Testing if a Rotor is Warped - No Dial Indicator!
HTML-код
- Опубликовано: 8 фев 2025
- Mike shows how to test for warpage of rotors using unconventional techniques, without fancy dial indicators or expensive tools. Spoiler: Mike's rotors are warped! He also shows how to replace them.
BONUS: Mike crashes into his house!
#rotors #warped #warpedrotors #mikethebackyardmechanic
I'm a retired mechanic, and I would always clean the rust off the face of the hub before installing a new disc (rotor), to ensure that the new one would sit flush against the hub. I would also always fit new pads when fitting new discs to ensure even wear during the bedding in process.
Good tips!
Not cleaning the hub may cause the new rotor not spin perfectly in a y-axis
Amazing how people make a video , teaching people incorrectly, and people think it must be the gospel truth just because someone made a RUclips video. Really sad!
@rsanchez9192 so if you know better, then load up your video. Otherwise, shut the F up.
@@rsanchez9192you seems to know better. Where's your video then?
I don’t think you need to use the impact to put the disc retainer screws on, just nipped up would be fine. I’d say they’re far over torqued from spec
Hey, I used a method very similar to yours to check run-out, but instead of using a jack stand I clamped a Mole-wrench on the caliper bracket and then attached a pencil to the Mole-wrench with a rubber band. Worked very well. If I had used a jack stand it would not have worked well because my car would have fallen on top of me ;). But most importantly, I then measured the gap between the pencil tip and the rotor at the low point, using a feeler gauge. In my case I found that, although the pencil was rubbing the disc at the high spot and there was a clearance at the opposite end, the measured clearance was well within spec. I know this is nowhere near as accurate as a good dial indicator properly used, but it my case I was measuring a gap of about 0,04mm against a spec. of max 0,1mm, so I am confident that my runout was within spec, even if my measurement should be out by 100%.
One other point: Once I had found the high spot with my pencil-rubbing, I carefully re-positioned the pencil to make sure that the tip was only just skimming the surface of the rotor at that point, and not pressing hard up against it.
Of course, I also repeated the process a couple of times to check that my measurements were repeatable, and was really surprised and delighted at how well this method works when you do it carefully.
I like you comment about pumping the brakes, crashing in the garage. Done that. Learned the hard way.
Kudos for making it to the end!
Don't torque one screw up without the other when fitting new rotors. Same as tightening wheel nuts. Or a cylinder head...
In most cases of brake vibration vespecially with vented discs the disc isn't warped the issue is caused by friction material backed into the surface of the disc, fitting new quality brake pads which have an abrasive break-in layer usually fixes the issue.
Rake vibrations were a major issue on 1970:s era European Fords with strut suspension particularly the Capri and abrasive coated pads were all that were required to cure the problem
I like that tip!
Put never seize on the threads of those hold down screws and they will not be so hard to remove. Also, you only have to tighten them just enough so they do not back out. Their only purpose is to hold the rotor in place while the brake caliper and pads are being put on or when changing a flat tire. When you put the wheel on and tighten down the lug nuts the rim is what will keep the rotor securely in place, not the screws.
The anti-seize is a good tip. I can't in good conscience leave them off due to the possibility that they are centering the rotor more than the lug bolts are.
Changing a flat tire? You can't be serious.
@@052RC
"Changing a flat tire? You can't be serious."
It is not likely that the rotor will tilt when changing a flat tire, but if it does it will cause the brake pads to be pushed apart. And unless you pump the brakes a time or two after getting the spare tire on, you will not have operable brakes until the pads are pushed back into place.
Imagine not knowing that and driving up to a stop sign and not being able to stop and not knowing why your brakes are not working.
@@oldtimefarmboy617 LOL, that is impossible when you change a tire, the brake mounting bracket and caliper keep everything in place. I have changed tire many time and never had an issue. Those screws are useful at the initial assembly at the factory where the vehicles was built, other than that they have no useful purpose. My Toyota and Nissan don have them.
@@diegopalomino1200
"@oldtimefarmboy617 LOL, that is impossible when you change a tire, the brake mounting bracket and caliper keep everything in place. I have changed tire many time and never had an issue. Those screws are useful at the initial assembly at the factory where the vehicles was built, other than that they have no useful purpose. My Toyota and Nissan don have them."
I did not say they are necessary. They are useful. Not just at initial assembly but anytime you have to do brake work or some other maintenance that would require removing the brake caliper, like replacing a front wheel drive CV drive shaft. Or if the rotor is still in good shape, replacing the brake pads.
I get a bit of a shake on the highway if I press the brakes hard and replaced the rotors about 2 yrs ago as the shake was MASSIVE then. 1 yr ago I replaced a stuck caliper, so possibly the rotor(s) are a bit out of thickness variation. Taking them to O'Reilly tomorrow to have them measure and if necessary cut them to be even. Never been cut so should have enough thickness to still be safe.
