Door lock problem/fix - long story

[lee]

I have had a series of door lock problems over the couple of years I've had my SVX. I know from older threads some of you have had problems with the lock too. The first time I "fixed" it by replacing the whole door lock assembly from a part-out. Then it returned, and I had a car that wouldn't lock the driver's door - although I guess that better than one that won't un-lock.

Anyway, given my financial condition I decided to delve into the lock. I'm sorry no pics, but my camera's battery was dead, so you'll just have to read along and try to use the little drawing I made (sorry I suck at artwork).



Before I start, I'm not going to explain how to take the door panel off, or get the lock assembly out of the door. I could do that if requested, but I seem to remember the directions from other threads.

OK, here's the problem/fix. If you open the motor assembly you will see a small electric motor driving a worm gear that turns a gear wheel. That gear wheel drives the piston in/out to actuate the physical lock. The gear wheel has a copper/brass face with a couple of insulating breaks. There are three (3) spring-type brass contacts (two thick, one thin - the lines reaching up from bottom of drawing) that reach out from the side to make/break contact so the motor knows when to start/stop turning, and in turn, the piston is far enough in/out to lock/unlock the door.

What makes/breaks the contacts? On the face of the gear wheel there are two upturned brass sections (in the drawing they are the two vertical lines in the middle of the gear). The purpose of these pieces is to cause the thin spring brass contact (the one on the right side) to jump off the surface, losing contact, and hence telling the motor it's time to stop turning.

I hypothesize the "springiness" of the brass deteriorates over time (metal fatigue). So instead of jumping the ramp, it bends inward along the edge of the ramp. Depending on which ramp it fails on, the door is either locked or unlocked and the motor extended the piston too far so its jammed in that position. The end result is you need to purchase a new motor (which means buying the whole frigging assembly), or try what I recently did. Take the gear wheel out (you have to remove the contact piece, two tiny phillips screws hold it down) and file down the height of the ramp. You can't file it flat, or it loses the disconnecting jump the motor needs as a signal, but with less of a hill, it matches the old brass contacts capabilities. You don't have to worry about what position the gear goes back into. As long as the locking piston moves up and down freely, the lock mechanism will find it's spot the first time it's connected back into the circuit.

So, what's the point here. I don't expect this to be a long term solution, but if your locks don't work, and you've got no bucks handy, you may want to give it a try. A new part is over $125 at SubaruParts. As usual, YMMV.

[b3lha]

Nice article. Well written.

I'll have a look at that next time I open the lock up to drain the water out of it. (My central locking stops working every time it rains!)

Phil.

[lee]

Thought maybe I should expand a bit on just what/how I filed on the upturned pieces before somebody tries to duplicate this. Looking at them in cross section they are vertical rectangles. I filed away so they actually have a ramp effect.

I tried my hand at graphics once again and will add below to visually explain. And kids, before you try this at home, keep in mind I had my old motor assembly (with gear) to fall back on....