Why replace scored rotors ???
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Joined: Feb 2003
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From: Jupiter, FL
SL 550
Why replace scored rotors ???
I've run brake pads down to the metal, the rotors were scored, maybe half a millimeter deep in places. I didn't notice any difference in braking, so I just put new pads on, and they worked fine.
It seems to me, that new rotors should have grooves in them anyway, for more surface area. What is the real story ??? Unless there's a performance problem, why replace them ???
It seems to me, that new rotors should have grooves in them anyway, for more surface area. What is the real story ??? Unless there's a performance problem, why replace them ???
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From: Huntington Beach, Ca.
'17 Jaguar XF
What's more important is the thickness of the rotor and if there's any cracks in it. Cracks mean overheating. One adverse affect of using worn rotors is they may not bed the pads in properly and you'll get squealing or poor stopping power. Starting out with virgin surfaces on the rotors is obviously more desireable and at only $110 for the set it's worth it.
Thread Starter
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Joined: Feb 2003
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From: Jupiter, FL
SL 550
mleskovar - that makes sense.
The other things would affect performance, which I would notice...
I've done other experiments on my cars, like NEVER changing the oil, just adding when low, and changing the filter once every couple years... never had a problem...
The cars you see burning oil have most likely run OUT of oil, and ruined the rings. They're lucky the car runs at all...
I had a 2 cylinder Volvo deisel in my sailboat. We ran it out of oil, and another time ran it out of water, and every time, after a cooldown, and fixing the problem, it started up, and ran (like a deisel).
It's all a matter of degree; like how much lead did you eat off the wall, or drink from your soldered plumbing system when you were a kid ??? Probably a billion times as much as they allow today...
The other things would affect performance, which I would notice...
I've done other experiments on my cars, like NEVER changing the oil, just adding when low, and changing the filter once every couple years... never had a problem...
The cars you see burning oil have most likely run OUT of oil, and ruined the rings. They're lucky the car runs at all...
I had a 2 cylinder Volvo deisel in my sailboat. We ran it out of oil, and another time ran it out of water, and every time, after a cooldown, and fixing the problem, it started up, and ran (like a deisel).
It's all a matter of degree; like how much lead did you eat off the wall, or drink from your soldered plumbing system when you were a kid ??? Probably a billion times as much as they allow today...
Last edited by JunoJim; Aug 4, 2008 at 09:22 PM.
Super Member
Joined: Jan 2008
Posts: 508
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From: california high desert
2003 S500, 03 C240, 03 E320, 03 tahoe
im not sure on the engine oil
mleskovar - that makes sense.
The other things would affect performance, which I would notice...
I've done other experiments on my cars, like NEVER changing the oil, just adding when low, and changing the filter once every couple years... never had a problem...
The cars you see burning oil have most likely run OUT of oil, and ruined the rings. They're lucky the car runs at all...
I had a 2 cylinder Volvo deisel in my sailboat. We ran it out of oil, and another time ran it out of water, and every time, after a cooldown, and fixing the problem, it started up, and ran (like a deisel).
It's all a matter of degree; like how much lead did you eat off the wall, or drink from your soldered plumbing system when you were a kid ??? Probably a billion times as much as they allow today...
The other things would affect performance, which I would notice...
I've done other experiments on my cars, like NEVER changing the oil, just adding when low, and changing the filter once every couple years... never had a problem...
The cars you see burning oil have most likely run OUT of oil, and ruined the rings. They're lucky the car runs at all...
I had a 2 cylinder Volvo deisel in my sailboat. We ran it out of oil, and another time ran it out of water, and every time, after a cooldown, and fixing the problem, it started up, and ran (like a deisel).
It's all a matter of degree; like how much lead did you eat off the wall, or drink from your soldered plumbing system when you were a kid ??? Probably a billion times as much as they allow today...
Thread Starter
Member
Joined: Feb 2003
Posts: 92
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From: Jupiter, FL
SL 550
Interesting - I was hoping to get an expert opinoin... Thanks 
To ease your mind, the vehicles I buy, I usually drive until they won't go anymore, so they go to the junkyard (usually after a couple hundred thousand miles) the best were 1974 & 5 RX7's, which burn oil in their cumbustion process, so I was cheating a little. Also, they have fewer soft metals and moving parts...
Of course, my wife's MB gets premium treatment. I'm an aerospace engineer, and some of us tried various self designed tests over several years... we even found a marine engine "zinc" that would screw into the RX7 cooling system, and it seemed to extend the radiator life...
To ease your mind, the vehicles I buy, I usually drive until they won't go anymore, so they go to the junkyard (usually after a couple hundred thousand miles) the best were 1974 & 5 RX7's, which burn oil in their cumbustion process, so I was cheating a little. Also, they have fewer soft metals and moving parts...
Of course, my wife's MB gets premium treatment. I'm an aerospace engineer, and some of us tried various self designed tests over several years... we even found a marine engine "zinc" that would screw into the RX7 cooling system, and it seemed to extend the radiator life...
Last edited by JunoJim; Aug 5, 2008 at 09:40 PM.
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From: Louisiana
03 E500 and Corvette
I've run brake pads down to the metal, the rotors were scored, maybe half a millimeter deep in places. I didn't notice any difference in braking, so I just put new pads on, and they worked fine.
