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19BUG70 Mon Nov 17, 2014 9:42 am

I worked on my brakes this weekend replacing the rear cylinders and brake shoes. I noticed when I was done that there was a leak near the brake booster (see pic) - there is no brake fluid in the reservoir right now so I am assuming after reading some threads on here it is backing up through the master cylinder. Does that sound right? Any advice on my next step?


merlinj79 Mon Nov 17, 2014 9:59 am

It looks like the MC is probably leaking past it's internal seals, which will flood the brake booster and destroy it's internal diaphragm.

But there's also some kind of fluid leak in the upper left of the picture, on the torsion housing tube. That is probably a leak from the reservoir, the tube from the reservoir to the MC, or both.

You'll need a new or rebuilt MC, a new or rebuilt booster, and probably the supply tube to the MC.

If it hasn't been soaking for long, it's remotely possible that you could flush out the booster to remove the brake fluid and see if it still works. But odds are good the diaphragm is toast, or will be soon.

kreemoweet Mon Nov 17, 2014 10:01 am

Which reservoir is empty? The upper one or the one on the M/C? If that's actually brake fluid on your booster,
you have a massive leak from the front seals on your M/C. The booster would have to be at least 1/2 full of
fluid (or have a holed main diaphragm) for brake fluid to be coming out the front like that. Bad News! You probably
need a new M/C and will have to remove and clean out and test the booster.

19BUG70 Mon Nov 17, 2014 10:21 am

kreemoweet wrote: Which reservoir is empty? The upper one or the one on the M/C? If that's actually brake fluid on your booster,
you have a massive leak from the front seals on your M/C. The booster would have to be at least 1/2 full of
fluid (or have a holed main diaphragm) for brake fluid to be coming out the front like that. Bad News! You probably
need a new M/C and will have to remove and clean out and test the booster.

The reservoir behind the drivers seat.

FYI - When I replaced the rear cylinder (passenger side) that had a pretty good leak. Also, none of this is surprising as the bus sat for almost 20 years.

Tcash Mon Nov 17, 2014 10:50 am

http://www.karpspowerbrake.com/

http://www.busdepot.com/j18100

merlinj79 Mon Nov 17, 2014 11:05 am

19BUG70 wrote: Also, none of this is surprising as the bus sat for almost 20 years.

In that case you might want to replace all of the brake lines as well...the steel ones might be rusted from the inside from moisture buildup due to not being flushed with fresh fluid. May depend on where it was stored.

At the very least, do an impromptu hydrostatic test...have a big strong guy press and hold the brake pedal as hard as he can to see if anything ruptures or balloons.

Obviously the rubber brake hoses are probably overdue as well.

19BUG70 Mon Nov 17, 2014 11:47 am

Tcash wrote: http://www.karpspowerbrake.com/

http://www.busdepot.com/j18100

Thank you - in reading other threads it looks like a rebuilt one is approx. $180 vs $280 for a new one. I'd like to save $100 but is that a good idea? In the whole scheme of things by the time I get the brakes in good shape $100 isn't going to seem like much. :D

merlinj79 Mon Nov 17, 2014 11:59 am

19BUG70 wrote: Tcash wrote: http://www.karpspowerbrake.com/

http://www.busdepot.com/j18100

Thank you - in reading other threads it looks like a rebuilt one is approx. $180 vs $280 for a new one. I'd like to save $100 but is that a good idea? In the whole scheme of things by the time I get the brakes in good shape $100 isn't going to seem like much. :D

I've been running a rebuild with no trouble for about ten years, but that was all that was available then. Assuming the rebuilder uses quality soft parts, the OEM hardware should last a very long time.

Tcash Mon Nov 17, 2014 12:05 pm

Look around. Can't find it right now, but there is one without the vent boot that is less money.

http://www.wolfsburgwest.com/cart/DetailsList.cfm?ID=211611905

19BUG70 Mon Nov 17, 2014 1:33 pm

I see the busdepot has two brake boosters. Any thoughts on if the more expensive one is worth it? I see you have to drill some holes on the more expensive one for it to fit.

http://www.busdepot.com/vw/0/0/22/0/1122

They also have a master cylinder for $199. There are lots of hoses/brands to choose from, I would appreciate any feedback on these if some are better than others. I appreciate the responses so far, thanks.

