I've not seen a warped or out of tolerance new rotor. But it's not uncommon for some, especially lower quality ones, to warp after a few significant heat cycles. I throw those out, as they cannot be fixed.
Check the runout on new brake rotors?
- Thread starter DIY4quality
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Originally Posted by Cujet
I've not seen a warped or out of tolerance new rotor. But it's not uncommon for some, especially lower quality ones, to warp after a few significant heat cycles. I throw those out, as they cannot be fixed.
I think the definition of "out of tolerance" is the issue. Out of tolerance on a sensitive application vs once that is not, can result in two very different situations.
Modern Nissan vehicles tend to be extremely sensitive to LRO. An older Toyota may not be. So, a somewhat poorly machined rotor can be installed onto the older Toyota without ever developing any issues.
Also, I have never seen a well-machined low quality rotor develop issues after a few heat cycles. I have installed a few of rotors of questionable quality (it was obvious that their cooling vane design did not fully match the OE rotor) and they were always trouble-free.
I've not seen a warped or out of tolerance new rotor. But it's not uncommon for some, especially lower quality ones, to warp after a few significant heat cycles. I throw those out, as they cannot be fixed.
I think the definition of "out of tolerance" is the issue. Out of tolerance on a sensitive application vs once that is not, can result in two very different situations.
Modern Nissan vehicles tend to be extremely sensitive to LRO. An older Toyota may not be. So, a somewhat poorly machined rotor can be installed onto the older Toyota without ever developing any issues.
Also, I have never seen a well-machined low quality rotor develop issues after a few heat cycles. I have installed a few of rotors of questionable quality (it was obvious that their cooling vane design did not fully match the OE rotor) and they were always trouble-free.
Out of the uncounted sets of rotors I have put on my cars over many years, I have had 2 rotors in the past few years out of spec brand new. Now I check every one before I use it in case I need to return it. One had just a few thous of runout, enough to be annoying shaking a little, but not enough to take off and get turned. The other was out like 20 thou and hopelessly unusable without turning.
Way back when, I never had issues with Brembo rotors made in Italy. Alas, I can't get those anymore for my cars, though I'd gladly pay for them. They're all made in China now.
What ABN_CBT_ENGR say above has merit, as surely all these rotors are made on automated machinery. However, I think one failing is cast iron needs some time to settle after being cast and cooled before it is dimensionally stable. The manufacturers are surely playing on the edge with that. They could make a perfectly good rotor, but during it's ride across the Big Pond, it warps quietly in the box.
The percentage of out-of-spec rotors I've seen in the past few years is high enough that I will measure every one now.
Way back when, I never had issues with Brembo rotors made in Italy. Alas, I can't get those anymore for my cars, though I'd gladly pay for them. They're all made in China now.
What ABN_CBT_ENGR say above has merit, as surely all these rotors are made on automated machinery. However, I think one failing is cast iron needs some time to settle after being cast and cooled before it is dimensionally stable. The manufacturers are surely playing on the edge with that. They could make a perfectly good rotor, but during it's ride across the Big Pond, it warps quietly in the box.
The percentage of out-of-spec rotors I've seen in the past few years is high enough that I will measure every one now.
Well, I measured it by putting new drums in and getting brake pulsation...that really sucked. Now I take my drums to the last machine shop in the area to work over before I replace them.
Originally Posted by The Critic
Originally Posted by DIY4quality
Good grief, those conical washers are pricey! But I do understand that you need them to protect the lug nuts and rotor from damage if you're torquing them all down for the runout test.
Old axle nuts may work as well. Never tried though.
You mean that any open-ended lug nuts should work. Not sure why you'd need washers/spacers unless you wanted to use them with the original (closed-end) lug nuts, right?
Originally Posted by DIY4quality
Good grief, those conical washers are pricey! But I do understand that you need them to protect the lug nuts and rotor from damage if you're torquing them all down for the runout test.
Old axle nuts may work as well. Never tried though.
You mean that any open-ended lug nuts should work. Not sure why you'd need washers/spacers unless you wanted to use them with the original (closed-end) lug nuts, right?
Originally Posted by DIY4quality
Originally Posted by The Critic
Originally Posted by DIY4quality
Good grief, those conical washers are pricey! But I do understand that you need them to protect the lug nuts and rotor from damage if you're torquing them all down for the runout test.
Old axle nuts may work as well. Never tried though.
You mean that any open-ended lug nuts should work. Not sure why you'd need washers/spacers unless you wanted to use them with the original (closed-end) lug nuts, right?
It is very rare to see a car with open-ended lug nuts nowadays. But yes, open-ended lug nuts may not require the use of any washers.
Originally Posted by The Critic
Originally Posted by DIY4quality
Good grief, those conical washers are pricey! But I do understand that you need them to protect the lug nuts and rotor from damage if you're torquing them all down for the runout test.
Old axle nuts may work as well. Never tried though.
You mean that any open-ended lug nuts should work. Not sure why you'd need washers/spacers unless you wanted to use them with the original (closed-end) lug nuts, right?
It is very rare to see a car with open-ended lug nuts nowadays. But yes, open-ended lug nuts may not require the use of any washers.
Originally Posted by The Critic
Originally Posted by DIY4quality
Originally Posted by The Critic
Originally Posted by DIY4quality
Good grief, those conical washers are pricey! But I do understand that you need them to protect the lug nuts and rotor from damage if you're torquing them all down for the runout test.
Old axle nuts may work as well. Never tried though.
You mean that any open-ended lug nuts should work. Not sure why you'd need washers/spacers unless you wanted to use them with the original (closed-end) lug nuts, right?
It is very rare to see a car with open-ended lug nuts nowadays. But yes, open-ended lug nuts may not require the use of any washers.
Yep, you can buy conical open-ended lug nuts on eBay very cheaply. Good for temporary use while performing the LRO test. Just make sure you get the right size for your studs.
Originally Posted by DIY4quality
Originally Posted by The Critic
Originally Posted by DIY4quality
Good grief, those conical washers are pricey! But I do understand that you need them to protect the lug nuts and rotor from damage if you're torquing them all down for the runout test.
Old axle nuts may work as well. Never tried though.
You mean that any open-ended lug nuts should work. Not sure why you'd need washers/spacers unless you wanted to use them with the original (closed-end) lug nuts, right?
It is very rare to see a car with open-ended lug nuts nowadays. But yes, open-ended lug nuts may not require the use of any washers.
Yep, you can buy conical open-ended lug nuts on eBay very cheaply. Good for temporary use while performing the LRO test. Just make sure you get the right size for your studs.
I checked the service manual for my Land Rover LR2 and it says the runout spec is 0.003". I'm considering purchasing Raybestos Element3 rotors. I'm impressed that Raybestos indicates the max runout in their product description, but they say their rotor has Lateral runout of 0.004” or less and a thickness variation of less than 0.0005”. I checked their R-Line model (one step down from Element3) and it says the same. Since 0.004 is greater than 0.003, does this mean their rotor could be out of spec for my vehicle right out of the box?
I just checked the more expensive Brembo rotor and the product description says the run-out tolerance is only 0.0025", about half the industry norm. This is really interesting. I had not considered choosing a rotor based on the runout spec, especially when it's brand new and matched to my vehicle by the manufacturer.
I just checked the more expensive Brembo rotor and the product description says the run-out tolerance is only 0.0025", about half the industry norm. This is really interesting. I had not considered choosing a rotor based on the runout spec, especially when it's brand new and matched to my vehicle by the manufacturer.
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