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-   -   Front brake discs at 1.4 mil,should i change? (http://986forum.com/forums/performance-technical-chat/46482-front-brake-discs-1-4-mil-should-i-change.html)

Bigsmoothlee 10-08-2013 11:48 AM

Quote:

Originally Posted by woodsman (Post 347801)
and so what's going to happen if your rotors are 0.10- 0.20" too thin when your new pads are worn out? NOTHING! They won't be able to absorb extreme heat (only found on the track) as well as new rotors would but only a driver who's driven MANY track miles could tell the difference. There are mechanics out there who insist that whenever they install new pads they MUST install new rotors as well!- forget machining they'll tell you, and why? Money.

I know this is late, but that is the stupidest thing ive read on this forum. Please do not give out ANY advice if you dont know what youre talking about. I dont know of any reputable shops that will slap new pads on unresurfaced rotors. You either replace the rotor, or you resurface it if it has enough material.

stephen wilson 10-08-2013 12:05 PM

Not debating min. thickness, but here's nothing wrong with new pads on an unresurfaced rotor, as long as it's worn evenly, and isn't grooved. I've done it for 20 years on multiple vehicles, including a race car. After normal bedding in, they're as good as new. I've never found someone who would skim cut a rotor, they always take too much material.

woodsman 10-08-2013 12:07 PM

Quote:

Originally Posted by Bigsmoothlee (Post 366693)
I know this is late, but that is the stupidest thing ive read on this forum. Please do not give out ANY advice if you dont know what youre talking about. I dont know of any reputable shops that will slap new pads on unresurfaced rotors. You either replace the rotor, or you resurface it if it has enough material.

I'm a machinist who's raced cars. Learn how to disagree without condemnation. This is a FORUM.

Topless 10-08-2013 01:07 PM

Quote:

Originally Posted by stephen wilson (Post 366695)
Not debating min. thickness, but here's nothing wrong with new pads on an unresurfaced rotor, as long as it's worn evenly, and isn't grooved. I've done it for 20 years on multiple vehicles, including a race car. After normal bedding in, they're as good as new. I've never found someone who would skim cut a rotor, they always take too much material.

+1

Fear of reusing a serviceable rotor without resurfacing is pretty unfounded. It happens 50 times a day at racetracks around the world without incident. It won't have that "perfectly smooth, all new components feel" but it stops the car just fine.

Bigsmoothlee 10-08-2013 02:24 PM

Quote:

Originally Posted by woodsman (Post 366696)
I'm a machinist who's raced cars. Learn how to disagree without condemnation. This is a FORUM.

As a shop owner, I personally took offense to your claim of "dishonesty" . I am straight forward with my clients, and I never use scare tactics to get people to do their maintenance in my facility.

In my experience, whenever I put a used rotor on the lathe, its usually worn unevenly or warped. This causes vibration and causes the pads to become noisy. The groves in the rotor overheat the pad ( since maybe 40% or 50% of the pad is making contact with the rotor until it breaks in ).

Can you get by if you slap new pads on an old rotor? Probably. Will you get cancer watching your food rotate in your microwave from the radiation coming out of it? Maybe, maybe not. Should you accuse a shop of being money hungry because they want their client to do the job correctly? Absolutely not.

woodsman 10-09-2013 01:01 PM

Quote:

Originally Posted by Bigsmoothlee (Post 366717)
As a shop owner, I personally took offense to your claim of "dishonesty" . I am straight forward with my clients, and I never use scare tactics to get people to do their maintenance in my facility.

In my experience, whenever I put a used rotor on the lathe, its usually worn unevenly or warped. This causes vibration and causes the pads to become noisy. The groves in the rotor overheat the pad ( since maybe 40% or 50% of the pad is making contact with the rotor until it breaks in ).

Can you get by if you slap new pads on an old rotor? Probably. Will you get cancer watching your food rotate in your microwave from the radiation coming out of it? Maybe, maybe not. Should you accuse a shop of being money hungry because they want their client to do the job correctly? Absolutely not.

I think clients would appreciate the OPPORTUNITY to gamble on their old rotors (turned or not) before they fork out for new ones. I know radial run-out can be a persistent problem but so can over-cautiousness or a lack of sufficient funds.

Hayden 10-10-2013 05:58 AM

Quote:

Originally Posted by woodsman (Post 366812)
I think clients would appreciate the OPPORTUNITY to gamble on their old rotors (turned or not) before they fork out for new ones. I know radial run-out can be a persistent problem but so can over-cautiousness or a lack of sufficient funds.

