Re: 10.1 brake question--The Truth! (long)

["Dave Ewing" <rabbit16v@prodigy.net>]

I upgraded my rear discs and 10.1" brakes before doing the master cylinder
and didn't have any problems.  I did upgrade to the bigger master soon after
that and the pedal did seem better but not dramatically.

I also disagree with the proportioning valve ideas on the list.  The
proportioning valve restricts the amount of fluid/pressure going to the rear
so as not to create an out of control rear lock up situation.  On earlier
cars (and some later) they have a level sensing proportioning valve which
will limit the amount of pressure/fluid going to the rear brakes based on
the load in the car/truck.  I have seen the small cylidrical looking
proportioning valves on everything from Rabbit pickup 85 and newer golfs, 85
and newer sciroccos, foxes, etc with no rear discs so there are different
proportioning valves.  IF you are doing the upgrade on a Rabbit, use the
Golf valves, if you are doing it on a scirocco, use the 16v valves.
Different valves on different cars have to be calibrated for different
weights or this would make the upgrade irrelevent since you would still be
having a locking up problem when installing 16v valves on a rabbit pickup
(more weight in the 16v than the pickup so more pressure/fluid to the rears
of the pickup causing a locking up condition).  The best way do get around
this is to use the aftermarket adjustable proportioning valves they you
won't have to swap 3 or 4 different valves in to find the right one IF there
is a right one for your car.

Another thing I don't agree with is that you DON'T have to have the 16v
pedal assy for this swap.  The 22mm master doesn't have an extra spot for
the pressure switch usually used on older VWs for a brake light switch.
Instead, it is an electrical switch on the pedal assy.  I have attached the
eye piece that the switch mounts on to my pedal assy because I didn't have a
16v pedal assy.  Now that I have one, sure I will use it and reccomend it
but I wouldn't let this part of the swap hold you back from doing the swap.

I have also realized that you may have to adjust the rod when swapping parts
from newer/different cars to older cars because the thickness of the
firewall could be different, the pedal assy could have a different throw,
etc. so be aware of that too if once your done with the swap you just can't
get the pedal that you think you should have after bleeding it 5 times,
check the MC rod.

Stainless lines are also a something I get tired of hearing about.  The
plastic on the outside is ONLY if you live on a dirt road, or if you off
road, or live somewhere where you will be throwing gobs of dirt/mud/etc.
onto your brake lines.  I have had S.S. brake lines on my car for 2 years
now and they are just as clean as they were when I put them on.  Granted I
live in W. WA state were it doesn't snow except in the mountains, the roads
I travel are town and freeway but I still put a lot of miles on my car and
haven't had any problems.  Southern/Western states should also have no
problem without having the plastic on the lines and more than likely the
rest of the U.S. since they are stainless and even salt on the roads
shouldn't hurt them.  I believe that this myth came from rally racers who
had problems with the lines using them for off-road which is what they were
meant for in the first place.

I have heard that cross-drilling your own rotors is bad?  Well, how long
does a set of rotors last when using them hard enough to need cross drilled
rotors with metallic pads?  NOT long!!  Most stock rotors these days are
soft so that the highly metallic pads that everyone has to use (asbestos
causes cancer so it has been replaced with small metallic fibers in the
pads) don't make that screaching sound that buses make.  That is why
sometimes you will get a metal to metal sound when you have 30% pad left,
because the pad wears away the rotor sometimes just as fast as the rotors
wears away the pad and you get a ridge on the rotor that rubs on the edge of
the pad when you still have a lot of pad left.  So, if this is true, and I
know it is, then what is wrong with cross-drilling your own rotors whether
they will crack or not because the life of the rotor is going to be
short-lived anyway?  Questions to ask yourself!!  Is buying a set of
cross-drilled rotors for $150 worth it when you can borrow your buddies
drill press and cross-drill your own for nothing then invest the $150
somewhere where it will make a real difference?  I have heard (from a very
reliable sourch) that the ATE power discs are the way do go if you do have
the money for aftermarket performance rotors anyway.  You don't have holes
to create cracking, they are made in Germany, and they really don't cost
that much if you know someone in the biz!  I have done both.  Cross-drilled
my own rotors, used stock, used aftermarket cross-drilled, and used the
power discs and the power discs are the nicest but clearly not the ONLY way
to go!!

Be careful when upgrading to rear discs that there are two different kinds
of calipers.  There are A2 calipers that have the parking brake cable
mounted at the bottom of the caliper and the Scirocco 16v calipers have them
mounted on the top.  The best way to tell is note where the bleeder screw
is.  Obviously the Scirocco 16v calipers are the nicer ones to upgrade to
since the cables fit perfectly on all A1 cars (except pickup which is a
breed of it's own) so you don't have to hunt or have some made.  IF the
bleeder is NOT ON TOP, THEY WON'T BLEED OUT!!!  Don't ask why I know about
this one!

When upgrading to the bigger master you WILL need the bigger booster.  The
"BIGGER" part that everyone is talking about is the bore, this means more
fluid, more pressure so you couldn't use the smaller bore booster that your
smaller bore master just came out of.  You also cannot use the A2 bracket
between the booster and firewall since they are different but you can use
the A2 booster and master.  Don't be fooled either, I believe that all A2s
have the bigger master and booster so don't pay a butt load of money for
this from someone else when they are a dime a dozen in the Pick A Part
yards.  I'm not sure on this one since I can't remember for sure but I
believe when upgrading an early A1 booster and master you have to have the
16v booster bracket.  I remember something like that but can't rememeber for
sure.

Mostly just use your common sense.  Realize that if there are prop. valves
on 2000lb cars and 3500lb cars that they must be different!!  They aren't
all the same.  Second, when getting "Suggestions" from someone, even on the
list, question the source for reliability.  I think we should voice our
proof when answering a question like this too.  I would trust someone that
works at a dealership on VWs or a German auto shop more than I would trust
someone who dabbles in their back yard (certifications help too) although I
have known the backyard mechanic to be right before the Dealership mechanic
also.  And last but defineately not least, Bentley, Bentley, Bentley.  If
you are swapping something from a different car, get that Bentley too.  If
the Bentley doesn't offer enough information, get a Haynes, Chilton, Clymer,
etc.  Don't trust your life (brakes) or being broke down on the side of the
freeway on a weekend night with drunks on the road ready to swerve into
someone on just what you heard from someone that said their friend's,
uncle's, sister who cut the toenails of the guy that new someone who worked
at Midas tells you.

Dave Ewing
15 years experience in Automotive and 8 in VWs (air and watercooled)
professionally, ASE Master tech, Bosch certified, Auto tech schools,
courses, etc.  Worked at VW performance shop and German Service shop for
last 5 years.  Have parted out numerous cars, built my own unbeatable (so
far) street car, working on drag car for next season and have done/helped in
numerous upgrades/rebuilds(engine/trans/cyl heads) swaps in
Sciroccos/Rabbits/Vanagons/etc.  I'm not bragging, just giving references.

Even if you aren't ASE certified or this or that certified, your time and
energy is worth just as much as the next guys so value your time!!


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