I have been consulting the enormous wealth of information in the service manuals (PDF files) but there's so many flavours of the R107 it's difficult to determine which pages are relevant to me.

You have the first flavor of climate control - the all manual type. It's covered in the 1972-1977 section of the CD.

There's a vacuum valve on the firewall in the engine compartment that controls the heat flow, but there's also an electrical component to it - somehow. I haven't studied that part of it much, because I haven't had to, but I know there's a microswitch at the bottom of travel on the outer two levers that have to be pushed closed to turn off the heat. My sister ran into it with her car, when the heat wouldn't turn off.

 

Thanks for the replies. So this is potentially an issue with the vacuum lines? That manual choke idea sounds interesting.

... I know there's a microswitch at the bottom of travel on the outer two levers that have to be pushed closed to turn off the heat. My sister ran into it with her car, when the heat wouldn't turn off.

What did she run into?

 

^^ The PO of my 79 bypassed the switch and installed a "choke cable" to turn the heat on/off. I haven't gotten around to fixing it because it works just fine and I'm really not a purest.

 

Do you know if the blower motor is running? Has the heater core been bypassed? Would his car have the monovalve?

Are you getting hot water into the cabin? (has the heater core been bypassed because of a leak?)

If your core is hot, does the blower move air past it to toast your delicate little toesies? You might have a fuse blown, or the motor may be having "issues". There are threads in the E.G. about doing various things for a blower motor repair, if not replace. Try for the repair, replace is expensive.

The climate control system is one place I haven't gotten to, yet. So I can only give you vague general hints.

Good Luck,
Scott

 

Hi Scott. Thanks for your reply.

Do you know if the blower motor is running?

Yep, the blower motor is running well (thanks to advice given on this forum).

Has the heater core been bypassed? Would his car have the monovalve?

Erm. I don't know.

Are you getting hot water into the cabin? (has the heater core been bypassed because of a leak?)

No leaks I'm pleased to report.

If your core is hot, does the blower move air past it to toast your delicate little toesies? You might have a fuse blown, or the motor may be having "issues". There are threads in the E.G. about doing various things for a blower motor repair, if not replace. Try for the repair, replace is expensive.

No hot air what-so-ever. Not a fuse unfortunately. What is the E.G.?

 

Interesting that a 1981 380SL would have the System 1 that was used for 1972-77 North American cars. In NA, the '81 380Sl would have had System II which has quite a different control panel. What is it that is in the right upper section of the control panel?

Section 1 of the A/C manual "should" cover it, but perhaps the later Euro cars are different?

 

I can't get any heat into the cabin..

Maybe you need one of these.

Any help much appreciated.

You're welcome.

 

Maybe you need one of these.

I do need one of those.

 

Here's the cable hookup.

 

Why go through all that when the valve is only 25-35 bucks?

 

I wanted to start throwing some ideas into the mix, and got a little distracted during the post since I was at work, sorry.

The E.G. is the Encyclopedia Germanica, Vol 107. http://www.benzworld.org/forums/r-c...r-c107-sl-slc-class/1450550-welcome-damned-old-car-encyclopaedia-germanica.html A veritable treasure trove of information. The collected wisdom, if you will.

If the blower is going and you have a hot heater core, the only other piece is the ducting of the heated air to the cabin. This is a part I haven't gotten to yet, so I'll have to defer to the expertise of those who have trod that path. I was just trying to get you started on the journey with the 'small stuff' that I knew.

Keep us up on your progress, we all love the saga of a good quest.


Best wishes,
Scott

 

You may have stuck or actually loose heat control levers.
Both will have a screw on the pivot that is used for teeth-latching the control lever with the contraption inside. Pop the cover under the gloves compartment and it will be on the top right hand side. Timing of levers is essential for proper engagement.
Bear in mind that flaps can get stuck in either full direction and are bitch to disengage when faulty. No vacuum action there, if you shift fast enough you'll hear flaps hitting limiters.
Hot control levers each have a vacuum switch that engages hot water valve (as per petsmga pic) the moment you lift levers from full down position.

You should be able to manually open heater exchange hot water supply by disconnecting vacuum (pic supplied by Petsmga) and springloading it in opposite direction from where it wants to be free. Hot rubber tubing is an indicator of open valve.
As per setup on first pic, you should have some heat by the windshield but no air in the footwell. Both driver and passenger sides full on hot.
But you must run fan to get any air unless moving.

@ MBGraham
That is headlight level control for cars where steering wheel is on the right side, ROTW headlights.

