Purpose of these fittings and hoses (rebuilt master cylinder)?

[KTPhil]

A rebuilt master came with these hoses and fittings. I am guessing they are used for bench bleeding, but I've never done that, and wonder how I am supposed to use these pieces. Maybe to expel all air before connecting the wheel lines?:

[RWK]

Yes, I have a similar situ. MC came with those also plus instructions, shows those lines going back into reservoir, like in an American car where the res. is mounted on MC.This bleeds air out of MC before you connect lines i guess, never done it that way either.
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73 Type 181
63 Type 113
63 Type 261- 428 071
62 Type 241-378 025 178 530

[Bonesberg55]

I bought a new master cylinder for my bay & it did not come with those hoses. I have bench bled American master cylinders before by running a hose from the fitting back into the reservoir. With the VW one, I read that you should be able to pinch the hose or put your finger over the hose end before you let the cylinder return to its normal position. The shorter the hose, the better as long as you can view bubbles. The number of repetitions is determined by whether or not you see bubbles in the hose. Once there is no air visible, temporarily plug the holes so you don't lose fluid & have to bench bleed again.

[Wildthings]

Some people do a bench bleed by taking the fluid from the outlet ports and running it back into the reservoir. Not sure how this would be done on a master cylinder with out a reservoir.

[KTPhil]

The reservoir mounts on top of the master, so the flowback arrangement can be done with a helper. I can mount the reservoir on it on the bench. I've never needed to do it, but I might try it this time. Kinda depends on how much scootch room I have under the front of the Bus.

[Bonesberg55]

[KTPhil]

Well, bench bleeding was a waste!

To install it in a Bay bus, you need the lower reservoir installed, and with it filled with fluid, it all dumps out the ports as you contort the damn thing into position. If not, air is let back in, so what's the point?

Bench bleeding just meant there was a lot more fluid to dribble all over me as I installed it.

Next time it goes in dry...


I can see on a typical American front engined car it makes sense, as you can bench bleed on the car and it all stays level and neat. Not on my Bus!

I'm letting it gravity bleed overnight and I'll try the 2-man usual bleed routine tomorrow. After I shower!

[kreemoweet]

[wrxnofx]

I just did this procedure. I didn't see the difficulty or make the mess. All I used was rubber plugs for the ports while bleeding. Here's how I did it:

1. Install the upper reservoir into the bus. It's tube will be sitting near where the lower reservoir will go.
2. Assemble brake switches onto master cylinder.
3. Assemble the lower reservoir into the master cylinder.
4. Fill lower reservoir with brake fluid.
5. Hold the master cylinder in one hand with palm pressing up against rear port plug and index finder pressing up against front port plug.
6. With other palm, press the plunger into the cylinder. After doing this a couple times, you'll feel the plugs wanting to pop out of the ports from air/fluid pressure. Ease up pressure on the front port plug while pushing the plunger in. Then push the plug against the port while releasing the plunger. This entire time your palm is pressing the rear plug into the port so it can't come out of the port. You're essentially bleeding the air out of one half the cylinder at a time. I had an oil drain tub on the ground catching the fluid that bled out.
7. When satisfied that no more air is coming out of the front port, press your index finger against the front port plug so it won't come out and ease pressure on the rear plug. Repeat the same procedure, letting the plug partially come out while pushing the plunger in, then pressing it back against the port when releasing the plunger.

That's it. Took me 10 mins. I took a 3rd plug and put it into the reservoir opening, shimmied under the bus holding the reservoir sort of level, and stuck it onto the studs. Connected up the hard lines one at a time, pulling out the plug quickly. Then connected up the line from the upper reservoir, filled the upper reservoir up, and bled the entire system.

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1977 VW Type 2 Bay Window Westy FI

[udidwht]

Not an issue when I installed the the MC in my 72 Westy. Once installed I filled it with brake fluid and bled down the system.
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1972 Westy Hardtop/Type-4 2056cc
96mm Biral AA P/C's~7.8:1CR
Headflow Masters New AMC 42x36mm heads w/Porsche swivel adjusters
71mm Stroke
73 Web Cam w/Web solids
Dual 40mm IDF Webers - LM-2 - 47.5 idles/125 mains/190 air corr./F11 tubes/28mm Vents - Float height 10.45mm/Drop 32mm
Bosch SVDA w/Pertronix module (7.5 initial 28 total @ 3400rpm)
Bosch W8CC plugs
Pertronix Flamethrower 40K coil
S&S 4-1 w/Walker QP 17862
3 rib 002 Trans
185R14 Hankook tires