I just repaired the leak in the fuel door lock actuator on my 300CD. A new actuator is about $45 and they're difficult to find in stock anywhere.

I did some searching and found a part number for replacement diaphragms.

BOSCH part no. 3 340 522 025 - $1.92 each

These seem to be made better than the original diaphragms. I bought ten and with the cost of shipping, still paid less than one new actuator.

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Chad
2013 Jeep Unlimited Rubicon
OBK#44
"Pleasure in the job puts perfection in the work." - Aristotle (384-322 B.C.)

SOLD
1985 300TD - Red Dragon
1986 300SDL - Coda
1991 - 300TE
1995 - E320
1985 300CD - Gladys
2006 Nissan Pathfinder LE
1998 Acura 3.0 CL

See Pic. Is the part that the Arrow points the part that you replaced?
A nice Fix.

If so I think that is what is wrong with My Door Vacuum Actuators except that there is parts crimped on above them that keep you from changing the Rubber Sleeve (diaphragm).

I have not gotten around to checking the Trunk of the Fuel Door Actuator (Pictured)

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84 300D, 82 Volvo 244Gl Diesel

That's great info. I was told a while ago the diaphragms weren't available anymore. Glad to know they are.

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Mac
2002 e320 4matic estate│1985 300d│1980 300td
Previous: 1979 & 1982 & 1983 300sd │ 1982 240d

“Let's take a drive into the middle of nowhere with a packet of Marlboro lights and talk about our lives.” ― Joseph Heller, Catch-22

How did you know you had a leak?

Ten?! Don't you think that is hoarding?

__________________
Current fleet:

1985 Mercedes-Benz 280TE - Waiting for heart surgery.

1985 Mercedes-Benz 300TDT - Rear ended 23 September 2016 and now looking for a new home.

1979 Mercedes-Benz 300TD - Parted out.

1964 Volkswgen Beetle - Vater's since September 1968 and undergoing a restoration.

1971 Volkswagen Sunroof Squareback with F.I. - in need of full restoration.

1971 Volkswagen Squareback automatic with F.I. - Vacationing with her caretaker until he is in better health.

Ten is not hoarding!!! Chad owns 3 old diesel MBs. I own 4 (oops, 5, counting the Ponton). I probably could use ten in a week. My current project (in the garage) has multiple leaks, so, there goes 4 (maybe more). I'm hoping this same diaphragm is used on the trunk. What about the fuel door? If so, then that's 6 on every vehicle Chad owns and I own.

So, Chad. Is the diaphragm the same for the trunk, door locks, and fuel door?

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daw_two
Germantown, TN

Links:
Sold last car --- 05/2012 1984 300D Light Ivory, Red interior
No longer selling Cluster Needles Paint
No longer selling New Old Stock (NOS) parts

Past:
3/2008 1986 300SDL "Coda"
04/2010 1965 190D(c) "Ben"
& many more

The diaphragms are inside the actuator. Those parts are seals for the actuator rod.

How do you replace them and where did you get them?

I had a dead door lock pod so I bore it open to see what's inside and where it was torn. Those diaphragms inside do not seem to be replaceable even if you cane crack theme open

That's the piece.

The car started having trouble shutting down and the door locks started to not work properly. I tested everything and it lead me to the fuel door actuator, which I just blocked off until the new pieces arrived.

On my cars they are the same, but I've seen several styles of fuel door actuators and I've seen an older design of the door actuators in w123s as well.

My wagon uses 5 of these and the CD uses 3. I've already had a new actuator get leaks in this piece too, so I wanted to keep a few extra around. It's a quick and easy fix when you have the parts on hand.

I bought them from Rock Auto. I've seen two styles of clamps on the rods. One is a large black plastic piece that the outer section pulls off the inner section. Pushing it down clamps it to the rod and locks the two parts together. The other is a white milky plastic piece that has a clip that pushes on from the side.

Both are removable and allow replacement of the seal/diaphragm. The new seal goes on easier with a bit of lube. I used 303.

