wayne said:
I have to replace both front discs (and pads) because they're worn. The
shop manual that I'm using says to clean the area with brake cleaner
before I start. It's supposed to remove the grime and toxic dust better
than using a blower. However, it doesn't say how to properly use the
cleaner; much less how to dispose of the byproducts.
Wayne
Personally, if I were to use the spray cleaner, and which means the
parts are out of the car, and because you are talking about the caliper
and not the discs, I'd use a soaked rag to clean the piston but cover
the piston to protect the rubber gasket. Since the caliper is
unmounted, hitting the slider pins won't be problem if you plan on
relubing them. Some disc pad kits come with lube but I've seen many
that don't (seems they want to save the few cents) so make sure you pick
up a squeeze tube of lube when you pick up the pads set. If you're
trying to spray the cleaner on the caliper while still mounted, you're
going to get it all over, like on the piston gasket, slider pins, brake
hose, underside of the fender, etc. I suppose you could provide cover
for those items while spraying.
The brake cleaner spray evaporates very, very quickly. The residue left
behind won't be the cleaner but what got cleaned off. So make sure to
spread newspapers or cardboard underneath. Fact is, you can spray the
stuff on your hands as a cleaner but have some grit soap nearby to
finish the cleanup (the cleaner will soon evaporate).
The main ingredients in brake spray cleaner are methanol, methyl
acetate, and acetone. Methanol is rubbing alcohol. Acetone will eat
through plastics hence the need to protect the caliper's piston gasket,
brake hose, plastic fender underliner, etc, plus it will dull the finish
on paint. Methyl acetate is another dissolver. It has 25% solubility
in water but considering how fast brake spray cleaner evaporates means
you'll have to do the degreaser or soapy cleanup immediately after
cleaning the surface. Different brands use different ingredients. Some
use ethyl benzene, heptane, xylene, They are dissolvers so be sure you
only hit the surfaces from which you want to dissolve something. That
means covering everything other than the target from the splash from the
spray. There's a reason why car shops just air blast the caliper and
rebuild shops might use cleaner (after air blasting): car shops don't
want to go through all the cover protection that, say, when spray
painting a door to prevent contamination elsewhere.
Besides, whose going to see the dirty caliper? Do you actually see it
through your wheels? If so, how does black on black become noticeable?
