In <960714220324_237689958@emout16.mail.aol.com>, Ceicia@aol.com
wrote:
>
>1. Has anybody else had this experience with a hit and miss problem with
>clutch hydraulics? by the way, I don't see any leaks either near the master
>cylinder or around the slave.
>
>2. Do I need to replace both the clutch master and slave cylinders? Can I
>just put a kit in them to save money?
>
There has been an awful lot of mail recently regarding clutch/brake
hydraulics. I thought I'd spend a moment or two to expound on the Zen
of Hydraulics.
(1) If you haven't completely rebuilt your hydraulics (or had it done
by a reliable mechanic) since you got your car, they need attention.
Now. Unless you are using silicon fluid (DOT 5), they need attention
every couple of years (see previous post on changing fluid).
(2) What is meant by rebuilt? Covers a lot of territory. The
absolute minimum is replacement of all rubber/seal components,
including the flexible lines. This involves complete disassembly of
the system and blowing out the lines.
(3) Why? Most brake fluids in LBC's are hygroscopic. They attract
water, it gets into the system and corrodes things. Iron cylinders
(e.g., masters or front slaves) tend to go first, then aluminum
cylinders (e.g., clutch slave). There is no way of knowing whether a
cylinder must be replaced without a complete teardown and inspection.
(4) If there is slight surface corrosion (discoloration) in iron
cylinders, this can be removed by gentle honing with a proper cylinder
hone. If there is pitting, the cylinder should be replaced. Aluminum
cylinders _cannot_ be honed effectively. Folks, the brake components
for most MG's are loads cheaper than those for any Toyota, so don't
skimp here.
(5) Some items (e.g., MGA master cylinders) are pricey. These can be
resleeved with brass or stainless steel. Master cylinders usually
cost $50/bore, slaves $35 each. Usually cheaper to buy slaves
outright. Do not expect DOT 5 fluid to work well with brass sleeves.
(6) _Never_ try to do rebuilds with the stuff on the car. The first
and last word when working with hydraulics is cleanliness, to
a surgical extent. This can't be done with crud falling off every
exposed surface into your cylinders. Clean all parts exposed to fluid
with a purpose-formulated cleaner (e.g., Brakleen). Lubricate only
with brake fluid. Keep your hands clean and free from grease. Most
rebuilds that fail do so due to contamination (or lousy rubber
parts....)
(6) Bleeding the systems can be very difficult. If you have a "gotta
pump it twice, but otherwise firm" problem, you have air in the
system. I have had good luck with pressure-type bleeders (e.g.,
Easi-Bleed). You can make one for a few bucks. It requires patience
and some thought (the bleeder for the clutch slave cylinder is usually
on the bottom, not the top where the air is....)
(7) If you have all the necessary bits, it shouldn't take more than a
long Saturday to completely rebuild your hydraulics, brakes and
clutch. Short cuts here are stupid.
Safety fast.... A. B. Bonds
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