[T2] [VB] disc brakes next - potential winter project

[Al Brase]

On a master cylinder, I think you want to get rid of the residual check
valves. What about 1968-69 master cylinder ...201Q? It has 2 fittings for
the two front lines like the 67 cylinder. The 1970 cylinder 201T? might be
about the same, but only one fitting for the front lines, so needs a tee in
the line.
Al

On Thu, Aug 17, 2017 at 9:51 AM, david raistrick <keen at icantclick.org>
wrote:

> On Thu, Aug 17, 2017 at 9:59 AM, Kevin Guarnotta
> <kevin at guarnottadesign.com> wrote:
>
> > Some stuff /questions I've come across
> > 1.Vented vs non-vented. Seems like vented is only a little bit more, so
> I'll probably go that way.
> > 2. Size - I see some listed as 5x130 and 5x205, I guess the 5 indicates
> the number of lug nuts, and the 205 or 130 is the space between the lug
> nuts? What is the stock size?
>
> for our purposes - 5x205 is stock wide 5 beetle/bus/etc.  5x130 is
> porsche.  5x112 is late bus/vanagon/etc.   4x...something bigger than
> 100... is late beetle.
>
>
> > Has anyone done this, and regretted it? Anyone use a kit they didn't
> like? Anyone use a kit they thought was relatively easy to install, and
> works well?
>
>
> I have the wagenswest babystang - they clear 14s.
>
> stock '65 wheels are 14s (14x5).  1955 to 12/63 were 15" (15x4.5).
> 1/64 - the end of the vanagon were 14 (excluding some vanagon alloys,
> but those might have been 14 too)
>
>
>  the babystang and bustang (bustang clears 15") and many others use a
> wilwood caliper (most common aftermarket mfr with excellent mfr and
> 3rd party support for pads and parts, including knockoffs) .   if
> wilwood ever goes away, 3rd party pad mfrs will still sell pads.
>
> The nice thing about using a wilwood (or clone) caliper is that there
> is significant amounts of technical data for them, and -many- various
> pad compounds to choose from, complete with dyno charts (heat vs brake
> force) for those compounds.  This is also true of 944 pads, but no 1st
> party data on pads, only 3rd party.
>
>
> from memory, sago uses a wilwood knockoff.  csp uses an undisclosed
> and possibily proprietary caliper (though more info may have been
> released)
>
>
> the babystang uses a mustang II rotor with minimal modification - the
> grease seal opening is machined to fit a bus grease seal.   in theory,
> you can get any mustang II 9" rotor (cheap as dirt and super common in
> the hot rod aftermarket), find any automotive machine shop to open
> them up, and have a new rotor.   these are vented.   also available
> drilled, slotted, cryoed, and pretty much any other worthless value
> add treatment available for brakes.. :)     off the shelf bearings are
> used to fit the rotor to the hub, and a modified 944 grease cap is
> used.
>
> I don't recall what the bustang uses, but it's a larger rotor also
> from a mustang generation.
>
>
> vented vs solid:  for fronts, you really do want vented.   that said -
> in a split bus, getting enough heat into the fronts can be a problem,
> so maybe it doesnt matter as much.
>
> slotted/drilled - have zero value in our application and only weaken
> the rotor.   slots "allow gasses to escape between pad and rotor
> during high heat applications"  and drilled "helps cool rotor and pad"
> - except, real road race cars dont use them....   motorcycles and
> bicycles do drilled, but that's because of the weight reduction.
>
>
> any of the kits are decent enough - just unbolt everything off the
> spindle, bolt up the new, bleed and go.    2, 4, and 6 piston calipers
> are used in various kits and require a bit more work to bleed.
>
>
> on the master:  you absolutely should switch to a dual circuit master.
>   in my researched opinion, the best option for this is still the '67
> master.  this is available in repro these days for reasonable money.
>     it's the closest to appropriate piston size for the fronts, and
> delivers good volume.   there might be some early rabbit and volvo
> masters as well, but they dont bolt straight in the same way...
>
> people will argue using a disk brake master - completely ignoring the
> fact that a disk brake master piston size was designed for a booster.
>
>
> wheel adapters:  most options will involve running a wheel adapter.
> that's OK.   a lot of cars run them from the factory and you dont even
> know it - dodge ram 3/4 and 1 ton trucks.  porsche 944s run them up