It's always nice to be able to place one order rather than several from different vendors, so far the items I have received from busdepot in the past have worked out ok.

jtauxe Mon Nov 17, 2014 1:37 pm

There was a thread about that WW one, finding a lot to be desired.

The one from BusDepot (also available at Just Kampers, where BD imports it from) is a Varga unit, built for VW in Brazil for Brazilian buses. It seems to be the real deal, though it requires modifying the mounting plate on the front beam for a different hole spacing.
http://www.busdepot.com/j18100
http://www.justkampers.com/211-612-103-g-brake-servo-vw-t2-1971-1979.html

Has anyone tried that?

Here are some options from VW Heritage:

Looks like this one is ATE from Germany, and priced to suit:
https://www.vwheritage.com/shop/211612103/brake-servo-68-79-studs-72mm-apart-ate-or-use-103-g/

This looks like the same Varga unit from Brazil sold by JK and BD:
https://www.vwheritage.com/shop/211612103G/brake-servo-vw-brazil-studs-89mm-55mm/

and the same thing with the MC installed, which could be handy:
https://www.vwheritage.com/shop/211612103GC/brake-servo-master-brazil-studs-89mm-55mm/

So, the Brazilian ones require modification of the mounting plate. Has anyone done that?

Does that expensive ATE unit fit on the late bay mounting plate without modification? That is, do these buses have stud holes at 72 mm x 72 mm? If so, it seems like that is the way to go, if money is no object.

kreemoweet Mon Nov 17, 2014 2:51 pm

The ATE part will fit all US bay busses as far as the mounting studs go, but I'm pretty sure its the larger-diameter (9 1/4 in.)
booster used from mid-74 to 79. It will definitely interfere with the parking brake cable on a '71. I don't know about
a '72, or what would be involved in making it fit. The same problem might arise with the Brazilian/Varga unit.
The vendor should be able to tell you the size.

As far as I know, there are only 2 posters in this forum who have shared their experience with the WW booster (and the "aftermarket" booster from Bus Depot may well be the same item): my own not-so-good review and another fellow who said he had
"no problems" with it.

What I would really like to know is where the booster "rebuilders" are getting their parts.

19BUG70 Mon Nov 17, 2014 6:04 pm

I contacted the seller on this item for the master cylinder.

http://www.thesamba.com/vw/classifieds/detail.php?id=1563576

Tcash Mon Nov 17, 2014 6:53 pm

Read the notes.
http://www2.cip1.com/ProductDetails.asp?ProductCode=C24-211-611-021-AAGR

19BUG70 Mon Nov 17, 2014 8:24 pm

Tcash - thank you. Seems like a simple change although I don't know what the different reservoir does. Maybe it's better to order one that uses the standard reservoir.....

This is new to me so I appreciate the help and advice. I certainly want to buy the correct parts to begin with. That's usually the hardest part.

Tcash Mon Nov 17, 2014 8:40 pm

You have a 72, that has some one year only parts. You may need to use the 73-79 master cylinder.
This may be the easiest site to use.
http://www.wolfsburgwest.com/wolfsburg_new/brakes/bus_brake/brakes_bus.cfm?type=2

Good Luck
Tcash

1967250s Mon Nov 17, 2014 8:49 pm

Looked at usual suspects, BD, GS, CIP, can't find MC repair kit, anyone know of one?

Wasted youth Tue Nov 18, 2014 12:12 am

FWIW, I had my 1977 bus brake servo/booster unit sent out to Karp's Power Brake last spring, and they did an excellent job. Totally worth it, and have great customer service.

19BUG70 Tue Nov 18, 2014 9:15 am

Tcash - great info as usual, what a great chart for reference. My initial thought is to send the booster to Karps for a rebuild, however buying parts from WW is really easy and I could order it all including the master cylinder at one time.

As far as the actual work of taking apart and installing the new pieces does anyone have any suggestions or things to look out for from their past experience? I do have the Bentley book...

kreemoweet Tue Nov 18, 2014 10:31 am

That note from CIP1 about the reservoirs makes absolutely no sense, and is surely incorrect. There is only a single master
cylinder for all 71-79 busses with boosters. The main reservoir is different depending on where the upper refill reservoir is located
and how the feed line is routed, but they all fit into the M/C the same way.



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