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Front Rotor Retaining Screw Broke - Not sure I care
The front rotor retaining screw stripped while I was trying to remove it. It then broke when I used an easy out. I was able to get the rotor off and I can get a new one on, however, I am not going to be able to reinstall the new retaining screw. I have had damaged rotor retaining screws on other cars and didn't worry about it and never had a problem. This is the first time I have seen a manufacture use thread lock on these screws. Has anyone else had this problem. Did you go to the trouble of replacing the hub??
That is a sick joke for someone to put locktite on a retaining screw. Absolutely no reason for that.
Can you start a pilot hole with a dremel and drill it out or cut a new straight groove for an impact driver? Not a big deal but need to take extra care while mounting wheels and watch wheel studs for extra wear because it cannot be fixed..
With how gingerly the wheel hangs on the hub when installing a wheel (even with a wheel hanger), I think I'd be worried it would be even more of a problem with the rotor possibly moving, too. Maybe, not - I'm trying to remember back to when I replaced rotors and can't quite remember how tight they fit.
My rotors and pads did not come in as planned, so I had to re-install the old rotor and pads. Thankfully, I only had the passenger side off. Chsu74 and DennisG01 yall are both right, it is a little funky to install the wheel while the rotor is not fixed. The good thing is the rotor has two dowel pin kind of thins that keep it positioned radially. I need to start planning a replacement of the hub. My believe it will be fine as long as I am the only one that pulls and installs that tire and normally I would be fine with this. BUT this is my daughters car and therefore I think I need to replace it in the near future.
That is a sick joke for someone to put locktite on a retaining screw. Absolutely no reason for that
Might want to rethink that ...
Mercedes specifies new screws be installed every time rotors are replaced. That’s because screw from Mercedes parts come with encapsulated thread locker applied. Probably a good idea to clean out the thread bore before proceeding, too.
Mercedes specifies new screws be installed every time rotors are replaced. That’s because screw from Mercedes parts come with encapsulated thread locker applied. Probably a good idea to clean out the thread bore before proceeding, too.
LOL. No. This screw just keeps the rotor on so you can put the wheel on without it clanking around. You actually think this small screw is going to help the brake rotor stop your car in anyway?
Been There.
Just forget and believe that this screw never existed. It just helps hold the rotor against bearing while we put calipers and tires. once you have everything back together, its going to be lugnuts doing all the holding at torque of 90+ lbs/ft
LOL. No. This screw just keeps the rotor on so you can put the wheel on without it clanking around. You actually think this small screw is going to help the brake rotor stop your car in anyway?
Not promoting the notion the screw is a major structural component silly boy, just that the loctite is there from the factory, not some cruel joke as you fantasize. Nevertheless, it’s probably a good idea to fit the screws and replace them every time ... as real engineers specify. Shadetree, shoot from the hip, path of least resistance solutions are ridiculous at best and often in fact dangerous and almost always ignorant.
Been There.
Just forget and believe that this screw never existed. It just helps hold the rotor against bearing while we put calipers and tires. once you have everything back together, its going to be lugnuts doing all the holding at torque of 90+ lbs/ft
Note that blue-colored loctite is kind of like using a nyloc nut. It's nowhere near as tenacious as red loctite. Using red in this case would be ridiculous - blue is just to make sure it doesn't wander out on it's own. Although I haven't looked closely enough, I would imagine the wheel, itself, would stop the screw from backing all the way out. But if it did back out a little bit, then the rotor would likely wobble when wheels are removed for rotation - requiring an extra step to re-tighten that little screw. Bascically, just an "annoyance preventer" kind of thing. Well, that's my opinion, anyways!
That little screw's purpose is to align the disc with the hub so that you can get the lug bolts in...so unless you wanna fettle around for an hour lining everything up when offering up the wheel to the hub; don't worry about that little guy - you could possibly use the supplied aluminium wheel bolt alignment tool that sits in your spare wheel well.
The lug bolts carry the stresses imparted from the wheels to the hub assembly; that little screw has a negligible stress load once the wheel bolts are tightened down.
