Mercedes W114 250 Coupe - help!

[Charles Morgan]

It's not just a switch, it's an M&S switch...

The reason for slightly fixating on a W116 is I know someone who breaks them regularly. As it is the entire construction I am after (switch, housing and bracket mounting into pedal box) it is likely that as a similar age of car that entire construction, if I can source one, is more likely to fit easily and look OEM.

I do indeed have the electrical plug too, connected to the gearbox. It's the connection to the wiring loom of the car that I need to sort.

 

[grober]

Taken from http://handbook.w116.org/ETM\75s.pdf page 7 of 10

Can't make out the fuse no but rated at 8 amp ? powered from ignition -on bus as opposed to the " always live" battery bus

 

[Charles Morgan]

Here is the box number on the plate Druk suggested it might be.

Connector from box

 

[grober]

Heres the 72 ONWARDS W114 arrangement basically the same. 18 SOLENOID 19 SWITCH 20 reversing light switch+ starter inhibitor

http://mb.bolinko.org/wis/w114/ETM/54_5_9.pdf

 

[Bellow]

Connector from box

Differs slightly...

Taken from http://handbook.w116.org/ETM\75s.pdf page 7 of 10

Can't make out the fuse no but rated at 8 amp ? powered from ignition -on bus as opposed to the " always live" battery bus

Appears, as per manual, to switch reversing lamps from gear lever.


The manual is unlikely to have in-gear start inhibitor - do you need/want it? If so, some slight rewiring required.

It's not just a switch, it's an M&S switch...

The reason for slightly fixating on a W116 is I know someone who breaks them regularly. As it is the entire construction I am after (switch, housing and bracket mounting into pedal box) it is likely that as a similar age of car that entire construction, if I can source one, is more likely to fit easily and look OEM.

I do indeed have the electrical plug too, connected to the gearbox. It's the connection to the wiring loom of the car that I need to sort.

If you can get the original part(s) yes, all the better. But a switch can be added out of sight behind the dash which will function just as well. Maybe without the 'click' though...

While we are down in the footwell, to what extent do the pedal boxes differ? Does the auto version carry the KD switch?

 

[grober]

The pedal boxes for the manuals seem to be substantial bits of kit bolted to the bulkhead.
However the throttle pedal appears to be entirely separate going from the picture below and from the previous diagram posted before and would appear to have its own cast bracket???
They may share the same design as the R107-- not sure- but as can be deduced from the picture they may be different " sided" for RHD and LHD cars.

 

[Bellow]

The pedal boxes for the manuals seem to be substantial bits of kit bolted to the bulkhead.

To withstand the forces and possibly to facilitate the pedals being pulled forward in a frontal impact.

However the throttle pedal appears to be entirely separate going from the picture below and from the previous diagram posted before and would appear to have its own cast bracket???

But probably different manual from auto. I wondered if the clutchless set-up had a different throttle pedal arrangement incorporating the KD switch.

Subsequent to my earlier post, looking at your wiring diag the start inhibitor and reverse light switch appear to be in unit - and inside the car. Can't work out why there are four terminals on CM's gearbox plug.

As an aside, and a slight (hopefully forgiveable) threadjack - do you have any links to decent photos, diagrams (esp sectional) of MB fluid couplings as used with this box?

 

[Druk]

The pedal boxes for the manuals seem to be substantial bits of kit bolted to the bulkhead.
However the throttle pedal appears to be entirely separate going from the picture below and from the previous diagram posted before and would appear to have its own cast bracket???
They may share the same design as the R107-- not sure- but as can be deduced from the picture they may be different " sided" for RHD and LHD cars.

That's the same as the 107. However the 107 throttle pedal arrangement must differ slightly because it's kickdown switch is floor mounted rather than on the bracket shown in an earlier post.

 

[grober]

Can't work out why there are four terminals on CM's gearbox plug.

As an aside, and a slight (hopefully forgiveable) threadjack - do you have any links to decent photos, diagrams (esp sectional) of MB fluid couplings as used with this box?

Not sure on the 4 terminals either---- in theory there should only be 2? maybe the others are blanks? Without looking inside the sheathing or tracing the wiring back difficult to say.

Not sure what you mean by fluid coupling.
If you mean the earlier hydraulic clutch fitted to the early cars which I assume is a development of the hydrak system I can only find this

from here.
Mercedes-Benz Ponton Hydrak Automatic Clutch © www.mbzponton.org

I did post this earlier

Datei:W114W115-Automatic-K4C025.jpg ? Mercedes-Benz Classic Wiki - Online-Lexikon rund um Mercedes-Benz Oldtimer

I am assuming that Charles later box has a torque convertor??




