Water Drains - Summary Attempt

[mauro12]

Thanks Pawel once again . Is still not clear 100% Why mercedes designed this drain holes, especially the way to let water pass inside the cabin from the air scoop and out again . It’s obvious that if you don’t have good and fresh hoses you will end up with a pool in your front carpets . I think I will buy a plug to avoid water passing into the drain hole near the wiper motor . I’m sure during an heavy rain , water could take that direction and for gravity could go into that hole which is connected to the passenger floor.
I have another question , the drains in the soft top compartment are covered by some factory plugs ? I didn’t understand well how the water is conducted outside the compartment . Maybe if you have some pictures . By the way the best option is to keep the car away from any rain. The only way to fight corrosion is a good storage and as less rain as possible . This is my personal opinion .

[Pawel66]

Mauro, the hole you indicated on your photograph, if it goes to the cabin indeed (I just do not remember it now), is probably not a drain hole. I saw it plugged on practically all photographs of working cars I have seen.

The holes under the coolant tank and under the booster - they go to cavities underneath and then water is supposed to go out to the wheel arches through the openings indicated in pdf. Some Members recommend to plug them. I did. But I injected cavity wax there first.

On the soft top compartment - the drain holes are equipped with hoses. These hoses go to the cavity near B-pillar. Then water drains out through the holes in the door sills under the B-pillar. You have all of it shown in the pdf, but I am attaching them below.

The useful plug is A0009973320, e.g. for the hole you showed on your picture.

[sandcrab59]

I just checked my 71 280SL and there is a rubber plug in the hole.
It had to be placed there at the factory during production.
Tom

[mauro12]

I think I will plug this hole . Probably it was done to pass some wires .
About the soft top compartment , here I send you my picture . The drain hole is in the left part on the top but I’m trying to understand what is this other hole marked is red . The plug is cracked and I have to replace but Is it a drain hole too?

[Pawel66]

I do not think it is a drain hole. The plug no. for it is, I cannot figure out now:

A 000 997 40 20 CAP IN FOLDING TOP CASE BOTTOM SIDE PART, FOR DETENT HOLE; 30.5 MM

or

A 113 683 01 10 CAP IMMERSION-PAINT HOLES

Sorry, just do not remember which one... I would buy both. You need 2 pcs for either of the PN. I think you will find the other one a bit deteriorated most likely and willingly replace it .

Those that go into that hole are nice looking with Mercedes tiny logo. Worth having them original. They are not expensive.

[mauro12]

This rubber plugs in the soft top compartment are drain holes too? What is their function ?

[Pawel66]

Well, the rubber plugs are to plug the holes, certainly not the drain holes. One pair is to plug the holes you marked, the other is to plug some other holes. One pair of the holes, as per the plug description is for paint to get to certain parts of the chassis during the immersion painting process. The other pair is to plug the holes made for some other purpose. There are several purposes the holes are made in the chassis - they are technological holes - for painting process, for installation of something, for rust protection application, etc.

[mnahon]

Hi Pawel,

I have one to add to your list that I discovered only recently. It's the front analogue to the one that's just behind the door, underneath the rocker cover. This one is just ahead of the door, underneath the rocker cover. Picture attached. It's a slot, rather than a hole, and it's intended to drain the cavity that's just behind the front wheel. Rust in this cavity often leads to rust at the front of the rocker or on the lower firewall behind the front wheel.

Meyer

[Pawel66]

Thank you! Amended pdf enclosed.

[Peter van Es]

Pawel,

had you added it to the Tech Manual you could have updated it there each time... https://www.sl113.org/wiki/ChassisBody/Drains

Could you have a go?

Peter

[Pawel66]

Peter, I stay away from loading anything there as I do not feel qualified enough. But if this one is worth it, I will, certainly.

[mBdrvr]

There is a Service Information Bulletin from 1967 on this subject for 600's but will apply to our cars on page 2 located here:

http://maxacars.com/MB%20FILES/Group%2060-81%2084-89%20Body%20Part%20C.pdf

[Peter van Es]

Peter, I stay away from loading anything there as I do not feel qualified enough. But if this one is worth it, I will, certainly.

