Should this part hold vacuum Euroheadlights? - Page 2 - PeachParts Mercedes-Benz Forum

lutzTD · #16 09-13-2009, 10:05 PM

there is a special reservior for the headlights. it is in the driverside fender below the door hinges.

fred98050 · #17 09-13-2009, 11:01 PM

The 300D and SD might be different, or some headlights might differ but today I went to look at a 300SD with euro headlights, the owner has done the upgrade himself and basically, T off the vacuum in the engine compartment to a check valve, to the switch and from the switch to the headlights. No reservoir and the system works great.

The install is following this diagram (posted in this forum):

Sev · #18 09-14-2009, 03:21 AM

Quote:

Originally Posted by MBeige

Only when letting the air back in (releasing the vacuum hold). But as I directly apply vacuum to the actuators in the headlights, they hold VERY well.

As for the source I tapped the accessories line on the brake booster hose (second vacuum plug). First one is for EGR/transmission/VCV. Right after the second plug I have a 3-way connector for the Euros and the accessories main line, which divides into the 4-way connector (2 for the central locking, 1 for climate control, 1 for ignition).

I did not tap a reservoir, I don't know how that is needed but I know it's part of the diagram. So with that instead of a 3 way check valve (2 in, 1 out) I installed a one way check valve (blue/black), which was NOS part I had from years ago that I never used. Checked it prior to using and air only goes one way so I routed it properly.

Still, the headlights do not want to move when I dial the switch from 0 to 3 and/or back. Is it supposed to be instantaneous?

When I set it to 3, the engine will not shut off. If it's at 0, 1 or 2, it shuts off immediately.

My other problem is why are the lights pointing UP, instead of down? These levelers are supposed to be to illuminate the road when the rear end is sagging with weight and the front end is pointing up. Headlight beams will not be able to cover the road in front so the leveler is designed to point the lights down, correct?

1. i personally would choose another vacuum source rather than the brake booster line-since that connects to the rest of the engine vacuum system.

2. if it points up instead of down, try switching the two vacuum tubes that go into the switch--this should reverse it and make it normal again.

3. if the engine won't shut off with the vacuum switch installed, and all that's new, vacuum-wise, is the switch tapped into the brake booster vacuum tube, then try disconnecting the large one-way vacuum switch that connects all the engine vacuum tubes, to the tubes that go into the interior via the firewall (just next to the brake booster). put a screw or golf ball tee into the vacuum connector going into the interior, and see if the engine will shut off. if so, then you can pinpoint the vacuum leak to one of the vacuum tubes in the engine bay--probably the new one you tapped into the brake booster tube.

Sev · #19 09-14-2009, 03:24 AM

Quote:

Originally Posted by fred98050

The 300D and SD might be different, or some headlights might differ but today I went to look at a 300SD with euro headlights, the owner has done the upgrade himself and basically, T off the vacuum in the engine compartment to a check valve, to the switch and from the switch to the headlights. No reservoir and the system works great.

The install is following this diagram (posted in this forum):

they are different, becuase the cluster was a completely new design on the w126 chassis, and included a vacuum tube going into the economy gauge (not present in 1991+ models), which could be used for the vacuum switch.

for the w123 you have to get crafty and choose another vacuum source, which is what mbeige did by using the brake booster as a source.

MBeige · #20 09-14-2009, 03:03 PM

Quote:

Originally Posted by Yak

I thought the Mity-Vac test would at least work on 0, but there may be a continous bleed from the switch that prevents the Mity-Vac from pulling enough vacuum to move the actuators. It makes sense if the switch bleeds off 5-6 in Hg even in 0 (from 17 to 11-12).

With the switch installed normally, try capping/plugging the green A/C line, then test the lights. If that doesn't work, also cap the central locks. This basically diverts all vacuum to the switch. If it doesn't work in this set up, then you may have a faulty switch.

Or - and I know it sounds silly - change the settings on your ACC. If you substitute "seat backs" for "light actuators" the same thing happens my car. I can't draw enough vacuum to move the locks, even though all components test okay in isolation. When I change the ACC setting, they move.

You might be able to "borrow" the A/C vacuum reservoir. Do you have a check valve with red/gray and green/yellow lines exiting it? The red/gray is supposed to go to your A/C reservoir inside the left front fender (behind the wheel liner). Do you have a T-connector you can install there? Hooking your lights there would add a continuous bleed to the A/C system, though.

Check here for more info: http://images.google.com/imgres?imgurl=http://i25.photobucket.com/albums/c70/cyberbach/VacuumValveSteeringLock.jpg&imgrefurl=http://www.benzworld.org/forums/w123-e-ce-d-cd-td/1456119-another-vacuum-problem-need-help-2.html&usg=__gOpju3wL66nSv1ViHsVsX6y2tas=&h=307&w=365&sz=14&hl=en&start=11&um=1&tbnid=79QetIg8ub3B4M:&tbnh=102&tbnw=121&prev=/images%3Fq%3Dmercedes%2Beuro%2Bheadlight%2Bvacuum%26hl%3Den%26rls%3Dcom.microsoft:en-us%26um%3D1

and here: http://home.comcast.net/~phantoms/vacuum/heating_ac.jpg

http://home.comcast.net/~phantoms/vacuum/heating_ac.jpg

I've been using the car for several days with the setup but so far I have not seen the lights point down when dialing it down to 3. The diagram I have is similar to Fred's setup except that no line goes to the instrument cluster for fuel economy gauge.

All vacuum systems have been working fine. When I find time to tinker with the car again I'll check back. Right now I just moved in to a new apartment and I'm staying under the manager's radar, so not much tinkering...for now.

Anybody got a place in SoCal/OC we could tinker with the cars?

lutzTD · #21 09-14-2009, 03:19 PM

the euro w123 cars I have pulled headlight height systems from go from the brake vac line on a tee from the locks/climate/ignition/transmission line to the reservior in the fender then to the vacuum height switch to the lights. I think the fender reservior should be duplicated either with the correct one or with another added one where ever you can find a space.

Yak · #22 09-14-2009, 06:02 PM

How do you have them adjusted? Is it possible the mechanical adjust setting is maxed out and they can't dip when the actuator releases them? Otherwise I'm out of ideas.

Actros617 · #23 09-14-2009, 07:03 PM

Your gonna to have a check valve that connects to the vacuum supply so that the vacuum tank dont loose any vacuum when your adjusting the headlight.