brake MC vent hole?

[ol'westy]

Hello gang,
I recently noticed a very small puddle under my 74 westy. Crawled underneath to find fluid dripping out of a tiny hole in the master cylinder.

https://www.thesamba.com/vw/gallery/pix/thumbnails/1547296.jpg

Is that a vent hole or a pin hole?

The reservoir level has not dropped that much and I haven't noticed any problems braking, but any kind of brake fluid leak can not be good

Is it still safe to drive while I figure out the problem?

This will be my first foray into brake repair. Any suggestions about what to do next?

Thanks for your help!

[kreemoweet]

Hey, that's gotta be the tiniest pic I've ever seen posted on thesamba. Completely useless.

Yes, the ATE (and perhaps others, but not the Varga/TRW M/C) M/C has a vent/drain hole that leads to the
space between the two stationary piston seals:

A little bit of seepage out of that hole seems to be normal. My own M/C has been doing so for 15 years or more.
If it makes an actual puddle, well it seems you're due for a new M/C.

At least with that hole (and it not being plugged with road crud or undercoating or whatever), you'll not likely
fill up your brake booster with fluid.
_________________
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'68 bug: seized by the authorities
'71 kombi: not yet seized by the authorities

Stop dead photo links! Post your photos to The Samba Gallery!

[BayCreamPuff]

Your picture is too tiny to make out what's going on.

The MC has a weep hole where it mounts to the brake booster (servo). The hole is designed to keep fluid from leaking past the seal into the booster. If the seal fails your booster will be full of brake fluid which can damage the rubber diaphragm inside.

Any idea when the MC was last replaced? May be time for a new one.

My MC was weeping and the brakes felt fine. Turned out the MC had failed and the servo was slowly filling with fluid. I replaced both with ATE units from CIP1.

MC - http://www2.cip1.com/ProductDetails.asp?ProductCode=C24-211-611-021-AAGR
Servo - http://www2.cip1.com/ProductDetails.asp?ProductCode=VWC-211-612-103
_________________
Cream Puff
'79 CA Stock FI Deluxe Campmobile

Earl Grey
'87 GoWesty 2.2 Westfalia

Marsha Mellow
'00 Eurovan VR6 Full Camper

[BayCreamPuff]

Here's your full size photo from your profile. How long was the bus sitting? Also what is that blue zip tie for?

_________________
Cream Puff
'79 CA Stock FI Deluxe Campmobile

Earl Grey
'87 GoWesty 2.2 Westfalia

Marsha Mellow
'00 Eurovan VR6 Full Camper

[SGKent]

damp might not concern me but puddle means failed / failing master.
_________________
“Most people don’t know what they’re doing, and a lot of them are really good at it.” - George Carlin

[aeromech]

I'm no expert but I'm thinking the hole is there to indicate to you that the seal between the mc and the booster has a leak. Water cooled engines usually have something similar on the water pump. Time to change some parts
_________________
Lead Mechanic: San Diego Air and Space Museum
Licensed Airframe and Powerplant Mechanic
Licensed Pilot (Single engine Land)
Boeing 727,737-200-300-400,757,767
Airbus A319,320,321
DC9/MD80
BAe146
Fokker F28/F100
VW type 1 1962,63,65,69,72
VW Type 2 1971 (3 ea.) 1978, 1969
VW Jetta
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Capable of leaping tall buildings in a single bound

[ol'westy]

Thanks for the replies. Apologies for the tiny pic. I somehow stuck in the thumbnail instead of the actual photo. Doh! Thanks to BayCreamPuff for getting to the original.

Here is another shot of the entire MC from the side.

The blue zip tie was installed by a PO. I assume it is to keep that electrical wire snugged up.

The bus generally sits 2-3 weeks between trips.

So consensus is my MC is going bad? Is replacing it a job somebody with ten left thumbs can handle?

[aeromech]

A couple considerations. The hard brake lines that thread into the MC can corrode and when you go to remove they can twist off leading to more work. Best to use a flare wrench in M12 to carefully remove the lines. Next, fluid is going to spill so be prepared for that. Next, there are two brake switches screwed into the MC. These should be tested on the bench or maybe replaced because one can fail and you'll never know it until the other fails and then your brake lights don't work. Be sure to install a new o-ring between the mc and where it bolts onto the booster. You may want to clean up the corrosion on the booster where they meet so you get a good seal. Also, you might want to buy a new condom for the plastic fluid line that comes from above and connects to the lower reservoir. Be sure to also buy two new bungs that connect the lower reservoir to the new mc.
_________________
Lead Mechanic: San Diego Air and Space Museum
Licensed Airframe and Powerplant Mechanic
Licensed Pilot (Single engine Land)
Boeing 727,737-200-300-400,757,767
Airbus A319,320,321
DC9/MD80
BAe146
Fokker F28/F100
VW type 1 1962,63,65,69,72
VW Type 2 1971 (3 ea.) 1978, 1969
VW Jetta
VW Passat
Capable of leaping tall buildings in a single bound

[BayCreamPuff]

The job isn't terribly hard, but gets a bit more involved if you need to replace the booster or reservoirs. You will need to bleed the brakes after installing the MC. You will also need to bench bleed the MC before installing it.

If you don't already own it, buy the Bentley manual, or search for the PDF online. It will walk you through everything you need to do.
_________________
Cream Puff
'79 CA Stock FI Deluxe Campmobile

Earl Grey
'87 GoWesty 2.2 Westfalia

Marsha Mellow
'00 Eurovan VR6 Full Camper

[ol'westy]

Thanks all. I do have the Bentley book but have never done brakes before. Any specialized tools I should be looking to acquire or gotchas I should avoid?

