Mercedes W114 250 Coupe - help!

[Charles Morgan]

Not good news. I was getting the nearside footwell primed for POR15 painting tomorrow and when vacuuming a small lump of rust fell into the well. Looking up and then having a good feel, the bulkhead at the top is pretty crusty, and I'll have to take out the dash and the ventilation grill outside to have a good look. This is a well known vulnerability of the car, I'm hoping it's just confined to the top.

Not a great way to round off the day.

 

[Bellow]

In the various rather random pictures I have come across the vacuum line seems to follow the line of the dipstick tube upwards [ in some it appears to be partially clipped to it??] so this might give an indication where it "appears " in the engine compartment- If I was to guess it will attach at the "bulkhead end" of the main inlet manifold plenum chamber???

I suspect the dipstick tube is bolted to the boss pictured below...

In this pic it can be seen that a twisted bracket appears to be attached to it.

And in the video, at 2.39, said bracket appears to be integral with the dipstick tube.

https://www.youtube.com/watch?v=n47fvv7BGYU#t=178

 

[Charles Morgan]

Removed the front scuttle grill. A clean up followed by a lot of hand exploration reveals that where the bulkhead under the windscreen meets the inner wings there is extensive body perforation and each movement resulted in cascades of rust particles into the footwell. As the bulkhead goes down into the engine bay it is impossible to determine what is going on as I can't get my hands down there and the firewall insulation prevents a visual inspection. This is going to be a big job as all the engine bay will have to come out, and somehow access created from above and the sides to weld, so all of dash etc to come out.

I have a horrible suspicion this is going to cost an arm and a leg if I have to get this done commercially.

 

[grober]

Remember this thread.
1968 Mercedes W115 - Supercharging | Retro Rides

and this one

Re: 1971 Merc W114 Coupe - More done! | Retro Rides


As you say you probably won't know for certain the extent of the rot till you get the engine and gearbox out! Hopefully better than the example cited above!

 

[grober]

Maybe time to join another forum??
MIG Welding Forum

 

[Bellow]

MIG welding is very easily learned. I learned how to to weld the floor of my W123. The tricky part is obtaining gas economically.

 

[Charles Morgan]

On the basis that a problem shared is a problem squared, I mean, solved, I had a council of war with Tony. Apart from the slight issue of access he felt that all the penetration at the two sides could be dealt with without huge amounts of things being removed, while any stuff in the middle (which doesn't seem from my manual explorations to be a problem going down) needs the engine and box out, which are coming out anyway.

A check of all the other rust spots highlighted in those delightful links Graeme, thank you, are all fine - a really good probe around the C pillar ventilation holes with a fine chisel merely revealed dirt on both sides, no corrosion of any note.

So Colin, his former apprentice, is going to come over and have a good look and see between the two of them if they can sort it without troubling the bank manager much. Fingers crossed.

Learning to weld is a good idea, but I think this is a job for the experts.

Meanwhile I have established that as per post 962 Bellow is correct that the dipstick tube does indeed have an integral bracket and from the length and shape of the thing, it is the most likely place for it to be. It also has clips for the vacuum line.

 

[Bellow]

Meanwhile I have established that as per post 962 Bellow is correct that the dipstick tube does indeed have an integral bracket and from the length and shape of the thing, it is the most likely place for it to be. It also has clips for the vacuum line.

If the boss were open to the manifold interior (as MB could have arranged it to be for auto application) do you suppose the vacuum line and the dipstick are both located on it? Piggyback style. Entirely feasible technically but it doesn't strike me as how MB do things.

 

[Charles Morgan]

I'd say highly unlikely Bellow, particularly from the photo where there is no sign of a banjo pipe underneath the bracket. I'm going to have a little nose round this afternoon.

Meanwhile no welding diagnosis for a fortnight due to holidays and busyness.

 

[Bellow]

Looking at the bracket as it is affixed to the dipstick tube in video (2.39) the angle doesn't appear compatible with a horizontal fixing. Unless, it is a slip fit around the tube or, the tube is a fair way from vertical when finally fixed. I cannot see a dipstick in Grober's full frontal pic (the shiny one) - possibly a manual. But, definitely there is a twisted bracket that bolts to that boss (different pic), and the vacuum banjo has to attach somewhere!

 

[Charles Morgan]

The dipstick tube is at an angle. I tried a sort of test fitting today (obviously not to the base of the box) and it does work pretty much as it should. The bracket has a twist in it.

What I got nowhere with was working out where any vacuum line might plug in - the potential hole at the end of the manifold Grober suggested is not wide enough fit the banjo bolt that the tube is fitted to at the box end.

Kickdown arrangements became much clearer though - the bulkhead has a dimple where the kickdown switch fits precisely - same on both right and left side, under the throttle pedal.

Lots of monolex freed up the heater controls on the duo valves which had been a bit crusty. So coming along, the problem with the rust does prevent me from doing a lot though, which is a bit irritating.

 

[grober]

Thats disappointing- here's a couple of piccys of an early 67 D-JET 280 SE
Note the cross engine linkage for LHD, but similarities to later linkages.

and the car

from this link

1967 Mercedes-Benz 280SE Factory Prototype (280SE, W108, W108.014) | Conceptcarz.com

 

[grober]

And some pictures of a contemporary R107 280sl 1975 automatic gearbox showing some of the wiring detail. Unfortunately the vacuum line is missing but the clips for it on the dipstick tube can clearly be seen.

 

[Bellow]

That pipe, rigid and preformed as it is, should find its meeting place with the manifold all by itself! This is a weird one...
Presumably the underside of the manifold has been checked for fixings

Does anyone know the precise function of the vacuum dashpot? And is it a fitment on injected cars? (Car in the video (the sole sighting of this damned thing?) is carbed).

 

[grober]

This is a detailed illustrated thread which deals with the evolution in design of the 722.xxx transmission vacuum modulator . Unfortunately does not deal with the early type on Charles' car. More likely to influence how the transmission changes rather than the control pressure lever from the throttle linkage which influences when the transmission changes -- as I understand it- altho there are "cross over " effects.
722.xxx transmission vacuum modulators - PeachParts Mercedes ShopForum

also dealt with in this video. [YOUTUBE HD]gM4KZvwsCW0[/YOUTUBE HD]

 

[Charles Morgan]

Presumably the underside of the manifold has been checked for fixings

Not yet, access to that side is difficult and also I haven't yet had a fiddle with the vacuum pipe. Given the shape of the two boxes is a bit different I am not sure the pipe on its own will point the way.

 

[grober]

Finally tracked down a good reference with some piccies to adjusting this older type regulator on a W116

Part no for the W116 is A0002700179 for what is described as a "vacuum box" I wouldn't be surprised if it isn't the same for the w114???

As you can see its a lot more fiddly than the later plastic bodied type!

Adjusting Automatic Transmissions

 

[tommyboy40]

Hi Charles, I've just read all 66 pages and what fascinating reading they make. I'm new to the forum and am impressed with the wealth of information and sharing. I'll follow this one closely

 

[Druk]

MIG welding is very easily learned. I learned how to to weld the floor of my W123. The tricky part is obtaining gas economically.

Hobbyweld 5 Original Welding Gas | The full range of gases from Hobbyweld rent free cylinder suppliers

 

[Charles Morgan]

I'm new to the forum and am impressed with the wealth of information and sharing.

First welcome, and second, I am equally impressed by how many people have gone to exceptional lengths to help, it is really rather lovely (especially as I need it!).