If it's like my W123, the big black line carries the vac to the power brake assist, and the rest of the vac splits off of that. When I have power brakes, then I can start from there and test backward to find the leaks. If you don't have power brakes, it's something more fundamental you need to address, like a new main line or more likely, new vac pump. Some have used rebuild kits and reported good results but I don't have the patience for that.
From my experience, major leaks are likely to be something simple like line(s) that have come come loose. If door locks don't work correctly, the most sluggish one is probably going to be the culprit...swap out the actuator for that one. If all don't work, it's probably the master valve in the drivers door. When you swap that out, I'd recommend fashioning a piece of coat hanger for the little armature on that one instead of using the new replacements that are commonly sold...or just use your original part if it isn't worn out. I used a new one when I replaced my master valve and that part broke in a year. The coat hanger part is working fine. Pix here:
http://groups.yahoo.com/group/diesel_mercedes/photos/album/948035862/pic/list
HVAC vac problems include the notorious center vent flap actuator, of which many stories have been written regarding repair. If that one were kaput I think I'd probably cap the line off and then run a screw through the flapper to hold it open, or install a mechanical choke cable to it. Who knows, I might even try to repair it the right way, though I think I'd use the method of partial part replacement (take the new part apart, get the rubber diaphragm out and swap that into the old part without removing the entire old part)...you can search peachparts forum for that one.
There is some stuff under the hood that can be leaking, probably an easy find there by using the hand vac pump. There is also the vac reservoir, the thing that holds nothing, looks like an egg crate under the back panel, can find it by looking under the back panel from the trunk side. And there are actuators for the trunk lock and the fuel door lock. I think my car is different from yours but maybe there are some similarities.
Jim
--- In diesel_mercedes@yahoogroups.com, "Nate" <vwnate1@...> wrote:
>
>
> Well it depends ;
>
> What color plastic line are you pumping vacuum from & where .
>
> In general no but , there's some wiggle room in there .
>
> Yellow : door , truck & gas flap central locking
>
> Green : HVAC
>
> Brown : engine kill
>
> -Nate
> Rodger wrote:
> >
> > Hello All
> >
> > I am trying to track down the vacuum leaks in my new 1978 300D.
> >
> > I am assuming that if I pump vacuum into a line and it immediately looses the vacuum it is not supposed to work that way, there is a big leak.
> >
> > I am also assuming that if it slowly looses the vacuum there is a smaller leak.
> >
> > Please let me know if I am right.
> >
> > thank you
> > Rodger
> > Placitas, New Mexico
> >
>
No comments:
Post a Comment