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Old January 8th 18, 11:20 PM posted to alt.home.repair,rec.autos.tech
Meanie[_3_]
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Default Drum brakes - do you disconnect the parking brake cable?

On 1/8/2018 1:34 PM, Mad Roger wrote:

>
> Thanks for your help as this is my first set of drum brakes ever.
>
> This is a side view closeup of the front unevenly worn shoe:
> https://s13.postimg.org/mezt8lvs7/brakes_drum_4.jpg
>
> I had been, for years, looking through the peep hole, but that showed a lot
> of meat on the shoes. You really have to remove the drum to see the actual
> shoe, so, after 175K miles on the same shoes, I finally removed the drum
> and noticed that the front show lower end, is worn tapering to the middle,
> while the rest of the shoes are just fine.


>
> The cylinder seems to not be leaking but that's all I can tell.
> There have been no unusual braking events so I'm not debugging anything.


They don't always have to leak. I've had a few that were stuck due to
some rust within the cylinder. I just replaced them since they were
cheap back in the days of yore. Though, I did take one apart and freed
it up with some cleaning. It appeared to work fine after that.
>
> I googled a bit, and it seems "normal" for Toyota 4Runner rear brake shoes
> to wear most in the front show on the bottom half. Something to do with the
> geometry. I can't complain, as the shoes definitely are original so 20
> years is a long time for a brake shoe to finally wear out.


I can't speak for normality but I just find it odd that it would wear
like that when there isn't a bad part. Usually, I would see one show
worn more so than the other, but never a tapered wear.
>
>>> 3. I measured the drum to be 2mm smaller than the maximum diameter:
>>> <http://www.bild.me/bild.php?file=9335528drum_brakes_2.jpg>

>>
>> Maximum diameter of what?

>
> The drum:
> http://www.bild.me/bild.php?file=942...m_brakes_3.jpg
>
> In that photo you can see that the inside of the drum has a molded in
> maximum diameter of 297mm. I assume that means the maximum diameter.
>
> My calipers are in US measurements where 11.615 inches converts to about
> 295mm.
>
> So I assume the drum is good by 2mm in thickness.
>
>> Are you aware of the adjusters? Each side has
>> one and it sits under the cylinder behind the hub.

>
> Yes. This vehicle adjusts automatically when you brake in reverse, so I've
> never dealt with them - but I am going to have to back them out for sure
> when I put the new brake shoes on.


Most adjusters work with the emergency/parking brake. Though, many
people rarely, if ever, use the parking brake and those adjusters can
rust up and stop pushing the shoe against the drum.
>
> You can see the adjuster he
> https://s13.postimg.org/senkcelrb/brakes_drum_1.jpg
>
> I'm just not sure what we're supposed to do about the parking brake cable
> linkages. I don't know yet if they have to be disconnected when putting in
> new brake shoes.
>
> You can see the parking brake cable he
> https://s13.postimg.org/5egwznnt3/brakes_drum_2.jpg


I have worked on many drum brakes and I have never had to remove a
parking brake cable. The cable is attached to the metal assembly and
that will just hang on the cable when you remove it and replace the
shoes. Though, if it's easy to remove and reattach, then there's no harm
in doing so.
>
>> It's job is to keep the shoes against the drum and is automatically
>> adjusted when the parking brake is used. Often, this is the reason why
>> drums are difficult to remove. They are adjusted from the other side
>> through an opening using an adjustment tool and often need to be
>> loosened in order to remove the drum. They also need to be tightened
>> after you replaced the shoes and re-install the drum. Retract them and
>> your diameter will be less than the drum.

>
> I understand what you're saying, which is that the brake shoes may be
> "wedged" against the drum, but I had the vehicle in the air and the parking
> brake off, so, any wedging shouldn't be too strong.


Agreed. There should be a slight drag and minor friction when you turn
the drum, but never should be too tight where it's difficult to remove
the drum.
>
> This is a closeup of the parking brake cable connection to the shoes:
> https://s13.postimg.org/b2n7qr2hz/brakes_drum_3.jpg
>
> As it was, putting the two 2-inch long 8mmx1.25 bolts in the two holes for
> the purpose pushed the drum off easily. I had to squish the shoes a bit to
> get the drum back on - and if necessary - I would have twisted the adjuster
> - but I didn't need to.
>
>> The parking brake cable doesn't need to be removed, assuming it's
>> functioning properly. Just ensure the parking brake is not engage when
>> replacing shoes. The parking brake assembly will be removed when the
>> shoes are replaced.

>
> Oh. OK. The parking brake seems to be a thick black cable that comes in at
> the bottom of these shoes.


Yes, attached to the metal assembly which turns that adjuster.
>
>> Much depends on the vehicle. Many shoes are identical and it doesn't
>> matter if they are placed in front or rear. Others are specific and
>> require proper position and seating. In your case, the shoes appear to
>> be the same but that wear is something I wouldn't simply "rotate" with
>> the other side. One side wearing more than the other is not normal and
>> should be checked, repaired/replaced then install new shoes with the
>> proper even thickness.

>
> I think I'll replace the shoes, but since they lasted 20 years, I was just
> wondering if "rotating" them every two or three or five years would have
> extended the life of them.
>
> It's a late 90's 4Runner.
>


All I can say is I've never "rotated" brake shoes, since IMO, they were
cheap when I used to work on many cars. I can sympathize when only one
shoe is worn while the other(s) have ample thickness. I hate to see such
waste. The choice is yours since it appears the shoes are the same on
each side, you could simply swap them and ensure that drag and minor
friction partake when you reinstall the drum. Honestly, if it were me in
my youth as a poor teen working on my own car, that's what I would do.
But now that I'm a wealthy millionaire (that's tough to say without
laughing) Ok, now that I'm financially stable, I would just buy them and
install. Since you have to remove all the hardware anyway, installing
new shoes would be the best option.

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