SCOTTRODS wrote: ↑Thu Nov 07, 2019 4:53 pm
58-67 Beetles had the vertical mount wheel cylinders on the fronts...
Ol'fogasaurus wrote: ↑Thu Nov 07, 2019 7:55 am
As far as the residual pressure valves I wonder.... Their use is to stop bleed back in the system to keep the line pressure which keeps the shoes from backing off and giving soft or uneven brake application. They were more discs than drum originally but do work well in both applications...
The basic layout of "standard" Beetle front brakes was unchanged through the end of production, perhaps you're thinking of Super Beetle fronts (which were actually derived from Type III rears). The vertical orientation will only cause air to remain entrapped if the bleeders aren't opened rapidly and far enough to create a healthy rush of fluid to come out, bringing the air bubble along. It should not be necessary to move anything around in order to accomplish bleeding successfully unless your technique is bad. "Gravity" bleeding is inappropriate on a VW IMO.
Starting in `65 the adjuster screw slots were widened and angled, and the shoe frame ends have a corresponding angle. A common mistake is to orient the adjusters wrong, which can cause the shoes to catch and develop a notch where they make contact. Odd things result, you can get a "false" adjustment and operation may be erratic.
The residual pressure check valves used on drum-brake master cylinders will hold too high of a line pressure for discs, resulting in drag/heat buildup and rapid pad wear. Their purpose was to hold a light pressure, not enough to overcome the return springs, to keep the lips of the wheel cylinder seals in firm contact with the cylinder bores to reduce seepage. On disc brakes there are no return springs to offer resistance so residual pressure valves are not desired.
There were several variations in the original early dual-circuit master cylinders; cars with disc front brakes took a different one than did drum/drum cars. But the ONLY M/C that has been available for decades is the 113 611 015BD "universal replacement" which services all dual-circuit Type I applications (other than Super Beetle).
It uses no residual pressure valves, just has tiny drillings at the outlet ports which are there to limit the backflow rate when the pedal is suddenly released so air won't be drawn in at the W/C seals in drum brake applications.
Those restriction drillings also limit the flow rate out of the M/C when bleeding but normally not by enough to cause any problem when foot-bleeding.
The "Formula Vee" package was dealer-installed and only cosmetic, no changes were made mechanically. Actually 1970 was the last year it was officially authorized, replaced by the similar "Super Vee" package in 1971. Again, no mechanical differences - just things like rims, decals & badges, steering wheel/shiftknob/etc.
But that didn't stop a dealer from using up any leftover Formula Vee kits on newer cars.
http://www.sebeetles.com/f_vee/
http://www.sebeetles.com/s_vee/