Subject: Re: [Shop-talk] Sticking/Draging caliper

From: [email-masked]
Date: Tue, 5 Jan 2016 20:00:12 -0500 01/05/2016 19:59:58, Serialize complete at 01/05/2016 19:59:58

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I just went through this on an older truck. I had to replace ALL rubber 
hoses on the system (upstream of that brake.)

Once I did, I cut open the hoses to see that they were almost completely 
collapsed (even thought they looked fine from the outside.)

I took pics of them, but I can't find them (I think I deleted them because 
they didn't come out that well.)

I'd start there.

Sent from my Commodore 64 on a 2400 Baud Modem.
Eric P
"Be as beneficent as the sun or the sea, but if your rights as a rational 
being are trenched on, die on the first inch of your territory." Ralph 
Waldo Emerson 
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<font size=2 face="sans-serif">I just went through this on an older truck.
I had to replace ALL rubber hoses on the system (upstream of that brake.)</font>
<br>
<br><font size=2 face="sans-serif">Once I did, I cut open the hoses to
see that they were almost completely collapsed (even thought they looked
fine from the outside.)</font>
<br>
<br><font size=2 face="sans-serif">I took pics of them, but I can't find
them (I think I deleted them because they didn't come out that well.)</font>
<br>
<br><font size=2 face="sans-serif">I'd start there.</font>
<br><font size=2 face="sans-serif"><br>
<br>
Sent from my Commodore 64 on a 2400 Baud Modem.<br>
Eric P<br>
&quot;Be as beneficent as the sun or the sea, but if your rights as a rational
being are trenched on, die on the first inch of your territory.&quot; Ralph
Waldo Emerson </font>
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[email-masked]
Archive: http://www.team.net/archive

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From: Ian McFetridge <[email-masked]>
Date: Tue, 5 Jan 2016 21:17:28 -0500

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Is the left-rear caliper the furthest from the master cylinder?  On my
4Runner (2004) this was the first one that would exhibit sticking (I
measured the stickiness by driving around the block and measure the
temperature on each rotor with an IR temp gun).  All the pins, slides, and
eventually the pistons would corrode and drag.  I could take the calipers
apart, sand, wire-wheel, and lubricate to get them to work again (and lower
the relative temperature measured).  OR, I found I could bleed the system
(carefully/well) and get the far caliper to stop sticking for a while--I
think you were going this direction with your logic of a blocked line.
Perhaps, air in the lines doesn't allow enough vacuum to retract the
piston?  Or the bleeding washes out "gunk" (tech term!).

Ymmv,
Ian

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<div dir=3D"ltr"><div><div>Is the left-rear caliper the furthest from the m=
aster cylinder?=C2=A0 On my 4Runner (2004) this was the first one that woul=
d exhibit sticking (I measured the stickiness by driving around the block a=
nd measure the temperature on each rotor with an IR temp gun).=C2=A0 All th=
e pins, slides, and eventually the pistons would corrode and drag.=C2=A0 I =
could take the calipers apart, sand, wire-wheel, and lubricate to get them =
to work again (and lower the relative temperature measured).=C2=A0 OR, I fo=
und I could bleed the system (carefully/well) and get the far caliper to st=
op sticking for a while--I think you were going this direction with your lo=
gic of a blocked line.=C2=A0 Perhaps, air in the lines doesn&#39;t allow en=
ough vacuum to retract the piston?=C2=A0 Or the bleeding washes out &quot;g=
unk&quot; (tech term!).=C2=A0 <br><br></div>Ymmv,<br></div>Ian<br></div>

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[email-masked]

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From: Matt Wehland <[email-masked]>
Date: Tue, 5 Jan 2016 20:47:55 -0600

Not sure, but I think the passengers side is the furthest.
The brake fluid on this car is pretty clean, I flush it every time I 
change pads or work on it.
The rear brake hoses were replaced in the last year or two.
I bought front ones, but never put them on.
Looks like I will be grabbing the flaring tools and digging up fittings 
and brake line in the morning so I can replace the brake hose.
And replacing the fronts while I am at it.