Thank you for your video. I have a 04 Lexus rx330. It had exact problem you described. I turned rotors, brake pulsing and steering wheel shimmy gone.
Glad it helped! I have a video for changing brakes on a Lexus is250 coming up soon.
I believe the screws are not needed other than at assembly time at the factory when the vehicle was built.
Note to anybody having this issue.. check the wheel bearing while your at it.. 😊. That way youll know and wont have to repeat labor IF the wobble persists after time spent and the wheel is back on😅
Very smart idea to test the rotors with simple tool, unfortunately one time before, I forgot to restore the brake because someone was annoying while working, sadly many things happened.
I had bad tires and thought it was bad rotors
I like the way you explain what’s happening good video 👍✌️
its not that rotor is warped . its the thickness variation that make the brakes shake. that is caused by wear from run out like you showed. so when the new rotor is installed run out needs to be checked under .002 or less or in about 10,000 miles it will shake again . not warped just worn uneven from run out. a on car brake lathe is the best repair if the rotors are thick enough.
Probably true. I plan to do a follow up video on rotors, addressing this issue.
Agreed. I get a bit of a shake on the highway if I press the brakes hard and replaced the rotors about 2 yrs ago as the shake was MASSIVE then. 1 yr ago I replaced a stuck caliper, so possibly the rotor(s) are a bit out of thickness variation. Taking them to O'Reilly tomorrow to have them measure and if necessary cut them to be even. Never been cut so should have enough thickness to still be safe.
I just did mine & crashed into my house for good measure. All good now 👍 thank you! 😜
HAHAHA! You "should have" watched my video until the end🤣
Thanks for the video.
Don't use impact wrench, use torque wrench on lug nuts.
Those small screws holding the rotor in place don't need to be that tight, IMO.
Yep.
Gotta clean the rust from any parts which have to allow movement and any metal mating surfaces, and use the right high quality grease! While you're under there, spray all rubber parts with 'Son of a Gun' protectant, it makes cv boots soft and flexible so they last longer! I'm also a CHEAPO backyard mechanic!
Interesting - I've never heard of Sun of a Gun. Sounds like a must have for older cars.
You might be screwing yourself up by tightening those rotor screws... And those pads looked pretty shot! I like the c-clamp to keep the pads from spreading
I have tightened and retightened those screws many times. It's fine. And yes, I should have changed the pads with the rotor, you are right!
You're pretty risky trusting that floor jack! You ever heard of jack stands?🤦
I would have repeated the same test before re-assembly. The cause could also be in the wobbly hub itself
there is another test for this but the rotor needs to be removed. I would do this test with new rotors because I've had this issue with those new but cheap rotors.
simply take the rotor and place it on a flat surface, like a tile or table or something you know for sure is perfectly flat.
then just take your finger and push on one end of the rotor and try a few more spots around. if you see it lifting on the other side or wobbling that means the rotor is warped, and will likely cause vibrations. it also depends how bad it is. recently I had two rear rotors, one was very slightly off, but the other had much more play.
rear rotors will have the vibrations you mentioned, coming from the seat instead of the steering wheel or even brake pedal, but only as you get up to speed.
Not a bad no-tool tip. I test them properly in a more recent video.
Why not test the new rotor to ensure that is is not warped,? Would also show us what a consistent measurement should be.
Troll
That's absolutely right, and I was planning on doing that. But then it was dinner time.
What about those screws on rotor in my car a dont have any that cause isssues?
Not sure where the pencil came into play you used a red gizmo, no pencil.
Also you dont impact lugs on unless you use torque bars which you didn't.
Lastky those little screws do not need to be hammered on just lightly snug with a phillips, those are just to hold the rotors steady , many mechanics dont even pit them back on
Good info!!!!
Why didn't he ever use a torque wrench?...
Certain screws I just know the feel - large ones are 100, small ones around 35... but I use the torque wrench in my videos now, or at least state the spec.
He did not use a torque wrench when tightening the lug nuts. Pretty sure they are over torqued.
Nice vid. Thanks.
I had no problem removing those rotor screws Just need to use the proper size screwdriver, Also I think you are way over tightening them on re install They only need to be snugged and flush
I might be over tightening them - but I initially could not remove them without the impact driver.
hey hey Hey' 💥 You didn't grease the slider pins! 😵 you'll be sorry 🎶💸
This video was fairly sloppy. I've tried to tighten it up since then.
Had my tires rotated and had the opportunity to see the tire being fastened to rotor. The mechanic did Not use the correct sequencing. Instead fastened as he went around the rotor. This wrong procedure is one cause for warped rotors especially when hot rotors meet water on the road. Yes it was at the dealership.
