By Jerry Rude
Summary
This is an article on how to convert your Twin Cam
or Special Europa brake system to work with the efficiency of the original
Series 2 Europa without the Girling Vacuum actuated boosters.
S2 Master Cylinder
My Europa Special had set for 9 years before I
purchased it. This resulted in the brake boosters self destructing in
place. The aluminum bodies of the boosters are very fragile, and galvanic
action inside the body will eat irregularities into the bores. This
rendered one booster not re-buildable. The cost of the rebuild is
expensive and according to those who have attempted a rebuild, has a 50-50
chance of being successful. I was quoted a price of $245 per booster for a
professional rebuild, and kits cost about $95. This assumes, however, that
you supply a rebuildable core. You can have the bores sleeved in brass or
stainless, but this costs 80 to 90 dollars per sleeve, and there are 5
bores in the body.
The Europa weighs only 1600 lb. roughly, which is extremely light. Why they were provided with boosters to begin with is beyond me, other than perhaps a marketing promotion.
A popular conversion is to bypass the boosters and install a Series 2 master cylinder. This is almost a direct bolt in. I obtained a core from a friend in Oregon, and had it sleeved in brass by Power Brake Exchange in San Jose CA for $95. I then purchased a rebuild kit from Dave Bean Engineering, and assembled the master cylinder, better than new, almost. Removal of the reservoir from the old twin cam master cylinder proved to be challenging.
Twin Cam Reservoir
The reservoir for the Twin Cam must be used on the
S2 cylinder as the S2 reservoir top sits forward about an inch and isn’t
sloped as the TC is. The S2 reservoir is still available new and if your
TC reservoir is in poor condition and you can’t find a suitable
replacement, you will have to purchase a S2 reservoir and modify the
fiberglass in the boot area of your car to work.
My TC reservoir was still in good condition, however, the trick was to remove it from the MC body. In talking with people about how to remove the reservoir, they said to pry up and twist. No amount of doing this was working for me as it was stressing the reservoir such that it was going to break or fracture.
I then came upon the idea to drill a hole, right at the ring grove which holds the reservoir on. It should be drilled 0.225 inch down from the top of the hole, make it just over 1/8 inch in diameter. Don’t drill too far, just through the cast iron. If you go too far you will go through the plastic, an all is lost. After drilling the hole, you will be able to see the ring that holds the reservoir. Try to pry the ring edge down and rotate the reservoir to remove it. This may be effective, but not in my case. It seemed like the ring clip was glued in place.
I then went down to the local hardware store and purchased a very small (1/8 inch diameter) grinding stone for my dremel tool. By inserting this into the hole, I ground the clip in two. This broke things loose and I removed the reservoir. The MC was still useable (the hole affects nothing except allows access for future removals) and so was the reservoir.
Attaching the S2 Master Cylinder
After rebuilding the S2 cylinder and attaching the
TC reservoir (its a direct bolt on) I fit the unit to the chassis. The
upper mounting hole in the S2 cylinder was overlarge, and I understand it
had a special nut which is no longer available. I made a small bush to be
able to bolt it down like the TC unit. Also, I had to grind down the top
of the flange to a 45 degree angle so it would miss the steering rack. I
did this on the grinder by hand, then painted to keep from rusting, and
bolted it on.
S2 internals
I then took the TC master cylinder apart to satisfy
my curiosity as to whether or not it could be modified to match the S2
bore dimensions. I had measured every part within the S2, and produced a
AutoCad drawing to compare to. It turns out that everything is identical,
except the pistons and they can be cut down to the S2 dimensions. So you
can take the TC master cylinder, send it in and have it resleeved to the
S2 bore sizes, have the pistons cut down to the right OD, and have an
equivalent cylinder to the S2.
So why do this when the S2 master cylinder is available? Well it seems that these cylinders are in very short supply. You cannot get the rebuilt units without giving them a core, all sources seem to have dried up.