This car has been pretty decent, around 200k on it so far, some repairs 
alternator, master cylinder, rear suspension, O2's,  but nothing that 
bothered me too bad for 10yrs 200k.

But brakes have been a hassle from day 1.
I always said that the master cylinder wasn't right, push down on the 
peddle and the car would start to stop fine, but then you had to keep 
apply more pedal pressure to keep it stopping.
Dealer mechanics said ' it stops fine'
And it did if you jammed the brakes, but used normally (and if you had a 
brain and some give a darn) you could tell something was wrong.
That and the fact that it ate REAR brake pads, while the fronts looked fine.
Master cylinder finally gave up, put new on in and the car stopped the 
way it should.

Also emergency brake cable (driver side) froze up years ago, causing 
dragging that caused enough heat to kill the OEM caliper.

Add to that pulling the whole rear interior apart looking for a clunking 
noise, just to finally figure out that the autozone supplied guide pins 
are too small and allowed the caliper to clunk around.
And then getting correct guide pins, lubing them with wheel bearing 
grease only to find out that the rubber seal on the guide pin was not 
compatible with the grease.
Rubber bushing swelled up like crazy.
Not only did it eat the brake pads, but took me forever to get the guide 
pin out of the housing.

Still like the car for what it is, but if I never have to touch the 
brakes again I would be a happy man.

Thanks for the advice and letting me vent.

Matt

On 1/5/2016 8:17 PM, Ian McFetridge wrote:
> temperature on each rotor with an IR temp gun).  All the pins, slides, 
> and eventually the pistons would corrode and drag.  I could take the 
> calipers apart, sand, wire-wheel, and lubricate to get them to work 
> again (and lower the relative temperature measured).  OR, I found I 
> could bleed the system (carefully/well) and get the far caliper to 
> stop sticking for a while--I think you were going this direction with 
> your logic of a blocked line.  Perhaps, air in the lines doesn't allow 
> enough vacuum to retract the piston?  Or the bleeding washes out 
> "gunk" (tech term!).
>
> Ymmv,
> Ian

-- 
Matt Wehland
(815) 295-4533

[email-masked]

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From: "Eric J Russell" <[email-masked]>
Date: Tue, 5 Jan 2016 22:03:20 -0500

> Is it possible for the hose to be slightly blocked, allowing pressure to 
> apply the brakes but keeping them from releasing?

Yes, the hose can delaminate internally and act like a one-way valve.

One way to check is to jack up the axle in question, apply & release the 
brakes and while noting the drag, crack open the bleed screw. If a little 
bit of brake fluid is expelled and the drag is noticeably reduced then a 
faulty hose is likely.

Eric Russell
Mebane, NC

[email-masked]

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From: Matt Wehland <[email-masked]>
Date: Tue, 5 Jan 2016 21:30:23 -0600

Thanks Eric, just the type of advice I was looking for.

Just tried it, got a little fluid expelled, but no decrease in drag.

Even so, the more I think about it, the more I am leaning towards hoses.
Thinking even the fronts could be impacting this, as if they swell/flex 
too much there might not be enough pressure in the system to retract the 
caliper.

Also the last few times I have done brakes on this car, I have not been 
able to get as firm a pedal as I wanted.
No matter how much nor how many times I bleed the brakes.

Probably one of the reasons I bought the front hoses, but I just never 
got around to putting them on.

Good intentions, lazy mechanic.

Hopefully replacing all the hoses will bring me some improvement.

Just not looking forward to spicing the hard line, not too hard, just 
never one of my favorite things.
And the location/routing of this one is not lending itself to an easy 
splice.

The hyundai  was the wifes daily driver, and she works a weird changing 
schedule, so never had much good down time before.
She just got a new car so it is now my second car (again).
Need to get it fixed up good enough so I can park my Mustang again and 
start working on it, lots of TLC needed on that one.  Lots needed.
Fiscally foolish to even put the money needed into the Mustang, but it 
was my first new car and I always planned on keeping it until I die.
So time to start spending 5k on a 3K car.

