New project - 1976 Hanomag/Mercedes 206d van - Who knows about it? - PeachParts Mercedes-Benz Forum

Stretch · #1 05-09-2019, 02:52 PM

For the vacuum pump =>

Search for 000-586-41-43-M36 on the pelican (parts) site and see if that's going to work for you at 14 USD it might just be worth the gamble. Disclaimer - I'm not sure this is the correct part - buy with caution

Don't forget to fit a new gasket between the pump and the engine block - very important!

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As for the clutch trouble:- Take it to bits - examine the flywheel very very carefully for blue coloured "hot spots" and cracks - if in doubt take it to a machine shop (with experience) and see what they've got to say.

Mark flywheel position before removal (if you do need to remove it) just in case there's no positive positioning (I don't think there is)

Before even thinking about fitting a new clutch buy a clutch alignment tool if you don't already have one

resto108 · #2 05-09-2019, 08:32 PM

There is no vacuum in a diesel intake manifold, that why there is a vacuum pump. You have to have a throttle to create vacuum.

Stretch · #3 05-10-2019, 09:01 AM

Quote:

Originally Posted by resto108

There is no vacuum in a diesel intake manifold, that why there is a vacuum pump. You have to have a throttle to create vacuum.

The OM615 is a bit of an oddity it does have a throttle valve controlling air going into the engine much like a petrol engine.

It certainly uses negative pressure in the intake manifold to control the "pig's bladder" (as it is often called on this forum) as part of the injection pump regulator / regulation. If this diaphragm breaks the tell tale sign is an engine that revs too high (but not run away).

I'm not sure what else is tapped off the intake manifold - best to find a workshop manual (which isn't likely to be easy unless you're prepared to pay Mercedes a lot of dosh)

invnsnt · #4 05-12-2019, 08:33 PM

Quote:

Originally Posted by Stretch

The OM615 is a bit of an oddity it does have a throttle valve controlling air going into the engine much like a petrol engine.

It certainly uses negative pressure in the intake manifold to control the "pig's bladder" (as it is often called on this forum) as part of the injection pump regulator / regulation. If this diaphragm breaks the tell tale sign is an engine that revs too high (but not run away).

I'm not sure what else is tapped off the intake manifold - best to find a workshop manual (which isn't likely to be easy unless you're prepared to pay Mercedes a lot of dosh)

This is all correct. On my OM615, you can seen the gas pedal linkage connecting to the throttle valve (circled in red), with the vacuum line connecting to the fuel pump.

What's nice about this is that I can still shut the engine off even if the vacuum pump fails. It does make the gas pedal linkage much more complicated, though.

resto108 · #5 05-13-2019, 01:35 PM

So sorry for my prior statement. I used to be on some sort of forum for my 65 Lincoln and it really pissed me off when people who didn't have a 65 Lincoln but who had worked on "a lot of Fords" would chime in with their rubbish advice that applied to a Ford, but not a Lincoln. And now I've done the same. Well, to make this an educational opportunity, does anyone know the reason? Generating vacuum seems out because it has a vacuum pump. Seems to me it would need to be arranged so it would get air and fuel at roughly the same rate, or does it literally just open all the way as soon as you step on the pedal and is only there to allow for shutting down the engine by starving it for air?

Stretch · #6 05-13-2019, 02:56 PM

Quote:

Originally Posted by resto108

So sorry for my prior statement. I used to be on some sort of forum for my 65 Lincoln and it really pissed me off when people who didn't have a 65 Lincoln but who had worked on "a lot of Fords" would chime in with their rubbish advice that applied to a Ford, but not a Lincoln. And now I've done the same. Well, to make this an educational opportunity, does anyone know the reason? Generating vacuum seems out because it has a vacuum pump. Seems to me it would need to be arranged so it would get air and fuel at roughly the same rate, or does it literally just open all the way as soon as you step on the pedal and is only there to allow for shutting down the engine by starving it for air?

Don't worry about it - the OM615 is a bit of a weird one (I think other earlier Mercedes diesels also had this weird arrangement - but I can't quote the numbers off the top of my head!)

I don't know for sure why this arrangement was used - I would hazard a guess (and it is only a guess) and say it is probably a Bosch thing. Or if it wasn't Bosch, perhaps the more commonly known configuration is more of a Bosch thing - dunno for sure.

If you want to "read all about it" the W123 FSM on the startek site for the non turbo OM61X engines has a big old write up in chapter 7 describing how the OM615 throttle valve system works. It then goes on to describe how the OM616/7 system works. Great anorak stuff (!)

invnsnt · #7 05-17-2019, 11:32 AM

Quote:

Originally Posted by Stretch

If you want to "read all about it" the W123 FSM on the startek site for the non turbo OM61X engines has a big old write up in chapter 7 describing how the OM615 throttle valve system works. It then goes on to describe how the OM616/7 system works. Great anorak stuff (!)

Maybe I'm dense, but I can't find this section on the startek site! I see all the other sections in the engine manual, but chapter 7 looks like its only 'testing and adjusting jobs' and 'assembly jobs' -- but no write ups of how the systems work.