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

Hi all,

I've picked up this 1976 206d campervan in slightly rough shape:
http://imgur.com/qQg32U6.jpg

Who has experience with these things?

I'm working on getting it started and drivable for now. It hasn't been running in about 10 years, but the engine turns over. It looks to be the OM615 engine, but I'm not sure the exact model of oil and fuel filters I need. I don't even see a fuel pre-filter installed. Next will be brakes, as they don't work - no resistance on the pedal.

I'll take some pictures of the engine + interior soon.

ian

Looks like a neat project. Keep us posted with details and pictures.

I'm pretty sure Kerry has a few of these. Hopefully he will see this and chime in.

I almost bought one of these but the chassis and body were too far gone. Plus, it did not have an OM615 engine plus TRANSAXLE in it, it had the old Hanomag motor made of unobtainium. Don't know if that transaxle has any other equivalent or relatives for parts.

There is a Hanomag forum that I belong to, but it is mostly in German.

Good luck on the car! Hope you got the one with the OM615 in it!
MB badged a certain number of those with a Hano power train, kinda like GM badge engineering.

Got a picture of the engine:
http://i.imgur.com/fX5fhnh.jpg

along with the number stamped on the exhaust manifold:
http://i.imgur.com/8bCpasI.jpg

Accessing the engine is a bit odd, with it sitting in between the driver and passenger seats. But from some images I've found online, it looks like I can remove the middle section of the cab behind the front bumper for better access.

I'd love it. My wife would shoot me. Perhaps my wife should shoot me ...if I bring more projects home...and don't finish the ones here already.

Well, it runs!
https://youtu.be/qwkJJf0zQ2U

(we were pretty excited as you can hear)

I'll be doing a valve adjustment and full fuel tank cleaning in the next couple weeks.

Amusing video.

That uneven idle is pretty bad though. Check the accelerator linkages.

I believe Kerry had one and has a lot of knowledge about them. Glad you got it running! Its very cool! the body looks fairly good.

My wife is getting about ready to I believe.

As a peace offering I sold my w116 and am trying to sell some of my non-car projects...

Of course I also just bought the stuff for a 4 speed swap into my grey car...

Anyway. Ian (invnsnt): That is a cool looking little van, and sounds good other than the loping idle, which shouldn't be a big deal to fix, I'd be excited too! Keep the pics and updates coming, I've never seen one of these before now!

On the topic of my earlier intention of cleaning the fuel tank:
When crawling under the van today I confirmed my suspicion that it has two fuel tanks -- one in the stock location in front of the rear axle, and one behind it. The filler neck has a Y fitting and connects to both. Without jacking it up, I can't really tell the layout of the fuel lines, so not sure if it pulls from both at the same time or if there's a valve somewhere. And have no idea which one the fuel gage measures. There are enough unlabeled switches in the cab for one to control a valve back there, though. The rear tank has a small leak - I think this happened when it got put on the flatbed - so I know that's empty, because its contents ended up all over the flatbed + driveway.

The uneven idle is usually the result of (air) leakage of the governor chamber.

With a new battery, I got the engine started up during the day. It shakes initially, but smoothes out nicely with a bit of pressure on the accelerator pedal, like in this video here. So I'm thinking the idle speed off throttle might be set too low? Will look into what you said, along with the accelerator linkage.

I've also got a video from the outside. I think next up will be brakes and clutch -- no pressure in the hydraulic system for either -- because it'd be great to at least pull the thing out of the garage under its own power!

Idle speed should be 700–800 rpm set with a warm engine (80ºC).

Before you should check the vacuum chamber of the governor, that should be air tight, otherwise your engine will be smokey and it will consume more diesel.

If the engine does not come up to maximum speed, the governor spring might have to be replaced. This happens sometimes if the engine has not been started for a long time and the governor is in the stop position.

Wow,I had no idea these existed.
That's so awesome.

I've got some long overdue updates. Been dealing with rusted, seized, or corroded everything, which as you probably know increases the actual work time by about 3 times what you estimate.

