Re: Cleaning hydraulic parts

[Scott Fisher <sefisher@domain.elided>]

Graham Hilder asks:

> What is such bad news please about using petrol? 

First thing that comes to mind: most petroleum by-products cause
deterioration in latex-based products -- something I learned first-hand
in high school, though I won't tell you *how*... Ahem.

More recently (and more repeatably), I discovered that some petrol-based
parts cleaner I was using at a friend's house ate away at the latex
gloves I was wearing to protect my hands from said petrol-based parts
cleaner.  The gloves swelled up, got soft, and eventually tore open. 
And while I think Alfa doesn't use latex seals in the braking systems
(but older British sports cars do, hence my indoctrination into Castrol
GT LMA as the only fluid I use), even the *slightest* chance of that
happening in *my* brakes is more chance than I care to take.  Besides,
the other reason I don't use petrol in my brake work is:

> these commercial brake-clean products... Do they really work? 

Yes, they really work.  They appear to be dry-cleaning fluid -- the
smell always makes me think of my grandparents' dry-cleaning shop when
I'd visit them as a child.  Brake cleaners are designed to evaporate
completely, leaving no residue behind.  Lately I've started buying the
non-chlorinated variety (no CFCs), which appear to be just as effective
and less environmentally harmful.  I use them not only for brake work,
but for general parts cleanup and wiping down my tools at the end of the
job.

In fact, here's a neat tip that uses spray-on brake cleaners for
something OTHER than brakes, one I learned from Bob Wandell ("The Import
Doctor"), a local Alfa shop owner, that helps when changing spark
plugs.  Changing spark plugs in an Alfa requires that you clean the
conical depression in the head where the plugs are located -- otherwise
grit, leaves, and other waste will fall into the combustion chambers. 
This assumes that you've got compressed air and an old but clean towel
readily available.

Take a spray-can of commercial brake cleaner, with the extension tube
that slips into the nozzle.

Spray brake cleaner all around one spark plug to loosen any oil, grime
or crud, which will run down to the base of the plug.  Then drape the
towel over the plug to prevent the cleaner from splattering all over.

Reach the nozzle of an air hose under the towel and spray a jet of
compressed air all around the plug, so that it sprays the liquid cleaner
up into the air.  Be careful to keep the towel in place so that the
cleaner doesn't get out -- it can mess up paint, and it's not a good
thing to get in your eyes (though it doesn't hurt as bad as you'd think
- -- ask me how I know...  I am now REALLY anal about eye protection, and
I recommend it to y'all as well.)

Check around the plug and make sure you've removed all the crud, then do
the rest of the plugs.  You can always give a quick wipe to the conical
depression with a clean rag to be sure, but the air jet will blow away
any sand, grit or crud that may otherwise fall into the cylinder.

In short: if the "Brakleen" brand brake cleaner is available in NZ, it
gets my highest recommendation for brake work as well as general cleanup
and degreasing.  

- --Scott Fisher
  Sunnyvale, CA

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