[scrivyscriv]

[SGKent]

[ol'westy]

About to start some spring repairs on the ol girl so am bumping this thread. From all the comments it looks like a new MC is in the cards. Do I need to pull the MC before I can check if the booster has filled with fluid? If possible, I'd rather have all the parts I need on hand before starting.
Thanks for your help

[kreemoweet]

You do not need to replace the booster just because it has fluid in it. If the booster has been working OK, then just
mop out the insides when you change out the m/c.

You might be able to get some idea of what's inside the booster by pulling the vac hose and sticking in one of those
springy picker-upper thingies with a swab of absorbant material in the grabbers. Alternatively, you could just get a new
booster to keep on hand in case of sudden need. The day is not far off when those things may no longer be available,
or only so at the cost of an arm, a leg, and your left gonad.
_________________
'67 bug: seized by the authorities
'68 bug: seized by the authorities
'71 kombi: not yet seized by the authorities

Stop dead photo links! Post your photos to The Samba Gallery!

[ol'westy]

Hello bus fans!
I returned from an extended trip to find a big puddle of brake fluid under my bus and the upper reservoir nearly empty. I had had some small leaks before, so figured it was time to do the MC brake job I knew was coming. This was my first time at it, so I got out my Bentley and went slow. Here is my tale followed by a few questions.

Pulling the brake pedal cover revealed an ancient mouse nest composed of the cushioning from the back of my passenger seat! Cleaned that up, and refinished the inside of the pedal cover.

Removing the lower reservoir from the top of the Master Cylinder proved surprisingly difficult. It attaches to the MC by two ports on the plastic reservoir that fit into rubber inlets on the top side of the MC. Eventually used a couple pry bars to get the rear port free and drain as much fluid as I could out of the lower reservoir. By drain I mean spill all over me and the floor. Pulling the front port free was easier, but I still managed to drain most of the fluid down my sleeve.

The brake light harnesses came off easily. One of the spade plugs for the left brake light was bent. I had already planned to replace the wiring circuits, so no big deal.

Removing the MC itself was quite simple. It looked like my problem was a missing or disintegrated O ring between MC and vacuum booster. I may have been able to just replace the ring, but the old MC was pretty rusty and I had already bought a new one so opted to replace it.

Fortunately, the inside of the vacuum booster was dry so that was good news. The face of the booster around where the MC attaches had some light surface rust. I cleaned that up with some careful scrubbing with a red (purple?) 3M pad so the new O ring would get a good seal.

The brake light circuits do not come with new seals and Bentley says to reuse the old ones. When I removed them from the old MC, there were no seals to be found. One looked like it had the remains of Teflon tape, the other maybe some ancient SealAll. I used gas line Teflon tape to attach the new ones to the new MC.

Installing the new master cylinder was refreshing easy. The upper reservoir attached much easier then it removed. I was ready to bleed the lines.

Since I was working alone, I made up a pressure bottle from a Home Depot sprayer and gauge from an old tire inflator. I also made up a pressure cap for the upper reservoir. I put in 8-10 lbs of air to check for leaks before adding fluid and bleeding. All was well for about five minutes. Then my 44 year old original plastic upper reservoir cracked!

Ordered a new upper reservoir and decided to replace the lower reservoir as well. Removing the line between upper and lower reservoir proved impossible. After a hour of colorful language and banged knuckles, I finally cut the old line and ordered a new preformed one.

So now I have new upper and lower reservoirs and preformed line in hand and am wondering about that 180 degree bend in the line where it attaches to the lower reservoir. When the lower reservoir is on the MC, the inlet port to the preformed line points to the drivers side at a 90 degree angle, not 180.

Am I missing something? Do I have to modify the preformed line? Heat and bend it? Cut the end to 90? How do y'all deal with this? Also any hints for bleeding the lines with a pressure bottle? What pressure do you use?

Any helpful advice would be appreciated. The weather is improving and I'd like to get the ol' girl back on the road.

[Tcash]

So now I have new upper and lower reservoirs and preformed line in hand and am wondering about that 180 degree bend in the line where it attaches to the lower reservoir. When the lower reservoir is on the MC, the inlet port to the preformed line points to the drivers side at a 90 degree angle, not 180.

Is this for your 1974?

Can you post some pix of the lower reservoir and the preformed line?

Do you have a link to the parts you bought?

None of the following preformed lines have a 180* bend in them.

http://www.jerseylooker.com/FicheDump/LateBaywindow/LateBay-6.html
http://www.jerseylooker.com/FicheDump/LateBaywindow/051-10-6-011.jpg
http://www.jerseylooker.com/FicheDump/LateBaywindow/051-10-6-010.jpg
http://www.jerseylooker.com/FicheDump/LateBaywindow/051-00-6-009.jpg
http://www.jerseylooker.com/FicheDump/LateBaywindow/051-00-6-008.jpg

[Tcash]

This is what the 73-79 hose looks like.
http://www.germansupply.com/home/customer/product.php?productid=17443

[ol'westy]

Yes, this is about my 74 westy.

Here is a pic of the new and old upper and lower reservoirs and the fill lines between them.

and here is the link to the line I purchased from CIP...
http://www2.cip1.com/ProductDetails.asp?ProductCode=VWC-211-611-805-G

Looking at the pic it is pretty obvious I have the wrong line.

[Tcash]

You may be able to dip that 180 in boiling water and get it pliable enough to bend it into a 90* bend?

[ol'westy]

The whole line is longer than the old one, but with the proper application of heat and leverage I might be able to twist it into a usable shape. Boiling water is certainly worth a try before reaching for the plastic washer hose that some other sites have suggested! It's just a bummer that the right hose (GermanSupply) and the wrong hose (every where else!) have the same part number!