Thin brake rotors.

[jsharp]

I put a set of brake pads on my '90 Mustang LX this weekend and was surprised at how thin the rotors were.

88K miles on the vehicle, and this is the first set of replacement pads it's ever had. The rotors show little wear, but yet are already under the service limit, one of them by almost .020"

I can only conclude these things were right near the limit when they were new, and almost any wear at all would push them under the limit.

Anyone ever else experience this?

 

[labman]

I haven't, but have heard of it. The manufacturers are shaving off materials any place they can to cut costs and weight. Many new rotors have little margin before below minimum. Once below minimum, the rotors heat up faster leading to fade sooner. Also the pistons in the calipers are extended further, perhaps eventually far enough to cause leakage.

 

[jsharp]

I reluctantly just threw pads on it since I plan on making some major changes to the brakes next winter and don't want to spend money on parts I'll likely throw away in a few thousand miles.

But darn. I didn't think this would be an issue...

 

[cangreylegend]

Both new rotors. Two different brands. See any difference?

 

[labman]

quote:

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Originally posted by jsharp:
I reluctantly just threw pads on it since I plan on making some major changes to the brakes next winter and don't want to spend money on parts I'll likely throw away in a few thousand miles.

But darn. I didn't think this would be an issue...

---

You should be OK til fall, if you stay out of the mountains, and avoid needing to make repeated hard stops. Your brakes will be fine as long as you don't ask too much of them. I hope you are not commuting into Chicago.

 

[cangreylegend]

BTW, above is for same car. Guess which one can survive a "shave on the lathe"?

 

[jsharp]

quote:

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Originally posted by JHZR2:
With the low miles on it in all that time, Ill bet that the rotors have rusted over and then scraped clean more than a few times... I think that when rotors rust over (after being out in the rain, humidity, etc), after theyre used a few times the scraping of the oxidized surface causes significantly more material loss than if the rotors had stayed rust-free.

JMH

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I wasn't able to get a mike down onto the rotor near the hub to see how thick these rotors were in an area of no wear but I guess even had I been able to the rust would have been a factor.

Now that I think about it, I had a Toyota I drove a similar amount the last few years I owned it and it had that problem. After sitting you could hear the rotors being "cleaned" the first few times you hit the brakes. The rotors on it were gone at the first pad change too and in about the same number of miles...

 

[jsharp]

quote:

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Originally posted by labman:

quote:

---

Originally posted by jsharp:
I reluctantly just threw pads on it since I plan on making some major changes to the brakes next winter and don't want to spend money on parts I'll likely throw away in a few thousand miles.

But darn. I didn't think this would be an issue...

---

You should be OK til fall, if you stay out of the mountains, and avoid needing to make repeated hard stops. Your brakes will be fine as long as you don't ask too much of them. I hope you are not commuting into Chicago.

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Nope. My daily drive to work is 17 miles one way through the country flatland. I have to use the brakes all of 7 times to get there and one time isn't even a complete stop...

 

[jsharp]

quote:

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Originally posted by cangreylegend:
Both new rotors. Two different brands. See any difference?

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Tell us the brands if you know them. I'm really curious...

 

[Kestas]

So, you got our attention, and developed the suspense.... tell us, which rotor came from which manufacturer?

 

[cangreylegend]

What you should note is that both pass the caliper min thickness test. The right one is made by Wagner, the one on the left I don't know but is the one that garages mostly order as "new" rotors and about $10 cheaper. When you pick up the rotors you notice the difference in weight.

Learnt my lesson in buying rotors. Check them out first!!! They're definitely not the same.

 

[JHZR2]

With the low miles on it in all that time, Ill bet that the rotors have rusted over and then scraped clean more than a few times... I think that when rotors rust over (after being out in the rain, humidity, etc), after theyre used a few times the scraping of the oxidized surface causes significantly more material loss than if the rotors had stayed rust-free.

JMH