50 years of automatic transmissions from Mercedes-Benz | Daimler Global Media Site > Classic > Daimler AG > Technology > Innovations History

 

[Bellow]

Not sure on the 4 terminals either---- in theory there should only be 2? maybe the others are blanks? Without looking inside the sheathing or tracing the wiring back difficult to say.

One! - if the box is earthed via the engine.

Not sure what you mean by fluid coupling.
If you mean the earlier hydraulic clutch fitted to the early cars which I assume is a development of the hydrak system I can only find this

Thanks Grober. Not the Hydrak (I found it) but the fluid coupling as used in the first four speed epicyclic autos as featured in the links below. Cheers!
[

I did post this earlier

Datei:W114W115-Automatic-K4C025.jpg ? Mercedes-Benz Classic Wiki - Online-Lexikon rund um Mercedes-Benz Oldtimer

I am assuming that Charles later box has torque convertor??




50 years of automatic transmissions from Mercedes-Benz | Daimler Global Media Site > Classic > Daimler AG > Technology > Innovations History

CM's box will have the fluid coupling - torque converters came later for MB - hence the extra ratio in their boxes over what the competition provided in theirs.

I'll give Charles his thread back now...

 

[Druk]

Not sure on the 4 terminals either---- in theory there should only be 2? maybe the others are blanks? Without looking inside the sheathing or tracing the wiring back difficult to say.

1981 107SL wiring diagram shows a 4pin connector to the gearbox electrical switch. The # numbers below refer to the pin numbering marked on the plug.

#5. 2.5mm violet/white from ignition switch.

#3. 0.75mm black/grey/red from fuse 8.

#4. 0.75mm grey/yellow to rear cluster reverse light bulb

#6. 2.5mm violet to +ve block near battery. (permanent + pos)

Check the colours in the cable Charles.

 

[Charles Morgan]

Just back from a long day out made longer by M25/M4 gridlock.

Some immensely helpful posts here, thank you.

Just another thought, the W114/5 instrument cluster has provision for a display showing the gear in use, so that might be part of the loom into the gearbox.

I shall check the cabling tomorrow.

 

[grober]

This pdf gives some useful details the W116 throttle pedal mechanical linkage - perhaps the w114 is similar? - unfortunately altho the kickdown switch is pictured its mounting on the bulkhead isn't.
http://handbook.w116.org/Engine\107\m117_45\30-320.pdf

 

[Charles Morgan]

#5. 2.5mm violet/white from ignition switch.

#3. 0.75mm black/grey/red from fuse 8.

#4. 0.75mm grey/yellow to rear cluster reverse light bulb

#6. 2.5mm violet to +ve block near battery. (permanent + pos)

Same colours! Without dismantling I can't check the pins, but good start so far.

 

[grober]

OK having had a look at the wiring diagrams I have deduced the following. http://www.startekinfo.com/StarTek/outside/11883/PROGRAM/ETM/81etm.pdf

#5 supply from ignition switch to starter lockout switch
#6 output from lockout switch to starter hold in coil via block

#3 supply from F8 to backup light switch
#4 output from backup light switch to rearlight assembly

I am forced to the conclusion that the connection to the kickdown solenoid from the kickdown switch is an entirely separate supply wire which may be missing?

It should be easy to test this out by checking continuity between the pins when the gearbox selector is in P or R

 

[Charles Morgan]

I have a horrible suspicion when I go to rummage through the sellers bits any wiring would have been long discarded or impossible to make out among the other stuff.

 

[Charles Morgan]

Nearside door stripped, window and mechanism out and off, rear window etc also out, plus door seals and chrome trim all round. Knowing what you are doing, having the right tools and nicer weather made this so rapid. Sadly rust in pretty much the same quantity but slightly different locations in the panel under the rear window, so more welding needed there.

 

[grober]

Further to the kickdown wiring saga I think the kickdown solenoid is the small rectangular box below the circular piston nearest the bellhousing in this picture? Do you have such a unit on your autobox Charles and has it any electrical connections?

 

[Charles Morgan]

I shall look tomorrow Graeme, although I don't recall seeing such a thing and there is no wiring either way.

 

[Charles Morgan]

There is clearly a fixing for it, but that has an old grommet in it, but no rectangular thing. I'll ask the seller if he took it out, but I'm rapidly losing faith in him having made any form of note of what was there.