The need for Rotor Screws?

[Medic531]

So a friend and I were changing my rotors on my 15 ex tonight and we got stuck on the front right wheel with the rotor screw. The screw ended up getting stripped and we tried everything we had and knew at the time to get the screw off. Finally we used a dremel to remove the head of the screw or tried to and now the screw and the rotor screw hole is so messed up its hard to tell where the screw is as the metal from the rotor and the scrw now blends in together. We are pretty sure either the entire head is off or very close to it but cannot get the rotor to come off. I searched on here for some ways to get the rotors off for when they are rusty and I may end up trying the bolts thru the caliper holes to push the rotor off. If I have to I can prob take it to a shop and have it removed.....the point of this thread is are the rotor screws even required for safe operation? My friend and I have never seen rotors with retaining screws before. So at the time of this post I have the front left rotor replaced and screwed in nicely while the old front right rotor is still on there.

 

[Stephen Cannon]

The screw should not affect safe operation. Sounds like you are down to a EZ Out kit to remove the screw. Yes I do recommend replacing the screw if you can save the insert threads but not critical for safe operation. That screw is for the most part a Factory screw. I simply call it the OSHA Screw. The original design of the screw is to help maintain the rotor on the hub assembly during production. The screw should prevent the rotor from falling off during assembly until the caliper, pads, rims and tires are installed further down the assembly line. The Rotor if you can imagine can be quite heavy especially if it falls from about waist level straight down on the poor assembly line works foot. Yes Steel Toed boots should be worn but it can still probably hurt. Simple version the screw should be replaced s a matter of keeping it from falling off the rotor hat while tire and rim is removed but you would not be the first one to not re install the screw and the rotors will be retained by the lug nuts. If you can remove the screw without damaging the threaded insert take the good screw as a sample. Take the good screw to your local Home/Depot or Lowe's and see if you can get a match for replacement. Probably want two or four depending on what axle rotors you are replacing. A dab of Anti Seize should help keeping from seizing and a future occurrence. If you decide not to replace the screw some people tighten a lug nut hand tight on the lug stud to help keep rotor retained. Remember the rotor should also be retained by the pads and caliper.

 

[Odrapnew]

On every vehicle that I owned which had those screws, I ended up drilling the head off. I usually left what's left of the screw since I couldn't grind it flush(no tool). I just align the hole in the rotor with that screw.

As Stephen said, its for production to prevent the rotor from falling off.

 

[KayGee]

They are not only for use on the assembly line. In fact some vehicles don't even use them at all (some Toyotas and others), or did use them, but discontinued them... https://www.miata.net/garage/tsb/M001_13.pdf

On vehicles that use wheel bolts to secure the wheels, they are usually a big help in keeping the rotor affixed when removing a wheel and keeping the holes in the rotor hat aligned with the threaded holes in the wheel bearing. In these instances you may find 2 screws are used (ex: Porsche - note: some cars with wheel studs also use 2 screws, like Honda). If you use the appropriate wheel installation tools for these wheels they will also aid in keeping all brake parts aligned when installing a wheel.

On cars with wheel studs, they are not really necessary beyond initial factory assembly and most people remove them at the first brake service. With that said, they can still be helpful in keeping the rotor affixed to the bearing when doing brake service.

As with everything on the internetz, there are always multiple answers ranging from partly correct/wrong to mostly correct/wrong, and even some that are total bullshit. Have fun.

 

[Odrapnew]

I've never owned a vehicle that didn't have wheel studs so I didn't think about wheel bolts, but makes sense.
I also corrected my post to specify my vehicles.

 

[Medic531]

Thanks for the replies guys. I got a package of replacements screws at Oreilys with a Phillips head vs those crappy torx heads.

My issue now is how the hell do i drill out the rest of the screw? I think some of the head is still remaining otherwise it should have came off with a little tap from behind like the other rotor. I wish we had taken a pic of it before we put the tire back on. We drilled a hole then we impacted a torx bit into the hole...that torx bit broke off in the hole.

Any suggestions on the type of metal drill bit that I need to use to drill out the remaining mixed metals?

 

[CDW6212R]

That bolt is not needed, superfluous. Other replies are correct for various applications and different types of people.

Skip past that, remove the rotor, then the screw remains, as much as you prefer, and install a new rotor.

Removing any bolt which the head is damaged or broken, is a PITA. Once you get to where not much is left or multiple metals are there, drilling and/or hammering with a drill/punch is the general procedure, to get deep enough to make the bolt let go etc.

Is the rotor threaded for that bolt at all, or just a hole and the hub is threaded for the bolt? It sounds like all that is needed is to remove the whole bolt head, and then the rotor can be pulled off. Using a large grinding wheel will eat a rotor or any bolt etc, easily and fast. Drilling with small bits can break many of them to get deep enough for most bolt removal. If it's going to break several bits, I'd get a cheap grinder and spend 30-45 seconds eating a hole/slot in that rotor to remove the head.

I had a rear rotor that would not come off of my last bought 98 Explorer. After several attempts over nine months owning it(I wanted to do brakes front and back, regardless of old pad thickness), I decided it had to be pulled with a puller, or cut off. I think it was the wrong rotor or a badly made cheap thing, the center hole was too small. I ended up with my grinder, a simple HF tool that was maybe $25. It took a while to slowly grind into the rotor next to the axle. I slotted the rotor center surface between the studs, a little at a time. It took about 20 minutes to carefully remove enough rotor at the center to lessen the strength of the inner circumference, and it finally would pull off.

