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  #1  
Old 09-15-2006, 04:33 PM
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Proof Hell Exists (kinda long)

After reading numerous threads on this and other groups concerning the Climate control systems on my 560SL, I decided to "attack" the issue. Armed with manual and hand-powered vacuum pump, I dove into the project. My main concern was why the center vents ALWAYS remained open. Secondary, why heat never made it to the floor. Thirdly, why the def vents stayed open regardless of setting. I should mention that, prior to this, I bought a reman control system from our good friend, Germanstar, to correct a problem with the buttons, so I was sure the "electronic" parts were "up to snuff".

Forget what you read in the manual about taking the vacuum line loose at the firewall and trying the I-IV tests so eloquently described as a failure in the main air flaps will give an erroneous reading. Instead, dive right in to the dash, remove the glovebox, and test the circuits there.

#1 remove the #1 circuit vacuum line from the switchover valve and attach the pump. Evacuate to 300 or so millibars... YEAH! The dreaded legroom pod is functioning (no loss of vacuum when evacuated and watched). Guess I don't have to worry about removing the heater box to repair (spoke too soon).

#2 remove the #2 circuit from the switchover valve and repeat above. Ok, looks like the short-throw def pod is fouled up. Now I know why the def vents stay open (partially) all the time. I can block off the valve and stop the needless vacuum leak anyway. I can live with that... But wait, doesn't the center flap pod share this line? Hmmm Why does it stay open all the time anyway. On to the next test.

#3 test #3 circuit as above... Great! The long throw is fully functional. At least the long-throw def valve is working. I think I read somewhere this pod is accessible thru the radio hole (and instrument panel, Strife and others). Maybe I'll have a look later.

#4 test as before... Crap. No vacuum. Wait, lets check each side independantly. OK! Passenger side works great... Rats, Driver's side no vacuum. No Problem, block off driver's side and good to go. At least I'll have 50% fresh air when called for/desired.

Crank her up and try... HEAT IN THE FLOOR! now move the dial to cool... Floor vents close! I guess vacuum leak was culprit with legroom flaps. Now about the center vents????

Here is where I get the title... I now know for a fact that hell exists (other than my christian belief)... Where would you send the guy(s) who designed this system??? Pulling the radio is a cinch, and exposes a decent view to why the center vents stay open... You guessed it. The heater box is broken around the rivets that hold the center pod. Well, that aint getting fixed anytime soon. Wait, what's this... the vacuum line runs straight to the center flap pod? What about the shared line to the short throw def valve (did I mention PO had pod work performed by a MB dealer some few years ago)? Some idiot bypassed the short-throw! Guess why... The diaphram must be shot because it will not hold a vacuum. Well, while in here, let's test the center pod anyway. Hmmmm... will not hold a vacuum. Like I said earlier. That's not getting fixed anytime soon.

All in all, I did learn a great bit, and did get the legroom flaps working. I can count the project somewhat of a success. Its easy enough to open and close center flaps with a wood dowel, since the pod is loose in there (and not rattling since the vacuum hose holds one side). The def vents will just continue to blow, I guess. I may make me a heavy black rubber mat to lay on the dash, covering those vents if I get industrious. I'm just proud to have heat in the floor for a change!

By the way... Whomever removed the def pod thru the radio must be a genius (sorry I forgot who reported that). I recall Strife performing the act thru the instrument panel access, but thru the radio would be an more impressive feat!

Maybe on day, when I have more money than sense, I'll remove the dash and heater box and repair correctly... Don't hold your breath!

Rory
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RM Smith
1988 560SL

"Where is it again that we are going, and why are we in this handbasket"?
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  #2  
Old 09-15-2006, 09:09 PM
88Black560SL
 
Join Date: Oct 2004
Location: NC
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Quote:
Originally Posted by Walrus View Post
Maybe on day, when I have more money than sense, I'll remove the dash and heater box and repair correctly... Don't hold your breath!

Rory
Got a week to put the car down? See my post in "107 Dash Removal" for a repaired heater box. I take it one of your actuators looks like the one below.

John Roncallo
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  #3  
Old 09-15-2006, 11:26 PM
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John,

Yep... Thats the bugger, although I never removed mine.
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"Where is it again that we are going, and why are we in this handbasket"?
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  #4  
Old 03-18-2009, 12:41 PM
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I've been searching through threads for a fairly good explanation of a 107 dash removal process. I've got the MB CD, but I'm fairly nervous about the entire process - afraid of breaking something. I think I've got to remove the A pillar covers in order to get the dash out - am I correct, and if so, where did you pry on the A pillar covers to remove them?