After trying (and failing) to source parts in the US, I finally bought a big box of parts from a 206D enthusiast in the UK, including all the wheel cylinders, the clutch slave cylinder, and a variety of suspension bushings + ball joints. I used my time off over Thanksgiving to install the front cylinders and start on the rears. It took quite a lot of effort to get the stuck rear driver's side drum off, but got it off eventually and discovered the culprit was a broken brake shoe. I'll need to buy a new one, but at least the wheel isn't locked up any more!
http://i.imgur.com/3HD6qGm.jpg?1

I've finished stripping out the old camper interior and wiring. Discovered a useful access panel for the fuel tank sending unit under the carpet, along with a few pounds of nuts and acorns from a previous furry tenant.
http://i.imgur.com/k1oSa5a.jpg?1

One issue I've been confused by is the clutch. It's stuck disengaged, which means I can't get the van moving under it's own power. Since the hydraulic lines were empty when we got it, I'm thinking the clutch slave cylinder may be stuck. But reading through the operator's manual again, it instructs you to "lock the throw-out lever in the clutch housing". So now I'm thinking the PO might've done this before the van was parked. I need to take a closer look with the front wheels off again -- it's a pretty hard to access area.

I've owned a 307d and a 409d van but those are quite different than the 206d. I didn't realize they made these into the late 70's. I met a guy in France with one (a class C conversion). He liked it but said the steering parts required frequent renewal. I bought MB van parts from Euro Auto Parts in the UK about 10 years ago. Patrick was the export guy and he set me up with everything I wanted. That engine is the same as the engine in a 220d sedan I believe. There were lots of those 206d campers in Europe at one time. There was a company in Indiana which produced a Class C motorhome on that chassis for a while. One couple put lots of miles on theirs over many years and its in some kind of museum in Florida if memory serves me correctly. If that owner is still alive, he'd be the guy to talk to about those vehicles since he owned it for so many years.

More than you'll ever want to know about Mercedes vans:

The history of the Mercedes-Benz vans | Mercedes 500SEC.com

Hi all! I've got some updates from the past few months:

- new clutch slave cylinder and hydraulic lines installed
- dropped and discarded leaky aux fuel tank, and redid fuel lines to OEM tank
- went through radiator hoses and replaced old ones
- assorted rust grinding + converting
- new tires on the rear after one blew out

I started the van this weekend for the first time since fixing the fuel tank and replacing the clutch slave cylinder + lines. Fired up just fine with some fresh diesel in the not-leaking tank. I then rolled down the driveway a bit to test out the brakes (they work pretty good for not being adjusted yet), but after all my work fixing the clutch actuation I still couldn't get it moving under it's own power -- I let out the clutch while in gear and nothing happened. So I was pretty bummed that evening, not knowing which of many things could still be wrong with the clutch or transmission. But the next morning, I put the front up on jackstands to get the drive wheels off the ground, hoping to see if I could shift through the gears and see some wheel rotation. It worked! I was able to shift through all gears, including reverse. I tried getting a video to demonstrate, but I accidentally was in picture mode instead (whoops).

So it seems to me just that the clutch is grabbing enough to spin the wheels when there's no load, but not grabbing enough to drive the vehicle.

I'm thinking it's one of three things now:
- clutch release fork needs adjustment; currently not engaging enough
- clutch friction surface is worn out and slipping
- pressure plate springs got weaker from sitting compressed for 10 years

I'm going to try adjusting the release fork first, since the other two mean dropping the transmission.

bonus video of me rolling down the driveway to test out the brakes, turn sound on for engine clattering: http://bit.ly/2ulTagc

Still having issues with the clutch actuation on the van. I compared the old slave cylinder rod with the new one, and the old one was about 1/8" shorter. I replaced the new rod with the old one, and it seemed like it fixed it -- the clutch wasn't slipping when I turned the wheels by hand.

BUT, the throw out bearing still isn't returning back to it's resting position off of the clutch release fingers after you let up off the clutch pedal, so the clutch plate is slipping against the flywheel. However, I can reach in there and push the clutch release fork back a mm or two, and then the clutch plate grips. So it seems like something in the hydraulic line is the problem. I might not've bleed the whole thing well enough? The slave cylinder isn't compressing enough for some reason. Seems like a lot of people have similar problems with bleeding the clutch system on 240Ds, too.

the clutch slave cylinder looks like this so there's no confusion:
http://i.imgur.com/s3qxn20.png

That picture makes it look like you can adjust the arm that the clutch receiver cylinder pushes on.

Hi all,

I've not posted any updates for a while -- I had been finishing up grad school and then moved across the country, but we still have the Hanomag!

