W109 300SEL Barn Find

[treedoc]

Last week after putting my wife on a plane to Switzerland on the way home out of idle curiosity I followed up on a car i'd heard about that had been sitting in a barn for 13 years, it now resides in my shed
Car is a 1971 300SEL 3.5 99,000 miles, all books, near perfect original paint, good chrome, wood, leather, carpets, so far only issues are an air leak from rear level valve and a frozen fuel pump.
Previous owner bought it unregistered along with the property, occasionally he drove around the 5 acre lot, washed and polished it and mainly just admired it

[Iconic]

Congratulations !
That is beautiful.
Barn find stories are fantastic.

[Naj ✝︎]

Hi, Treedoc,

Nice find !!!

Checkout 6.3 section on the M100 group.

Lots of air suspension help and some experts in Brisbane too.

http://www.m-100.cc/forum/default.asp


Enjoy 
naj

[Louis]

Very nice find !!!

[Benz Dr.]

We just finished the 600 we've been working on and they use the same air valves. They either leak externally or internally. The manuals explain how to do the tests to figure out which. They may be leaking either way, or both ways.
 
We were able to fix all the air valves on the 600 plus the main air valve by cleaning and testing them. There are places that rebuild them but it's costly. We simply sprayed soapy water around the valve where the lever comes out and the leak showed up. Even a very small leak will make the car settle down. Once they're good the car will stay up for a long time.
 If you raise the car for any reason make sure you pull the ride height cable out to the middle or locked out position. If you don't, all the air will escape. I have some spare parts for this car from a 300SEL 2.8 and 6.3

[treedoc]

Dan,
Currently I'm only looking for two "get home slowly" inserts for the front wishbones, two came with the car and also a parts drawing of the Bosch air valves, I'm going to have a crack at fixing the rear one myself as my dackground is industrial hydraulics
Geoff

[Benz Dr.]

Pretty hard to find those prop up things today. We use small blocks of wood but I suppose anything soft like some old rubber would do. I'm not driving the car at this point just moving it around. Sometimes you can add enough air through the shrader valve to get it to come up and then the main air pump can handle it as long as you keep the engine running. That would be a very large leak if it didn't come up at all.

The control valve has very little inside of the housing. There's a couple of valves and a plastic rack and pinion inside. I've seen the pinion crack and then quit working but I don't know how common that is.
After you remove the control lever set the valve up in a vice. Put a large enough socket behind the brass cone and push the shaft out through the back until the cone pops out. It's kind of all pressed together that way.
 
The problem isn't so much getting it apart, it's more like getting all the very special seals inside. Some are available I suppose but some aren't. Not sure why it costs several hundred to rebuild one. I can see it for the main one because there's a lot of stuff in there but the control valves seem  less complicated. 

However, I don't have all of the test equipment or all of the right parts to do it either.....

[treedoc]

Dan,
Appreciate your comments on air valves, I have since solved all the external and internal leakage problems
We are lucky here in Australia to have a retired German Mercedes engineer by the name of Claus Gronau who now specialises in reconditioning 600 hydraulic valves and 600 & 300 air suspension valves, so I sent him all four air valves out of my 109.
You are right, not all of the seals are available from MB or Bosch so Claus makes his own, a piece of meticulous engineering in it's own right, see attached photo of re-condition of valves after passing through his hands, new seals fitted throughout, bodies finely bead blasted, all steel parts re zinc plated then tested.
Claus can be contacted via
cwgronau@hotmail.com

[Benz Dr.]

Hi,
there are a couple of guys that do air valves so no one is stuck but it's still exspensive.

[treedoc]

Reconditioned air valves now reinstalled, I should have steam cleaned the car before I started, 40 years of grease and grim made a difficult job worse.
Fired the engine and up she came a little high but left adjusting to another day, stayed up overnight so next morning put cabin control into full raise position, all worked well until I lowered it back down, rear end dropped all to way to fully low, turned the engine off, hissing sound coming from the rear, yes we had "popped" a rear air bag.
Four new air bags now on order

[JPMOSE]

Wonderful!   I love my 3.5....interesting sound to the car when running.   Mine had a slight muffler leak from the prior owner not running it long enough to burn off the moisture.   So I went ahead and replaced the entire exhaust system with MB parts.  The finished product still has a rumble like a 1960's V8 automobile.  So don't expect anything different!

One piece of advise -- the supply of W108, 109, 110, 111 and 112 availableparts from the MB dealer are not as good as the W113 and other later chassis.  I would say that all the parts to keep her running, plus glass, seals, etc. are available.  But cosmetic parts are often NLA.   I would assess all the parts needed to make her the way you want her and seek them out while you can.

Glad you are keeping the original suspension! 

[treedoc]

Good advice JP,

MB Classic Centre California are currently selling RH & LH mirrors for 108 / 109 and 113's

Our 300's door seals are in reasonably good shape, I have been advised to treat them with Paraffin oil to soften and preserve them, anyone care to comment?

[Ulf]

Nice - I'm sure your wife will never dare to leave you home alone while traveling again :-)

[treedoc]

Ulf,
She's got used to returning from Switzerland to an automotive surprise' one time I meet her at Brisbane Airport with a 1994 W140 S500C Coupe, see below, complete with red sash and a doszen long stem red roses. It didn't work
Her first drive a few days later started out with her backing into a fence post, she immediately got out of the car and never sat in the drivers seat again, so we onsold it.
After another trip it was an R129 SL500, she drove that for about a year then decided it was too good for use as a shopping basket, I kept the 500 for me and she has finally settled on a W170 SLK230, which she absolutly loves this one.

[Ulf]

 

[m300cab]

anyone ever try to replace the shocks with aftermarket air shocks?
and bypass the air bellows suspension?

[Louis]

anyone ever try to replace the shocks with aftermarket air shocks?
and bypass the air bellows suspension?

Bite your tongue and say 3 'Hail Mary's' !! Don't you dare .....Buy a W111 with conventional shocks & springs suspension if maintaining a W112 is driving you to consider such an option.......

[thelews]

Air bags are not a big deal for anyone who understands the system.  There are so many more parts to the system that cause air leaks and air bags are only one of them, and a relatively easy fix.  They're also integral to the air suspension system that gives it it's unique, high quality ride.