Brake fluid gone- no leaks UPDATE

[Raynor Shine]

I recently installed big brakes and brake mc. This week, the brakes make a horrible grinnding backing out of the garage. I immediatley know where to look. THe brake resevoir is dry. Fill it up, bleed brakes, everything is OK. THis morning I go out, just to check fluid level & its all but gone. I have no leaks around the van at all, not even the slave cylinder. I know it's going somewhere, but where?

Could the brake mc leak into the booster & it hold the fluid? I have no leaks at calipers or rear cylinders. Looks like I may have gotten a faulty brake MC but not sure. what do you all think?

Thanks

[r39o]

Bet it is in the booster or being sucked into the engine via the booster.

You sure you have NO leaks elsewhere????????
_________________
"Use the SEARCH, Luke" But first visit the Vanagon FAQ!

1990 Multivan EJ 22, Rancho trans 0.82 4th, Small Car front AC, CLKs w/ 215/65-16, homemade big brakes 303mm, Konis, Recaros, etc....

Click to see my ads for Cup holders, Subaru clutch fix and CLK wheels (no wheels currently)

[Raynor Shine]

r- thanks for the quick response, NO leaks that I can find. Everything is dry in the van & the brake parts too. Not even the plastic line to the clutch slave cyliner which I had problems with on a previous van. I wonder why would it be that much so fast? I was gonna replace the brake MC again. But need to get a new one first.

[r39o]

The booster is under vacuum from the engine. If the master is leaking into the boaster then it can get sucked into the engine. At least that is what I am told. Maybe you can see if the vacuum line to the booster in the engine compartment is wet? If wet, you know what is happening.

Now I gotta go look at mine because I have mentioned something!
_________________
"Use the SEARCH, Luke" But first visit the Vanagon FAQ!

1990 Multivan EJ 22, Rancho trans 0.82 4th, Small Car front AC, CLKs w/ 215/65-16, homemade big brakes 303mm, Konis, Recaros, etc....

Click to see my ads for Cup holders, Subaru clutch fix and CLK wheels (no wheels currently)

[Raynor Shine]

update- more confusion. So I bled brakes again today, wife help!, ran around brakes OK, but when I stop, I can hear a slight gurgling sound from behind the instrument cluster.
I let the van idle for a while & reved it & huge plums of white smoke pour out of the exhuast. Im talking Cheech and Chong somke. It stopped after about 2 minutes.
I think I have a falulty brake MC and the brake fluid is being sucked into the engine throught the brake booster as R390 mentioned. Would you agree?

[82WestyMan]

Though unusual, having the MasterCyl leak into the PowerBooster and into the engine is not unknown. Essentially 2 problems need to be happening for this to occur:

1 - The MC has to be leaking out the bore. The most common failure (in the automotive world) is a leak between the interior seals, bypassing the interior piston and back into the reservoir... ie - no pressure / sinking pedal but no missing fluid. They can also leak all the way down the bore and out the back. From there the fluid can go down the outside of the booster and/or into the booster. (Out = trashed carpets / big mess… IN = your problem)
2 - The PB has to be leaking also. There is a large rubber diaphragm inside the booster. Vacuum from the engine on the 'far side' of the diaphragm helps 'push' the pedal by letting air into the side closer to the MC, hence 'pushing' the pedal down. There needs to be a leak in the diaphragm also for the fluid to cross over to the 'vacuum' side.

It then can be drawn back to the motor by the vacuum from the intake side of the engine, thru the combustion and out the tailpipe as smoke.
The best you can do at this point is replace the MC & PB together. Just to make sure you have the brake fluid completely out of the vacuum side of the system, I would run water thru the entire vacuum line from the PB back to the engine, removing the check valve just on principle and cleaning that separate.
Brake fluid is pretty amazing stuff. petroleum based but water soluble but very hydroscopic, it can draw moisture into itself just thru the vent cap in the reservoir (since the rest of the system is closed), lowering its boiling point... the reason why you should change your brake fluid every couple of years.
_________________
"The floggings will continue until morale improves"
"I never did give anybody hell. I just told the truth and they thought it was hell" - Harry S. Truman
82 Westfalia - w/ a Raby 'Camper Special' engine

[?Waldo?]

Actually, when the pedal is not depressed there is a port that allows vacuum to both sides of the booster diaphragm. When the pedal is depressed, the vacuum to the MC side of the booster is blocked and a port to atmosphere is opened.

Andrew

[r39o]

You need a new MC.

I do not know if the booster is compromised. Using a spare from a junker wold be wise, but not strictly 100% needed.

Don't drive the van. Fix it!
_________________
"Use the SEARCH, Luke" But first visit the Vanagon FAQ!

1990 Multivan EJ 22, Rancho trans 0.82 4th, Small Car front AC, CLKs w/ 215/65-16, homemade big brakes 303mm, Konis, Recaros, etc....

Click to see my ads for Cup holders, Subaru clutch fix and CLK wheels (no wheels currently)

[Raynor Shine]

Thanks for all the input! The van will remain parked until the new MC comes. I have it mostly ready to be worked on, kinda bums me out that I put a new one in , I was second guessing using the DYANA model & should of trusted my instinct. I hate repeating jobs like a new MC.

