Climate Control Center Vent Publication

[Walrus]

With John Roncallo's excellent pictures, I have put together a small website illustrating the structure and function of the Center Vents on the vacuum-operated climate control system of the 107SL. It is very elementary, but maybe helpful for anyone who is interested in the function and diagnosis of this perplexing system. As time grows, I may add to this; however, I'd like to hear if it is helpful to anyone or not. Please feel free to critique the site, and offer suggestions/ask questions. Also, feel free to share with anyone who could use the info.

Thanks again...

Rory
http://users.adelphia.net/~rmsmithco or http://users.adelphia.net/~rmsmithco/vacuum1.htm

CIAO!

[ljmauricio]

EXCELLENT!! We'll all need this info sooner or later.

[smack]

This is terrific. First time I actually understood how all these pieces interrelate. Thank you so much for taking the time to archive this.

[opnwide]

Thanks for all your efforts, such a usefull thing for all of us.

[Pili380SL]

Thank you!! You're a credit to this forum

[Walrus]

Thanks for all the kind words... I hope some may find the little website helpful.

Rory

[Bill Wood]

This DIY is now in the Wiki HERE.

[Mike Miller]

I wish someone would do this for an R129!!!!!!!!!!!!!!!!!!!!!!!!

[Walrus]

Originally Posted by Mike Miller

I wish someone would do this for an R129!!!!!!!!!!!!!!!!!!!!!!!!

Your assignment, Mr. Miller, should you choose to accept...*
I could not have produced this without the excellent pictures of John Roncallo, documenting such salient features that text alone cannot adequately describe. I dare say someone out there has probably documented a similar repair of the 129... Perhaps they will step up to the plate?







*apologies to mission impossible...

[Mike Miller]

Thanks, Walrus. I will keep my fingers crossed.

The reason I asked is that although my climate control system appears to work great, it has one funny thing it does. With the A/C on and fans blowing, if I accelerate hard, I loose the airflow. The harder I accelerate, the more I loose. When I let off the gas, full air flow returns. At highway speeds and only moderate acceleration, the air flow remains strong.

This tells me I must have a vacuum leak or some valve or other that is not operating as advertised. I have looked at the vacuum schematic for this car to see if I can locate the problem. I think it would be easier to be dropped off, blindfolded in the middle of Istanbul and told to find my way home

[Walrus]

Originally Posted by Mike Miller

Thanks, Walrus. I will keep my fingers crossed.

The reason I asked is that although my climate control system appears to work great, it has one funny thing it does. With the A/C on and fans blowing, if I accelerate hard, I loose the airflow. The harder I accelerate, the more I loose. When I let off the gas, full air flow returns. At highway speeds and only moderate acceleration, the air flow remains strong.

This tells me I must have a vacuum leak or some valve or other that is not operating as advertised. I have looked at the vacuum schematic for this car to see if I can locate the problem. I think it would be easier to be dropped off, blindfolded in the middle of Istanbul and told to find my way home

Mike,

If you have a reservoir (vacuum tank) then I would suspect a check valve... Other wise a slight leak in a line somewhere perhaps. My 2001 Ford PU used to do the same thing. Accelerate on highway and the sound of the fan would change, and air would stop blowing from the vents. Discovered a hole in a vacuum line.

[Mike Miller]

I'll take a look. Don't know where to start, but what the heck. What could go wrong????

[Walrus]

I need to update the website I put up earlier. The last two days I have been repairing my vacuum elements. I finished ta'nite, and took her for a shake-down run. Everything still works to my great pleasure (never know since you have to disturb SOOOOO much stuff).

Summary:
Took out radio, climate controls, shifter wood, console, glove box, carpets, under-dash panels, carpeted bolster and eventually driver's seat. All this to get at the bottom of the heater box. After removing a few other asundry parts, I removed the bottom of the heater box, repaired crack(s) via mending plate, and renewed the legroom vacuum element. Next I reached up inside heater box, and thru the front vent, and removed the center vent pod. I repaired broken box via mending plate, renewed vacuum element, and re-installed (since my heater box was broken, I could easily remove the pod by dropping it down after disengaging the lever from the flap). I reinstalled the bottom of the heater box and then attacked the Defroster pod. After grinding a bit, I was able to disengage the operating lever, grabbed my pod-popper, and pulled out the little bugger (leaving the top part still in the mount). I renewed the elements, and reinstalled using a #8-32 pan-head allen screw and nylon lock nut to reattach the operating lever. Buttoned everything back up and VOILA!

I should mention my loving wife shampoo'ed the carpets while they were out, bless her heart!

I'll try and post more info later...

[samflyer]

Originally Posted by Mike Miller

....my climate control system appears to work great, it has one funny thing it does. With the A/C on and fans blowing, if I accelerate hard, I loose the airflow. The harder I accelerate, the more I loose. When I let off the gas, full air flow returns. At highway speeds and only moderate acceleration, the air flow remains strong.

My SL does this too. From my understanding this is due to power management "logic" MB uses, ie, less power needed (lower acceleration & speeds) allows more power to aircon, and vice versa. I don't know if this is 100% correct, but the info I got reflected this.

Sam

[Mike Miller]

Sam,
Thanks for your info. I have had opinions in both directions. If it is power management, then fine, I can live with it and deal with my other issues. If it is not, then it gets added to my list of R129 Wonders.