stuck caliper...

Confound it!! So I was all set to replace clutch master and slave cyls
today on my 94 Civic, and hit a massive NYC pothole on the way to my
friends' garage (level, enclosed). Shortly after the pothole I hear this
scraping sound from my left front wheel, worse when I braked.

So I get to the garage and get the wheel off to discover that the
outside pad is worn completely down, compared with the right wheel which
has still thick pads with tens of thousands of miles left on them. The
pothole must have knocked out the last vestiges of the pad, thereby
causing the backing plate to score the rotor. DAMN! I don't think it's
scored too badly to use--a bit within the outside half-inch of the
rotation. I expect the new pads would seat OK after a few thousand
miles. I'll sand it a tad to deglaze--180-grit OK?

OK, I flip the caliper up and find that the damned piston is stuck
extended. The other side is retracted as it should be. Looks like I get
to do my brakes now, too. Hell, may as well get my hands even dirtier...
I'm game. Too bad my wife and I have to take the train to our
Thanksgiving destination...

Q is this: I didn't have time to deal with disconnecting the brake line
to see if it's the hose that's frozen (it bends fine, but I guess that
wouldn't tell me much). How should I proceed? Hose or caliper? I don't
have the ability to spend days running back and forth between the car
and the auto parts store, which would have to order the parts anyway, so
I'd rather order more and return what I don't need.

It appeared that the hose is in several sections. Is there a likely
section that gets plugged? I've checked Majestic and SL Honda online,
and can't find a front caliper assembly in the parts list. I'm in the
right section, but no caliper listed, and the ominous "some of the parts
displayed may no longer be available" note on the diagram. I can't find
the hoses at all. HELP! Any problem getting these parts through my local
auto-parts place?

An item of note: the piston doesn't screw in on the front. Don't know
about the back, but I can just use a C-clamp on the front. BTW, I picked
up Bendix "OEM" pads before I thought to check if the caliper was
stuck--these OK?

Thanks as always for the collective wisdom here. I'd be less confident
without you.

 

INNER pad worn, outer pad not:
1) Caliper pins seized and caliper not floating
2) Outer pad seized on mount bracket and not floating

OUTER pad worn, inner pad not:
1) Inner pad seized on mount bracket and not floating

Brakes dragging:
1) Piston seized in caliper bore

Parking brake ineffective:
1) Aftermarket pads
2) Parking brake clevis seized and not pivoting
3) Parking brake cam shaft weather seal failed

Brakes pull to one side:
1) Sticky caliper piston on one side
2) Seized pad or caliper on one side

50 grit is better. Sand all you want.

You mean you can't push the piston in with a C-clamp?

Then the piston is seized in the caliper. Time for a rebuild or replacement
with remanufactured calipers. A tip here: replace the PAIR. If you don't
you'll likely find the brakes will pull to one side. Maybe try replacing
the one side, if you get pulling replace the other.

*Highly* unlikely anything's wrong with the lines. 99% of brake trouble is
with the calipers, sliders and pads.

Because it has no parking brake.

On the back you have drums.

Those AREN'T "OEM". They are aftermarket "OEM style". Roll of the dice here
for you.

Collective wisdom can be found condensed here:
http://www.tegger.com/hondafaq/rustybrakes/brakeintro.html

 

On a 94 Civic EX? (Abness has posted in the past that he has an EX.)

Majestic says at least some EX's have disc brakes on the rear.

 

I haven't seen reports of brake hoses plugging with debris.

Brake pistons do freeze in their cylinders, though. I completely disassembled my
front brakes this past summer. As you can imagine, it doesn't take but a little
rust buildup on the piston/cylinder walls to impede operation.

Rust comes from moisture getting into the brake fluid. Brake fluid does have a
chemical tendency to absorb moisture, so a little rust shouldn't be a surprise.

I double checked you at Majestic (94 Civic EX manual tranny) and see what you
mean.

Yet they have the caliper listed for my 91 Civic. It's also listed for the 93
Civic EX.

I'd email Majestic. I bet they have a full caliper. Better, they do sell
remanufactured calipers. Still better, have you ever worked with local salvage
yards? I priced remanufactured calipers at these where I live and even went to
look at them. They look a lot better than mine (externally). The price was far
less than Majestic's new calipers and IIRC their reman'd calipers, too.

Autozone and/or Pep Boys I believe sells reman'd calipers, too.

