Small screw on disk brake rotors.

Is this only a location screw? How necessary is it?

Thanks.

I think it's mostly to keep the rotor from falling off when the wheel is off. Not very.

It's nice to have when you don't have wheel studs so the holes always line up on the first try when swapping wheels... Or when doing pads the rotor does not get all cocked and make you burn yourself holding it in place... but not necessary.

Yup, just for assembly. I ditch them all the time.

I usually keep them.. but liberally apply anti-seize to them.

One nice thing about them, on some cars you use that same hole to remove the rotor. The Rotor itself is sometimes drilled and threaded for a larger bolt than what is used to hold it in place to the hub. By threading the correct bolt that fits into the rotor only, it will push against the hub and lift the rotor off by where it is usually most held on by rust

Assembly screws for manufacturing, not needed, soft metal so they inevitably strip out, I NEVER put them back on... soak the night before with PB, use a torch, do NOT use an impact or you risk strupping them badly...

Cool.

Thanks guys!

and when you're changing rotors (pads if it's necessary) … the work around is to take a lug nut (doesn't work that well for theses weird cars with wheel studs ) and run it on backwards all the way up … will hold the rotor in place while you replace the caliper bracket, or pads …depending on the style of pad

'course it helps to remember to remove the lug nut before replacing the wheel …

I cursed those, until I had the screwdriver tip from a manual impact driver(that you use with a BFH) on an electric impact gun. Now I only slightly dislike them.

Manual hammer impact FTW to remove, learned THAT one the hard way. I don't reuse them because I stay away from those stupid German and Italian cars which use lug bolts instead of lug studs (as the FSM decreed should happen so many centuries ago).

MotoIQ recently had an article on this very problem:

http://www.motoiq.com/MagazineArticles/ID/3610/Wrench-Tip-Stop-Stripping-Screw-Heads.aspx

TL;DR version: The "screwdriver bit in a socket wrench" trick.

Hammer Screwdriver Time!

volvoclearinghouse wrote: Hammer Screwdriver Time!

+1.

I attack those with an impact driver, or a hammer screwdriver. That works 90% of the time. If not, it's time for a drill, just drill the head off. I don't reinstall them because 75% of my 'customers' come back to me for repeat work and I hate dealing with them.

Those impact screwdrivers are like $12 at harbor freight.

Can also be useful for certain oil pump and water pump housings.

Oddly enough, even though I live in the rust belt I've never had any problems removing those screws. On BMWs at least, they use an Allen head; make sure to clean out the socket well so the wrench will seat, and it doesn't hurt to give the screw a whack with a hammer first to break loose any rust.

I'm convinced that BMW, MERC, maybe other euro cars use much better metal. I live in the rust belt, and as a matter of course, exhaust studs break, they don't come off. On my 92 300D, every exhaust manifold, and turbo stud, as well as the down-pipe studs and exhaust bolts all came off with a ratchet and hand power. That has never happened to me other than that 290K mile old Merc.

DrBoost wrote: I'm convinced that BMW, MERC, maybe other euro cars use much better metal. I live in the rust belt, and as a matter of course, exhaust studs break, they don't come off. On my 92 300D, every exhaust manifold, and turbo stud, as well as the down-pipe studs and exhaust bolts all came off with a ratchet and hand power. That has never happened to me other than that 290K mile old Merc.

BMW uses copper nuts on stainless exhaust studs so they don't corrode/rust from the heat. They always come right off - even after 200k miles.

If you break it of or drill the head off make sure that it gets ground flat to the wheel flange, as to not cause epic vibration when the rotor is reinstalled and the hole doesn't line up.

poopshovel wrote:

volvoclearinghouse wrote: Hammer Screwdriver Time!

+1.

Exactly my first thought. Of course, I didn't find mine until after I was done...

Giant Purple Snorklewacker wrote:

DrBoost wrote: I'm convinced that BMW, MERC, maybe other euro cars use much better metal. I live in the rust belt, and as a matter of course, exhaust studs break, they don't come off. On my 92 300D, every exhaust manifold, and turbo stud, as well as the down-pipe studs and exhaust bolts all came off with a ratchet and hand power. That has never happened to me other than that 290K mile old Merc.

BMW uses copper nuts on stainless exhaust studs so they don't corrode/rust from the heat. They always come right off - even after 200k miles.

Yeah, those are great. Problem with Mercedes is they quit using them as OE install at some point, so I always kept a bag of about a hundred around the shop to replace the crappy junk they came with, I used them on the J-H exhaust to head studs because the reduced hex (12mm) allows use of a socket where removal of the stock 13 mm nuts was 1/4 turn at a time (thanks, Lotus). They come in a hex and also a square version that's great for blind holes on manifold flanges.

I always reinstalled them (with antisieze) so I didn't have to worry about a customer saying I left bolts out of their car when they saw it.

logdog wrote: I always reinstalled them (with antisieze) so I didn't have to worry about a customer saying I left bolts out of their car when they saw it.

You're just adding lightness.

stan wrote:

poopshovel wrote:

volvoclearinghouse wrote: Hammer Screwdriver Time!

+1.

Exactly my first thought. Of course, I didn't find mine until *after* I was done...

You just stick that in the screw and start banging, right? I tried to take one off with one (for the first time) a few months ago, and it didn't do anything. Thought maybe I was using it wrong. I have up, and have to drill it out this weekend (it ended up stripping), along with trying the other 3 rotors.