[MR2] Anyone rebuilt a mastrer cylinder before?

[Aaron Willis]

As big a cheapskate as I am, I've rebuilt (rather than replaced) dozens
of brake and clutch components, and will doubtless do more in the
future.  It's a very simple procedure.  Remove the master cylinder, and
then remove a snap ring on the back end of it, and all the guts will
come tumbling out.  This is where the honing your friend mentioned comes
in.  You will need a brake cylinder hone and an electric rill.  Here are
some brake cylinder hones for reference.  Be sure to get one that is
small enough to get into the master cylinder bore:
http://www.mytoolstore.com/kd/kdbrak08.html

The honing procedure is child's play.  Chuck the hone in the drill,
insert into bore, dial in some preload, pull the trigger, and keep the
hone moving up and down the cylinder as it rotates.  I usually use about
half-speed on the drill (600 RPM or so) but I suspect that's not
critical.  Use some lubrication though to avoid chatter and/or damage. 
I do the honing under running water - yes, water - to flush away
material as it is removed from the bore and the hone.  Water is
obviously not something you want in the brake system by any means, but
it will absorb the remaining brake fluid, thus making for easy cleanup,
and is benign and cheap.  Final cleanup is also criminally easy; just
rinse it thoroughly and dry it by any convenient means.  Compressed air
or heat are ideal.  I'm sure the use of water will rub some people raw,
but it sure beats trying to chase incompatible fluids out of a part, and
if dried correctly, no water will be present on assembly.

One other note: most aftermarket rebuild kits contain nothing but the
rubber seals.  Toyota's rebuild kit includes the seals, pistons,
springs, etc, basically everything that goes inside the master cylinder.
 Wherever you source it, I would always suggest a Toyota rebuild kit
over an aftermarket version.


On Sat, 3 Jan 2009 11:08:10 -0800, "William Brandt"
<wbrandt1 at sbcglobal.net> said:
> Well, yesterday I got a surprise. Being unemployed since March and going 
> back to school in 2 weeks, I thought it would be nice to finally fix that 
> pesky s l o w (every 6 months top off) m/c and while I was at it replace
> the 
> original brake hoses.
> 
> I spoke with my friend Ralph Willis at Maita Toyota - I have known Ralph
> for 
> years and he is an ex factory mechanic with lots of advice - anyway -
> 
> Toyota no longer stocks the master cylinder for the 85-86 - don't know
> about 
> the 87 but Ralph said by the part number it changed a bit - no remans 
> available (?????)
> 
> But he discovered that there is an assembly you can buy that fits in the 
> "bore" - he said some honing should be done first to clean out the bore - 
> told me the procedure - anyone done this?
> 
> It surprises me because usually a manufacturer will stop supplying sheet 
> metal or trim before necessary parts -
> 
> Wondering if any of you have done this?
> 
> BTW the savings would be substantial - a new m/c if available would be
> about 
> $185 (my cost) - list over $200 - while the kit he said was around $60.
> 
> Bill 
> 
> 
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-- 
Aaron Willis - '85 AW11 7A-GE, MSnS-Extra, E85, etc
Club discount on OEM Toyota parts - email me at work! awillis at lithia.com