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Discussion Starter #1
My front rotors are pulsing when I brake at high speeds, and I'm starting to feel it at slower speeds. Should I have them machined, or should I replace them?

Also, how easy is it to replace the pads?
 

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what do you mean pulsing? and what do you mean machine?

if your rotors are going bad it would be best to replace them.

and brake pads are pretty easy to replace, the only hard part is that stupid metal piece that holds them in.
 

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The Librarian
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Moved to "Wheels, Tires, Brakes & Suspension"

Here's a good write up on how to replace the front pads and rotors:
http://www.focushacks.com/index.php?modid=40

"Pulsing" generally means you have an uneven build-up of brake pad material on the rotors.
You could try cleaning up that build-up first before replacing anything.
From 60mph, hit the brakes hard and hold them there till you're down to 10mph. DO NOT STOP!!!
Do this 5 or 6 times, without letting the brakes cool in between.
After that, drive without hitting the brakes at all (if possible) for a good 5-10 minutes (50-70mph) to let them cool.
This is basically the same procedure you use to bed in new pads and rotors.
You're just doing it again, to evenly distribute the pad material.
NOTE:
1) Obviously, you're going to need to find a very lightly travelled road to do all that in order to be safe.
2) If you can, do the entire procedure twice within a short period of time for best results.

By the way, here is a great thread with all sorts of brake information:
Brake information and educational materials
 

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Thanks WD40, I think this will help my my "bad vibrations" problem
 

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Discussion Starter #5
Moved to "Wheels, Tires, Brakes & Suspension"

Here's a good write up on how to replace the front pads and rotors:
http://www.focushacks.com/index.php?modid=40

"Pulsing" generally means you have an uneven build-up of brake pad material on the rotors.
You could try cleaning up that build-up first before replacing anything.
From 60mph, hit the brakes hard and hold them there till you're down to 10mph. DO NOT STOP!!!
Do this 5 or 6 times, without letting the brakes cool in between.
After that, drive without hitting the brakes at all (if possible) for a good 5-10 minutes (50-70mph) to let them cool.
This is basically the same procedure you use to bed in new pads and rotors.
You're just doing it again, to evenly distribute the pad material.
NOTE:
1) Obviously, you're going to need to find a very lightly travelled road to do all that in order to be safe.
2) If you can, do the entire procedure twice within a short period of time for best results.

By the way, here is a great thread with all sorts of brake information:
Brake information and educational materials
I'll try that, but isn't it usually from rotors that are warping?
 

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Discussion Starter #6
what do you mean pulsing? and what do you mean machine?

if your rotors are going bad it would be best to replace them.

and brake pads are pretty easy to replace, the only hard part is that stupid metal piece that holds them in.
Usually you can get your discs machined to avoid the high cost of new discs.
 

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^^ high costs? check the centric rotors on CFM... search that part number, i found them for 42$ a piece from a wholesaler... not bad to just ditch the rotors when they start to go out.
 

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Shot me 3 deer!!!
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how many miles on the rotors, you can probably have them cut if its low!!
 

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If you're a normal driver there's no real downside in having the rotors turned/machined as long as you stay within allowable specs. You should be able to extend their useful lives by quite a bit this way. If you race or track the car new rotors are advisable.
 

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Discussion Starter #10
^^ high costs? check the centric rotors on CFM... search that part number, i found them for 42$ a piece from a wholesaler... not bad to just ditch the rotors when they start to go out.
I'm in Canada and the shipping from CFM is $121. It kind of negates any savings.
 

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I'll try that, but isn't it usually from rotors that are warping?
Rotors actually do not warp, insted, on a 1 piece rotor, the inside endge can cup or lean to the inside.

A pulsoing is usually a build up of pad material or uneven rotor thickness which can be do from several things. What WD40 posted is a very good idea. Machining rotors should never be an option due to the fact that the hard spots in the rotor than contribute to unenven rotor thickness. These hard sposts can deflect the cutting tool or further in the futur will just come up agian in the feel of your pedal.

If you would like to buy rotors, I think we can ship them cheaper. Otherwise, just go to your local parts store and grab some rotors. Remember to clean all contact surfaces (hub, rotor, wheel contacts) as any debris can cause an imbalance and later uneven rotor thickness. Also, make sure to torque your wheels correctly, as over torquing or not enough steps can cause the rotor to wear unevenly.

Hope this helps,

Jason
 

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i was asking myself this same question about two months ago. i just ended up replacing the whole set up (pads and rotars). it's cheap enough and i think you will be more pleased with the resulst compared to if you just resurfaced the rotars...
 

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Discussion Starter #16
I just took the car out for a short spin and the pedal was really soft. Some brake fluid spilled out when I was compressing the caliper piston back in. Can I just add brake fluid or do I have to bleed the lines now?
 

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Machining rotors should never be an option due to the fact that the hard spots in the rotor than contribute to unenven rotor thickness. These hard sposts can deflect the cutting tool or further in the futur will just come up agian in the feel of your pedal.


Jason
Tell that to a Honda engineer. I hate the term cutting a rotor.

First of all, you sould never machine a rotor that pulsates.

You can and SHOULD re-surface a rotor that does NOT pulsate.

Also, the only way to machine a rotor is with an on-the-car lathe. It stays true to the hub/spindle that way.
 

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Ah the confusion..... machine, cut, turn, whatever. The manufacturer provides you with a spec for the minimum thickness of a rotor. And rotors do warp for a number of reasons.

So....you put the rotor in a brake lathe and measure the run-out with a dial-gauge. If it's too much you can actually see it. The manufacturer also gives you a spec for maximum run-out.....say .003". If your rotor exceeds that limit, you cut the rotor till there is no run-out. Then you measure the thickness of the rotor. If the thickness is greater than the manufacturer minimum specs......you're good to go.

Keep in mind.....a rotor cut to the minimum thickness is likely to warp sooner than a brand-new rotor.

On-car brake lathe......I don't like them. They can be quicker to use, but they seem to get out of adjustment all the time, so I never trust them. I prefer the old-time brake lathe, mounted on a bench. The thing can be 40 years old and work perfectly.

Your brake pedal is pulsating? Most of the time, machining the rotors will fix the problem. I've done it thousands of times over the years.....
 
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