Constant Speed Solenoid

[pembash]

My 1970 280SL is without a Constant Speed Solenoid. I bought the car without it. I only discovered it after seeing similar Pagodas that the CSS was missing from my car. Does anyone have a spare one! I am told a new one costs over $300. I have also not been able to figure how it is without it and there is no indication that the car was once equipped with it.
My car is fitted with A/C but it is not used as it needs gas refilling. However, when I put the gear in D or R the RPM drops but the engine does not cut off.
Grateful for any input on the subject!!
Best
Bob
P.S. Mr. Joe Alexander is requested to kindly give his advice.Thanks.

[Cees Klumper]

With an automatic transmission and A/C, your car should definitely have one. Maybe your engine was replaced at some point with a manual transmission engine? What is the engine number?
There is not much to the installation, you need the proper bracket and of course the wiring in place. The wiring ought to be there "somewhere". I have a spare one around, however it was not always able to move the linkages sufficiently so it is not 100%. These units are not easy to repair, although I came across some instructions how to. At a cost of Euro 290 it is worthwile to try.

Cees Klumper in Amsterdam
'69 white 280 SL automatic

[ja17]

Hello Bob,
Does your car have the vacuum dashpot on the venturi?

Joe Alexander
Blacklick, Ohio

[pembash]

Hi Joe,
Thanks for your response. Forgive me for my ignorance but if you could kindly explain what and where "the vacuum dashpot on the venturi"  is located and it's uses. I'm rather raw on mechanics!
Best
Bob

quote:Originally posted by ja17

Hello Bob,
Does your car have the vacuum dashpot on the venturi?

Joe Alexander
Blacklick, Ohio

[ja17]

Hello bob,
Must USA 280-SL cars with automatic transmissions have this vacuum throttle control mounted on the venturi. It is merely a vacuum cell which has a vacuum line going to it. This unit increases the idle speed when the car is placed in gear at a stop. I have a picture of it somewhere on this computer, I will go searching for it. If you have the BBB (factory manual) page 07-14/7 has an excellent description , photo (lower left) and the adjustment procedure (upper right).

Joe Alexander
Blacklick, Ohio

[JPMOSE]

Cees,

Would it be possible for you to post the procedures on how to fix a Constant Speed Solenoid?  I think this would be very beneficial for others.  

I "thought" my CSS wasn't working and checked on the price yesterday through Millers.  It is now $400 new. [:0]  I finally got my neighbor to sit in the car while I check it.  Luckily it does work and just needed to be adjusted.  

Best Regards,

J. P. Mose
1968 250SL

[TheEngineer]

A simple KISS fix would be to just set the idle speed with the transmission in any of the "drive". (I like to use R). So it idles a little fast when you put it in neutral: Big deal.

[Cees Klumper]

The difference in the idle would be about 2-300 RPM's (at least I think it is on my car), which personally I would try to avoid. If only to avoid a jerky response when putting the car in drive or reverse.

I just checked but could not locate the repair instructions anymore. I do recall it involving drilling open the unit, so it is not an easy fix. Never tried this myself. There may be value in picking one of these up at a junk yard even if your CSS is operating fine now, just in case it ever goes bad.

Cees ("Case") Klumper in Amsterdam
'69 white 280 SL automatic