Removing stubborn brake rotors

The techniques and hints mentioned below may do harm to your and other people's life, health and property. Please do not follow my hints unless you understand what you are doing and consider yourself mechanically experienced. Make sure to follow your car manufacturer's service manual when working with your car. Always wear protection and follow safety rules!

I did not drive my trusty 10-years old Honda Stream minivan for the whole summer (as I rode a bike) so I felt its brakes do not grip as well as they used to. So I've taken a look at the brakes and found them way too rusty and dented. So I grabbed replacement brake discs and pads at a local auto parts store and set out changing them.

At first, the procedure looked pretty straightforward - you are to take off the wheel, dismount brake cylinder and support, unscrew two small bolts keeping brake rotor attached to wheel hub and you are almost there. Just put everything back in reverse order with your shiny new brake rotors.

However, wheel parts appeared very rusty and hard to disassemble.

So I got stuck right away having trouble unscrewing the two little screws tightening brake rotor to wheel hub. They stuck so hard that even heating them with a propane torch and working them with an impact driver did not really help. So I end up stripping them and had to drill off their heads.

Now I could feel how stuck the rotor is. I've googled around and found a good bunch of suggestions on rotor removal. Here I mention some of them ordered by their severity to the stuck part.

• Spray and soak brake rotor with a penetrating lubricant like WD-40, Liquid Wrench or a 50/50 mix of acetone and ATF. The latter is reported to work best. Let it stay for a while and soak well. If you have time, spray it repeatedly for a couple of days. Make sure to spray from both outer and inner sides of the rotor. Aim at contact points of brake rotor and wheel hub. Once you are done with soaking and lubing, try hitting brake rotor from all directions but mostly from inside out with a moderately heavy hammer. Be careful not to harm the bearings by striking rotor too hard!

• Put one or two 8-10mm bolts with a nut and a shim into brake support mounting holes effectively pushing brake rotor out of wheel hub. There's a risk involved with this method - putting too much force may bend the mounts so be careful.

• Heat the hub-covering part of brake rotor with a propane torch and then fast cool it with water. The theory is that the expansion from the heat followed by a sudden shrinkage caused by cooling would break bound parts apart. The risk here is to overheat the seals and lubricant in the wheel bearings. My personal feeling is that you'd need an acetylene torch (which is much hotter than propane) to do any harm to  these delicate parts.

• People on the Internet also suggest using a large three leg puller. Use it to pull brake rotor by its edges against wheel hub. I had no appropriate puller around so I did not try that method myself. I've seen reports that puller tends to break off parts of rotor's edges so be careful with that. It's most effective to combine the puller method with heading and hitting ones.

• Finally, the sure solution to the stuck rotor problem is to use an angle grinder to literally cut brake rotor off the hub. I used this method and was amazed how fast and effective it is compared to the other techniques I mentioned above. I'll describe my experience with this metal cutting method in greater details.

A word of warning: the angle grinder is not a toy! That powerful machine may seriously injury you if misuse it. Always wear goggles, gloves and hold angle grinder with both hands. Never position your eyes in-line with the cut off wheel, as it may break and parts will fly out in the direction of its rotation.
 

First take a small (100-120mm) and thin (1-2mm) cut off wheel (for steel) and make two parallel cuts of length 80-100mm each and about 5mm deep. Make the outer cut at 5mm offset from outer edge. Try to place the inner cut as close to rotor surface as possible.

Be careful not to cut through the rotor and get to the hub. Hint: once the cut off wheel is almost went through the rotor's body, you will notice a small cloud of rusty dust popping out of the cut.

Then take a narrow chisel and work both cuts to make the surrounding metal bending and cracking.

Helping yourself with a pointy hammer you will soon uncover a good part of wheel hub. Soon the brake rotor will inevitably get loose and you could take it off the hub by hand.

Once I got rid of my old brake rotor, I still had to extract the bodies of (now headless) screws popping out of wheel hub. For that I've taken a 6mm socket head and just struck it forcibly on screw's body. Then unscrewed them easily with a small ratchet.

If 6mm head gets loose, try the 5mm one.

Prior to putting on your new rotor, make sure to sand rust and dents off wheel hub. Otherwise your new rotor may not perfectly  combine with wheel hub what may produce vibration when braking. A good practice is to put some high temperature brake lube (I used modern ceramic one) at the rotor-hub contact points to prevent their bonding in the future.

Finally, the new rotor is on.

Hope this brief write-up helps someone.