Master Cylinder - Which one is this?

[SPLITV]

Replaced front brake parts and trying to bleed with little success, getting fluid through at all wheels but nothing on the brakes?

Could the Master cylinder be failing?

Also which is this one and is it a big job to replace?

Thank you...

[Eric&Barb]

You have to bleed it as a dual master cylinder, because it is a dual master cylinder.

Up at the very top of the split bus forum is the stickies, up at the very top of those is "Split Bus FAQ and How Tos - *Read before posting*". Left click on that and scroll down to the brakes section and read up about the dual master cylinder conversion.
Lots of other need to know VW stuff all from the best of the best threads posted in that sticky.
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[Yannvanh]

Looks very wet to me...
Maybe u can take it off, inspect and rebuild it?

If your bus is a 67, your dual master cilinder is probably OG

[SPLITV]

thank you Eric, will have a read. Would you know the part number for this MC?

thank you Yannvanh. MC is actually on a 58 PV so it would seem someone has already done a conversion at some point.

It looks wet due do spilling brake fluid while topping up.

[earlywesty]

Was it working properly before? I ask as you must have the brake lines in the correct port as they provide different (less) pressure to rear brakes than the front circuit.

[PEPPE]

it says "ind. bras," so it looks aftermarket. pumping the full throw of the master cylinder during the bleeding, can damage the seals.

[Clara]

Open the brake line before the flex hose and see if fluid comes out there. Maybe your flex hoses are bad.
Have you looked inside the drums?

What does getting fluid through at all wheels but nothing at the brakes mean?
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[Eric&Barb]

Looks like 1971-79 bus MC. If you follow the directions you can redo the brake lines at the MC to allow using the pedal pan.
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[ToolBox]

Check the adjustment of the corners you installed new parts on. New parts need to center to the drums and it is a multiple adjust process and not a one and done deal.

[johny__utah]

Does appear to be a later master cylinder like E&B has stated. Also looks to be faulty. Get yourself a 1967 only. 211611011Q German or Brazilian 98-8654-B. Keep in mind your current reservoir bottle may not fit a 67 if it ends but being earlier unit. Also, your pedal push rod may have been cut short to work on earlier MC's. Another thing.. Did you adjust your brakes all the way out before starting the bleeding process?
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[SPLITV]

Answers for above...

Rear brakes have been replaced about 8 months ago, and the brake lines.

All was working until a cylinder failed at the front right. Although, not brilliant.

All the parts at the front have now been replaced, front hoses, internal brake lines, shoes, springs, adjusters. Drums appear in good order.

(Lesson learned: Don't install the drum brake line upside down or it will catch on the inside drum edge and chew it all up).

What I mean by fluid at all wheels but no brakes.

I can bleed the fluid to each wheel, I've put nearly 3/4 litre of fluid through to get rid of the bubbles. The fluid seems to be running through fine now but I'm still getting very little, practically nothing on the brake pedal.

Further information:

Van is a LHD: does that change the order in which you bleed?

Also Eric:

Looks like 1971-79 bus MC. If you follow the directions you can redo the brake lines at the MC to allow using the pedal pan.

Not sure what you mean by the pedal pan?

Before bleeding I adjusted the fronts to tight so you can't move hub but left the rears as I thought they would be ok due to the garage work.

I've not checked the push pedal rod for any modifications.

I'm learning, so go easy please.

[Eric&Barb]

LHD or RHD bleed difference is that one always starts at farthest wheel from MC on each axle first.

https://www.thesamba.com/vw/forum/viewtopic.php?t=...mp;start=0

ALL brake stars on dual master cylinder system need to be tightened up to bleed the brakes properly. Otherwise you are wasting valuable time and energy pushing rear brake shoes in and out and not using that work to push out air bubbles in the front.
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[Clara]

When the system was completely open and empty it can be difficult to get all the bubbles out.
I found that giving it a bleed, then not worry about all the bubbles. Let it sit overnight. The bubbles tend to clump on their own somehow. The next day it seems easier to get a clean bleed.

But even when there are some bubbles in there there should be brake action where the shoes are moved against the drums.

Often after the initial rough adjust on new parts and the first round of bleed I go back and do another adjust. Having moved the shoes can help center them. And if that shifted them over it may need another adjust to get good pedal movement.
_________________
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[ToolBox]

[SPLITV]

thanks for all the replies...

I've had another go today and had some success, short lived though.

Got the brakes working, all seemed good, had a drive around until I started to smell the drivers side wheel brake.

It seemed to get stuck on. Also noticed a small leak from the master cylinder near the pushrod bit.

I've had a look for a replacement part but am a little confused. My MC only seems to have one brake light port.

Anyone any idea? Or know which part number. I've looked at the suggestions above but even they look different.

[94touring]

What's the distance between reservoir ports? If 100mm you should be able to use a Forst 211611021T, or any that cross reference to that. It's non servo for drums. If your reservoir isn't 100mm you can always just buy a reservoir that fits it.

[Eric&Barb]

[SPLITV]

Hi Eric,


The hoses at the front have just been done and is this Pedal Pan something that fits underneath the master cylinder etc because I don't seem to have this part.

Also, the bit I'm confused about is why the other new parts seem to have two "brake light switch" ports while this on mine only has one?

94touring: I'll need to check the size. I've just looked at that part number and it just looks completely different.

[easy e]

[SPLITV]

Thank you easy e...

Just had a look and I don't have one of these...

Also Eric, I've just read through your conversion post in the FAQ's and am I not right in thinking that this conversion has already been done on my van?