Recently, I completed what was felt like a big challenge, and a first for me:

https://i.imgur.com/LYN04Vg.jpg

I pulled out the engine and transmission in order to get to the clutch and pressure plate. I got some advice that it's easier to pull and have it out of the vehicle instead of removing only the transmission and have to deal with reinstalling it laying on your back.

The whole assembly slides out the front. I made a holding fixture out of some scrap wood to try and simplify the process:

https://i.imgur.com/Ly6T9uK.jpg

I'm separating the engine and transmission to check out what's going on with my slipping clutch. Hopefully, just the clutch plates need replacing. While the engine is out, I figure I'll go through and replace any cracked rubber lines (I see at least one on the intake), rebuild the vacuum pump, and adjust the valves. Any other jobs you'd recommend on this OM615?

Separated the engine and transmission to check out the pressure plate and clutch:
https://i.imgur.com/STJx87f.png?1

I noticed the pressure plate was very crooked. When we got the bus, the clutch was stuck open, so I was thinking maybe some of the spring was seized in its compressed state. But then I looked a little closer, hey what’s that shiny thing in there? Is that… a ball bearing? Two ball bearings??

https://i.imgur.com/aZOP3pD.png

They were stuck between the spring fingers and the pressure plate housing. I futzed around with some clamps until I had everything fully compressed and then shook the balls out like one of those maze puzzle cubes that people put five dollar bills inside for joke birthday presents. Now where did they come from?

Transmission spins fine, and all the gears work. The throwout bearing is undamaged, too. I don't see anywhere else they could have come from in the transmission. Maybe they got there on accident while when the PO replaced the clutch or did other work in the area? It seems to me like they've been stuck in the pressure plate springs since we purchased it, and would explain all the clutch engagement problems I've been having!

Now to wait on new parts to arrive from Europe :D

Balls from an old failed throwout bearing?

Maybe! But the current one is undamaged.

how is the pilot bearing?

It spins fine, but I haven't taken the flywheel off (since I don't have the right sockets yet) to fully inspect it.

Wow, that is an odd one! As I read along, I was thinking that you needed to replace the clutch disc. Glad you figured that out. Now to discover the source.


How does the pilot shaft / bearing in the transmission look?

It's listed as a needle bearing in the parts diagrams, so I don't think that could be the source.

In the meantime, I've adjusted the valves and cleaned up the valve cover before replacing it. The cams were in great shape! And the valve adjustment wasn't nearly as difficult as I had expected -- but I'm glad I shelled out for some bent wrenches. I've also been removing and cleaning up the engine accessories. The water pump + housing looks OK -- some scale on the inside that should come off with a citrus flush. The vacuum pump is the old style used in the W110, and I can't find a source for diaphragm repair kits that isn't <$150 shipped -- yikes! I might see if a junkyard 240d vacuum pump fits to make future repairs easier. Since this bus is so bare-bones, the only thing using vacuum from the pump is the brake booster. The shut of valve on the fuel pump looks like it uses vacuum from the intake manifold instead of the pump. Is this true for the other diesels, too?

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!

#####

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

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)

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.

https://i.imgur.com/Nw1hiFl.jpg


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.

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 (!)

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.

It isn't the easiest information to access with out a flash player that they happen to be using at the moment...


...so I've added direct links to the PDFs on startek for the non turbo chapter seven to this thread =>


http://www.peachparts.com/shopforum/3920886-post74.html

Thanks Stretch! I've also found the FSM for the W114/W115 models -- of which the 220D shares the same engine as my van, with a few small differences: Some Good Reading

Still waiting on clutch parts and engine mounts, but in the meantime I've reinstalled the vacuum pump, water pump, and thermostat housing with new gaskets. I also flushed out and de-scaled the engine and radiator. It really needed it!

After pulling off the intake and exhaust manifolds, I noticed that there's not one, but two butterfly valves on the intake. One is actuated by the gas pedal linkage, and the other seems to just rotate freely. It looks like the second one would be good for shutting off the engine in an emergency, but there's no way to close it unless you take off the engine cover and reach in to do it by hand. I'll have to do some more research on this.

I spent this afternoon laying underneath the engine bay cutting out the old transmission mount -- the metal sleeves of the bushings had seized to the bolt.

The second flap is devised to be free (not attached to anything), see:

http://www.peachparts.com/shopforum/450221-post10.html
http://www.peachparts.com/shopforum/diesel-discussion/71958-can-right.html

Added in the early 60ies and some documents describing the operation of pneumatically governed IP pumps show only one flap in the intake(like here):
https://www.startekinfo.com/StarTek/outside/12265/disc_2/program/Engine/615/07-010.pdf

Thanks for the information! Anybody have a part number for the gasket between the butterfly valve assembly and intake manifold? And any general maintenance you'd recommend while it's disconnected?