Matt

On 1/5/2016 9:03 PM, Eric J Russell wrote:
>> Is it possible for the hose to be slightly blocked, allowing pressure 
>> to apply the brakes but keeping them from releasing?
>
> One way to check is to jack up the axle in question, apply & release 
> the brakes and while noting the drag, crack open the bleed screw. If a 
> little bit of brake fluid is expelled and the drag is noticeably 
> reduced then a faulty hose is likely.
>
> Eric Russell
> Mebane, NC
>
>

-- 
Matt Wehland
(815) 295-4533

[email-masked]

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From: Jeff Scarbrough <[email-masked]>
Date: Wed, 6 Jan 2016 07:55:29 -0500

On Tue, Jan 5, 2016 at 10:30 PM, Matt Wehland <[email-masked]> wrote:
> Thinking even the fronts could be impacting this, as if they swell/flex too
> much there might not be enough pressure in the system to retract the
> caliper.

It's my understanding that most modern two-circuit brake systems
operate one front and one rear wheel on each circuit.  So pressure
held on a front brake might affect a rear brake.  But you could easily
verify by running the same apply>spin>bleed test on the front.  I
might look at the caliper support to make sure it's true to the hub
and secure to the car.  I also might try a different brand of caliper.
Rock Auto has several choices for about the same as the AutoZone
price.

Looking at the pictures, I'd make sure that E-brake lever isn't
flopping around and doing something unseemly.

And would it be less trouble to replace the entire brake pipe instead
of messing around underneath trying to make a splice?  Where's the far
end?

Jeff Scarbrough
Corrosion Acres, Ga.

[email-masked]

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From: Jim Franklin <[email-masked]>
Date: Wed, 6 Jan 2016 08:15:37 -0500

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For what it's worth, both my Subaru Impreza and my Mini Cooper use rears =
faster than fronts. And I can feel the rears bite before the front. =
Maybe it's a safety thing, to settle the car before really slowing it?

If I have to brake hard, I don't notice which bites first, but 99% of my =
braking is the last 50' or so, or removing just a bit of speed, so light =
braking, I can feel the rears, and sometimes I think that's all I'm =
using.

Did you replace the proportioning valve too? It might have a piece of =
gunk in there messing the L-R balance up.

jim

On Jan 5, 2016, at 9:47 PM, Matt Wehland <[email-masked]> wrote:

> That and the fact that it ate REAR brake pads, while the fronts looked =
fine.

--Apple-Mail=_883AF206-00CF-4D2E-94D3-871AAD536FDA
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<html><head><meta http-equiv=3D"Content-Type" content=3D"text/html =
charset=3Dus-ascii"></head><body style=3D"word-wrap: break-word; =
-webkit-nbsp-mode: space; -webkit-line-break: after-white-space;">For =
what it's worth, both my Subaru Impreza and my Mini Cooper use rears =
faster than fronts. And I can feel the rears bite before the front. =
Maybe it's a safety thing, to settle the car before really slowing =
it?<div><br></div><div>If I have to brake hard, I don't notice which =
bites first, but 99% of my braking is the last 50' or so, or removing =
just a bit of speed, so light braking, I can feel the rears, and =
sometimes I think that's all I'm using.</div><div><br></div><div>Did you =
replace the proportioning valve too? It might have a piece of gunk in =
there messing the L-R balance =
up.</div><div><br></div><div>jim</div><div><br><div><div>On Jan 5, 2016, =
at 9:47 PM, Matt Wehland &lt;<a =
href=3D"mailto:[email-masked]">[email-masked]</a>&gt; =
wrote:</div><br class=3D"Apple-interchange-newline"><blockquote =
type=3D"cite"><span style=3D"font-family: Helvetica; font-size: 12px; =
font-style: normal; font-variant: normal; font-weight: normal; =
letter-spacing: normal; line-height: normal; orphans: auto; text-align: =
start; text-indent: 0px; text-transform: none; white-space: normal; =
widows: auto; word-spacing: 0px; -webkit-text-stroke-width: 0px; float: =
none; display: inline !important;">That and the fact that it ate REAR =
brake pads, while the fronts looked =
fine.</span></blockquote></div><br></div></body></html>=

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From: Paul Parkanzky <[email-masked]>
Date: Wed, 6 Jan 2016 08:20:45 -0500

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All of my VW's have also used the rears faster.  Somebody once told me it
was to make the car brake flatter so that you don't feel the nose dive with
light braking.

