Hi new to the forum. I have a 78 I'm trying to get back on the road. I'm doing the rear brakes and I want to change the rotors also. I have the calipers off and inside hub flange. I've adjust the emergengy brake to off as far as it will go and I can not get the rotors off.
Any suggestions?
Thanks Ken

 

While you can take them off with the spindle, you are getting into a lot of work. If all you want to do is replace the rotor put the inner flange back on and drill out the 5 rivets holding the rotor to the spindle. If the rivets are already gone, hit it with a hammer to loosen it from the axle flange.

If you want to proceed with removing the spindle and service the bearings it is easiest to remove the trailing arm and put it in the press. You will need a bearing splitter(and the press) to remove the outer bearing from the spindle once you have it out of the trailing arm. You want to check the end play before you start your disassembly if you intend to reuse the bearings. The outer bearing has to come off spindle for reassembly even if you intend to reuse it.

As I said, a lot of work. May be worth the effort if you have no idea of the condition of the bearings.


Steve g

 

Drill the rivets. If the brakes are all you want to do, you don't want to go down the wheel bearing road.

 

Thanks everyone for replying.
Will drill out the rivets and give it a try

 

Before you do, read up on 'rotor runout' on C2/C3 cars and how to deal with it. Usually rotors last the life of the car. Why are you changing them?

 

Good advice from Mike. You probably do not need replacement rotors. If run out and minimum thickness are okay, my advice is to leave well enough alone.

 

If you do go into the bearings and press off the bearings, throw them away. You will most likely ruin the bearing in the process. Even if it looks OK. Remember to pack the bearing and put the seal on the spindle before pressing the bearing back on.

 

You don't put the outer seal on the spindle then press the outer bearing on. That would make it a pretty tough job getting the seal seated in the bearing support.

The proper way to do it is to go through your shim selection process first, of course. Then you pack your bearings. Set the outer bearing in the spindle support them tap the seal in place over it. Have your spindle pointing up on the bench. Flip the trailing arm over and set it on the spindle. Now drop your spacer, shim, and inner bearing on the shaft in that order (omit the seal). Set the flange on the spindle shaft. Now take the whole thing over to the press and set it down wheel flange down. Block it up so you are not sitting on the wheel studs. With a hollow spacer, press the flange down. This will press the outer and inner bearings onto the spindle. When it is fully seated take it out of the press. Lift the flange off, install the inner seal, reinstall the flange, washer and nut. Torque to spec and insert cotter pin.


Edit: If, when you put the inner brg and flange on the spindle, the bearing is not on far enough that the flange spline will engage the shaft spline, use a pipe type pressing tool and press the inner brg on, pressing on the inner race.

This entire method of installation is critical. You always want to be applying pressure on the inner races only at all times, never through the rollers. If you follow the pressure when using this method of install the pressure is: press, flange, inner brg inner race, shim, spacer, outer brg inner race. No pressure on any rollers
Steve g

 

I've searched for an explantion of what this is & have not found it, just lots of threads mentioning it.
I've never heard of it until I came to this forum.

And these rotors last the life of the car? How can that be?

 

Using a dial indicator on the face of the rotor you measure the amount of runout or wobble the rotors have. Runout is more critical on older corvettes than most other cars because they use a floating piston with a lip seal whereas most cars use a floating caliper with a square cut o-ring type seal.

With a floating piston lip seal system, excessive amounts of runout cause the piston to move back and forth frequently and quickly which causes the lip seal to flutter which in turn pumps air into the system.

They don't last any longer than any other rear wheel rotor, the key being rear wheel rotors don't do as much braking as the front and generally don't wear as fast. These older cars used organic pads rather than semimetalic that is mostly in use today. Semi metalic pads wear rotors, organic sacrifices the pad almost exclusively.

Measure the thickness in several spots to make sure they are even. If the runout is okay and the thickness falls within spec, reuse them. You may still want to drill the rivets to remove them and service the parking brakes, but mark them so that you get them indexed to the spindle as they were when you measured them.

Steve g

 

I'm surprised that you can't find much explanation, I've worn out a couple of keyboards as have some other regulars.

Neither the rotor or spindle were finish machined when mated, only afterwards making them forever a matched pair. By replacing one half or the other, the finish machining or shimming may need to be done once again.

I don't know of any other production car that used this process, but there you are. The fixed calipers added to the sensitivity of the design.

Compare your rear rotor to the size, thickness and material content of any modern car of the same weight. It's oversized by a large margin and as such lasts for decades.

You didn't answer why you feel the need to change them.

 

Weigh one.