Can you tell my 85 300Dt sat for the winter (lots of posts). I apparently have a brake fluid leak, and that lower mounting rubber ring is all wet and the fluid is way low. Suggestions? How do I get at that thing? It's the tank by driver side dash.

Sorry, it's the brake fluid reservoir that is leaking, driver's side toward dash. Do I have to drain to get at a nut?

the resivoir is interferance fit into the grommets to the master cylinder, and yes it will leak out if you yank it off.

__________________
Proud owner of ....
1971 280SE W108
1979 300SD W116
1983 300D W123
1975 Ironhead Sportster chopper
1987 GMC 3/4 ton 4X4 Diesel
1989 Honda Civic (Heavily modified)
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Section 609 MVAC Certified
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"He who fights with monsters might take care lest he thereby become a monster. And if you gaze for long into an abyss, the abyss gazes also into you." - Friedrich Nietzsche

Just order two new grommets (for about $3 total) and yank that damn thing off and into a drain pan.

Replace the grommets, stick the reservoir back on, then do an engine wash with gunk or something that will remove the fluid. As long as you wash it off within about 10min there won't be a problem with spilling it.

__________________
1984 300D Turbo - 4-speed manual conversion, mid-level resto

1983 300D - parts car

1979 300TD Auto - Parts car.

1985 300D Auto - Wrecked/Parts.


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"If you don't know where you are going, any road will get you there". Lewis Carrol

Ah, so you just yank it off. All right, dumb question. But I obviously needed the help.

I just replaced my grommets last night and did a fluid flush with a power bleeder. Question - anyone know how far down the resivior is supposed to go into the grommets. Mine does not "bottom out", but does appear to be seated well and so far no leaking from that area. I could not get it to go any further down, and if I tried to first put the grommets on the resivior and then push it into the master cylinder it would not go - too tight.

Oh yea, I leaked fluid all over from using the power bleeder. I thought it was coming from the cap but maybe it was from one of those two test buttons. I read in another post that if fluid leaks out of one of those while using a power bleeder you can replace them?

__________________
'85 300D - 206K (sold)
'81 240D - 149K (sold)
'03 Jetta TDI - (sold)
'79 300D - (sold)

Is it necssary to bleed brake lines after brake fuid reservoir grommet replacement? I need to do the grommets, but I cant do the bleeding for several days. Will the grommet repair cause dangerous braking conditions?

Hard to say....becasue the potiential is always there...I would find the time adn do both...or delay it a few day when you can do both. To be safe.

__________________
Proud owner of ....
1971 280SE W108
1979 300SD W116
1983 300D W123
1975 Ironhead Sportster chopper
1987 GMC 3/4 ton 4X4 Diesel
1989 Honda Civic (Heavily modified)
---------------------
Section 609 MVAC Certified
---------------------
"He who fights with monsters might take care lest he thereby become a monster. And if you gaze for long into an abyss, the abyss gazes also into you." - Friedrich Nietzsche

I just minutes ago had similar issues as hockey nut. Brake fluid reservoir not totally seated, wont go if grommets put on reservoir first. Any tricks to the trade in regard to getting the reservoir to seat besides lots of wiggle? Screw driver, lubricant, etc?? Thanks for the previous reponse Doctor.

rblookc,

I have gone a few days now and it does not appear to be leaking around the grommets. I wish I would have looked closer at the old setup before replacing. I am now thinking the base does not have to be bottomed out, at least that's what I hope. I tried and tried to get it to go all the way down and it wouldn't go. Does anyone have experience with this?

__________________
'85 300D - 206K (sold)
'81 240D - 149K (sold)
'03 Jetta TDI - (sold)
'79 300D - (sold)

That's what I'm hoping; I never want to push a plastic part too hard.

Another question ... I dont really know the 617 brake system very well. The rear compartment in the reservoir is nearly full while the front compartment is at Min. How do I remedy that? The fill cap seems to fill rear compartment only. Does the system balance itself out? And what do those two buttons do?

- Brake Clueless

The rear section will overflow into the other section. Just keep adding fluid. The buttons are for testing the warning light on the panel.

The bottom of the reservoir should rest on the top of the rubber grommets. (ie: none of the pipe should be visible.) The grommets should be inserted into the master cylinder before the reservoir is installed. The service manual recommends installing the front pipe with the reservoir rotated 180 degrees from normal. Then rotate to proper position and insert rear pipe. Then it says "Watch out for perfect seat."

Well, I guess I'll have to take it out and try it that way. I'm just a little frustrated after working for a couple weeks doing odds and ends on my 240, plus I flushed the brakes on my 300 too. I have a new Motive power bleeder, which is nice but...on both vehicles it goes drip,drip,drip out of the black test buttons when pressurized. So, I have to hurry around the car doing the bleeding,. Oh well, things could be worse. Maybe I can get away without bleeding it this time

Thanks for the info - I'll see if I have some success that way

__________________
'85 300D - 206K (sold)
'81 240D - 149K (sold)
'03 Jetta TDI - (sold)
'79 300D - (sold)

That sounds familiar. I built my own power bleeder thanks to folks on this site. I replace both rear calipers, rotors, pads, and brake lines. Then I went to use my handy dandy power bleeder and brake fluid just poured out of those two cracked black buttons. What a mess!
My 8 year old daughter ended up helping me bleed my brakes.
"Now honey, push the pedal 3 times then hold it all the way down until daddy says OK". It was actually a great father daughter experience, and she LOVED helping dad.
My oldest daughter is in college and my son will be a HS senior next year. I don't have many more of those moments left.
I'll use the power bleeder another time.....


**By the way, will new black button-things keep these reservoirs from leaking?

__________________
Jimmy L.
'05 Acura TL 6MT
2001 ML430 My Spare

Gone:
'95 E300 188K "Batmobile" Texas Unfriendly Black
'85 300TD 235K "The Wagon" Texas Friendly White
'80 240D 154K "China" Scar engine installed
'81 300TD 240K "Smash"
'80 240D 230K "The Squash"
'81 240D 293K"Scar" Rear ended harder than Elton John