The grinder will eat any metal, but it throws it fast in one direction. Be careful if you use a grinder for anything, and plan for the debris to go in the safest direction possible.

 

[Odrapnew]

Thanks for the replies guys. I got a package of replacements screws at Oreilys with a Phillips head vs those crappy torx heads.

My issue now is how the hell do i drill out the rest of the screw? I think some of the head is still remaining otherwise it should have came off with a little tap from behind like the other rotor. I wish we had taken a pic of it before we put the tire back on. We drilled a hole then we impacted a torx bit into the hole...that torx bit broke off in the hole.

Any suggestions on the type of metal drill bit that I need to use to drill out the remaining mixed metals?

I think on only one of my vehicles, after I got the head drilled out I could actually unscrew the remaining threads by hand. The rest were ground down to not interfere with the hole in the rotor(didn't install new screws).

Also, why would you go with a Philips head? The Torx should be able to handle more torque before stripping.

Honestly, if you cannot unscrew the remaining threads by hand or with a pair of pliers, just grind them down so they don't interfere with the hole in the rotor and call it a day.

@CDW6212R - the rotor has a clearance hole, so the screw is not treaded into the rotor, just the hub.

 

[Stephen Cannon]

We have obviously established what the original purpose of the screw is and also established that it should not effect safe operation. If you can't get the head of the screw off or EZ Out and the screw head interferes with rotor removal. There is one more drastic step. Cut around the head with a angle grinder and possibly risk damaging the rotor requiring replacement. I would get the new rotor first and keep it close by. If you don't need the new rotor you can return.

 

[Napalm]

with the head off - if you still can't budge the rotor, it's being held on with rust around the hub to rotor interface. Very very common.

you need a rubber mallet, or a dead blow hammer. some PB blaster penetrating oil or liquid wrench - spray down each lug hole then if possible spray down the backside of the rotor to hub. wait about a minute or 2. faceing the rotor - tap the rotor on the outer edge towards the hub. This will help to shear the rust layer - it needs to shear off. Then another spray. Then again facing the rotor - tap the rotor on the outer edges - toward the car to help rock the rotor on the hub. If needed alternate with the taps on the edge of the rotor for that shearing action again.

It should come off - I've never had one not. some just take a bit more taps. when you place the new rotor on - run some copper anti-seize on the hub to rotor interface.

NOTE before doing any of this - run 2 lugs nuts down on the rotor or at least on the studs - so the rotor doesn't come flying off.

 

[KayGee]

Maybe it's best for some people to just leave things to the 'professionals'.

 

[Stephen Cannon]

If you do eventually get the rotor off and there is enough of the threads showing on the screw. Get a good pair of Vise Grips, some PB Blaster and you could slowly grab and manually rotate the screw out. After that if threads are in good shape try a different screw and try again.....Or not!!

 

[Odrapnew]

it almost sounds like you're trying to say that it would be really helpful if the rotor had a hole that you could put a small screw into to secure it. It's amazing how things can come full circle so quickly sometimes...

Not exactly.

He's not saying tighten the lugs all the way down on the rotor(EDIT, I just realized the first part of his sentence does say to run lugs to the rotors, my bad). I'd stick with the 2nd part of the sentence and put a few lugs on the end of the studs so if the rotor does all of a sudden break loose with a hammer hit, it doesn't fly off.

If that screw was installed and holding the rotor to the hub, it would make it much more difficult(if even possible) to break the rust.

In addition, we've already established the screw head is stripped and needs to be removed a different way. I just take a 3/8" and/or 1/2" drill bit and drill the screw head out. Once the head is smaller than hole in the rotor, the rotor is removed and then the remaining screw is either unscrewed(if possible), ground down, or just left alone.

I went through this last year when I replaced my rear rotors. Took a lot of hammer whacks and penetrating oil to get them to break loose.

 

[613GT500]

If you live up in the great white north, where there's more salt on the roads then the closest salt water source, you make sure to get rid of the rotor screw ASAP!
It will rust and you will have to either drill it out or use a manual impact driver.

 

[tincbtrar]

While the screw is probably unnecessary, I keep mine on with all cars. It helps keep the rotor seated well while doing brake work.

A small tip, get an impact screwdriver for the initial removal. You should be able to knock it out with a punch or two. If you want to reinstall it, put some antisieze on the threads. It won’t rust and it will easily pop back out with your impact screwdriver next time.

 

[Napalm]

Maybe it's best for some people to just leave things to the 'professionals'.

sorry but why say this? The guy is trying to learn - even the best mechanic at one time or another went to school or was taught something. So let's not bash on the starters here.

Thank you.

 

[RhinoQuartz]

sorry but why say this? The guy is trying to learn - even the best mechanic at one time or another went to school or was taught something. So let's not bash on the starters here.

Thank you.

And sometimes you've reached your limits and should know when to hand it over to someone who's been to school and knows what they're doing. Everyone has limitations.

Btw, while this forum is interesting and informative, it is not a substitute for professional education and experience.