I agree with you. Went in to my indy, they said I needed new brakes (46k on odo) and I was enthusiastic about changing them out, but then the shop (diehard porsche fans, mind you) says I need new rotors, etc., and then throw that price out there.

What happened? I walked - can't afford that for just a brake job at this time, or anything else on their list that I got done for 25%-35% less at another porsche mechanic who is much more laid back about this stuff. Regardless, I have a brake pad light on and compromised safety with a car that is off the road during prime top-down weather.

Which is the better scenario for that customer on the road a few months later? I presume the "can't afford to drive a porsche" argument will be used against this statement. Maybe they are right in their recommendation--I'm not going to say they are flat-out wrong--they aren't. However, their "go oem or go home" attitude is well noted in the local community, and a turn-off for lots of customers.

urban 10-10-2013 07:25 AM

I always replaced pads without even resurface the rotors. And usually it was ok. Each rotor took like 3 to 4 pads before wearing out of factory spec (on the Alfa Romeo that I had). I never used race performance pads (unless on motorbikes), just regular road use Ferodo or Brembo ones. The Brembos usually were better, but they ran out sooner too. On my motorcycle, I had a problem with the 2nd pair of pads, they started to vibrate a bit under slow breaking.

kk2002s 10-10-2013 08:06 AM

I am in total agreement with re-using safe(within spec, no cracks, etc.) rotors with new pads. Even unturned, in-spec rotors should do no more than wear the pads a bit faster.
But - We live in a liability paranoid world so if I were a shop, new pads, new rotors would be the standard job.
I don't even think a customer signing a release (Old rotors, in spec, legal jargon, Blah, Blah, Blah) would release a shop from liability if there were an accident that could be some how traced back to stopping the car

So if your car is pure shop repaired, pads & rotors would be expected
DIY - its your call and your responsibility to keep it safe

Topless 10-10-2013 09:17 AM

Quote:

Originally Posted by Hayden (Post 366893)
I agree with you. Went in to my indy, they said I needed new brakes (46k on odo) and I was enthusiastic about changing them out, but then the shop (diehard porsche fans, mind you) says I need new rotors, etc., and then throw that price out there.

What happened? I walked - can't afford that for just a brake job at this time, or anything else on their list that I got done for 25%-35% less at another porsche mechanic who is much more laid back about this stuff. Regardless, I have a brake pad light on and compromised safety with a car that is off the road during prime top-down weather.

Which is the better scenario for that customer on the road a few months later? I presume the "can't afford to drive a porsche" argument will be used against this statement. Maybe they are right in their recommendation--I'm not going to say they are flat-out wrong--they aren't. However, their "go oem or go home" attitude is well noted in the local community, and a turn-off for lots of customers.

Well, driving around on worn out pads and out-of-spec rotors is probably not the best plan. Maybe time to learn how to do your own brakes. :)

New or turned rotors is just standard procedure and good business for a Porsche shop. It makes certain that the cars brakes are at their best and feel smooth, fresh, and new which eliminates callbacks from: "You guys said you did my brakes but I still hear a grinding noise. I'm not leaving until this car is right and I'm not paying for a job half done."

We Porsche drivers can sometimes be a PITA ;)

As a DIYer, I never resurface a rotor measured within spec that I deem serviceable. If it is heavily grooved, I go new. Rotors are cheap and expendable with front OEM Zimmermans at about $100. Hospital stays are expensive so choose wisely.

Hayden 10-10-2013 10:24 AM

Quote:

Originally Posted by Topless (Post 366918)
Well, driving around on worn out pads and out-of-spec rotors is probably not the best plan. Maybe time to learn how to do your own brakes. :)

Would love the time to do this. That's partially why the car is sitting. Maybe I will get a chance to tackle it. The wear indicator flashed once while it was 100+ degrees out after some hard braking and hasn't been driven much since. No light, and no abnormal sound or feel.

Regardless, y'all make a good point about liability with mechanics. It makes sense, and I suppose complaining about it doesn't change that fact, so...DIY for me or wait 'til I can afford the full treatment. :)

Bigsmoothlee 10-10-2013 10:29 AM

Quote:

Originally Posted by woodsman (Post 366812)
I think clients would appreciate the OPPORTUNITY to gamble on their old rotors (turned or not) before they fork out for new ones. I know radial run-out can be a persistent problem but so can over-cautiousness or a lack of sufficient funds.

