I have 2 W108's, both with carbs and the associated linkage.

There is a sliding portion between the front carb linkage socket and the furthermost front ball socket.

On the 250, this portion slides 1/2" before the carbs see an RPM increase. There is a lot of 'play' in the accelarator pedal.

On the 280S, this portion is fixed, with no play, so any pushing on the accelator pedal results in an immediate RPM increase.

Which one is correct? I am concerned, because the transmission pressure linkage is connected at the bottom on the lever. Thanks.

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1970 280S M130 engine- good runner
1971 250 M130 engine- #2 rod bearing, gone
1971 280SE (blown engine,parts car)
1977 German 280S W116-only 33 years old

I can't speak for the 280S, but the 250's linkage sounds exactly correct.

In any case, seems like the trans rod should move when the carb levers move.

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Chuck Taylor
Falls Church VA
'66 200, '66 230SL, '96 SL500. Sold: '81 380SL, '86 300E, '72 250C, '95 C220, 3 '84 280SL's '90 420SEL, '72 280SE, '73 280C, '78 280SE, '70 280SL, '77 450SL, '85 380SL, '87 560SL, '85 380SL, '72 350SL, '96 S500 Coupe

"I can't speak for the 280S, but the 250's linkage sounds exactly correct."
Sounds like you have a 250 that does slide 1/2".

So, what you are saying is that it should slide that 1/2"? Thanks.

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1970 280S M130 engine- good runner
1971 250 M130 engine- #2 rod bearing, gone
1971 280SE (blown engine,parts car)
1977 German 280S W116-only 33 years old

I didn't say "1/2 inch" but that sounds about right. If you look at the bellcrank on the block, you'll see that you can loosen the bolt that holds the two pieces together, and adjust the gap.

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Chuck Taylor
Falls Church VA
'66 200, '66 230SL, '96 SL500. Sold: '81 380SL, '86 300E, '72 250C, '95 C220, 3 '84 280SL's '90 420SEL, '72 280SE, '73 280C, '78 280SE, '70 280SL, '77 450SL, '85 380SL, '87 560SL, '85 380SL, '72 350SL, '96 S500 Coupe

Munich,
It's been a long time since I've fooled with any of the 108s, but I'm going to guess that the slip section on the 250S is to allow movement of the little switch with the two wires on the front carb. The 250S has the old K4A025 transnission which has no control pressure rod. That little switch on the carb keeps the solenoid on top of the transmission energized and keeps the trans at low control pressure. Moving the throttle linkage moves the solenoid to mid position and medium comtrol pressure. Kick down moves the solenoid to full pressure. The 280S came with the K4C025 trans somewhere in 69. If the window switches are in the console, you have the new tranny with a control press rod. The 280SLs continued to use the old tranny because there was no room to install the K4C025.

If that little switch is out of adjustment, it can make for very harsh downshifts.


Peter

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Auto Zentral Ltd.

Munich,
You are confusing me, because there was no W108 250 series produced in 71. If you have a 71 250 series, it is a 250/8 car with a 2.5 liter or a 2.8 liter depending on the chassis #. A 114.010 would have a 2.5 liter M114 engine. A 114.011 would have a 2.8 M130 engine installed.

Peter

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Auto Zentral Ltd.

You are correct. The 1971 250 has the 2.8L engine and the chassis is a 114.

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1970 280S M130 engine- good runner
1971 250 M130 engine- #2 rod bearing, gone
1971 280SE (blown engine,parts car)
1977 German 280S W116-only 33 years old

Munich,
Now that we have established that you have a W114 with a high compression 2.8 liter engine, what was the original question? The 72 yr model is low compression.

Peter

__________________
Auto Zentral Ltd.

There is a sliding portion between the front carb linkage socket and the furthermost front ball socket (towards radiator).
This sliding linkage is a horizontal piece. It's 2 pieces of thin channel-shaped metal, with a slot and rivet(?). These channels slide horizontally, one inside the other.

On the 1971 250, it slides 3/8"+, then the RPM's increase.
On the 1970 280S, it doesn't slide, (there is no 'play').

Which one is correct? I am concerned, because the transmission pressure/ RPM relationship may be incorrect on the 280S (which is 'flareing' between 2nd and 3rd gears.).

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1970 280S M130 engine- good runner
1971 250 M130 engine- #2 rod bearing, gone
1971 280SE (blown engine,parts car)
1977 German 280S W116-only 33 years old

I'll have to dig into my archives.

Peter

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Auto Zentral Ltd.