Jeff:
My car spent nine years on blocks in the garage and the discs probably
looked worse than yours (although its tough to say without actually
seeing them). I thought I'd need to have them honed. However, I
thought that I really had nothing to lose by sanding them first (you
don't want to have them honed unless you have to because they can only
be worked so many times). I rebuilt the entire brake system and pulled
the disks to clean and repack the bearings. While I had the disks off,
I thoroughly hand sanded the disks and rear brake drums with fine grit
emory paper (like my Keneth Ball Workshop Manual suggested) until they
were shiny smooth. The most important part is next. Use a good solvent
(Ball suggested trichloroethene but that's a little hard to find these
days) and thoroughly clean the disks, drums, shoes and pads so that
there is no oil on any of the parts from your hands. I used acetone
but, MEK, MIBK, 111-trichloroethane, methylene chloride or any other
chlorinated solvent would work well. Don't use a petroleum based
solvent like mineral spirits. I knew after completing the sanding and
cleaning that the brakes were going to work great before even putting
them back on the car.
My master cylinder and brake lines sat for days after emptying and
blowing them out with compressed air before I began refilling with DOT
5. During the system refill with the DOT 5 I used one of these vacuum
bleeders rather than the pump method. I would highly recommend buying a
vacuum bleeder. It makes it a one man job, you will waste less fluid (I
spent $30 for a quart of DOT 5 at Car Quest and used approximately 3/4
of it), and you will get a superior bleed job. Another great thing
about the vacuum bleeder is that it has an opaque fluid collection
reservoir that the bled fluid comes in to. As a result, one observation
that is readily apparent is that DOT 5 has a much lower specific gravity
than the old paint eating crap that is in your system currently. The
globules of old fluid sink like a brick through the DOT 5 bled fluid and
settle in the bottom of the reservoir. Essentially, I kept bleeding
until I wasn't getting any more old brake fluid coming through. In all
I probably got about 1/2 teaspoon of old fluid come through the entire
bleed. After I got the car back on the street the brakes worked better
than any time during my ownership (1975).
My 70 Mk III is the shop getting its new paint job. I saw it this
morning with all the paint off and down to bare steel. Only one
surprise. Apparently before I bought it in 1975 the PO took one in the
passenger rear. It'll be easy to fix though. However, lots of new seals
and gaskets to buy. I'll being making our friendly suppliers very happy
soon. All the work I did back in 1980 is in good shape though. When
its done I'll send you a picture for the round-tail web site.
Ron St. John
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