Yeah... and that hub needs to be cleaned - and it's unlikely ANYONE does that. No excuse not to use the right torque pattern though.
I have difficulty figuring out which way is off and which way is on with the impact screwdriver
It goes the direction you are twisting it. I admit it was not intuitive at first.
Thanks for video
The car got a new half shaft very recently too. :)
Another point - although it wasn't mentioned here, you should never replace just one disc (rotor), always change both sides, or you will have a braking imbalance.
Such an obvious point I didn't think to make it. Thanks!
I always believed that you needed to replace rotors in pairs until the owner of an automotive machine shop told we otherwise. He said the measurement of a new rotor and used one is so close it doesn't matter, just as long as you replace both sets of pads. I've recently done this without any issues.
@@dalemihocik4732 It's not so much the thickness of the disc, it's the condition of the surface that makes the difference. If you have a brand new disc with a completely flat surface, it is going to give a different braking efficiency from a part worn one with even light scoring. This could be critical on front brakes, where balance across the axle is essential.
@@rickconstant6106 Your correct about the surface condition of the disc, I failed to mention that the rotor would have to be in out of the box condition minus a few thousandths of wear.
Did you check the hub to see if that was the problem and not the rotor
IN the updated video I test the rotor runout more thoroughly.
Hi, can you have a warped rotor but only have occasional indicators? My breaks will occasionally feel like they are pulsating, I guess is what you could call it but it's very random. Also had mechanic look at it and said everything looks fine. Had tire shop do brake check and got the all clear. We have replaced the 2 anti lock brake sensors but still happening
Why would you replace the tone wheel sensors for a vibration? Let me guess, Scotty Kilmer told you to do it.
leave those dang screws off only there for factory assembly
can warped rotors cause a steering wheel wobble at highway speeds? i get this bad steering wheel wobble and rims and tires are balanced, all zeroed out.. cant figure out why i got this steering wobble. tried everything.
Not likely, without putting on the brake.
First thing to try is to retorque your wheels in a proper star pattern. I had a shimmy with my new rims until I did this.
If that doesn't do it you need to take things apart and make sure things are clean and mounted flush and correctly (rotor, wheel, hub face).
If the shake comes and goes at different speeds, its probably a balancing issue. If not, its most likely a broken tire. Rotate your tires and see if the problem moves to the rear.
Clean the wheelhub and then put Some coppergrease on it. So it Will losen up easily next time
Good tip. I have been doing that since.
did i miss it?or did he not check new rotor or lube any parts
I have a newer video where I am more meticulous.
Great video. Is it necessary to check for warpage on new rotors? I'm about to replace the rotors and pads on my car at this time.
All rotors will have some warpage each car has its own spec
1/1000 of an inch, wrapped 10/1000 of an inch, couple of human hair thickness, really make much difference in braking efficiency, just wondering ?!
4/1000 or 0.004 of an inch is spec. You won't feel much at 0.010, but you will start to feel it at 0.030.
Pump up the jam
VW spec is 8Nm for this little screws. Definitely you should check specs for yours car, clean hub's and don't rebuild neu rotors witch old break pads 😮
All true. I try to do things more by the book these days.
Why not
Well... I didn't have one.
Rotors are so cheap I just replace them with the pads, checking to see if the hub is warped is more important.
Yes, replacing them with the pads is a good idea. The rotors for the Pilot are $130 bucks from the store although I have found them significantly cheaper online. I'm still doing research to determine rotor quality.
If this was a Japanese car those screws on the rotors are not Phillip screws but JIS screws and that is why those screws get messed up You need a #3 JIS screw driver to remove them or the next time the same thing will happen again
that's not warped rotor, but hub runout!
Guess I'm confused, you mention using a pencil the next thing I see is the plastic guage.
I have an upcoming video where I use an actual indicator! That will clear up the confusion.
New roter old pads, huh?
The real sorry thing is, I had an extra set of pads that I forgot to use!
Always check the hub for runout, easy to do and only takes a few minutes and clean the hub! Always torque the wheel lug nuts as per proper procedure. This is not a good video, much misinformation.
I plan to do a follow up video soon to not only correct mistakes but provide more (better) information.
How do you know it isn't run out from the wheel hub? .003 of an inch will cause pulsating.
In my later video I check the rotor off the car.
I think it's too difficult to have the rotor perfectly vertical to test this way.
Verticality does not affect the runout that I was testing. If the rotor was tilted 45 degrees, it would still spin the same.
There is no such thing as a "warped" rotor, it's uneven glazing. Rotors could sustain heat to the point of glowing hot and still wouldn't warp.
I understand. And these rotors are "warped" again (less than a year later), so I am going to do a better breakdown of what is happening.
Third... 🥺