Power bleeder needed for Master Cyl?

[mr matt]

As my 55 bug has front disc brakes, and the MC just quit, the MC needed for this setup is a split window bus MC.'

Bought one from WolfW, and they state:

"BRAKE MASTER CYLINDER, fits through 1966 Bus. **PLEASE NOTE: A power bleeder must be used when installing this master cylinder. This is necessary to fully evacuate air from the unit."



I take it to mean MC must be on the car(?). In the past for other MC's for my other VW's, I always bench bled the MC.. but it is not feasible with this MC?

Also if you use a power bleeder, does the brake pedal have to be pushed and held down while bleeding the brakes?

This is what I bought this in case if I need it to do this job...

MC link if helpful... https://www.wolfsburgwest.com/cart/DetailsList.cfm?ID=211611011J

Thanks in advance!
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1955 3-fold semaphore Oval beetle
1971 Convertible beetle
1977 Westfalia, FI, Berlin interior

[RLFD213]

I have had good luck with bleeding as follows. Fill the whole system and gravity bleed it. Just open all the bleeders and as one starts to run fluid shut if off until all 4 have had fluid coming out. Then adjust the brakes and do some pedal pushes with an assistant and bleed it normally. I don’t bench bleed masters and don’t use a power bleeder.

['64cal lookdub]

[Who.Me?]

[CanStan]

I have an Amazon pneumatic bleeder like that. But it’s smaller with less attachments and 1/2 the price. I’ve used it a bunch of times and it works great! It more or less does the same as the gravity bleed mentioned above, just a lot faster. You’re also limited by how big your compressor is. It will drain a smaller air tank pretty quickly. Overall, I’d say it’s well worth $20-$30, even if it’s the kind of tool you only use once every year or 2.

No need to push the pedal, and I’ve never needed to bench bleed the M/C.

[Bobs67vwagen]

I bench bleed the master, install it, and then bleed each wheel with a mighty vac vacuum bleeder. I would try that method first before using a power bleeder. Good luck-Bob

[mr matt]

Thanks all, so it seems at least with mechanical bleeders, you do not need to push the brake pedal at all..

Much appreciated!!
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1955 3-fold semaphore Oval beetle
1971 Convertible beetle
1977 Westfalia, FI, Berlin interior

[BulliBill]

I've got the Type E Motorsports front disc brakes and stock rear drum brakes on my '67 Campmobile, and I absolutely love the addition of the disc brakes! Okay, on to my brake old brake fluid flushing/new fluid bleeding process...

First off, re-adjust all four of your drum brakes or just the rear drums if you have front discs too. Read about how to adjust drum brakes elsewhere. Adjust your e-brake cables while you are at it too! And how long ago was it that you replaced all four of your rubber flex brake lines? If you don't remember or it's been over five years or so since you last replaced 'em, do that now too! They always look okay on the outside, but they are swelling closed like a bad artery on the inside. Do it!

I "bench bleed" the dual-circuit master cylinder with its dual chamber brake fluid reservoir in a bench vice until no air bubbles of any size come out of any of the M/C output ports. Then I transport it (see what I did there?) to the Bus and install it to the frame. Then one clear bench bleed line at a time I quickly detact each bench bleed clear line and quickly screw on the appropriate metal brake line. Then once all lines are attached nice and snug, I break out my Schwaben 3-liter European pressure brake bleeder system (I got mine at ECStuning.com for about $63 - https://www.ecstuning.com/b-schwaben-parts/3-liter...b4QAvD_BwE ) to continue by pressure bleeding the whole brake system all by myself. No assistant needed! My wife and former brake assistant loves that!

For an additional $19 I added their brake bleeder catch bottle ( https://www.ecstuning.com/b-schwaben-parts/brake-bleeder-catch-bottle/007481sch01a/ ) which can hold a full liter of bled brake fluid. No muss - no fuss.

