Doug & Rett Leithauser wrote:
I like the idea of a dual master cylinder, but I bet that having a booster
only
in the front will give you way too much front brake. My car, & a lot of
others are running without a booster, & I don't find the pedal to be too
hard this way. (maybe I'm just used to it) If I were to try to redesign the
brake system, I'd try a slightly smaller bore master cylinder and trash the
booster.
Doug Leithauser
Doug,
BTDT. Twice. Once when my Alpine was hungry for hydraulic fluid, and recently,
when my Tiger did the dame thing. C.A.T. sells a
wonderful gadget. It's a piece of braided stainless hose about 10" long, with
fittings to connect the "goes-inta" line from the master cylinder
to the "goes-outa" line to the distribution block. Cost about $10 to members,
and is properly flared for bubble flare fittings. When your
booster goes, you disconnect the lines and the hose. Remove the booster (no
mean trick), and join the lines with this piece. A little blood
letting (bleeding) is in order, but not too bad. The Alpine servo boost ratio
is about 2.25:1 (don't quote me, this is what Lucas-Girling says
about which Lockheed replacement to substitute)
The Tiger is 3:1. Again, it depends on whether you're stock MkIIA, replacement
MkIIB (unavailable available rebuild kits, or $350 if you find one), and whether
your using the 5" or the 7" booster (per Lucas-Girling).
In any event, I have been through both scenarios. Assuming that you haven't
changed the master cylinder bore, I have found that the pedal
pressure is higher (by the ratios described) but still in range of older legs.
In a moderate stop everything seems harder, but adequate. BUT,
in a panic stop the story is very different. The good news is that you don't
lockup the rear wheels because Sunbeam forgot the
proportioning valve. A measure of how hard they "squeeze" the Schilling. The
bad news is you just can't get enough pressure on the front disks to get
adequate capability in a "STOP NOW" condition. This is not obvious until you
try it.
I suppose Gorilla legs would make the matter mute, but to me it is not
acceptable. I replaced the booster as soon as I could. Sure, I can
lock up the rear brakes when I am vigorous, but it's the front discs that do all
the work, with the weight transfer. This is important in
racing, Autocross (although I am told you don't need brakes), and emergency road
use.
Let's face it. Sunbeam doesn't put another inch of weld, nut cage, or other
cost item, it doesn't absolutely require. There are many area's where the "bean
counters" have prevailed over the designers. Once I got my newly rebuilt
Girling MkIA unit in place I immediately recognized the change. It went from
"OK, unless you really have to stop NOW, to easy to use at any time, and it
doesn't lock up in a panic.
I know this is a rather long message, but I believe that the subject is
important enough for a thorough airing. I hope you will consider these
experiences, and account for the very costly design requirement on the original,
when most just let it pass.
Here's hoping that you never have cause to validate the engineering requirement.
Steve
--
Steve Laifman < One first kiss, >
B9472289 < one first love, and >
< one first win, is all >
< you get in this life. >
_/_/_/_/_/_/_/
_/ _/_/_/ _/_/_/ _/
_/ _/ _/ _/ _/ _/ _/_/_/_/
_/ _/ _/ _/ _/ _/ _/
_/_/_/_/_/__/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/
_/
_/_/_/
|