-Paul

On Wed, Jan 6, 2016 at 8:15 AM, Jim Franklin <[email-masked]> wrote:

> For what it's worth, both my Subaru Impreza and my Mini Cooper use rears
> faster than fronts. And I can feel the rears bite before the front. Maybe
> it's a safety thing, to settle the car before really slowing it?
>
> If I have to brake hard, I don't notice which bites first, but 99% of my
> braking is the last 50' or so, or removing just a bit of speed, so light
> braking, I can feel the rears, and sometimes I think that's all I'm using.
>
> Did you replace the proportioning valve too? It might have a piece of gunk
> in there messing the L-R balance up.
>
> jim
>

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<div dir=3D"ltr">All of my VW&#39;s have also used the rears faster.=C2=A0 =
Somebody once told me it was to make the car brake flatter so that you don&=
#39;t feel the nose dive with light braking.<div><br></div><div>-Paul<br><d=
iv class=3D"gmail_extra"><br><div class=3D"gmail_quote">On Wed, Jan 6, 2016=
 at 8:15 AM, Jim Franklin <span dir=3D"ltr">&lt;<a href=3D"mailto:jamesf@gr=
oupwbench.org" target=3D"_blank">[email-masked]</a>&gt;</span> wrot=
e:<br><blockquote class=3D"gmail_quote" style=3D"margin:0 0 0 .8ex;border-l=
eft:1px #ccc solid;padding-left:1ex"><div style=3D"word-wrap:break-word">Fo=
r what it&#39;s worth, both my Subaru Impreza and my Mini Cooper use rears =
faster than fronts. And I can feel the rears bite before the front. Maybe i=
t&#39;s a safety thing, to settle the car before really slowing it?<div><br=
></div><div>If I have to brake hard, I don&#39;t notice which bites first, =
but 99% of my braking is the last 50&#39; or so, or removing just a bit of =
speed, so light braking, I can feel the rears, and sometimes I think that&#=
39;s all I&#39;m using.</div><div><br></div><div>Did you replace the propor=
tioning valve too? It might have a piece of gunk in there messing the L-R b=
alance up.</div><span class=3D"HOEnZb"><font color=3D"#888888"><div><br></d=
iv><div>jim</div></font></span><span class=3D""><div><br><div><div>On Jan 5=
, 2016, at 9:47 PM, Matt Wehland &lt;<a href=3D"mailto:[email-masked]=
" target=3D"_blank">[email-masked]</a>&gt; wrote:</div><br><blockquot=
e type=3D"cite"><span style=3D"font-family:Helvetica;font-size:12px;font-st=
yle:normal;font-variant:normal;font-weight:normal;letter-spacing:normal;lin=
e-height:normal;text-align:start;text-indent:0px;text-transform:none;white-=
space:normal;word-spacing:0px;float:none;display:inline!important">That and=
 the fact that it ate REAR brake pads, while the fronts looked fine.</span>=
</blockquote></div></div></span></div></blockquote></div><br></div></div></=
div>

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From: Matt Wehland <[email-masked]>
Date: Wed, 6 Jan 2016 07:24:40 -0600

On 1/6/2016 6:55 AM, Jeff Scarbrough wrote:
> end? Jeff Scarbrough Corrosion Acres, Ga. 

That is my thought too, have to get the front off the ground and get 
under it to see.

-- 
Matt Wehland
(815) 295-4533

[email-masked]