Constant Speed Solenoid

[knockmacool]

Car back after receiving new spark leads and a few other bits, but CSS is stuck. Is this a repair or replace item? I know its expensive. If repairable, any recommendations in Ireland or UK?

[Ulf]

Don't have a clever answer for you, but what are the symptoms? Jerky driving?

[Cees Klumper]

I have not read reports of successful surgery on these things. I replaced mine a year or two ago with new after it had become too 'weak'. I recall someone a long time ago reporting they had drilled or otherwise forced the thing open, but I don't think he was successful. I saved my old one, and plan to open it up at some stage and see what might be possible.

[knockmacool]

what are the symptoms? ?

Stalls on coming to a stop or being put in to gear,  a pain in stop/start traffic.

[J. Huber]

Maybe it was the placebo effect but I have lubricated mine before and it seems to help it move. Of course. it can also be adjusted -- I take it you have tried that? There is a "sweet spot" where the idle/ linkage/ and CSS come together. It can be tricky. Mine may be similar to Cees' old one in that it has lost some of its oompf but it still works with some careful tweaking.

[knockmacool]

Basically frozen. It is running very well but the "sweet spot" disappears once its warmed up; stalls when I come to a standstill and need to rev to engage Drive... Willing to try a little lubrication... wd40 or what do you suggest?

[wwheeler]

I guess you need to find out if it is stuck because of the guides or bearing being too tight or if electrically it is being held. If you disconnect the leads to it, the plunger should move back and forth easily. If it doesn't, then adding a spray lubricant/penetrant like PB Blaster might help. It is worth a shot. There is supposed to be rubber bellows on the front to keep the junk out. Most original bellows are dried up and cracked by now. They sell new a bellows, but you have to take the cover off to replace it. The screws that hold the cover on are peened and are not meant to come out. That's frustrating! New ones aren't cheap either. 

[J. Huber]

If its stuck I'd try the WD or PB. Mine was never fully frozen -- it just would move slowly. I think I used WD first but also may have spread some grease as well. My bellow piece is split a bit and that itself can add to the friction. Lube it and see if it helps. You may also have to increase the idle RPMS just a scoash.

[Jordan]

Excuse my ignorance  but do manual cars have a constant speed solinoid and if so where is it located (picture?).  I have searched the tech manual and can find nothing.  I'm still trying to sort out what everything is under the hood.
Many thanks.

[ja17]

Hello Jordan,
Most W113 used a CSS if they were automatics to keep the idle constant when set in gear. The latest USA versions used the CSS to keep the idle constant if the AC was switched on. A vacuum dashpot was added to the intake venturi to take over the function of increasing the idle when theautomatic transmission was set in gear.

Normally the standard cars did not use a CSS.  It is possible that the latest version USA cars with AC and standard transmission may have had a CSS. ?  More confirmation needed here.

Some late USA cars with automatic transmissions and no factory AC did have a CSS installed at the factory but it was never hooked up ! Instead they used only a vacuum dash pot

Also look through "The Linkage Tour" and you will find the location and function of the CSS.

[bogeyman]

My 1970 4 speed has a css - not hooked up though.

[knockmacool]

Apparently, NLA from MB, part number is A000 072 0500 and apparently should be fitted to all fuel injected six cylinders between 59-71

[Raymond]

It doesn't help you because you have an automatic.  But Joe, and not the information you were given, is correct.  There was no need for a CSS on manual transmission cars without A/C.  Without the A/C or Automatic to drag down the idle, what would you need with a device to correct the idle?  My '68 has A/C and it doesn't have a CSS.  It has a simple damper that only slows the drag down of the idle to prevent sudden stalling.  Since installing the Sanden compressor, even that is unnecessary.

[knockmacool]

Ray, sorry, yes, you are correct; it was installed in all automatic fuel injected six cylinder engines 59-71

[hands_aus]

If you have an automatic have you checked the pressure switch for continuity when in drive?
Also the switch on the inlet manifold needs to be adjusted correctly.

If neither or one of those are not working correctly you might not have voltage to operate the CSS.

[knockmacool]

Thanks, Bob. I have checked the CSS and it moves freely before I turn the ignition, but is frozen once the electrics are on. Do I assume I have a short somewhere? BTW, where is this pressure switch you refer to?
Also the car always started first turn of key, now it needs a few pedal pumps. Is this symptom related to CSS? I don't think so, just odd it was returned with these two issues.

[Larry & Norma]

The pressure switches are on the gearbox, one each side connected by a wire running over the box.
The switches detect when the car is put into gear, one forward and one reverse. They switch to ground
so you may have a permanent short to ground. Disconnect the wires from the CSS. With the ignition on
one wire should live (12volts). Check if the other is connected to ground. It should only go to ground
when the car is in gear. Make sure someone is in the car with a foot on the brake if you check the in gear
condition.
It is possible that the terminal strip on the gearbox may have been wired incorrectly.
Hope this helps