Need help from brake guru for w126
 

I'm having problem with doing the front brake on my 420sel. I replaced the the both the front discs. Had a hard time putting in new pads. I did one side. I used the old pad and a screw driver to push the piston back. The new pads went in pretty tight.

How much drag is acceptable on the disc? The disc does not spin freely. I have to muscle it to get it to turn. I think it is too tight. I don't have this tool http://www.samstagsales.com/images/kk126-00.jpg

John

everything sounds pretty much normal.that is the way i change pads.they go in tight unless you painstakingly clean all the old brake dust out of the calipers.drive round the block to bed in the new pads and all will be okay.

Using the old pads to compress the piston is also the way I've done it also,
but I use 2 vise grips on the ears/pin hole of the pad and then open up the bleeder screw.

A small wire brush will do wonders for removing all the corrosion on the slides. Takes you five minutes per caliper to do all eight surfaces where the pads ride.

Then take a dab of grease (specifically for brakes) and lightly coat all eight surfaces.

The pads will drop right in and the rotor will spin freely. Try it.;)

I did the same job recently on my 420. The advice about cleaning the crud off is difinitely the right thing to do. I always use a C-clamp and the old pads to open the calipers. I replaced rotors as well and the new pads went on easily.Once complete, the first application of the brakes will snug them where they're supposed to be.