Leak point in Climate control vacumm 45oslc

[450slcguy]

Hello,
I'm in the process of restoring my vacumm routing under the dash for the climate control. Previous butcher owner disconnected and pulled many lines.

My question is: on the specified leak points do I just leave the vacumm tube open? Wouldn't this create a loss of vacumm in the associated branches off that line? I'll be breaking my back and neck all day today under the dash and would appreciate any info.. John

[450slcguy]

I got most of the routing done today, but still would like to know about the leak point and how to terminate it, someone who knows about the climate control vacumm routing should know, the cd dosen't explain how how this workd or how to terminate the hose.

[mbdoc]

The 1973-80 450SL's have 3 different vacuum systems!

What year car & is it a USA version?... Does it have Auto climate control (1977-81)

[450slcguy]

Hello,
1980 450SLC USA, and yes it does have auto. climate control. Specifically I'm talking about leak point #38 on the on the ACCII vacumm diagram, the green colored lines going between control button 3 and main vacuum switch #19.

[Richard Wooldridge]

Hi there,
That vague "specified leak point" is actually a coil of green WIRE plugged into the vacuum T fitting! It's around 3"-4" in diameter and maybe 3 - 4 feet of wire in all. the strands of copper in the insulation must provide a VERY small amount of air leakage so as to allow the system's vacuum to drop off when the off pushbutton is depressed. I imagine that in a 25 year old system there are enough built-in leaks that the specified leak point could just be plugged.
(I did leave it in my system, however.
Be sure to "check" the check valve that's under the hood next to the driver's side hood spring for correct operation - there are two check valves there, blue body, black end. One is for the door locking vacuum system, the other for the climate control system. On my 450SL, the climate control check valve was plugged, no vacuum thru it. I ordered out all new 4-way and T rubber connectors for my car as the rubber was hard and they leaked at the fittings.

Regards,
Richard Wooldridge
'82 300D/4.3L V6/T700R4 conversion
'79 450SL
'75 280C

[450slcguy]

Richard

My leak point "wire" is missing, can I replace it with a regular coil of wire, say about 14/12 ga. or so? thanks

[Richard Wooldridge]

Hi there,
Yes, I think #14 is about right, but use whatever fits tightly into the T fitting. Use around 3 feet of wire, coiled up.

Regards,
Richard Wooldridge
'82 300D/4.3L V6/t700R4 conversion
'79 450SL
'75 280C

[450slcguy]

One more question - Under the dash on passenger side of climate control there a 3 inline check valves(#82,83,35 on vacuum diagram), 2 of mine are missing, and the one that is there is solid black. Are all three check valves suppose to be the same? Can I substitute the black/blues one as replacements(like the ones on the firewall)? I've been online and the only ones I see are the black/blues ones? Thanks

[Richard Wooldridge]

Hi there,
Yes, they are all the blue body, black end variety on my 450SL. (82, 83, and 34 on my chart - 35 is the thermostatically controlled valve on bottom of the control unit.) Performance Products item #80-011, $11.95 ea. 1-800-243-1220. If you call them they will send you a great Mercedes catalog, or you can order the parts over the phone. Phil on this forum may have them also, but his online catalog is weak so you may have to call him for price and availability if you want to order through him.

Regards,
Richard Wooldridge
'82 300D/4.3L V6
'79 450SL
'75 280C

[450slcguy]

thanks Richard, $7.20 ea. @ ***************, greatest prices by far