I'm not sure what the consensus is here at the group re Autozone et al. reman'd
calipers, though. I think some folks have concerns about non-OEM rubber. Isn't
as tough, in short, but I dunno how true this is.

My own experience: My 91 Civic is on its third set of pads. Both the second and
third set of pads were non-OEM. I think the second set was intermediate in
price. The third set is Raybestos, top of the line for my car. I checked for
rotor wear a few months ago, and nothing seems out of the ordinary. At the
current rate, if thickness is the only consideration, they should easily last
another 159k miles.

I'm pretty sure next time I need new pads I will go OEM, though. First, because
they are about the same price as the top of the line Raybestos I bought. Two,
because I am a bit concerned that the Raybestos pads are harder. So they last
longer, but may be wearing the rotor more. Even though I don't have any signs of
abnormal wear.

I do have some scoring on one of the rotors, but the brakes work fine. I'll
monitor it everytime I rotate my tires, but otherwise I lose no sleep over it.

I have a manual transmission and almost always downshift, using the engine to
brake, though, so brake problems will be less obvious unless I go looking for
them.

I'm sure others will comment about pads here, so keep checking back, as always.
Or you can google. It comes up a lot.

 

Blast! I just wrote a whole message but Thunderbird ate it. First time
that's happened. Will try to reconstruct

Actually, discs. Civic EX with ABS.

Just finished reading your FAQ--fabulous. Thanks for taking the time and
care to put that together.

You mention "too many problems" with aftermarket pads. Such as? I don't
care one way or the other, the Bendix cost about the same as OEM. (BTW,
I know they aren't actually OEM, that's why I stuck it in quotes.) On
nice thing was that the shim was made out of aluminum--no rust issue
there, though I do wonder if there could be a disintegration issue. They
do come with a "lifetime" warranty, whatever that means fo brake pads,
so I guess the aluminum shims work out fine.

I'm particularly intrigued by the pins question. It seems to me from my
recollection that the lower pin was frozen, but I didn't fully
appreciate the problem until seeing your FAQ. The upper was fine, nice
and greasy and smooth, and I didn't see any rust.

Given that a reman caliper, which I just found after calling Majestic,
is only $72 (well, a bit more after shipping back the old one to recover
the whopping $140 core deposit), it doesn't make sense for me to rebuild
it if the piston is in fact seized. I didn't have a C-clamp handy
because I had thought there were screw-type pistons all around. As I've
said, I'm new to this level of auto work.

Thanks again for the great brake FAQ.

 

That's good. It happened on my old Pontiac, hence the question.

Yeah, I called them earlier and they pointed me to their reman section,
found 'em there.

Maybe I'll give the Bendix pads a shot, and keep an eye on them. They
are the "ImportQuiet" line, which makes me think they'll be softer, and
I'll just get an idea of how long they last. I'll google around, too.

Same here.

 

Hm. Didn't know that, thanks. Must be just the lower models that had drums,
then.

 

"Caroline" <> sprach im

I find it's more often gum than rust that sticks up the pistons. Rust tends
to invade from the outside, weather being the source. Rust sticks at first,
but rapidly becomes a fluid leak.

Honda, unlike Toyota, uses non-stainless steel pistons. Toyota's are
stainless. Wish Honda would do that too. With Toyota you just clean the gum
off and put it back. With Honda you end up replacing the piston, and it's
not cheap.

One problem with reman calipers is that nobody seems to use silicone grease
on the piston and seals when putting it all back together. They all use
brake fluid as a lubricant because it's cheaper. Silicone grease helps
prevent the buildup of gum and keeps the pistons moving freely for much
longer. Brake fluid dries out and BECOMES gum.

If the caliper is not yet installed, you can just pop the piston out of the
new calipers with some air pressure (even with a bicycle pump with some
electrical tape wrapped around the end to seal it), smear it with some
silicone and reinstall. Observe surgical cleanliness here, by the way,
that's crucial.

If it's already installed, it's a bit more complex:

You can get around this with the judicious use of a syringe from a
woodworking supply store <http://tinyurl.com/6z9j2>, and some silicone
grease.
http://www.tegger.com/hondafaq/rustybrakes/syringe.jpg

What you do is to have a helper step on the pedal as necessary to push the
piston out of its bore most of the way, so the dust boot is mostly
extended. One full pedal push will move the piston about 1/16".

NOTE: ONLY do this if you've been regularly using the pedal-push method of
brake bleeding, or put a block of wood under the pedal so it can't go any
farther than what it does in normal driving!

