Just put new rotors on the wife's car. A few weeks ago, put new calipers and pads on after finding both fronts had frozen guide pins and the inboard pads had worn thin. Rotors were replaced about a year ago when she noted that the brakes were pulsating. Thought all was squared away, but I took it to put gas in it, and there was bad pulsating. Ordered new AC-Delco front rotors, and confirmed the pulsating is gone. So is it likely they warped because the pins froze and they were dragging?
Stuck calipers = warped rotors?
- Thread starter Dave Sherman
- Start date
Of all reports of "warped rotors" on many forums over many years, when queried, I've yet to get a report back on the actual runout measurement of warpage. I have seen a few with that had that information up front. Of those, none had the pre-warpage runout measurement. (There are also a few where the measurement was made on installation, and the posters stopped there and were asking for help).
The point is, most "warped rotors" I've seen and dealt with, in real life and online, were actually a case of uneven pad deposit. Not saying it doesn't happen, but in the many "warped rotors" I've fixed myself, including some stuck calipers, the problem was uneven pad deposit.
Where "warped rotors" were verified by measurement, I've yet to run into anyone (beyond myself) that had the install runout numbers.
The worst "warped rotor" feeling vehicle I've encountered measured less than .001" runout, but the pad deposits were on opposing sides and opposing ends of the rotors. The "warped" feeling was unreal, practically violent. But the rotors were in spec.
But to answer the original question, yes, stuck calipers can and do cause the throbbing brake issue.
The point is, most "warped rotors" I've seen and dealt with, in real life and online, were actually a case of uneven pad deposit. Not saying it doesn't happen, but in the many "warped rotors" I've fixed myself, including some stuck calipers, the problem was uneven pad deposit.
Where "warped rotors" were verified by measurement, I've yet to run into anyone (beyond myself) that had the install runout numbers.
The worst "warped rotor" feeling vehicle I've encountered measured less than .001" runout, but the pad deposits were on opposing sides and opposing ends of the rotors. The "warped" feeling was unreal, practically violent. But the rotors were in spec.
But to answer the original question, yes, stuck calipers can and do cause the throbbing brake issue.
Uneven pad wear, deposits, etc. can definitely be caused by stuck calipers.
Why wouldn't you replace the rotors when replacing the pads and calipers?
Why wouldn't you replace the rotors when replacing the pads and calipers?
AutoMechanic
Site Donor 2024
Yes the stuck calipers will cause the rotor to heat up because you are going down the road with the brake pad against the rotor so it warps them also wears down the pads.
I have heard this many times but the brake lathe strongly disagrees. Those shiny magnetic chips are not pad deposits.
- Joined
- Dec 28, 2014
- Messages
- 2,846
To answer your question, yes, absolutely stuck calipers will warp your rotors. And I think you made a good decision to replace the calipers rather than try to free them up, grease and think they’re fixed.
- Joined
- Dec 28, 2014
- Messages
- 2,846
I agree and in the grand scheme of things does it really matter?
Pad deposits would lead to parallelism and that would lead to warped rotors. It would change the metallurgy and cause heat, and warp them (excessive lateral run out).
But I have never seen/noticed brake pad material stuck onto a rotor or noticed it when lathing a rotor. As a matter of fact, I don’t even cut rotors anymore...they’re too cheap and thin already. Cutting a rotor usually means one thing to me...that the car will come back in six or less months with a pulsation complaint.
Silly question, but if it was uneven pad deposits, what would that look like? The old rotors were shiny and didn't seem to have localized discoloration.
- Joined
- Dec 28, 2014
- Messages
- 2,846
Some darker marks, perhaps an imprint of the pad. But darker looking smudges on the rotor, all around the rotor.
I've had rotors warp from stuck pins, sticking calipers, internally collapsed brake hoses and loose bearings/ hub assy's .
Any thing that can cause excessive one sided pad drag will warp a rotor over time, sometimes quickly others slowly.
As other's have said uneven pad wear is a sign of something else going on.
Any thing that can cause excessive one sided pad drag will warp a rotor over time, sometimes quickly others slowly.
As other's have said uneven pad wear is a sign of something else going on.
I sold my Ammco 4000 lathe last year, no point in keeping it anymore for the reasons you cite. The guy I sold it to does mostly light to medium trucks where the rotors have the bearing in them and plenty of meat on the OE ones. I bought it used and came out of it whole so that's okay.
- Joined
- Dec 28, 2014
- Messages
- 2,846
My Ammco has been sitting doing nothing for five years and same for my on the car brake lathe.
AutoMechanic
Site Donor 2024
So has ours pretty much. We don’t have an on car one though. We had someone come in and want them machined but they were way out of spec they were original after 200,000 miles and then we said sir you need new rotors and explained why he got mad and left insisting we were trying to rip him off. Later he showed back up and said you were right I didn’t know they had to be a certain spec. I can’t think other than that the last time I had someone asked for them to be machined. According to the parts stores I’ve talked too since I know many of the parts people they do them almost daily they said so maybe the people that still get it done are DIY people that or they are lying to me lol. If my boss ever goes to sell the brake lathe I’m buying it lol since I want to open my own shop one day. It’s an Ammco as well.
- Joined
- Dec 28, 2014
- Messages
- 2,846
I mean, I’ve cut my own rotors just to get a little more life out of them. They usually last 6-12 months before they start pulsating again. For a customer it’s not something I even consider doing anymore. These rotors are so thin to begin with and cheap. It’s not like 30 years ago where you could cut these things 2-3 times and not have a problem. And like I said, they’re pretty reasonable to replace.
The brake lathe is going the way of the engine in the car cylinder boring machines, armature lathes and roll over toe setting boards.
I have used them all at one time or another but not for many years.
I have used them all at one time or another but not for many years.
Stuck calipers cause terrible pad deposits.
Source: Have a Ford Super duty. It's not good at much, but it hangs at least one caliper per year.
I did have the rotors milled down last year. Saved some $$$ over new. They weren't warped so much as rusted bad because I never drive the truck.
Source: Have a Ford Super duty. It's not good at much, but it hangs at least one caliper per year.
I did have the rotors milled down last year. Saved some $$$ over new. They weren't warped so much as rusted bad because I never drive the truck.
My Camry rotors had .001" runout and terrible brake shudder when I sanded off the pad deposits.
The proud side of the .001" was the non-deposit sides.
After sanding and breaking in again, no shudder, at all.
Just one experience of many
The proud side of the .001" was the non-deposit sides.
After sanding and breaking in again, no shudder, at all.
Just one experience of many
Last edited by a moderator:
Similar threads
