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front brakes question

jamesgland's Avatar
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03-12-05, 07:13 AM   #1  
front brakes question

I have a question about front brakes and rotors.

Is it absolutly neccessary to have the rotors grinded down smooth?

What would happen if I just replace the brake pads when the rotors have grooves in them?


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cuedude's Avatar

Join Date: Jan 2005
Posts: 348

03-12-05, 04:56 PM   #2  
Turning Rotors

Hi Jamesgland,

I am no mechanic, but I do know that if you simply replace your pads without turning the rotors with grooves already in them, you are doing 2 things that you really don't want to do. One...you are greatly shortening the life of the new pads. And 2...you could (possibly) actually break a rotor due to uneven heating. Maybe a moderator could add to this with more information. Very dangerous situation. Please think about it some more?


jeff67's Avatar

Join Date: Dec 2001
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03-12-05, 07:14 PM   #3  
In addition, you will gain substantially more braking power with smooth rotors because you'll have a lot more rotor to pad contact. It would definitely be worth having a smooth rotors when you need to come to a sudden, unexpected stop.

hopkinsr2's Avatar

Join Date: Feb 2005
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03-12-05, 07:53 PM   #4  
If the rotor are grooved much, than only part of the pad is doing the stoping & it will overheat. What kind of car-model do you have? Sometimes it's cheeper to replace the rotors than re-surface them. if you nickle & dime on brakes, Spend your savings on insurance!!! You'll be glad you spent the money on "premium" brakes when the kid runs into the street in front of you chasing the tennis ball. THINK about it

zzzz1486's Avatar

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03-13-05, 12:16 AM   #5  

just replace the rotors, you can usually get them for about $20 a piece and if that keeps you from getting in an accident, thats money well spent

davo's Avatar

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03-13-05, 05:43 AM   #6  
If it is minor grooving less than .015" it should be no problem.I would have to see the rotors but your best option is to have them refinished or replaced to prevent future problems as mentioned by others.I don't think your rotor will crack unless the grooves are deep and you would know by common sense that something doesn't look right.If in doubt always go the route of safety by being over cautious with brakes.By the way if there grooves are from metal to metal contact just replace the rotors that are affected.

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03-21-05, 11:04 PM   #7  
Sure you can replace the pads without grinding.
They run a little hot for a few kilometres, but then dig a groove into the pads.

It makes hardly any difference to the pad life and you're not going to break the disc - running them down thin does that.

car nut's Avatar

Join Date: Aug 2003
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03-22-05, 04:57 PM   #8  
Many repair shops will tell you they must be refinished or replaced. However as Davo & z999 said the condition of the rotor indicates what needs to be done. General motors service manuals say NOT to refinish or replace unless the rotors are out of specification. They gave a groove depth like Davo said, they must not be less than the minimum thickness, they must not be out of specification for parallel & run out. If the pedal does not pulsate when the brakes are applied the rotors are probably with in specification for parallel & run out.

Davo's common sense comment is right on track. If you use rotors or drums as is be sure to break the glaze by roughing up the surface as best you can with coarse sand paper. This will allow the new pads or shoes to seat in better, and they may squeak if you don't do this.

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