 

That is about the third time the valve has been suggested. It was in the first response, is only 25-30 bucks. Can be tested as you stated.

 

And that's a 4th time so I that's what I'm going to concentrate on first. I've put aside all day tomorrow to diagnose/solve the problem. Thanks for the suggestions everyone. I'll report back if I have anything useful to say.

 

BTW - in the picture I supplied above showing the cable hookup there is a check valve on the red vacuum line to the actutor-valve. That didn't make any sense as it has to open and close. I removed it and the valve works fine. I had fixed vacuum lines under the dash last year and got the controls to operate as they should but never bothered to check that part of the system as the cable hookup worked. So it's another case of a A-hole indy that had his mitts on the car at some point.

 

Right. Haven't been able to get on with today as it's been raining hard during the few hours of precious daylight (today's the official end of 'british summertime').

Okay, as the vacuum lines in the car are generally pretty flaky*, I'm guessing the pipe that's meant to blow the valve open isn't pushing enough air. I can't test this as I assume the engine needs to be running to do so.

The pic here showing this bag containing various hoses. Is that a bad sign? Also, if anyone has a second, can any one offer a simple overview of the correct arrangement of the levers on the dash? Completely unintuitive to my eyes. Also, what does DEF mean?

This must sound seriously dumb.
Any help much appreciated.

 

.


DEF=windscreen defrost

 

DEF=windscreen defrost

As in Defrost Leppard, Defrost Comedy Jam, etc. Anything that leaves you cold and slightly freezer burned.

 

.


lfedje, or one of the other early model owners have posted control instructions. If we can find it, we can EGv107 it.

 

Great. Thanks for that. Googling 'what does 'DEF' mean?' doesn't bring up any even remotely related results.

 

From the owners manual

 

That is superbly useful. Thanks. That section in the public domain 560SL manual is of a completely different type. http://dl.dropbox.com/u/7996346/560sl_om.pdf

 

.



Added 10/31/2010

 

Right-o. Hello again. Having a problem with putting enough time aside for working on the car. Stealing 5 minutes when I can. Just a couple of further dumb questions and plea for advice.

In the first pic. The hot water valve has a vacuum hose up its butt and all looks good apart from something broken off the end (arrowed). Can anyone shed any light on that? Is that the remnants of some kind of DIY choke cable solution as per petesmga's on this thread?

Unrelated: In the second pic, I noticed there's an earth strap hanging loose off the (what looks like) the power steering pump. What the eff? I can't see where that's meant to attach. Is it even meant to be there? (Haven't noticed any earthing issues).

Semi-related: I have some serious vacuum issues in other areas of the car. I've never had a car which relies this much on such a system. Is the tool I need to buy to test and diagnose tons of problems something from the Mityvac range? Would that be a good place to start?

Again, apologies. Any help much appreciated.
Cheers
Ben

 

Wire goes to the bolt on the chassis in the vicinity of the yellow marker.

White stuff may be a boken lever - actuator.
Vacuum element is suposed to pull the lever to open the valve.

 

Vacuum element and valve are one piece on this model. PN 107 830 05 84. About $25.00 over here.

 

Thanks for those replies. I appreciate the effort. I've ordered the part. Surprisingly cheap (as you said).
Cheers

 

Man alive. Another little surprise. Found half a bolt blocking off the faulty valve. The new part wasn't that expensive and fairly easy to swap out. Wondering why someone would go to trouble of sawing a bolt in half. Am expecting more surprises.

 

Wondering why someone would go to trouble of sawing a bolt in half. Am expecting more surprises.

Sorry to say, but my bet is a leaking heater core.

 

Yes. I'm expecting something along those lines. Groan.

 

^ ^ ^ ^

Don't!

Don't be surprised if you find nothing else wrong.
When this valve goes faulty, it leaks hot water all the times and that is the least desirable failure in hot summer months.
Leak is not fixed if you just plug the valve and leave the system pressurized. Complete elimination of pipes is required for leaking heater core.

 

^ ^ ^ ^
Don't be surprised if you find nothing else wrong.
When this valve goes faulty, it leaks hot water all the times and that is the least desirable failure in hot summer months. Leak is not fixed if you just plug the valve and leave the system pressurized. Complete elimination of pipes is required for leaking heater core.

Just to put this thread to bed, yep. Works great. No leaks. Lovely hot air. Thanks for all the help.
Cheers

 

This tread to bed until springtime when that valve cannot shutdown the heat no matter what... than its US$25 + PP