A6360740280

I'd check for excessive wear on the shaft and lubricate from time to time...

new parts!
 

Finally got my new (well, NOS and used) parts in the mail from Germany, and starting buttoning the engine and transmission back up to reinstall. I've read the clutch alignment tool from a 90s S10 fits the 240d, so I'll try that out. Then with the new engine and transmission mounts I received, it should be a little easier putting the engine back in than it was taking it out with the seized transmission mount.

I also need to reline the rear brake shoes. I'll probably try giving this a go at home first, and then call around some truck/RV shops if I can't figure it out.

Excited to hear it run again!

Got the engine back in a a couple of hours one afternoon last week. It's been taking longer reconnecting everything! Lots of crawling underneath the van, which I haven't had to do in a while, with the engine out and everything. I' hoping to start it up again in the next week or so. Been running around the shops for different small parts -- brake fitting adapters, hose to bypass the heater, and taps and dies to clean up threads. The threads on the steering tie rod are damaged -- hoping that it's easily fixed.

I've also noticed the crank pulley has a rust hole in it. I haven't been able to source a replacement yet. Should it be the same part on the 220D/240D? No AC so only one groove.

https://i.imgur.com/9nmxVpA.png

Yours appears to only have three bolts. I have always seen six bolts, even on the early 615 in my shed. Maybe one with six holes will still work, don't know for sure.

Buttoned everything up over the weekend -- primed the fuel filter, connected up the oil bath air cleaner, and new coolant hoses and clamps connecting up the radiator. After fixing an unexpected waterfall from the thermostat housing (make sure that O-ring is in the right spot, oops), I connected up the battery and finally tried cranking the engine. Nothing. All the lights turned on, what could be wrong? Well, I missed the battery ground cable bolted to the transmission. Tighten that down and it cranks! After bleeding the fuel out of the lines and replacing the old corroded ground cable with a new one, it started right up with a satisfying clatter: https://www.instagram.com/p/B2NsjzklqgX/

I'm going to run some diesel purge through it, adjust the valves again, and then try and even out the idle. I'm planning on checking the fuel pressure, compression, injection pump timing, and cleaning the injectors. Anything else?

I went on an injection pump repair tangent in this thread: http://www.peachparts.com/shopforum/diesel-discussion/401513-replacing-pneumatically-governed-om615-m-pump-mw-off-om616.html

With the repaired pump back in, I've starting trying to figure out the timing, both reading through threads here and the FSM. Looks like one thing I've overlooked until tonight is bleeding the air out of the IP. Is this the correct screw to loosen to bleed the air out of the pump?
https://i.imgur.com/edCIts4.png

I also spent a day last month at a pick-n-pull removing a OM615 from a surprisingly decent '74 240D -- it may end up in the van if I can't fix the stuck ring on cylinder 2!

Possibly is, but the return line takes care of that anyway. Still have to bleed at the injector pipe nuts as well.

Transaxle
 

Hi all, I just joined and I am picking a 206D camper next week, The van is all good, I'm on a learning curve at the moment by reading as much as can.
Are there any known problems with the transaxle on the 206? Regards Charlie

Not to my knowledge! The other owners I've talked to say that the drivetrain and frame are quite robust. The body does rust, though, and mine has plenty. Should be a bit easier for you to get parts in the UK, too.

Today I procrastinated on fixing the IP timing by dropping the gas tank for a proper cleaning and pulling all the old fuel lines for replacement. I probably will just swap in my spare OM615 -- not sure if it's worth my time trying to free this presumably stuck piston ring with MMO soaks and a future italian tune up when I have a spare ready to swap in, and then popping the head off the original engine.

Wow, finally able to connect (long story)... I've owned a 1976 L206D British van conversion called the "Ultra Autobahn" for over 40 years (KatieKat Website Myrtle) and stumbled upon this site and still playing catch-up. Been in mothballs but runs fine (20-year-old fuel via super filtration). Have all the factory workshop manuals, and would like to discuss source(s) for obtaining brake cylinders (at least one, as the others should be rebuildable) and relining the brake shoes, and what type of diesel fuel should I use for this OM615 (I think) engine? Thank you.