__________________
Chad
2013 Jeep Unlimited Rubicon
OBK#44
"Pleasure in the job puts perfection in the work." - Aristotle (384-322 B.C.)

SOLD
1985 300TD - Red Dragon
1986 300SDL - Coda
1991 - 300TE
1995 - E320
1985 300CD - Gladys
2006 Nissan Pathfinder LE
1998 Acura 3.0 CL

For those heading to a jy to pick up a few of those, take your mityvac with you and check before you take them off. Cut the line going to whichever one you are heading to, left rear gets the least work, and check it. Never fun to pop a part and then find its bad.

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1985 300D 198K sold
1982 300D 202K
1989 300E 125K
1992 940T

"If you dont have time to do it safely, you dont have time to do it"

"The democracy will cease to exist when you take away from those who are willing to work and give to those who would not."

I am new to all this, so thank you all for your help!

I figured it be a vacuum leak, but wasn't sure how noticeable. Interesting it was so.

Where else are they used?

You bought these parts from Rock Auto? Or, the other part?

Thank you!
Adriel

__________________
Current fleet:

1985 Mercedes-Benz 280TE - Waiting for heart surgery.

1985 Mercedes-Benz 300TDT - Rear ended 23 September 2016 and now looking for a new home.

1979 Mercedes-Benz 300TD - Parted out.

1964 Volkswgen Beetle - Vater's since September 1968 and undergoing a restoration.

1971 Volkswagen Sunroof Squareback with F.I. - in need of full restoration.

1971 Volkswagen Squareback automatic with F.I. - Vacationing with her caretaker until he is in better health.

yep. It will not fix the leak. Time to go shopping again.

The diaphragm should be rectangular shaped.

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85 300D turbo pristine w 157k when purchased 161K now
83 300 D turbo 297K runs great. SOLD!
83 240D 4 spd manual- parted out then junked

If it's the shaft seal that's leaking, it should fix it.

A leaking diaphragm is another matter.

I have pulled a bunch of the door actuators in the yards. 9 out of 10 are usually good. I don`t take a Mity vac with me, I pop off the door panel, remove 2 8mm screws, pull off the 2 vac lines and pop off the rod.

Suck on either one of the 2 vac lines and if they hold vac will, hold your tungue to it.

I took one apart to see how the innerds were put together. seems like the 2 halves were just snapped together and I pryed them apart. (Don`t have one in front of me at the moment) the rectangle diaphram had a small crack from years of use and heat etc...

the rubber piece the rod goes through at the top doesn`t seem to be replaceable because of the way the plastic piece the rod snaps into if fixed to it. don`t think it can be taken apart to be reused to work.
usually what I have seen is the rubber cracks at the rod.

Chad, this is a good tip and if they work for the trunk and fuel door, this is a good cheap DIY repair.


Charlie

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there were three HP ratings on the OM616...

1) Not much power
2) Even less power
3) Not nearly enough power!! 240D w/auto

Anyone that thinks a 240D is slow drives too fast.

80 240D Naturally Exasperated, 4-Spd 388k DD 150mph spedo 3:58 Diff

We are advised to NOT judge ALL Muslims by the actions of a few lunatics, but we are encouraged to judge ALL gun owners by the actions of a few lunatics. Funny how that works

Yeah Charlie, now that you mention it, I do remember when I bought my first 300D T a long time ago, one of the very first thing I did was to fix the truck lock vacuum actuator. I remember taking the vacuum motor apart and used wet suit urethane repair adhesive (Aquaseal) on a punctured diaphragm. It is still working fine to this day.

__________________
85 300D turbo pristine w 157k when purchased 161K now
83 300 D turbo 297K runs great. SOLD!
83 240D 4 spd manual- parted out then junked

I brought my mity vac to the yard and the 300D I found all of the door lock diaphragms were bad. None would hold vac in either lock or unlock. What other models use the same door lock pods? just the 123?