Any help would be greatly appreciated. I've got a 78 Euro SL and most of the vehicle is similar enough to the US version so as to enable me to get repairs done with the available manuals, threads, etc. I've got to fix a piece of the heat control mechanism that has broken and after trying to go through the instrument cluster opening, the radio opening, and the heater control opening, I'm giving up on the notion of solving my problem without actually removing the dash.

Kind regards,

David Lee
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  #5  
Old 03-18-2009, 05:35 PM
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David,

A lot of the work can be done without removing the dash. Navigate to my site: http://www.rmsmithco.com for a look. Roncallo supplied a lot of pics (used there with his permission) and I added my own twist to the repairs.

Good Luck
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1988 560SL

"Where is it again that we are going, and why are we in this handbasket"?
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  #6  
Old 03-18-2009, 08:47 PM
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Walrus:

Your website was very informative and when I combined your site with the links you provided to Roncallo's site I gained quite a bit of insite into what's under the dash.

One thing I failed to mention is that my 107 is a '78 Euro, and all the heater controls are completely manual. The only vacuum pods I have under the dash connect to the fresh air vents (I think). The entire mechanism to control temps and route air from floor to defrost vent is entirely manual - I suspect exactly like the '73 US 450s. Since some of my mechanical parts are broken I would like to just take the dash out and see what the previous owner has done to the car, because I know things aren't like they would have been straight from the factory.

I was curious where to "pry" on the A pillar covers so as not to crack or break them.

Sorry for leaving out this info in my previous post.

Regards,

Dave
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92 300E - 116K miles - Sold
77 Euro 350SL - 67k miles
94 Explorer 147k miles
2009 Hyundai Genesis - 65k miles
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  #7  
Old 03-19-2009, 12:22 PM
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I never noticed the model... You are correct in that there are considerable differences. The dash, however, is likely the same. Perhaps John or someone else can point you in the right direction, as I have not done the "Dash Out" thing (yet).

If I recall correctly, AlldataDIY is a fairly good source for info.

Cheers
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RM Smith
1988 560SL

"Where is it again that we are going, and why are we in this handbasket"?
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  #8  
Old 03-20-2009, 01:46 PM
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Quote:
Originally Posted by Walrus View Post
After reading numerous threads on this and other groups concerning the Climate control systems on my 560SL, I decided to "attack" the issue. Armed with manual and hand-powered vacuum pump, I dove into the project. My main concern was why the center vents ALWAYS remained open. Secondary, why heat never made it to the floor. Thirdly, why the def vents stayed open regardless of setting. I should mention that, prior to this, I bought a reman control system from our good friend, Germanstar, to correct a problem with the buttons, so I was sure the "electronic" parts were "up to snuff".

Forget what you read in the manual about taking the vacuum line loose at the firewall and trying the I-IV tests so eloquently described as a failure in the main air flaps will give an erroneous reading. Instead, dive right in to the dash, remove the glovebox, and test the circuits there.

#1 remove the #1 circuit vacuum line from the switchover valve and attach the pump. Evacuate to 300 or so millibars... YEAH! The dreaded legroom pod is functioning (no loss of vacuum when evacuated and watched). Guess I don't have to worry about removing the heater box to repair (spoke too soon).

#2 remove the #2 circuit from the switchover valve and repeat above. Ok, looks like the short-throw def pod is fouled up. Now I know why the def vents stay open (partially) all the time. I can block off the valve and stop the needless vacuum leak anyway. I can live with that... But wait, doesn't the center flap pod share this line? Hmmm Why does it stay open all the time anyway. On to the next test.

#3 test #3 circuit as above... Great! The long throw is fully functional. At least the long-throw def valve is working. I think I read somewhere this pod is accessible thru the radio hole (and instrument panel, Strife and others). Maybe I'll have a look later.

#4 test as before... Crap. No vacuum. Wait, lets check each side independantly. OK! Passenger side works great... Rats, Driver's side no vacuum. No Problem, block off driver's side and good to go. At least I'll have 50% fresh air when called for/desired.

Crank her up and try... HEAT IN THE FLOOR! now move the dial to cool... Floor vents close! I guess vacuum leak was culprit with legroom flaps. Now about the center vents????