It seems to me, that new rotors should have grooves in them anyway, for more surface area. What is the real story ??? Unless there's a performance problem, why replace them ???
It seems to me, that new rotors should have grooves in them anyway, for more surface area. What is the real story ??? Unless there's a performance problem, why replace them ???
If you reuse them you MIGHT,, have squeel until they fully bed the pads. I would say if you are within the criteria and want to try it give it a shot then report back. But otherwise I would buy new rotors.
Don't consider myself an expert,, but have had to make many things work and I have made grooved rotors work. Best of luck.
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From: Philadelphia area
2010 ML550, 2010 E350 4M, 1966 Corvette Convt C2
I believe that the rotors would be much more likely to crack along the grooves particularly if they are deep. The bottom of the groove could very well be beyond the min thickness spec for the rotor.
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From: Jupiter, FL
SL 550
vetdvr - thanks - the more knowledge the better... no squealing yet...
sosh - I've never heard of rotors cracking. Besides, I would guess they'd crack radially (greater stress) rather than circumferentially.
I've studied crack propagation, and you are right, the crack very often is deeper than you might think...
sosh - I've never heard of rotors cracking. Besides, I would guess they'd crack radially (greater stress) rather than circumferentially.
I've studied crack propagation, and you are right, the crack very often is deeper than you might think...
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From: Philadelphia area
2010 ML550, 2010 E350 4M, 1966 Corvette Convt C2
vetdvr - thanks - the more knowledge the better... no squealing yet...
sosh - I've never heard of rotors cracking. Besides, I would guess they'd crack radially (greater stress) rather than circumferentially.
I've studied crack propagation, and you are right, the crack very often is deeper than you might think...
sosh - I've never heard of rotors cracking. Besides, I would guess they'd crack radially (greater stress) rather than circumferentially.
I've studied crack propagation, and you are right, the crack very often is deeper than you might think...
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From: Louisiana
03 E500 and Corvette
I have seen and even once experienced a rotor cracking around the entire circumference in a worn groove. It was not in a car but an aircraft. made quite a mess out of the entire wheel and strut assembly. I, in fact have never seen one crack on a radius. I have seen partial cracks on the circumference. A grooved rotor is also more inclined to warp. Any squealing would be the least of your problems. Quite frankly you sound as if you are running your own personal destruction derby.
So for groves follow the specs. If your depth of grove is within spec as I previously said.. it might work. The depth of the grove is the real issue.
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From: Philadelphia area
2010 ML550, 2010 E350 4M, 1966 Corvette Convt C2
I have also seen rotors crack and lead to failure. this is why there is a specification for thousands of inch maximum as a specification. I have also failed an entire multiple disc system when landing at 170,000# Total weight and the antiskid system malfunctioned and landed with locked wheels. made for really smoky landing.
So for groves follow the specs. If your depth of grove is within spec as I previously said.. it might work. The depth of the grove is the real issue.
So for groves follow the specs. If your depth of grove is within spec as I previously said.. it might work. The depth of the grove is the real issue.
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From: GMT -8 hours
Mercedes-Benz
When it happened to me I was landing at CDG and I was lots heavier than that!! Fwd right side truck, thought it would be ripped off the aircraft (A330). Shut down that runway and had to take all pass off and they did something to free up the wheels to get the aircraft to the gate where they had to inspect the entire truck, struts, replace lots of parts. One of the multiple discs cracked all the way around and separated locked everything up. This A/C was pretty new at the time and all discs were well within limits and it had just come out of a B check.Opinion was that it was a defective disc that had previously been grooved with something stuck in it like a pebble.
Thread Starter
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Joined: Feb 2003
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From: Jupiter, FL
SL 550
LOL - I've worked for Pratt & Whitney for 30+ years, on the military side. We've seen some pretty horrendous stuff that doesn't get released to the public...
I assume you know that most commercial aircraft use retreaded tires...
I assume you know that most commercial aircraft use retreaded tires...
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From: california high desert
2003 S500, 03 C240, 03 E320, 03 tahoe
MB spec is no machining of rotors
I've run brake pads down to the metal, the rotors were scored, maybe half a millimeter deep in places. I didn't notice any difference in braking, so I just put new pads on, and they worked fine.
It seems to me, that new rotors should have grooves in them anyway, for more surface area. What is the real story ??? Unless there's a performance problem, why replace them ???
It seems to me, that new rotors should have grooves in them anyway, for more surface area. What is the real story ??? Unless there's a performance problem, why replace them ???
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From: South Florida
STS,FGT,12C,P85D,M4
that's what they tell you when they would have to foot the bill, take it in again when it's on your tab and see what they say...... they'll say you MUST replace the rotors.....
when we bought our last CPO S500 it was a lease turn in and the dealer gave me a list of everything that was replaced which included brake pads front and rear.the front rotors were grooved and it took the service manager to convince me that this is standard maint procedure.replace pads only, as long as the rotor thickness and runout were within tolerance.he also said that if you dont abuse the brakes most MB rotors will go three pad replacements on a set of rotors.
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From: california high desert
2003 S500, 03 C240, 03 E320, 03 tahoe
i new it was the economical method
Super Member
Joined: Jan 2008
Posts: 508
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From: california high desert
2003 S500, 03 C240, 03 E320, 03 tahoe
im gonna have to post my method of speed