Quote:

Originally Posted by Topless (Post 366918)
Well, driving around on worn out pads and out-of-spec rotors is probably not the best plan. Maybe time to learn how to do your own brakes. :)

New or turned rotors is just standard procedure and good business for a Porsche shop. It makes certain that the cars brakes are at their best and feel smooth, fresh, and new which eliminates callbacks from: "You guys said you did my brakes but I still hear a grinding noise. I'm not leaving until this car is right and I'm not paying for a job half done."

We Porsche drivers can sometimes be a PITA ;)

As a DIYer, I never resurface a rotor measured within spec that I deem serviceable. If it is heavily grooved, I go new. Rotors are cheap and expendable with front OEM Zimmermans at about $100. Hospital stays are expensive so choose wisely.

Thats exactly what Im talking about! Noise and vibration are two big reasons the rotor needs to be smooth on a customers car, in fact, if a client insists I dont resurface his rotors or refuses to replace his rotors, I make sure to make him understand he has no warranty if his pads make noise.

Kk2000s, if you cant afford to do brakes on a boxster, you cant afford to drive. There is really no excuse not to be able to afford maintenance items like brakes when you have ebay and amazon at your disposal. You can do one of two things.

A. Buy the parts online and bring it to ANY reputable shop
B. Buy the parts onine, and do it yourself.

woodsman 10-10-2013 11:24 AM

New parts worship
 
Quote:

Originally Posted by Hayden (Post 366924)
Would love the time to do this. That's partially why the car is sitting. Maybe I will get a chance to tackle it. The wear indicator flashed once while it was 100+ degrees out after some hard braking and hasn't been driven much since. No light, and no abnormal sound or feel.

Regardless, y'all make a good point about liability with mechanics. It makes sense, and I suppose complaining about it doesn't change that fact, so...DIY for me or wait 'til I can afford the full treatment. :)

'The full service' probably includes new parts that many DIY'ers re-use: brake pad wear sensors, anti-vibration inserts and rotors. This is where knowledge and shopping around can get you what you NEED despite tight funds. In Canada, litigation is FAR less common and so the hysteria to ward it off is less great. The world is changing and soon shops won't even HAVE a lathe, designed and built, specifically for resurfacing rotors, as they've had for decades. Perfectionism costs and is partially responsible for the throw-away world were now stuck in. I say; IF IT AIN'T BROKE, WHY FIX IT?! underneath PERFECTIONISM IS THE FEAR OF FALLIBILITY--- lets keep it in perspective and our finances will follow!

BYprodriver 10-10-2013 11:38 AM

Quote:

Originally Posted by woodsman (Post 366928)
'The full service' probably includes new parts that many DIY'ers re-use: brake pad wear sensors, anti-vibration inserts and rotors. This is where knowledge and shopping around can get you what you NEED despite tight funds. In Canada, litigation is FAR less common and so the hysteria to ward it off is less great. The world is changing and soon shops won't even HAVE a lathe, designed and built, specifically for resurfacing rotors, as they've had for decades. Perfectionism costs and is partially responsible for the throw-away world were now stuck in. I say; IF IT AIN'T BROKE, WHY FIX IT?! underneath PERFECTIONISM IS THE FEAR OF FALLIBILITY--- lets keep it in perspective and our finances will follow!

Well said! Replacing rotors instead of machining saves alot of time, allowing more brake jobs in less time, by less skilled "technicians" How many shops discount the labor when they don't have to remachine the rotors? Bigsmoothlee?

Bigsmoothlee 10-10-2013 12:14 PM

Quote:

Originally Posted by BYprodriver (Post 366929)
Well said! Replacing rotors instead of machining saves alot of time, allowing more brake jobs in less time, by less skilled "technicians" How many shops discount the labor when they don't have to remachine the rotors? Bigsmoothlee?

I certainly discount the labor! It wouldnt be fair otherwise! Being honest, fair, having an excellent reputation will keep your shop packed with cars.

As for time? Yes, it takes less time to change rotors, But more brake jobs in a day? I get maybe 2-3 brake jobs a week. The rest is usually more complicated stuff

BYprodriver 10-11-2013 03:10 PM

Well good for you, I agree with that theory. Kinda rare here in SoCA. With all the traffic brakes are big business here, I've seen 1 mechanic do 5 cars in 8 hrs. I don't know of any dealerships that still machine rotors. :(


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