Here is where I get the title... I now know for a fact that hell exists (other than my christian belief)... Where would you send the guy(s) who designed this system??? Pulling the radio is a cinch, and exposes a decent view to why the center vents stay open... You guessed it. The heater box is broken around the rivets that hold the center pod. Well, that aint getting fixed anytime soon. Wait, what's this... the vacuum line runs straight to the center flap pod? What about the shared line to the short throw def valve (did I mention PO had pod work performed by a MB dealer some few years ago)? Some idiot bypassed the short-throw! Guess why... The diaphram must be shot because it will not hold a vacuum. Well, while in here, let's test the center pod anyway. Hmmmm... will not hold a vacuum. Like I said earlier. That's not getting fixed anytime soon.

All in all, I did learn a great bit, and did get the legroom flaps working. I can count the project somewhat of a success. Its easy enough to open and close center flaps with a wood dowel, since the pod is loose in there (and not rattling since the vacuum hose holds one side). The def vents will just continue to blow, I guess. I may make me a heavy black rubber mat to lay on the dash, covering those vents if I get industrious. I'm just proud to have heat in the floor for a change!

By the way... Whomever removed the def pod thru the radio must be a genius (sorry I forgot who reported that). I recall Strife performing the act thru the instrument panel access, but thru the radio would be an more impressive feat!

Maybe on day, when I have more money than sense, I'll remove the dash and heater box and repair correctly... Don't hold your breath!

Rory
i have exact same symptoms. is there an easy way just to pin down or hold the defrost vents closed so the center vents work?

i am in AZ we dont need heat. we just need a/c. A/c works on outside vents and out the defrost, but on really hot days we lose too much cooling in the dash vents and it gets sweaty in there!
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  #9  
Old 03-21-2009, 12:30 AM
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Rusty (by the way, they still make gun oil),

I suppose the def vents can be mechanically blocked. Remove the radio and look into the opening to the left. There you will find the short/long throw pod. You could fashion some kind of mechanism to lock the vents closed by manipulating the linkage there. You will need to mechanically open the dash vents as well, if not already open.

All this provided you have the Climate Control system ACIII (or whatever its called, 1986-89 560SL). I suspect similar for earleir vacuum controlled systems, but I am not familiar with them...

Review the diagram on my page and pay close attention to the default or relaxed position of each pod (Spring actuated). That spring in each pod is kinda stiff, I'll tell you! It takes a good bit of force to compress it (and I'm amazed the vacuum generated in our systems is sufficient).
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RM Smith
1988 560SL

"Where is it again that we are going, and why are we in this handbasket"?

Last edited by Walrus; 03-21-2009 at 01:01 AM.
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  #10  
Old 03-21-2009, 11:03 AM
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Thanks for the great advise, I also have my center, and def vents open all the time very little heat to the floor. I haven't found a hand pump vacuum tester yet, but since nothing moved I figured it was the control unit. Thanks for saving me the money of buying a new unit before I trace down what is really wrong
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  #11  
Old 03-27-2009, 01:04 PM
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Quote:
Originally Posted by DAVID LEE View Post
Walrus:
One thing I failed to mention is that my 107 is a '78 Euro, and all the heater controls are completely manual. The only vacuum pods I have under the dash connect to the fresh air vents (I think). The entire mechanism to control temps and route air from floor to defrost vent is entirely manual - I suspect exactly like the '73 US 450s. Since some of my mechanical parts are broken I would like to just take the dash out and see what the previous owner has done to the car, because I know things aren't like they would have been straight from the factory.

I was curious where to "pry" on the A pillar covers so as not to crack or break them.

Sorry for leaving out this info in my previous post.

Regards,

Dave
You shouldnt need to take the dash out unless you want to replace the whole heater box, I worked on my manual system and apart from the levers below each vent the rest is in behind the centre console with levers operating directly on the flaps. You can get to the heat blending flaps by removing the fan under the hood.
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  #12  
Old 03-29-2009, 12:07 PM
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I tried your suggestion and guess what I was looking at wihen I took out the blower motor - the evaporator. Oh well.

Anyway, I had already taken out the dash and console, and was glad I did. It is MUCH easirt to see things and much less contorting to see them. I reworked all the vacuum lines, adjusted all the levers, etc. such that now the climate control system works as it is supposed to work. I also took out the fresh air vent flaps and reworked them so that they shut off the air when they are supposed to. Those tiny little vacuum valves operated by the heat levers are a trip anren't they?

But...I still have the problem with the messed up air deflector, so my next step (today) is to remove (or at least attempt to) the heat box; get it out on the bench and figure out how this monstrosity works (or in my case - doesn't). I took a bunch of pictures that I thought I would post once I'm through with this journey in hopes they will perhaps help someone else.