Trust me, you are qualified enough. And remember, if you put it up on the Wiki, others can easily help out and correct mistakes...

[mauro12]

I blow compressed air from the drain hoses in the soft top compartment , they are free but I could feel any air escaping from the underside of the car . Maybe the route of this drain tubes is too long to feel the air out .

[Pawel66]

Trust me, you are qualified enough. And remember, if you put it up on the Wiki, others can easily help out and correct mistakes...

Thanks! I did put it in!

[Pawel66]

I blow compressed air from the drain hoses in the soft top compartment , they are free but I could feel any air escaping from the underside of the car . Maybe the route of this drain tubes is too long to feel the air out .

mauro, 3 points:

- you may want to insert longer hose with air into the drain rubber hose; it leads to that chamber you see on the picture, so yes, there is quite some space there
- you may pour some water to see if it is coming out
- they way to closely examine this is to either dismantle the upholstery inside to see part of the rubber hose and make sure it goes through the pillar out and/or to remove the rocker sill cover to see the holes in the sill

[Peter van Es]

Thanks! I did put it in!

I see it. However, I meant for you to put it in there not as a pdf, but as text and individual pictures. That way it becomes searchable, and editably by any full member. I realise that will take a bit of study, but that's the whole intent of the Tech Manual.

[Pawel66]

Ok, will give it a try, thank you!

[mauro12]

Is quite curious why Mercedes didn't do this drain hole with a direct connection from the hole itself and the underside of the car . Instead of this , the rubbers hose discharge the water into this compartment and after down to the hole . This could create rust from the inside out . To inspect this you have to cut the car . I’m scared to put water and try . Maybe with a flash light you can see if the light is coming in the underside .
Compressed air is not enough .

[Pawel66]

I am not sure which place you are describing. Rubber hoses are there between the air scoop and outside of car at the firewall. So they lead water out of the car. The holes on flat surfaces near the coolant tank and brake booster lead to box area, from where water runs out through outlets in the wheel well - out of the car. The hole near wiper motor is, most likely not a drain hole, should be plugged. Which place are you referring to?

[mauro12]

I’m referring about the drain holes from the soft top compartment .

[mnahon]

Mauro,

I've also never liked the idea of letting the water get dumped from the softtop compartment into the body cavity; too many things can go wrong. But it's clear the Mercedes engineers expected water to get into places that it should not be---this is why there are drains everywhere. I continue to believe that many of our cars rust due to repairs or restorations in which the drains end up getting plugged.

If you want to visually see whether your drainage is working properly, you'd have to remove the upholstery cover behind the B-pillar; and remove the black rocker cover on the outside. You have to check (a) whether the tube from the softtop compartment is there and properly directed; and (b) whether the drain hole in the body cavity is indeed free and clear to let the water drain. You won't be able to do this using a flashlight with the car fully assembled.

Here's my solution to the softtop drain problem. I've extended the tube from the softtop drains to bottles under the parcel shelf. As long as your softtop cover seal is in good condition (to minimize the amount of water that ends up in the softtop compartment), this is effective. You just need to empty the bottles occasionally if you drive in the rain, and the parcel shelves are easily accessible.

[Pawel66]

I’m referring about the drain holes from the soft top compartment .

I see!

Well, agree it is not the best solution. You have the advise from mnahon, I also wrote about it in one of the previous posts. It is not very difficult to remove upholstery and it is not difficult to remove the rocker panel cover. It definitely is worth the effort of checking if this water passage is not clogged, in my opinion.

Last winter I had my car on the lift all winter to go through this type of maintenance: check all the drain holes (and I drilled, actually, a couple of them that I had missing) and wax all the cavities and closed profiles (there is a MB maintenance brochure on that here). Even if you drive in the sun only - you wash your car, you may be caught by rain and also moisture is forming in the cavities - water will always have a chance to get there. 

[mauro12]

Well it seems not so easy to my ability . Where do you put cavity wax in your car ?

[Pawel66]

In essence as per the attached pdf.