I pour about 32 ounces of new brake fluid into the pressure tank, cap it off, hook up the tank hose and screw its cap to the brake fluid reservoir. Then I pump the bottle pressure up to about 10 - 12 PSI maximum on the tank pressure gauge with all of the brake bleeder valves still "closed". Then for a couple of minutes I relax, have a sip of beverage and closely watch the pressure gauge on the pressure tank to see if there is any pressure loss on the gauge, indicating a leak somewhere which will deserve your attention first. If no leakage, your Bus brake system is tight and ready to proceed! Then I crawl under the Bus and crack open each bleeder valve in the proper order (different for all four drum brakes vs front discs and rear drums). I crack the bleeder a little and watch for the old discolored fluid to drain and then watch the new, clean fluid to come out nice and easy watching for less and less air bubbles until there are no more air bubbles at all. Tighten up the bleeder valve snug, then I ALWAYS go back to the pressure bleeder tank and pump the pressure back up and make sure there is still plenty of new fluid in that tank before moving on to the next brake bleeder valve. "Rinse and repeat" three more times. Before disconnecting the pressure tank system, I pump it up one more time and watch for any pressure loss, who knows, maybe you didn't snug up one of the bleeders valve quite enough. If so, you'll see a brake fluid leak at the bleeder valve, so snug it a little more. You are done!

Ever since I gave up on the "pumping the brakes with 2 people" method of bleeding brake and upgraded to both "bench" bleeding the M/C and then using a quality pressure bleeding kit I have had much more reliable success when flushing old fluid with new fluid and then bleeding the brake system! Did I mention I own and maintain eight old VWs?

Hope that helps!

Bill Bowman
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I'm looking for these license plate frames for my fleet:
Coeur D'Alene - Lake Shore Volkswagen
Mission VW - San Fernando
Thornton VW - Stockton

Thanks for any help!

[70bus]

I have the Schwaben setup just like Bill's and I can affirm it is the easiest way I've ever done my brakes. Other methods, things would sometimes seem fine until a bubble I missed found it's way to a spot to cause soft pedal. Not an issue now.
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Craig K
70 Neunsitzer
65 Pritschenwagen
"If Von Dutch was alive, he'd walk in there with a pistol and shoot these people." - Robert Williams

Raul the 65 singlecab

Karl the 70 nine-seater

[mr matt]

Thanks Bill... I like the diagnostic of pumping up the pressure tank, and see if it drops in pressure indicating a leak somewhere.

I do not have a direct way to pressurize my reservoir as it is of this type, the lid being rubber and a cork-on-metal surround. Not my actual reservoir, but like it

Here is my hook up to my MC .. so I am guessing will try to hook pressure bottle hose right up to the MC

My prob is .. and this may be more suitable for the bug oval forum as that is my car here.. is the car was in a garage over the winter, and when pulling the car out in the summer, there was no brake pedal whatsoever..went right to the floor.. Check and found my reservoir was dry!! what?!! So I looked for signs of leaks everywhere, and found none. Even pulled the seat out and followed the brakeline along the outside of the tunnel and it was perfect.

Someone said to me MC could have leaked from its' boot, between the firewall, and that is why I did not see any fluid marks anywhere. Guess that is possible. Replaced the MC with a bus MC( mandated for having front disc brake conversion), and it seemed to me the MC was not working right during the bench bleed... as not much fluid was coming out pushing on the piston...but as I only replace these - what once every 10 years or so, thought I would try it out anyway. It is made by EMPI as I found out later. - and I do not like EMPI quality at least from the past.


So after install and bleeding, not getting much brake at all, if anything (pedal goes to the floor, and when I bleed, with someone pushing on the pedal, sometimes fluid comes out.. sometimes not at the bleeder screws). So got another MC from WW, and will be trying that.


With the current MC still in place and with the end of the tube going to the MC being somewhat see-through ( silicone tubing) from the reservoir, it appeared oftentimes that the MC was not pulling fluid from the reservoir. This is all very strange.

If the new MC still does not give me any pedal, I am pretty much stumped. Again, during the bench bleed, there was very little fluid coming out so am thinking it is the EMPI MC.

Will see what is going on soon I guess..

Thanks again for all input.
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1955 3-fold semaphore Oval beetle
1971 Convertible beetle
1977 Westfalia, FI, Berlin interior