Merry christmas.

[Raynor Shine]

yesterday I got my Brake MC out, the seal had been leaking into the brake booster!. I siphoned out almost a whole pint of the nasitiest black fluid I have seen from the booster. It also took me about 1 hr to dab out the rest with long pliers and cut up rags. Installed the new MC & bled. Not a difficult job, but the 13mm nut that holds the MC to the booster on right gave me a hard time. Now to re adjust the rear brakes!.

[Terry Kay]

News Flash---

It is almost certain that the brake fluid has compromised the diaphram of your current booster with the leaking brake fluid.

Knowing that the interior of any power brake booster has been soaked with brake fluid would require a replacement immediatly.
No sooner.
No Later.
You'll discover this one day very soon when the brake pedal goes to either hard as a rock ---or just goes away.

The rubber inside that chamber doen't like a brake fluid bath--and will fail.

It would be very wise & prudent move on your part to get a new booster in your Van ASAP prior to driving it.
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T.K.

[brooklynvanagon]

The failure mode should be no boost. How could the brakes go away? The metal rods won't dissolve.

[Raynor Shine]

Terry- I always dig your input, I was curious though based ont the age of these things & they way we all work on them, this can't be the first occurrance of this situation. I hope. Based on feedback from several sources( vw mechanics) I was told the booster almost never fails and to get as much fluid as I can out, which I did and replace the brake MC. But I am always concerned of something else failing. Have you seen this before?

THanks
Dave

[Terry Kay]

Dave,

Once the seal on any MC has been leaking into the booster, it's just a real good idea to replace the booster.

Well, let me say this--
It's a common sence thing to me, because , yes--I've had them fail shortly thereafter.

How long?

I had a 58 Pontiac's booster go in 2 days.
I've had cars / trucks go a month or two before losing the boost to the brakes.

From that point on I though it was a good idea just to bite the bullet and do the job right and replace them both.

Brakes are something I just don't wanna screw around with--no jippin' the job.

Way back when I used to have a booster press, and I rebuilt them.
( It's like carb, starter , generator, alternator rebuilding--a thing of the past--)
You'd be amazed at the garbage that is in the booster after they get a few years old.

And the parts to be replaced were just a new diaphram & a rail road car spring--- that's it.

The diaphram is what get's eaten up by the brake fluid, and will cause you to lose the boost to the brakes.
( the hose to the booster will get spongey too---if the fluid was getting sucked to the engine-- it's not a bad idea to take a look at the inside of that also)

For me to tell you your booster or hose is bad--or going to fail, is like me telling you I knew the Titanic was going to sink--

It's an iffy issue, and I sure wouldn's pass on replacing them, and I don't on my stuff or customer's.

Ya gotta have brakes all of the time.

I wouldn't have brought this up unless I knew it was the best way to handle this situation--honest.
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T.K.

[hiram6]

Be a shame not to get the full confidence and benefit of your brake system upgrades by not going fullbore and cutting a cormer on the MC and brake booster. Obviously you know the need for good brakes since you've upgraded to the big brakes package, so why not do it 100%?

Did you upgrade the flexible lines to the stainless braided?
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1985 Westy, 1.9L automatic (Daisy)
1996 Mazda Miata
1998 Jeep Grand Cherokee 5.9 Limited

You can't lie around on the beach and drink rum all day.................unless you start first thing in the morning.

[Captain Pike]

Ever peel up the carpet on a cronic clutch or master leak. The paint and the seam sealer melt from contact with this crap. It will attract moisture and rot out the booster from the inside, only a matter of time. Buck it up and replace it, Everyone on the road will feel better.
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LEARN TO SELF RESCUE
59 Panel bus, 1966 Single cab. 73' 181. 73 Westy. 91' H6 Vanagon 3.3L.
.....................All Current.......................

[Terry Kay]

<< Everyone on the road will feel better>>

A man with a worthwhile thought--

No crash,bang, boom.
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T.K.

[Randy in Maine]

I say drive it.

If the booster goes bad in a month or a few years, send it here:

H&R Auto Parts Rebuilders.
10328 Oakwood Drive
Dallas, Texas
75217

(972) 286-5516

They can rebuild it for cheap money (<$100) and quickly also.

[Terry Kay]

<<[quote="Randy in Maine"]I say drive it.>>

Big gonads with somebody else's ride.

<<If the booster goes bad in a month or a few years, send it here:>>

Be sure and call 1-800-InsurYu to cover the folks your gonna wack just as the booster fails.

Good idea--

Fix later what could right today.

Brilliant.

You change your oil after the engine blows up ?
Install brake pads & shoes after you wack another vehicle ?
Buy tires after they blow out one by one?
Change the wiper blades when you can't see outa the glass no more?

I like your concept in frugality--I just hope I am no where near your ride---
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T.K.

[Ron Mueller]

I would have to agree that changing the brake booster after it was soaked in brake fluid would be the wisest decision.
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Ron