Re: squeaking and nosediving

[Scott Fisher <sfisher71@domain.elided>]

--- bradley artigue <brad_artigue@domain.elided> wrote:
> Hello everyone,
> 
> Even with new brake pads my 82 Spider has squeaky
> brakes. 

There's an adhesive spray goo that many people (and
shops) like to put on the backs of the pads -- keeps
them from vibrating under partial pressure.  I've
never used it.  

However, you have bigger problems than squealing
brakes, so let's talk about them.

> I am inclined to suspect the master cylinder,

While the MC may be causing problems for you, it's
neither the first nor the only thing I'd suspect given
your other symptoms, and here's why.

> 1) The braking action is not smooth but seems to
> have two "phases" - soft and hard ON

That could be an MC problem (and no sniggering from
the rest of you, thankyouverymuch).  So when you bled
the brakes, did you read the part in the manual that
told you that you could feel this when you had both
brake bleeders from one side open?  (You *did* bleed
the brakes by draining first both wheels on one side,
then both on the other, yes?  Spider, Berlina and GTV
dual-circuit braking systems require this -- no idea
about Milanos and 164s.)

> 2) The squeal is random, moving from brake to brake
> (and sometimes not at all). 

So... the master cylinder is in one place.  The
individual wheel cylinders are in different places. 
I'm suspecting that it's the individual wheel
cylinders that are not always working properly...

I'm particularly suspecting that you've got one wonky
wheel cylinder that isn't always acting like it
should, and that the dual-circuit system is unable to
get anywhere with it (the soft phase of your pedal)
and then it works when the MC gets to the circuit for
the other side (the hard phase).  The squeaking may be
inconsequential.  If pressed to make a one-in-four
bet, I'd bet it was the right front caliper that's
giving you problems, for no reason other three or four
of the five or six cars I've done brakes on all had
stuck right-front calipers.  No idea why it's usually
that one, but two M.G.s, an Audi, and an Alfa have all
had stuck right front calipers.  Go figure.

> The brakes are properly bled.

So you *did* bleed first one side, then the other,
yes?

> 3) When I got the car the resovoir was nasty and
> impossible to clean up.  
> The car still had what must be the original brake
> fluid (107000 miles).  It 
> has since been changed but I think the damage has
> been done.

The Berlina was like this when I got it, with many of
the same symptoms (mushy pedal, black goop in the MC,
uneven braking).  So far I've only flushed the fluid;
it got better for a while but has since deteriorated,
which is why I know the approximate prices for brake
components off the top of my head. :-)

It's that cruddy black brake fluid that has me
convinced I need to rebuild the calipers as well as
replace the MC.  The black gunk came out the bleed
hoses immediately -- the stuff inside the calipers was
as black as the stuff inside the reservoir on my car. 
It's ALL bad in there -- fix everything.

> Thoughts?  Individual caliper action is good 

What did you to do determine this?  I see you recently
replaced the pads -- did the pistons all retract
cleanly when you put in the pads?  That's a start, but
it doesn't guarantee proper action.  When the rubber
seals deteriorate, sometimes there can be weeping
around the seals, or a piston can get cocked in the
cylinder and not move correctly or something.  Or it
can allow air to weep into the system and give you
problems that way.  

> and the calipers are not internally corroded. 

Have you already pulled the pistons and inspected
them, or is this again just based on the fact that the
pistons retracted easily (that is, you didn't have to
bang on them with a hammer) when you slipped the new
pads into place?

Even if the calipers aren't corroded, I'll bet you
that a good portion of the black crud that came out of
the system was dissolved rubber, and it wasn't ALL
from the master.

> I'm thinking MC, what do you think?

I'm thinking the MC is only about $90 worth of the
$250 in parts required to rebuild all four calipers,
replace the master, replace the rubber flex lines, and
install new pads, so you might as well do it all at
the same time.  And since you've already put in pads,
that's about $70 off my estimate, so you're only maybe
$180 plus shipping away from having perfect brakes.

I am a firm believer in overkill when it comes to the
brakes.  Yes, you could individually rebuild each
caliper and then the master till the problem was
solved and then you could say definitively which one
thing was the worst.  But you'd have to refill and
rebleed the brakes each time, and that costs another
$5 and takes another 20 minutes, and I'm just too
cheap and lazy to spend the time and money to find
exactly what's wrong over the course of several
weekends when I can do it all at once and have the
whole system just be RIGHT. :-)

Besides, and more seriously, the brakes are a system,
and if you've got deteriorated rubber in one part,
you've almost certainly got it in other parts.  The
caliper rebuild kits are only about $13 at most
providers (IAP, Centerline, and Vick Autosports are
the catalogs I've been reading), and calipers are
fairly easy to rebuild -- at least it's easy if you've
got compressed air.  

Now, I understand the realities of each individual's
budgets and car situation differ, and you may need to
do the MC this month, and the calipers the next, and
the hoses the month after that.  I can afford to let
the Berlina sit in the driveway till I can spend the
full $250 on the brakes and do it all at once, as I've
got other cars with good brakes that I can drive (and
with the weather as nice as it's been, driving any car
other than the Spider makes my lower lip quiver and a
tear well up in my eye).  So that's why I'm saving up
my pennies to do it all at once -- the fact that I'll
only have to bleed/flush once as I'll have all the
components out at the same time is just gravy.  If
this is your only car and you can't wait or leave it
down for a month, then by all means start with the MC.
 It could also be that the MC seal for one of your
braking systems has worn out and the other one is
good, which is why you're getting the soft/firm pedal
action.  But I'd be pre

However, I'll add one other comment about the uneven
braking -- and it's hearsay, but plausible: A friend
once traced his car's uneven braking to an internal
tear in one of the rubber hoses.  It was acting like a
valve: press on the pedal and the system would
pressurize, but the backpressure was keeping the torn
flap in place and refusing to release that caliper. 
Didn't happen all the time, but it happened enough. 
Eventually the blister on the brake hose got his
attention, he dissected it (after replacing the brake
hose) and saw the torn flap.  Once again, brake hoses
are fairly cheap, easy to install, and require
bleeding/flushing when done.  

So take a look in your catalogs and your on-line
providers and any other resources you've got in your
neighborhood -- see what's involved in rebuilding the
rest of the brakes as well as the MC.  

If nothing else, compare the $13 or so for the caliper
kits plus the $15 or so for each of the (three) flex
hoses to the cost of a new Spider nose cone...

--Scott Fisher
  Tualatin, Oregon
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