Oh crud... Urgent help needed in San Diego! - Page 3 - PeachParts Mercedes-Benz Forum

tangofox007 · #31 01-01-2014, 01:48 PM

Quote:

Originally Posted by sixto

Is this it?

That's it. I didn't want to post that myself, as Tommy W would surely have accused me of having done a Photoshop job on it.

Bio240D · #32 01-01-2014, 02:02 PM

You beat me to it! But here is a pic of the weep hole on the 83 240D just for supporting evidence!

Cheers and Happy New Year Everyone!!
Chris

tangofox007 · #33 01-01-2014, 02:11 PM

Quote:

Originally Posted by Bio240D

You beat me to it! But here is a pic of the weep hole on the 83 240D just for supporting evidence!

Just in case Tommy W asks, could you furnish a sworn affidavit stating that you did not drill that hole yourself?

Bio240D · #34 01-01-2014, 02:16 PM

I will absolutly provide, in triplicat, a sworn affidavit stating I did not drill that hole!

t walgamuth · #35 01-01-2014, 03:34 PM

Quote:

Originally Posted by sixto

Is this it?

From - Testing Brake master cylinder - Pelican Parts Technical BBS

Sixto
87 300D

That picture is of a Porsche I believe.

t walgamuth · #36 01-01-2014, 03:36 PM

Quote:

Originally Posted by Bio240D

You beat me to it! But here is a pic of the weep hole on the 83 240D just for supporting evidence!

Cheers and Happy New Year Everyone!!
Chris

It looks like I can see the bottom of this hole. How can that be a weep if we can see the bottom of it? Also if there is a seal between the MC and the booster, which I seem to remember is an o ring, what purpose would this serve? ...and why do people's boosters fill with brake fluid if there is this weep for a leaky mc to leak out of?

Hey if I am proven wrong here I will pay up, you don't have to call me Tommy.

ROLLGUY · #37 01-01-2014, 03:45 PM

Quote:

Originally Posted by t walgamuth

It looks like I can see the bottom of this hole. How can that be a weep if we can see the bottom of it? Also if there is a seal between the MC and the booster, which I seem to remember is an o ring, what purpose would this serve? ...and why do people's boosters fill with brake fluid if there is this weep for a leaky mc to leak out of?

Hey if I am proven wrong here I will pay up, you don't have to call me Tommy.

I have the same question. I am sure the hole is not between on the vac side, or vac would leak. If the hole were in between the vac and the MC piston, would not moisture get in there (brake fluid attracts moisture)? There also seems to be fluid leaking from that area on most all boosters I have seen, so does that mean the leak is from that hole?

t walgamuth · #38 01-01-2014, 03:50 PM

OK, I looked In the garage for a master cylinder but only found two clutch masters.

Then I looked in my books and found both the seals previously mentioned and the weep hole, which they call a leak hole.

So it looks like I lose. Tangofox, do you take paypal?

I still don't understand then how boosters manage to fill with brake fluid....?

The Leak (weep) hole is a two stage affair with the inner hole not much bigger than a needle and the outer bigger, maybe 1/16" which explains why it appears to have a bottom in the above picture. Perhaps also explains why it might plug up?

I just saw the above post by roll guy and I think I know the answer to his question. There is a pair of seals sealing the stem of the mc and the weep is between them so the outer seal is for brake fluid or perhaps is to keep out moisture from the air and the inner seal is for vacuum. If the brake mc seals fail the fluid passed will (theoretically at least) come out the weep hole (if its not plugged).

ROLLGUY · #39 01-01-2014, 03:59 PM

Quote:

Originally Posted by t walgamuth

I just saw the above post by roll guy and I think I know the answer to his question. There is a pair of seals sealing the stem of the mc and the weep is between them so the outer seal is for brake fluid or perhaps is to keep out moisture from the air and the inner seal is for vacuum. If the brake mc seals fail the fluid passed will (theoretically at least) come out the weep hole (if its not plugged).

That makes sense, thank you. I am glad I did not take part in that bet!

t walgamuth · #40 01-01-2014, 04:06 PM

Its tricky.

Without the drawing I found I did not understand what I was looking at, and I never noticed the little weep hole. The seal is not on the actuating rod but is on the cup apparatus it goes into.

I suspect the weep holes may mostly be dysfunctional as I have never noticed any moisture coming from them.

Bio240D · #41 01-01-2014, 04:07 PM

Regarding the brake booster filling up with brake fluid when the mc fails:

Consider what would happen if the seal on the brake booster push rod was leaking a little bit of vacuum, and it wouldnt need to be much, we would have air being sucked INTO the weep hole continiously. This would take any leaking brake fluid into the booster rather than letting it come out the weep hole. I'm pretty sure this is what actually happens.

Cheers
Chris

t walgamuth · #42 01-01-2014, 04:21 PM

Quote:

Originally Posted by Bio240D

Regarding the brake booster filling up with brake fluid when the mc fails:

Consider what would happen if the seal on the brake booster push rod was leaking a little bit of vacuum, and it wouldnt need to be much, we would have air being sucked INTO the weep hole continiously. This would take any leaking brake fluid into the booster rather than letting it come out the weep hole. I'm pretty sure this is what actually happens.

Cheers
Chris

I can see that but when the engine is shut off it would drain, If not plugged.

I am thinking that the two seals on either side of the weep fail as quickly as the braking seals, the weeps plug and then any leak goes straight into the booster.

Adriel · #43 01-01-2014, 04:57 PM

Apparently DoT-5 is no longer available except online... Grrr...

Looks like I could get it in on Friday via Amazon... However, I am confused! What brand: North American, Bel-Ray, or Mogul? Or, does it matter?

How much do I need?

BWhitmore · #44 01-01-2014, 05:03 PM

The brand does not matter. I would recommend 1 quart at least because you will need to bleed the brakes. All brake fluid is DOT approved.

Adriel · #45 01-01-2014, 06:04 PM

Quote:

Originally Posted by BWhitmore

The brand does not matter. I would recommend 1 quart at least because you will need to bleed the brakes. All brake fluid is DOT approved.

Well, the P.O. apparently wasn't clear, and what he meant was DoT-4. I have DoT-3 which will work for now.

Got to eat, then will consider doing the bleed.