> front.    The differences are in the quality of the adapter. :)   If
> you're using a mustang rotor, you'll be adapting 5x4.5 to 5x205.  if
> it's a porsche rotor, it'll be 5x130 to 5x205.  if it's a vanagon
> rotor, it'll be 5x112 to 5x205.
>
>
> track width:  all options change the track width a bit.  some narrow
> it, some widen it.  if you're running 15x4.5's your track width is
> already a little different than if you ran 14x5s.    Generally, the
> vendor can tell you how much it changes (+.5" or -.5" or whatever) and
> you can judge if your tires will still clear inside and out before you
> install it.   Handling change will not be noticable (in a bus).
>
>
>
> on my babystangs - I had two significant problems.   1) the pad
> compound Nate sent was entirely inappropriate for the heat generated
> in a split camper.  that is to say, it never actually comes up to
> temperature in daily driving use.   you need a cold-oriented pad.   I
> was able to find an alternative compound and that drastically improved
> things.   2) the caliper sat a little to close to the spindle, causing
> the pads to "ride" on the joint between the rotor surface and the hat.
> This caused the outside pad to be effectively useless since it didnt
> grab the rotor.  I used some measured washers to find 4 washers that
> spaced the rotor out the same distance on both sides to clear, and
> that helped.
>
>
> On all of these that use fixed (instead of floating) calipers:  You
> want to make sure to "center" the caliper any time you loosen/tighten
> it.   basically, have it loose enough to wiggle, then have your helper
> apply brake pressure (or use a reversed friction clamp under the
> floor...), that will center the caliper based on the rotor.  tighten
> while pressure is applied.   there are many many long threads on
> hotrod forums about failing to do this.... :)
>
>
>
> if I were buying again:  I'd call/email russ at oldspeed.   last time
> I talked to him, he uses a 944 rotor for his 14" and 15" kit - he
> basically cuts the rotor down to around 9" to fit in the 14" wheel.
> still uses a wilwood caliper.   From the stuff I've seen, his overall
> quality of the kit is better though.  I dont know what compound he
> supplies. :)
>
>
> I'd also recommend reading the threads on thesamba - there is a LOT of
> data in there, some of which was supplied by me... :)
>
>
> For me - with the powerlite caliper and 7912 style pads, switching
> from the BP-10 compound to the Polymetric E compound was a good
> impovement because of increased 100-500 degree braking power.   over
> 500 they're not as good.   maybe if I were braking down mountains all
> day long I'd want something else.
>
>
> Also:  DO NOT expect drastically better braking or less pedal effort.
>    A well tuned set of front drum brakes with just broken in german
> shoes will out perform any non-power options available that will fit
> inside our wheels.   the 15" options might be a bit closer than the
> 14" options.    That said - you'll get consistent performance over the
> life of the brakes, instead of having to adjust them twice on a long
> road trip....     my babystangs with the PolyE compounds are
> definitely close performers now.     You're generally also still going
> to be limited by the front tire grip.    Pedal effort will NOT
> decrease, and in fact will be harder - drum brakes "add" power at
> speed as you apply pedal pressure, it's not a linear increase (because
> the drum pulls the shoe into a wedge..there are some good videos out
> there on this).   with discs it's straight linear effort.
>
> Switch to discs because you are tired of adjusting them, or because
> you never actually bought good german shoes so you dont know what a
> good set of drums can really do, or because you dont like the price of
> those shoes, or because you're tired of wheel cylinder failures.  :)
>
>
>
> anyway - ask away, I've got a ton of notes around this stuff if you
> want to know about any particular options.
>
>
> oh - the 944 bolt on conversions: if you're only with 15s only, that's
> by far your cheapest option, even buying new calipers/rotors (NA
> calipers/rotors are pretty cheap).   but then you also need 5x130
> adapters and I dont know what the track width change is...)
>
> Figure somewhere in the $1500 for a kit, otherwise.   Money well spent,
> IMO.
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