What is the trick to removing the rear disc after removing the caliper and applying penetrating oil to the hub?

You wouldn't happen to have the emergency brake on would you? (just asking, no offense meant) BTW, I am guessing W126 chassis.

Yes, it is a 126 chassis and no, the emergency brake is not applied. The metal shield to the rear of the disc prevents access to tap the disc from the rear except at the area where the caliper installs.

I would need to rotate wheel to tap uniformly. Can't rotate without taking transmission out of park and can't do this without emergency brake engaged. Can this job be done without the use of a lift?

I should add that I have the wheels safely blocked and am using a jack stand. I could place the tranny in neutral but I do not want to guess on how the procedure is performed. The 126 shop manuals do not cover this subject in any detail.

I did that job in July. One disc slipped off, the other was stuck. I had better luck pounding on the wheel mounting surface. And I mean pounding. I conclude that it's better to loosen whatever's keeping the disc on the hub than to try to pry the disc off the hub.

If the front wheels are blocked and the rear wheels are in the air, it should matter that car is in neutral. Again, if you pound on the wheel mounting surface, it won't matter that the car is in park.

Good luck,
Sixto
78 450SEL
91 300SE

Jack500,

There may be slight differences on how the rear disc is mounted. For example my '84 300SD (126) doesn't have a allen screw to keep the disc on the hub. It was frozen and took a lot of penetrating oil, pounding on the mounting surface and most important of all...patience. On a '91 420sel that I worked on it was almost the same except it had a 5mm allen screw that held the disc to the hub. Good Luck...

Nolan

Make sure you remove the retainer screw. Think it's a 5mm allen. If the rotor is frozen to the axle, there are a couple of ways to get it free. Spray very liberally around the center of the axle opening in the rotor with penetrating oil. Let it soak a good 10 or 15 minutes. Start tapping aroung the outside edge of the wheel mounting surface with a good sized hammer, rotating the rotor as you tap. The idea is to break free the rust bond between the axle and the rotor. Do not try to bang (tap)on the backside or edge of the rotor. You risk cracking or breaking it. Keep trying to rock the rotor off the axle as you tap away. You can tap (if you will) fairly briskly. If this fails to loosen it, spray again and try it again. If this also fails, applying some heat to the joint between the rotor and axle will usually get it free. Having said that, be advised that the application of heat can be a risky proposition as well. You need to keep it localized to the area of concern. NEVER heat the metal to a visible glow. It will lose it's temper. Apply just enough heat to get it it smoking a bit. Tap it a few more time while hot, it should come free. Let it cool before you handle it. HAve fun...

Old fashioned tip from old UK Ford sufferer. If possible always tackle disk removal with hot brakes. It's amazing how much easier they will dismount, after a few high speed stops to heat the disks.

Use a puller ;)
 

1. I use a puller, forgot if it was 2 or 3 jaw but it came right out. ;)
2. Be careful when you do this because when it comes off the puller jaws sometimes swing out and might hit your knuckles. I use a long socket wrench and slowly rotate it at the same time stand to the side. :D
3. When it comes off it’s a loud “clink” so look out for this. At the same time your puller will probably fall to the ground . :D


Good luck
Thai GI sends...