6.3

reassembly of main air tank drain valve

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S class

3/30/2017 7:56 AM

I needed to disassemble and clean the drain valve on the main air tank of a 6.3. All the bits cleaned up as per the photo below. However, I am unsure of the assembly sequence. I have laid out the components in the photo as I believe they should be. Can anyone confirm specifically the small cup piece which is circled?

It seems it should be below the perforated brass disc, flat side up against the E-clip, cupped side down to the tapered spring. Yes? No?

Thansks in advance.

116.036 - trusty rusty
116.036 - Rooikat
116.024 - the merc
116.028 - Penelope
116.032 - Esmeralda
126.037 - Scheckter
126.037
107.046

S class

3/30/2017 7:57 AM

116.036 - trusty rusty
116.036 - Rooikat
116.024 - the merc
116.028 - Penelope
116.032 - Esmeralda
126.037 - Scheckter
126.037
107.046

tcj-old

3/30/2017 8:29 AM

Hi Ryan,

all is correct. A picture tells more than 1000 words: this is how to cup goes:

If you ever need spareparts, we do have #1,#2, #4 and #6 available here - more to come (part number count from left to right in your picture)

Thomas

Thomas

112.021 300SEC
116.028 350SE
116.036 450SEL 6.9

S class

3/30/2017 10:04 AM

Thank you very much, I appreciate the help. I can now reassemble the valve with confidence.

116.036 - trusty rusty
116.036 - Rooikat
116.024 - the merc
116.028 - Penelope
116.032 - Esmeralda
126.037 - Scheckter
126.037
107.046

Jack English

3/31/2017 4:04 PM

Thomas: Do you have the tank inlet check valve? I'm driving around with one borrowed from MPM. I'd like to return it while it still works.

Jack English
300SEL 6.3 #4768

olliw109

3/31/2017 4:05 PM

Hello Ryan, seems if the part reached you in the meantime, good to know! I hope you can use it for your customer.

300 SEL 6.3 3478+5327
Oliver

tcj-old

3/31/2017 4:54 PM

quote:
Originally posted by Jack English

Thomas: Do you have the tank inlet check valve? I'm driving around with one borrowed from MPM. I'd like to return it while it still works.

Jack English
300SEL 6.3 #4768

Hi Jack,

we do have a good reproduction. There should be one left, but I cannot find it now - so they are out now. New ones are approaching, but this will take some weeks.
If thats early enough...
Thomas

Thomas

112.021 300SEC
116.028 350SE
116.036 450SEL 6.9

Jack English

4/2/2017 2:14 PM

Thomas: I have been looking for some months for this or a suitable substitute. Please put me on your list when the new ones come in. Thanks.

Jack English
300SEL 6.3 #4768

tcj-old

4/2/2017 3:09 PM

Hi Jack,

thanks! Will let you know when the new ones are here.

Thomas

112.021 300SEC
116.028 350SE
116.036 450SEL 6.9

Jack English

4/2/2017 10:24 PM

Curiously enough, I have found (on the interweb) a company that makes pneumatic valves of many sorts that has a valve that looks identical to the check valve I have been pursuing. It costs less than US$7.00 but comes with SAE (inch) fittings. I could not convince them to make it with metric sized fittings for less than several thousand units, probably more units than there are cars that require them. This is all computer set-up etc. I was willing to order 50 but not more than 100. SO, it is likely that some European company makes the identical check valve in metric sizes. I just can't find one.

Jack English
300SEL 6.3 #4768

S class

4/3/2017 4:27 AM

quote:
Originally posted by olliw109

Hello Ryan, seems if the part reached you in the meantime, good to know! I hope you can use it for your customer.

300 SEL 6.3 3478+5327
Oliver

Yes Oliver, thanks for your help. We decided to remove and service all the fittings, replace all seals etc. The tank itself went for ultrasonic cleaning. I have received it back just this morning. It is currently painted in red oxide, so I will paint it black now. I am also considering to paint it with stone chip schutz, but I'm not sure if this would be correct.

Another question - should one apply any sort of coating on the inside to prevent future corrosion?

116.036 - trusty rusty
116.036 - Rooikat
116.024 - the merc
116.028 - Penelope
116.032 - Esmeralda
126.037 - Scheckter
126.037
107.046

tcj-old

4/3/2017 4:45 AM

Hi Ryan,

mercedes noted in the late 60ies that tanks do corrode and pieces of rust are falling down. When the owner drained the tank a piece of rust came to sit on the seal of the drain valve so it was leaking now.
So mercedes made 2 changes
- the late drain valve received a sieve to prevent rust from entering the valve. You can see the sieve on your picture
- the late tank was make of (I think) stainless steel.

So at least the tank 1093200152 doesn't rust anymore.
If you look inside and you see only shining metal and dirt than
no coating is required.

Thomas

112.021 300SEC
116.028 350SE
116.036 450SEL 6.9

S class

4/3/2017 10:49 AM

Hi Thomas,

OK thank you, it makes sense that it could be stainless, because it felt too light to be mild steel.

116.036 - trusty rusty
116.036 - Rooikat
116.024 - the merc
116.028 - Penelope
116.032 - Esmeralda
126.037 - Scheckter
126.037
107.046

tcj-old

4/19/2017 11:36 AM

Hi Jack and others,

the first new check valves are here.
Here is how it looks like.
Left to right
- our new check valve
- early original mercedes check valve
- later original mercedes check valve

If you need one just send me a PM.

Thomas

112.021 300SEC
116.028 350SE
116.036 450SEL 6.9

Jack English

3/3/2025 5:33 PM

Quoted Text

Hi Jack and others,

the first new check valves are here.

Here is how it looks like.

Left to right

- our new check valve

- early original mercedes check valve

- later original mercedes check valve

If you need one just send me a PM.

Thomas

112.021 300SEC

116.028 350SE

116.036 450SEL 6.9

Thomas, are there any of the air tank check valves still available? Mine broke

Ron B

4/25/2017 8:30 AM

If you have a look on older trucks with air brakes they have the same drain valves .[:)]

quote:
12-14-2004, 11:49 PM #8
Tom Hanson
MBCA Member

What the heck, try to stuff a MB 6.9 liter V8 in it. What a machine that would be..
__________________
Tom Hanson
Orange County Section

tcj-old

4/25/2017 8:43 AM

Hi Ron,

thanks! Do you have a link? As far as I know these check valves with correct threads are only available from Martin Werminghausen and me.

Regards,
Thomas

Thomas

112.021 300SEC
116.028 350SE
116.036 450SEL 6.9

daantjie

4/25/2017 4:59 PM

I guess you guys are talking about what we call here in NA a "drain cock"

http://www.canadiantire.ca/en/pdp/mastercraft-brass-drain-cock-0587718p.html

The Benz ones seem quite specialized though...

Daniel
1977 450 SEL 6.9
Vancouver, BC

Art Love

4/25/2017 8:24 PM

They are talking about two totally different units. It started with the drain valve/cock but changed to the check valve which is in the high pressure line between the tank and the air suspension. One is a drain to release water and oil sludge from the bottom of the tank and the latter is a one way high pressure air valve. Ron is talking about the former and Thomas the latter.
Art

tcj-old

4/26/2017 2:05 AM

Hi Art,

you are right, I missed that Ron switched back to the drain valve[:)]

Thomas

112.021 300SEC
116.028 350SE
116.036 450SEL 6.9

Jack English

4/26/2017 3:10 PM

I am sorry; I'm the one who also asked about the check valve. Please return to drain valve.[8D]

Jack English
300SEL 6.3 #4768

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