Regards,

Dave
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94 Explorer 147k miles
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  #13  
Old 03-30-2009, 10:08 AM
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Well, I survived the Heat Box removal attempt, and so did the Heat Box (miraculously), although I could not get ALL of the heat box out unless I disconnected the A/C evaporator hoses so that the evaporator could be removed from the heat box - YES, the evaporator slides into the heat box so that it is IMPOSSIBLE (without a Sawz-all) to remove the heat box in the service manual prescribed manner without removing the evaporator 1st. Something the Service CD does not tell you.

Anway, I removed the bottom of the heat box (after finally locating all the metal clips that hold it together) and once the bottom was out, I could remove the Front half of the Heat Box (the piece that covers the heat exchanger coil). Again, several metal clips, 4 of which cannot even be seen until the Heat Box bottom is removed.

Once the Heat Box front was removed, I was able to see what the problem with the "stuck flap" was and I'm working on a solution for that. The Heat Box is quite a contraption. Seemingly pretty well built, but nonetheless quite a contraption. I don't know that I could have done to design any better, but....
It would have been great if the CD would have had some pictures showing the inside of the Heat Box so you could get an idea of how the box was made. I believe that would have been helpful in taking it apart.

More to come as I make my repairs and put it back together.

Regards,
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94 Explorer 147k miles
2009 Hyundai Genesis - 65k miles
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  #14  
Old 06-27-2009, 10:42 PM
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Walrus, I need your help. 1987 560sl switchover valve vacuum from intake seems to be ok vac, guage shows and holds vacuum. switch # 1 guage shows and hold vacuum. switch # 2 vacuum guage shows 0 vacuum. Switch #3 vac. guage showa 0 vacuum and switch # 4 same as switch # 2 and # 3 0 vacuum. I cheched pod 43 and vacuum guage shows and holds vacuum. Please direct me to the next step . thank you Richard
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  #15  
Old 07-03-2009, 06:00 PM
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Smile

It's been 2 months since I fixed my heater box issues. While I had the dash out I thought I would try and fixed the cracks in the dash using the CA glue and baking sode technique described on this site. Using the described technique I was able to mend the cracks (about 1.5" long) to the point that it cannot be discerned they ever existed (unless I showed you where they were). The previous owner had also screwed his mobile phone mount to the side of the console, and with the same technique I was able to fix the holes and depressions so that the repair is not noticeable. It is amazing what happens to baking soda when you combine it with Ca glue. I then went to my local auto paint supplier and got some dash paint that matched and after completely dismantling the entire dash, and console, repainted everything and it looks absolutely brand new. Will the cracks reappear? Who knows, but since I had to take the dash out anyway, I really had nothing to lose. The most difficult part of the dash crack repair was getting the texture back into the surface. I had some left over material from reuphostering the kick panels and such, so using the rocker panel paint that was suggested and texturing it with the material, I got a pretty good match. The texture took quite a bit of practice and it isn't perfect, but it's good enough to be unnoticeable.

Anyway, back to the heater box. The problem with the heater box is was the the plastic pieces that mate with the metal pieces in the floor deflectors get warped and at some point, when you adjust the heat lever all the way up, the deflectors get wedged in a position that makes them impossible to move with the lever mechanism. So..I drilled out the rivets that held them together, replaced the totally deteriated foam with some I got at a local craft shop and riveted the pieces back together. After leaving the heater box on the bench for several days and moving activating the mechanisms with the levers, I realized I still had some problems. Not wanting to ever remove the heater box unless it became absolutely necessary, I discovered that when the levers were pushed all the way up and I put some "tension" on one of the lever mechansisms on the side of the box, I could insure that the flap would NOT get stuck again. So..I bought some small springs in the hardware section of Lowes and was able to mount the springs in such a way that when the heat levers are pushed up all the way, that a small amount of "tension" is placed on the levers and this insures that the flaps won't get stuck again. But, just in case, I also drilled a 1" hole in the side of the box (passenger side) in a strategic location, mounted a rubber grommet, and inserted a round metal snap in cover (also from Lowes) that will allow me to reach in with a long piece of wire should one of the levers ever get stuck again. Naturally, I would need to remove the console, but a much smaller task than removing the heater box.

I've got quite a few pictures of the process, including pictures of the finished dash. I "think" I've uploaded a picture of the completed dash as an attachment.

Anyway, I'm glad that I took the dash out and did the refurbish. Lots of work, but as I look out the front windshield and don't see any cracks in the dash anymore, I consider that it was time well spent.
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