Front brake discs at 1.4 mil,should i change?

[woodsman]

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.

[moresquirt]

Thx everyone for your input especially the mathmatic algebra lesson,(im weak in that area) but based on that info i feel pretty safe on making that 3rd set off pads with original rotors go the distance,and as mentioned i do not track and never will,i do occasionally drive hard but don,t do brake power slides ect.For those interested at now almost 93000 kilometers (55000 miles) i am still on the original drive belt which looks like new (have a new spare ready to go if needed) original water pump with no play in the bearing,its tight ,smooth and quiet,just changed my plugs,because, and probably dident need to as they looked perfect,no metal in the oil filter either (IMSB OK) , have to say this car has been pretty reliable so far in the 30000 kilometers i have owned it! Thx again

[Bigsmoothlee]

Originally Posted by woodsman

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]

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.

[Topless]

Originally Posted by stephen wilson

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.

[woodsman]

Originally Posted by Bigsmoothlee

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.

[Bigsmoothlee]

Originally Posted by woodsman

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]

Originally Posted by Bigsmoothlee

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]

Originally Posted by woodsman

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.

[Topless]

Originally Posted by Hayden

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.