly back inside the casing (if you break the casing during removal you can add a drop of glue to secure it back):

Attachment 13889

Attachment 13890

When properly extended, the switch should look like this:

Attachment 13891

Now you can put the switch back in its bracket and readjust the bracket using the 13mm nut. There is a tiny amount of freeplay in the brake pedal assembly designed to allow the switch to operate. Make sure the pedal presses the switch enough when released to allow the switch to work properly.

Done! Now you'll never have to worry again about a flat battery due to brake lights.