Use Brakleen or other aerosol brake cleaning solvent to remove the dirt
from the piston and boot first.

Then you ease the syringe under the boot and inject silicone as close to
the hydraulic seal as possible all around the perimeter of the piston. Turn
the piston with a set of channel-locks so you can more easily apply
silicone to the portion that was closest to the top of the caliper. Now
push the piston back in all the way with a C-clamp. Pedal-pump it back out
again and repeat a few times.

When you're done, if the siliconing has been done properly, you should see
the piston move out with a pedal push, but then move back IN again slightly
when the pedal is released.

The grease is just silicone dielectric grease. I use Zip-Slip just because
for me it was easy to get. http://www.themoldersedge.com/polish.htm

Here's another example:
http://www.mgchemicals.com/products/8462.html

Googling for
silicone dielectric grease
turns up many more.

 

sometimes they just collapse on the inside. the outside might have a
plastic coating so you dont know. pretty rare, though.

different strokes

id rather replace 5 sets of front brake pads than 1 clutch. FWIW,
sometimes i "blip" the throttle and slip it into neutral and coast to a
stop. and if i wanna mess with someone who i think might be a bit too
close, ill use the parking brake

 

ive never had a "problem" per se, with aftermarket. maybe a little more
noise or dust, but nothing i cant live with.

as long as you can take the worn out pads back and get a new set from
the same place, its all good.

nah- screw type in the rear. get a large c-clamp from a place like
harbor freight and try it.

you might not really have a stuck caliper at all. who knows?

 

"Downshifting" without double-clutching is not smart. You are NOT supposed
to use the clutch as a brake pad.

Downshift properly and there is zero wear on the friction disc.

 

If you have an authoritative web citation on how much the clutch parts wear due
to engine braking, I'd love to see it.

At 159k miles with the original clutch on my 91 Civic, and no signs of clutch
failure, I'm not inclined to change my braking style.

I did a quick Google and some folks say the wear on the clutch is insignificant.
Others say as you do.

 

What a lot of people do is to use the clutch like a brake pad, which means
they let the clutch slip to achieve braking action. They let the engine
revs fall, then engage the clutch in a lower gear to use the lower revs to
pull the car speed down. It's functionally as though they were using the
parking brake to slow the car, but using the clutch as they would the
parking brake.

Ignorant. And very expensive.

As of today, 237,811 miles (and counting) on my original. Owned the car
since new, too.

There's still about 1/4" of thread showing on the cable sheath before it
runs into the rubber jacket. How many miles is that? No idea. Could start
slipping tomorrow for all I know.

 

if the seal is running on a corroded surface. where you have a steel
piston & an aluminum cylinder [like the master cylinder assembly], the
seal is static on the steel, and slides on the non-corroding alloy
surface. in this situation, there is little or no wear acceleration
above what would happen normally. the exception is where corrosion is
chronic on a system that has not moved /and/ has badly contaminated
[wet] brake fluid. then you get electrolytic reactions between the
steel piston & alloy cylinder & severe pitting, but even then, due to
cunning design, the main compression seals are ahead of the pitting area
as the pistons are behind them. the exception is the wiper seal at the
rear, and if that leaks, it's a pita, but it's not as serious as a main
compression seals.

for front [honda] slave cylinders, you have a very hard smooth well
sealing surface for the seals to slide on, the chrome. as long as the
chrome remains intact, again, wear is insignificant. chromed pistons
can corrode, but that is lessened considerably by regularly changing
brake fluid and doing the silicone trick you describe below.

the stainless/non-stainless argument has factors in favor for each.
stainless can still corrode. depends on environment & grade. most
stainless still pits badly in salt. honda [nissin, etc.] pistons are
chrome plated forged steel. this is a very high quality base
material/fabrication route. chrome plating is also many times more wear
resistant than most stainless steels. there's also the potential for a
fatigue advantage - stainless has no fatigue endurance limit, a lot of
non-stainless [ferritic] steels do. finally, the smooth surface of the
chrome is pretty much as good as it gets for fluid seal quality & long
life - as long as it remains intact.

as above, the single easiest way to prevent corrosion on a chrome steel
piston is to make sure the brake fluid is changed regularly.

the silicone grease is very important. but brake fluid is cited for the
inner seals because it contains rubber preservatives. left to its own
devices, the rubber would become hard & crack over time. my personal
view is to lightly silicone lube the piston on assembly, then ensure the
boot has sufficient silicone to make the seals air/water tight from the
outside.

