Early Bay brake Q - Why is the bleeder screw on the lower cyl?

[MikeyM73]

Edit: with front drums and dual wheel cylinders. Just curious as air rises so I would think it would make it a little harder to bleed from the lower wheel cylinder rather than the upper. I don't have a Bently (yet) so would you bleed from the lower, then when no more air, crack the upper hose connection during bleeding? Or is bleeding from the lower sufficient?

Thanks,
Mike
_________________
'73 Pop-top Westy, found sitting in a field for 10+ years, cleaned up, rebuilt furniture, reloved. Original 1.7 block/fully polished crank, 93mm 1.8L balanced AA pistons & cylinders, new 1.8L balanced rods, HAM 42/36 heads, Scat C25 cam & lubalobe lifters, Dual HPMX40s, R2C filters w/ Outerwears pre-filters, functioning thermostat & flaps, Pertronix Flamethrower III, 4-1 exhaust w/ Cherry Bomb 2" turbo muffler & OEM heater boxes, averages about 19-22ish on the highway.

[guitarman63mm]

The bottom screw is for purging old fluid that accumulates crap in it. You are correct, you can only effectively purge air from the top caliper screw.
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Jimmy

- 1974 Safaré Custom Camper. 091 trans + Dual Weber 34 ICTs + Pertronix SVDA + 1.7L 914 T4 engine.

[MikeyM73]

Oops.. I'm so sorry.. I mis-spoke. This is for a friends bay window with front drums and dual wheel cylinders where the bleeder screw is on the bottom wheel cylinder. Same deal?
_________________
'73 Pop-top Westy, found sitting in a field for 10+ years, cleaned up, rebuilt furniture, reloved. Original 1.7 block/fully polished crank, 93mm 1.8L balanced AA pistons & cylinders, new 1.8L balanced rods, HAM 42/36 heads, Scat C25 cam & lubalobe lifters, Dual HPMX40s, R2C filters w/ Outerwears pre-filters, functioning thermostat & flaps, Pertronix Flamethrower III, 4-1 exhaust w/ Cherry Bomb 2" turbo muffler & OEM heater boxes, averages about 19-22ish on the highway.

[Amskeptic]

[aeromech]

I could be mistaken but doesn’t the rubber brake hose attach to the upper wheel cylinder and then a hard brake line inside the drum connects to the lower. That would make the exit want to be on the lower I think
_________________
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[HarryFD]

So, I have a question. This is the left front bleeder screw on my 1970 Bus.

How do you flush your brake fluid? Since it is on the bottom, if I open it, it is very possible to get air into the cylinders and then very hard to get it out.

What is the correct procedure?
_________________
1970 Deluxe Sunroof Bay Brilliant Blue/Cloud White
1973.5 911 Targa
2009 MB C300

[HarryFD]

So, I have a question. This is the left front bleeder screw on my 1970 Bus.

How do you flush your brake fluid? Since it is on the bottom, if I open it, it is very possible to get air into the cylinders and then very hard to get it out.

What is the correct procedure?
_________________
1970 Deluxe Sunroof Bay Brilliant Blue/Cloud White
1973.5 911 Targa
2009 MB C300

[airschooled]

[HarryFD]

[MikeyM73]

Aeromech, you're correct. I know the V-Dub Engineers were a very intelligent bunch of fellows but the logic escapes me as to why the one and only bleeder screw would be on the bottom cylinder. Unless, someone at some point in time, perhaps mounted a lower cylinder up top and vice versa which I doubt because all the photos I have seen show the bleeder screw on the bottom.

Robbie, that makes sense - after bleeding normally, give it another go by cracking the upper hose.

Can't be too difficult, right??
_________________
'73 Pop-top Westy, found sitting in a field for 10+ years, cleaned up, rebuilt furniture, reloved. Original 1.7 block/fully polished crank, 93mm 1.8L balanced AA pistons & cylinders, new 1.8L balanced rods, HAM 42/36 heads, Scat C25 cam & lubalobe lifters, Dual HPMX40s, R2C filters w/ Outerwears pre-filters, functioning thermostat & flaps, Pertronix Flamethrower III, 4-1 exhaust w/ Cherry Bomb 2" turbo muffler & OEM heater boxes, averages about 19-22ish on the highway.