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Old January 10th 18, 05:55 AM posted to alt.home.repair,rec.autos.tech
Clare Snyder
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Posts: 72
Default Drum brakes - do you disconnect the parking brake cable?

On Wed, 10 Jan 2018 03:34:21 -0000 (UTC), Mad Roger
> wrote:

> On Tue, 09 Jan 2018 21:48:57 -0500,
> Clare Snyder wrote:
>
>> I have 358000km on the original rear brakes on my Ranger - and the
>> shoes had over half lining left when I last checked them about 15000km
>> ago. I've had the new shoes for 5 years, and the original owner had
>> them for 4 years before he sold me the truck - - -

>
>I don't disagree with your experience now that I've done some homework.
>It's amazing how *long* brake shoes last, at least on the rear.
>
>I suspect I'd get double the mileage that I saw if the Toyota brakes would
>only wear evenly. Most people on the Toyota forums get more than 175K miles
>but this truck was driven in very hilly country for more than a decade.
>
>> Actually it does not take a LOT of scoring to fail a drum - requiring
>> it to be turned. Then there are two different "fail" measurements -
>> there is a max wear and a max turn. If it is worn past a certain limit
>> it must be replaced, and there is a limit you can turn it to - usually
>> 2 different measurements.

>
>The problem here is that *none* of us are referencing an actual
>manufacturer's specification.
>
>I looked up the specs for a scored rotor when I had a Lexus LS 400 in the
>early nineties where I was shocked at the spec. As I recall, it was thicker
>than a dime, and maybe even a dime and a half as I recall, for it to fail
>the rotor.
>
>I didn't look up drums at the time (it had disc brakes all around), but I
>think we're all talking out of our asses (me included!) unless and until we
>dig up a real spec from the manufacturer.


It's been over a decade, so I don't remember ther exact specs, but I
did government safwety checks as well as servicing LOTS of vehicles
(including 4runners and Land Cruisers) and gouges in both rotors and
drums do not have to be terribly deep or wide to mandate
resurfacing/replacement.
>
>It's usually *hard* to find the scoring spec; it's a lot easier to find the
>thickness and runout specs, so I'm not saying it's an easy spec to find.


not hard at all. here's one:
https://www.cbsparts.ca/admin/bullet...nd%20Rotor.pdf

and another:
https://www.cbsparts.ca/admin/bullet...20Problems.pdf

see page 402 at :
https://books.google.ca/books?id=O01...limits&f=false

"If scoring or light grooves cannot be removed by hand (with emery
cloth) the drum MUST be refinished or replaced"

There is NO ALLOWABLE AMOUNT OF GROOVING ALLOWED ON A DRUM when
replacing friction m,aterial- PERIOD.

read ALL of:
http://www.aa1car.com/library/drum_brakes.htm


>
>>>
>>>The shoes are $157 for a set, and the cylinders are $102 each at Toyota.

>>
>> I believe thre are quality aftermarket sources at a fair bit less.

>
>I agree.
>
>The RockAuto site someone quoted had an axle for a lot less than twenty
>bucks, so Toyota is about ten times aftermarket.
>
>I called the local parts store and they have FF friction-rated shoes (I
>asked them to read me what it says on the shoe) for $17 per axle.
>
>At that price, it's not worth shopping around by price - but only for the
>friction rating.
>
>I haven't found the friction rating for the OEM shoes yet, so it's
>impossible to buy shoes without that information. When I call for the
>friction rating I get tons of bull**** about the pad material where it's
>meaningless without the friction rating.
>
>I mean, a brake pad has a primary job, and that's not dust or noise but
>friction. First comes friction. Then we can talk about dust or noise or
>warranty.
>
>But friction comes first. Without the right friction rating, it's
>worthless.

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