<< I do have a confession to make- there is one person on the list who's
e-mails always get read first and saved. These are from Thomas Walter,
whom I would readily nominate as the most "Learned Roadsterite".
FWIW
>>
Uh, thanks! I always look for postings from Gordon, Bill,
Ross, and quite a few other folks as well.
Nice thing about the list is just being able to have
a "roadster meet" every morning over coffee (usually
when I catch up on email). At times I get swamped, and
pretty much am off the list for a few weeks... other
times probably a little too verbose.
So with all that, boy did I blow it this weekend!
A friend needed brakes done on her 280ZX. I explained
I would be glad to help out, but I am not cheap*. ;-)
Got the rear pads and rotors replaced last week. Did
help a shimmy under braking problem. This weekend I
replace the front pads, repacked the wheel bearings,
and cleaned up the "sliders" on the front brakes.
Also replaced a couple of bad rubber hoses on the
front brakes, and flushed the brake fluid through
the system.
In a bit a of a rush to head over to the roadster
meet, I let Sharon drive off in her Z without doing
my test drive and "bed in the brakes". DUMB!
She called in a bit of panic this morning, but
seems her car was not stopping as well as it had!
YIKES!
Got it back up here, and took it for a drive.
It would pull sharply to the left under braking.
Odd. Usually if one caliper is working better than
the other, that happens. I took it up to 70 mph,
checked the mirrors, and STOMPED the brakes hauling
it down to 20 mph. Drive a bit (let the brakes cool),
and repeated this routine for a good five times. Usually
I will do a series of ten hard stops to make sure the
brake pads are "bedded" in, but I really have not had
to do this with more modern brakes in some times.
Once I got the brakes nice and hot... the car took
for ever to stop! WHAT. Air in the lines. Acted much
worse when hot.
Dawned on me yesterday, when I was bleeding the brakes
I let the master cylinder get too low. Probably sucked
in a good amount of air into the line. Despite the
multiple bleeding (to purge all the old fluid out of
the system, and replace it with new fluid) air was
still in the system.
This time I started with bleeding the master cylinder
first. That is why those bleed nipples are there.
Hooked up my trusty hose (silicon hose I found at
the pet store for a fish tank, flexible to fit over
the nipple nicely, and remain tight). I do a "loop"
over the nipple, then down into a catch can. Assistant
will pump the brakes then "hold it" as I crack open the
bleed nipple (7/16" wrench on a roadster). Nice pulse
of fluid, then close the nipple and let you assistant
"pump and hold it" again.
Once the master cylinder is done, I will move to the
spot furthest from the master cylinder (left rear on
the roadster. I know, but it if the LEFT rear due
to all the plumbing). With the car on excellent jack
stands, I crawl under it until I get at the rear
nipple. Once again "pump and hold it". After four
series, refill the master cylinder with fresh fluid.
The old yechy fluid (usually brown or black) will
soon be coming out clear (you've flushed that line).
Repeat on the right rear brake, then the left front wheel,
then right front. Do not let the master cylinder get too
low on fluid or you'll "suck air".
With the silicon hose, and "loop it up" then back into
the catch bottle it is a simple mater of seeing what
the fluid looks like. If you see a little air bubble,
do not worry. Since the nipple is sealed at the bottom,
and not by the threads a little air will get back in
around the threads. Hence the little air bubble.
I have used this trick to bleed brakes solo. I'll
crack open the brakes, pump like made, then close
it. Since I use anti-sieze on the bleeders when I
rebuilt everything, it prevents air from leaking
back in, so I can do a solo bleed pretty easily.
There are also some "check valve bleeders" that I
have seen, but seems you should use them with
a little teflon tape around the bleeder threads
to prevent a little air from getting back in.
OLD BRAKE FLUID: NASTY STUFF! I'll stock pile it
in the original Castrol GT/LMA brake fluid bottles,
but mark them "old brake fluid". When we have our
semi-annual hazardous waster drop off, I'll collect
up all the bottles and drop them off.
For the roadster:
TOOLS:
STURDY JACK STANDS.
18" of silicon air hose (fish tank air hose). Good stuff, not
the cheap hose.. you'll never get that stuff over
the bleed nipple.
2 bottles of Castrol GT/LMA (12oz size).
7/16" wrench for the bleeds. (An 11mm also fits, but if you
find a 10mm on the rear, someone used 510 brake
cylinders!)
A helper who understands "pump" and "hold".
Agility of a 18 year old (man, climbing under the car,
then back out to refill a master cylinder
is getting harder for me). Maybe a second
helper to keep the master cylinder full
while bleeding?
Porter, Stout, or Ale (heck helps me get under that car!).
Back to the 280ZX. After getting the brakes "bedded in"
and bleeding the master cylinder (air!) the car was back
up to proper stopping. Still a slight pull to the left
under braking, which is odd. If pads are not bedded in,
they can glaze over. It is possible, but need to check
a little further.
Total was about $200. $100 for parts (discounted), but
included rear rotors, front and rear pads, front brake
hoses, and front grease seals. $100 for labor, which
I'll use for my fund raising money! ;-)
MORAL of the STORY: DO NOT RUSH THE BRAKES, and ALWAYS
test drive it before letting someone else head off for
home! Dumb on my part, just grateful she didn't get
into an accident on the way home!
Your Humble Servant,
Tom
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