On Sun, 17 Jan 2010 07:24:01 -0500, "Stormin Mormon"
No, actually it is EXACTLY the same.
EVENTUALLY both the rings and pads may seat and do their job, but both
will have reduced life and reduced effectiveness.
Up here in salt country it is rare indeed to find a set of rotors
that will last the life of a set of decent pads without requiring
machining or replacement.
Happens once in a while, but it is definitely the exception rather
than the rule.
yeah,that's what I did the last time,on my Sentra SpecV.
I also had to replace the left front caliper bracket and slide pins because
the pins had rusted into the bracket,causing uneven wear on the pads.
I had less than 1/16" pad material left on the outer pad,very lucky the
rotor wasn't scored. the inner pad was nearly new.
I tell ya,the Internet is fantastic for parts shopping;
it's saved me SO much money over buying local,even after paying shipping.
Used to be I could do that too - but the rotors on the mystique were
bad - all 4 of them, at less than 120,000km. The rotors on the PT were
bad at 115,000km.
The rotors on the TransSport were bad every 70,000 kms, and before I
caught on to the carbon metallic pads, the Aerostar needed rotors
every 2 years ( pads were still about half lining, but hard as glass
and had "eaten" the rotors). With the carbon metallic pads I got 3
years out of them (both pads and rotors) and they still looked like
new when I sold it.
| As for machining vs replacing? On today's cars, with rotors often
| available for less than $40 and machining costing 30+, why would you
| EVER machine the rotor??
About 25 years ago I had a Honda Accord which I took to a Honda Barn for
service. They frequently machined the rotors. What did I know? It was
my first car. Eventually on one service I got a sad call that my rotors
were too thin to machine and would have to be replaced. The cost to replace
was just slightly _less_ than the cost to remove/machine/install. Maybe
this is related to high labor charges at dealer shops, but since then I've
always insisted on replacement.
On 17 Jan 2010 00:09:49 GMT, ddl@danlan.*com (Dan Lanciani) wrote:
Back when the rotors on front drive cars were mounted to the BACK of
the hub and the front bearings needed to be pressed apart, it was a
We invested in an "on car" brake lathe to skim the rotors on Toyota
Tercels because to remove them was a roughly 2 hour job and involved
replacing seals and a "crush spacer". The oncar lathe could do the job
in less than 15 minutes. Honda had a similar setup, and because they
were replaced so often the "economy of scale" allowed the parts prices
to drop to the point that if you were taking them apart anyway it just
did not make ANY sense to machine the old rotors.
The same has transpired with generally all makes now - with the
generally underbraked cars today, and the ecology limitations on brake
pad material, rotors have become "consumables" and the price reflects
that reality (in most cases)
It really depends on the vehicle. Back in the day you could run two or
three sets of pads on one pair of rotors, with a cleanup on a brake
lathe at each pad change. Newer vehicles tend to not have as much meat
on the rotors and sometimes they'll be worn enough after one set of pads
that turning them would bring them at or close to the replacement spec.
I am real disappointed with the brakes on the newer GM products. Had to
have the rotors turned at less than 30K miles due to a bad pulsation.
Previous company car wore out the brakes completely at less than 50K
miles. "they don't make 'em like they used to" indeed. The benefit to
going light on the brakes is less unsprung weight, (theoretically)
better handling, better fuel economy.
replace "roosters" with "cox" to reply.
there's a minimum thickness spec stamped on the rotor hub.
you need a micrometer to measure it.
IMO,unless you had a pad's backing plate grind into your rotor or it's
grooved,you don't need to replace them,nor turn them,unless the car has a
LOT of mileage on it.(modern pads don't use rivets)
In fact,turning them may make them more prone to warping,and then you need
BTW,it's pretty easy to replace brake disc pads yourself,especially on the
fronts,which wear faster. The rear caliper piston may have to be -turned-
(screwed) back in rather then simply pressed in like the front caliper
Mechanics probably replace rotors because it's easier than
measuring,turning,and then maybe having them warp and you back for warranty
repair.Of course,they make profit on parts sales,too.
I'm with Jim and the other guys who say replacing rotors or turning
them everytime pads are replaced isn't necessary. I'm surprised no
one here has mentioned RTFM. The service manual from the auto
manufacturer that is. I've been doing the brakes on my Mercedes
myself for years and it now has 135K miles. I've never touched the
rotors unless necessary and that has only been when they were worn
down close to min spec. What does the MB shop manual say? That
the rotors should be checked for thickness and run-out As long as
they are within spec and look OK, nothing needs to be done.
Some folks claim that rotors routinely get "glazed" and the new pads
won't work unless that is corrected, If the rotors got glazed, the
old pads wouldn't be stopping the car either. I've just replaced
pads many times and never had an issue with any braking problem.
Rotors in normal usage just have a smooth shiny finish to them from
metal being worn off.
Other thoughts. In many cases, if the rotors could be re-used by
turning them, it's not worth it. With today's labor rates, for the
same price as turning them or just $20 more, you can get new ones.
Shops likely tell people they have to be changed for 2 reasons:
1 - It's more money in their pocket
2 - It somewhat reduces the risk to them because with everything new,
there is a little less chance that the car will come back with a
problem. That's especially true where they have some employees
working that don't even know what a micrometer is.
I have faith in the mechanic shop that services my Sprinter, which I use in
my electrical service. It's been years since I've done any real auto
mechanics, so as I recalled, you would just turn the rotors when doing a
brake job. I suspected the rotors probably weren't made like they used to
be, and I would certainly rather put money into new ones, than weakening old
ones, especially considering the weight I carry.
On Sat, 16 Jan 2010 17:43:30 -0500, "Stormin Mormon"
Definitely makes sense when warranty is involved.
Now, if you are replacing the pads yourself, there is no warranty
anyways (read the fine print) so if the rotors are not grooved or
corroded and you just want brakes, you CAN get away without replacing
Up here in "salt country" that doesn't happen too aften any more,
because the rotors are usually pretty scaly before the pads get beyond
The new hybrid ceramic pads are showing some promise in reducing the
rotor corrosion - might actually get full pad life out of both the
pads and rotors - but for pretty close to two hundred bux a set I sure
I have also got a set of "kevlar" aramid fiber (motorsport) pads on
the one vehicle to see how they work out. Hard as hen's teeth to find
around here, and they are "pretty proud of them" too, judging from the
I've got the Kevlars on the Mysique and the Hybrids on the PT Cruiser
When I had the Aerostar the only brakes that stopped it reliably and
quietly without eating rotors were the "carbon metallic" pads.
On the Pontiac TransSport it didn't matter what you put on for brakes
because you were going to be taking it apart for wheel bearings or
ball joints at least once a year anyway so the labour was already
covered to replace the cheapest pads you could buy.
What a peice of junk
Don't replace the rotors unless absolutely needed. The objective is
to replace the (cheaper) pads well before the rotors become damaged.
It's a good idea to inspect the pads yearly, perhaps more often if you
are driving on a lot of salted roads.
Not true any more. The pads for my PT cruiser cost over double what
the set of replacement rotors cost.
Same for my Mercury Mystique.
You CAN buy pads for roughly the cost of one rotor if you are buying
the cheapest available of both.
Recommendation is to service the brakes twice a year - spring and fall
- to be sure the caliper sliders are not stuck, the pads are not stuck
or worn, and the rotors are not corroded. Knocking off the ridge of
rust from the edge of the rotors can extend the life of both pads and
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