Front rotors loose... but then won't come off.

[tinmanSC]

I'm doing the brakes for my friend's 07 Mercury Milan, 3.0 V6, AWD (I think this is the same as the Ford Fusion). The front rotors are cracked and pitted. In replacing them, I've removed the 2 little torx screws that hold the rotor in place and the rotor is free moving. The rotor was pretty rusted on there. I applied some heat and got it loose with minimal fuss. All points of the rotor do move and come out from the wheel hub, but only about 1/4 of an inch. I can pull the entire thing straight out, but it stops after about 1/4 inch and won't move past that. My experience with rotors has been that once you get it loose, it pops off. Is there something I'm missing here?

 

[JC1]

You can whack the daylights out of the rotors with a small sledgehammer until they come off.

I would also try and spray them with WD40 in between the bolts etc. It might take 30 minutes to get one off. There is usually rust between the hub and rotor. What I usually do it apply some bearing grease between the rotor and hub on reassembly. Makes it easier for the next time.

Regards, JC.

 

[bdcardinal]

http://www.youtube.com/watch?v=mtsTJCRljAs

When all else fails try this.

 

[tinmanSC]

The rotor is loose. It was rusted to the hub, but it is now free from the hub and moves. I'll upload a video.

 

[yonyon]

You have a build-up of rust on the rotor behind the hub. That area of the rotor where brake shoes would ride if it were a drum instead of a rotor, that is loaded with rust. I would avoid avoid using the method in bcardinal's video (although if it comes down to it, that should work) as this may bend the knuckle a little and cause issues with the new brakes. I suggest:

-Pull the rotor as far from the hub as you can. Use a hammer to repeatedly strike the rusty area (even though you can't see the rust) while rotating the rotor. Some rust should fall off. Push the rotor back onto the hub, spin it, then repeat several times until the rotor is off. If you have air tools available, use an air hammer or needle scaler instead of a regular hammer to vibrate the rotor.

If that doesn't work.

-Using a large hammer, strike the rotor from the inside out. Turn the rotor about 120 degrees. Repeat until the rotor is off. This method may or may not damage the bearing.

 

[yonyon]

If that still doesn't work it's torch time.

I guess you could also remove the center nut then pull the rotor and hub off together, then clean the offending rust out `on the bench' like a gentlemen.

 

[tinmanSC]

Originally Posted By: yonyon
You have a build-up of rust on the rotor behind the hub.

This sounds quite plausible. Back to the garage I go.

 

[tinmanSC]

http://www.youtube.com/watch?v=PZv_IW7AfbE

 

[yonyon]

After seeing your video:

Yeah, it's rust behind the hub, but not very bad. Get a smallish hammer and give several (maybe a dozen) whacks to the rotor all around in rapid succession. Spin the rotor, then wiggle it off.

 

[Tegger]

Originally Posted By: yonyon
-Pull the rotor as far from the hub as you can. Use a hammer to repeatedly strike the rusty area (even though you can't see the rust) while rotating the rotor. Some rust should fall off. Push the rotor back onto the hub, spin it, then repeat several times until the rotor is off.

Use an 8oz (1/2 lb) ball-peen hammer so you can concentrate the force on the walls of the "top hat". Many lighter blows all around are better than a few Thor-type whacks. You're trying to shatter and break up the rust, so you want to force the metal to resonate. If you hammer on the part where the hub contacts, the force will be dissipated into the hub instead of vibrating the top hat.

If these brakes have threaded holes for bolts to help pull the rotor off, use them in conjunction with the hammer.

I have a solution for this situation that is based on a Honda Canada fix for rust elsewhere on the brakes...

 

[Bgallagher]

Whenever I do brake work I usually soak everything in penetrating lube and give it a couple whacks. Then I leave it overnight to saturate and if that doesn't work I hit it with a torch to break the rust free. Obviously I am not melting the rotor but the heat helps break rust free 99.99% of the time. I have never had an issue

 

[SLCraig]

When you finally get it off just remember to put some anti-seize on the mating surfaces afterwards. Should make the job easier next time around.

 

[tinmanSC]

Thanks for all the help guys. You were right, rust had encroached on wheel hub around the back of the rotor and it was "hugging" the wheel hub. This caused the rotor to be loose, but unable to come off all the way. I took some nuts, washers, and bolts and tried to use the method suggested, it broke the bolts! I got some higher grade bolts and soaked it like mad in pb blaster, hoping to soften it up. It worked, and they came off after only 2 days of frustration. Sigh

 

[bdcardinal]

Originally Posted By: tinmanSC
Thanks for all the help guys. You were right, rust had encroached on wheel hub around the back of the rotor and it was "hugging" the wheel hub. This caused the rotor to be loose, but unable to come off all the way. I took some nuts, washers, and bolts and tried to use the method suggested, it broke the bolts! I got some higher grade bolts and soaked it like mad in pb blaster, hoping to soften it up. It worked, and they came off after only 2 days of frustration. Sigh


Glad you got it sorted out. That is one thing I do not envy about the rust belt. Here the brake and suspension parts come off fairly easily.

 

[yonyon]

Originally Posted By: tinmanSC
It worked, and they came off after only 2 days of frustration. Sigh


Two days! If you're going to continue to do work on your own vehicles in a rust-prone area you need to invest in a high powered vibrator and some lube. A good torch would be nice but isn't absolutely necessary.

For a vibrator, my tool of choice is a pneumatic hammer. For your purposes a small one is probably the way to go. A dedicated mini needle scaler would probably work as an adequate low-cost substitute and as a bonus you get a needle scaler. That doesn't work if you don't have compressed air though, so you might have to make due with an electric hammer if you don't have air and don't want to buy a compressor. If that's not a good option, you could go with good cheap overkill: go to a pawn shop and buy the cheapest thing they have with a one cylinder gasoline engine on it. Take the engine off the tool and you have a bulky, awkward, and inconvenient gasoline-fired mega-vibrator. This will shake some serious rust off of things.

Lube: penetrating oil. Kroil is amazing stuff. Vibrate first, then Kroil, then vibrate again if needed. It isn't the cheapest penetrating oil around, but if your time is worth more than $0.15 per hour and you live with rust it's worth it. Hells bells, even if you consider your time to be worthless, it might save you some money on parts that you break trying to break some rust.

 

[Tegger]

Originally Posted By: tinmanSC
they came off after only 2 days of frustration. Sigh

You didn't do it properly, then. It's never taken me more than an hour per rotor for even the worst-rusted ones. And I live in the very heart of the Rust Belt.

An 8oz hammer, judiciously applied, and the bolts through the top-hat's face, are all you should need. NEVER EVER use penetrants! You want the rust to remain as dry and as frangible as possible! Fluids will damp the impacts from the hammer, allowing the rust to stick in place instead of fracturing off.

 

[tinmanSC]

Originally Posted By: Tegger
Originally Posted By: tinmanSC
they came off after only 2 days of frustration. Sigh

You didn't do it properly, then.


I don't mean to sound curt, and I'm not defending myself (don't feel the need to) but..... obviously.

This is the first rotor I've come across that is like this. Learned a lot. By two days I don't mean I was working on it for two 8-hour days. After my tool broke and I replaced it with a stronger one, it was probably 30 min per rotor. And you do of course realize that starting off by telling someone they did something wrong isn't the best way to make them receptive to your message (seems people think those rules change on the Internet)... Still, thanks for the advice.