Max
Last edited by Max Blast; Sep 15, 2019 at 03:55 PM.
But if it did back out a little bit, then the rotor would likely wobble when wheels are removed for rotation - requiring an extra step to re-tighten that little screw.
No way the screw would back itself out since the wheel is always tighten down.
However, this is a forum and we always welcome knowledge and wisdom imparted by people who believe their local dealership SAs walk on water.
No way the screw would back itself out since the wheel is always tighten down.
However, this is a forum and we always welcome knowledge and wisdom imparted by people who believe their local dealership SAs walk on water.
I hope that second sentence was not directed at me. It's a rude, unfounded, and unwelcomed wisecrack if it was since, at no time, was I referencing an MB dealership.
Now... does the wheel hub sit completely/tightly against the screw? Doesn't the screw head sit slightly "less than" flush... meaning it could back out a little bit (since that's what I was really questioning - NOT that it would back itself out fully). Although, it would likely not cause a "real" problem if it did back out a bit.
I hope that second sentence was not directed at me. It's a rude, unfounded, and unwelcomed wisecrack if it was since, at no time, was I referencing an MB dealership.
Now... does the wheel hub sit completely/tightly against the screw? Doesn't the screw head sit slightly "less than" flush... meaning it could back out a little bit (since that's what I was really questioning - NOT that it would back itself out fully). Although, it would likely not cause a "real" problem if it did back out a bit.
If i recall correctly - the screw sits slightly recessed when tightened - and flush with surface when the lug bolts are tightened.
At that point it might as well not be there.
And if it backed out and fell into a pocket on the back of the wheel face, it wouldn't have any measurable deleterious effect.
If i recall correctly - the screw sits slightly recessed when tightened - and flush with surface when the lug bolts are tightened.
At that point it might as well not be there.
And if it backed out and fell into a pocket on the back of the wheel face, it wouldn't have any measurable deleterious effect.
Thanks. I just couldn't remember well enough from when I last did rotors. So the only "problem" it would cause is maybe a wobbly rotor when rotating tires. Not a huge deal - just annoying.
No way the screw would back itself out since the wheel is always tighten down.
However, this is a forum and we always welcome knowledge and wisdom imparted by people who believe their local dealership SAs walk on water.
On my other German car I have to re-tighten them every so often, they work themselves out otherwise. I actually used a bit of blue locktite on them last night to see if that helps.
On my other German car I have to re-tighten them every so often, they work themselves out otherwise. I actually used a bit of blue locktite on them last night to see if that helps.
A solid part of the rim sits against the retaining screw when the wheel is bolted on. How does it work itself out?
If you're a fisherman, you can stick a piece or two of line into the hole before inserting the screw. It actually does a really good job acting like a thread locker, but like a nyloc, is not hard to loosen. Just passing on a little trick I learned many years ago - one of those things you put in your "mental" toolbox for possible use later on.
A solid part of the rim sits against the retaining screw when the wheel is bolted on. How does it work itself out?
My other car does not have the rim covering the screw. It easily works itself half way out after a couple of days of spirited driving...Happens on all 4 corners
Does not happen with MB for me, but I am not pushing the truck
A solid part of the rim sits against the retaining screw when the wheel is bolted on. How does it work itself out?
You can see that the screw is recessed. It could work its way out by about 1/4 turn even if covered. I don't remember the shape of the inside of the wheel, whether solid does in fact cover that hole.
The retaining bolt won't ever back all the way out; it will run into the wheel at some point. I'm surprised Mercedes puts Loctite on them since for the last 30 years I've been putting anti-seize on these screws on all my BMW's, since what happened to the OP is the more common scenario. Generally when you round off one of the Allen heads on these, you just drill the head and pull the rotor. There is always enough of the bolt left to get a Vice Grip on there (after hitting it with penetrant/heat/etc) and remove what remains.
An easy solution to the OP's problem would be to rotate the rotor one bolt, mark and drill a hole a bit smaller than the original screw, then tap the new hole to the appropriate size. That shouldn't take more than a few minutes. There are four more spots on the hub for you to try to get it right....
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