Has anyone tried to convert a the vacuum leak prone 123 central locking system to the better 126 system?

I have a spare 126 central locking pump and I can envision fabricating a toggle switch in the driver's door to switch the pump between lock and umlock. The 126 pump supplies a vacuum to the system when it is in the lock mode. When it is in the unlock mode, it provides a positive pressure to the system.

Will the vacuum elements will have enough power to UNLOCK the doors when the line is pressurized? I figure the vacuum elements will have enough power to LOCK the doors when the line has a vacuum pulled on it.

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Tom Evans
69 280SE 91K (wish I still had it)
73 220D 98K
78 300D 134K
78 300D 185K
81 300SD 301K (still have)
82 300SD 321K (still have)
84 300D 268K
84 6.2 Diesel GMC Suburban 225K (a whole different story!)

Why do you want to convert a simple system into a more complex system? Also, the W126 system also uses vacuum, not pressure.

Would that still be using all the other elements from the w123 system that would be prone to the leaks?

Having never worked on a vacuum system before, I was able to locate and repair every leak in the system in 2 evenings (about 3 hours) of testing with a Mity Vac and about $20 in vacuum connectors and hose. That included pulling 3 door panels, the hatch panel and repairing an actuator.

IMO, I would leave the system as is. It is very easy to troubleshoot, especially once youv'e been aquainted.

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Chad
2006 Nissan Pathfinder LE
1998 Acura 3.0 CL
OBK#44
"Pleasure in the job puts perfection in the work." - Aristotle (384-322 B.C.)

SOLD
1985 300TD - Red Dragon
1986 300SDL - Coda
1991 - 300TE
1995 - E320
1985 300CD - Gladys

Craig,

I've owned two 126s and three 123s. The 126 uses pressure to unlock and vacuum to lock. There is only one hose to each of the vacuum elements on a 126, not two hoses as on a 123. You can have a pretty significant leak and the 126 will work just fine. It will also work if you don't use the car for a month (no leakdown). The 126 system is much easier to troubleshoot and maintain.

__________________
Tom Evans
69 280SE 91K (wish I still had it)
73 220D 98K
78 300D 134K
78 300D 185K
81 300SD 301K (still have)
82 300SD 321K (still have)
84 300D 268K
84 6.2 Diesel GMC Suburban 225K (a whole different story!)

If you're thinking of replacing the entire locking system with a 126's, why not just replace it with new 123 components. That way you'll have something good for another 15-20 years without going to the trouble of a retrofit to the 126 system.

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DJ


84 300D Turbodiesel 190K with 4 speed manual sold in 03/2012

Sorry, I didn't realize the W126 uses pressure to unlock, but it should have no leaks anyway. It's hard to imagine anything much simpler to troubleshoot and maintain than the W123 system, if it doesn't leak it works. Mine will hold vacuum for at least a week, probably longer but that's about the longest it ever sits. You can replace the entire system with new parts for a few $100, converting to the W126 system is likely to be much more expensive unless you use junk parts. I simply replaced all the actuators after the first time one leaked, the system has worked perfectly for several years and a couple of 100K miles.

I've parked my car for over a year, came back to it and all the locks worked.

just my $0.02

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You can try unlocking using the pressure side of a MityVac. If that doesn't work, use a second pump to do the unlocking.

Ideally you'd fit both front door switches and the trunk switch off a 201, 124 or 85-up 126 so you can have central locking from all locks.

Another idea is to hook up a vacuum pump to the reservoir line. You'll need isolation valves since it will take forever to vacuum the reservoir. Basically you keep the system intact and use the vacuum pump as a back-up.

Sixto
87 300D