don't agree about the block - see above. both you & curly regularly
repeat that advice. i don't doubt the sincerity of your intent, but
it's bad advice in any situation requiring brake bleeding. i can see
that it's possible to get away with it on hondas because they bleed
quite easily, but other vehicles can be sob's and the /only/ way to
bleed them reliably is to use full pedal travel to expell all air.
otherwise the air simply compresses & expands within the cylinder again
the moment the pedal is released. if the cylinder is corroded enough
for this to be a concern in the first place - it should be replaced
anyway. pitting can be a fatigue nucleator. i've never seen it happen,
but theoretically, a cylinder could burst if a fatigue crack propagated.

i appreciate the concern about scoring seals & causing leaks, and on low
grade detroit iron, that has some validity, but in high quality honda
systems, corrosion sufficient to be a concern is rare. any
"coincidence" about leakage following any brake bleed proceedure is much
more likely to be caused by fresh brake fluid interacting with
contaminated old seals.

much better to disassemble and clean the whole workings. all pressing
the piston back in does is ensure the goop gets forced up past the seals
contaminating the fluid & getting stuck in the cylinder/piston gap where
it can cause wear & further corrosion.

/if/ pushing the piston back, it's also prudent to open the bleed nipple
first. avoids pushing contaminated fluid back up into the master cylinder.

thanks for the links! like your applicator!

 

If you re-read my paragraph above, you'll see I was recommending the block
of wood under the pedal for the purposes of pushing the piston out so you
can inject silicone grease under the dust boot. I did not mention bleeding.

If the brakes have been neglected, full pedal pushes are distressingly
likely to wreck the master cylinder seals.

 

jim beam <> sprach im

Of course, but I'd rather have air in the system than a failed master
cylinder, which is what you're likely to get if you try the full pedal push
method with brakes that have been neglected.

If the brakes have stubborn air in them, the answer is to remove the
caliper from the mount bracket so you can turn it in your hands. Put a
block of wood in to keep the piston from moving, then while turning it, tap
it with a nylon mallet and then bleed. The shocks of the mallet will jar
the bubbles loose.

The only seals are the hydraulic seal in the caliper and the master
cylinder (unless you have ABS). The fluid would have to be pretty bad to
have the master cylinder damaged from pushing the fluid back through it. If
it's that much of a concern, bleed the brakes before pushing the pistons
in.

That's a good idea.

 

don't get me wrong tegger, i'm not criticizing you - just pointing out
stuff i've learned. you can see the same wear features appearing in
working non-leaking parts that have seen a few years service as you do
with stuff that's known to be defective. the only difference is the
degree of wear. rubber seals that have not oxidized or de-polymerized
are very resilient. if you're talking some junky old piece of iron
that's of the kind that can host corrosion all the way down the master
cylinder, you're right, seals can see accelerated wear. but that
cylinder's not long for this world anyway because the seals are probably
degrading chemically as well as wearing physically.

check the difference in physical properties of a new seal and one that's
old, crusty & known to leak. the new ones are flexible, tough & don't
retain marks in the surface if you press with your fingernail. old ones
are either soft like a gummy bear if they've been contaminated with oil,
or hard like some old paint from the bottom of a dried out can if
they've oxidized. both retain marks from the fingernail test because
the material's surface has degraded.

bottom line is that if the component can't function to spec, and that
includes the ability to use the full length of the cylinder in the event
of brake line outage or something, then it should be serviced or replaced.

 

OK, thanks for the info.

Seems crazy to me. I mean, aren't they designed to wear out? Must refer
to faulty materials, not regular wear, but I'll read the fine print.

That's what I'm hoping. Will try on Tue and hope for the best.

 

I'm hoping the caliper is fine and that I won't have to replace it now,
but if I do, is there any place I *don't* want to smear the silicone
grease? If I'm smearing it on the piston (even just on the sides where
it contacts the cylinder) I'd think it would come into contact with the
brake fluid--that's OK?

I doubt I'll be disassembling the installed caliper to grease it, would
be more cost effective to replace it, I think.

Thanks for the links to the grease. Hopefully the hardcore h/w store I
go to in Brooklyn will have an equivalent.

 

Don't get silicone on the rotor friction surface. But since the caliper is
OFF the rotor as you work on it, that's not a problem. Anywhere else is
fine, including contact with the brake fluid.

You don't need to disassemble the installed caliper. The procedure I gave
specifically avoids that.