Correcting
Popping From Front Brakes On Cars With the Emergency Brakes on the
Front (900s up to 88 MY)
When
the caliper gets a bit of wear where it slides, you get the clunk in
reverse when applying the brakes. This applies to 900s up to 88 with
the emergency brakes in the front.
You can fix the problem with the parts you already have on the car. First remove the front wheels and grab each caliper with the emergency brake released (chock the rear wheels!) and see how loose it is. This is just for future comparison. Note that the movement in the caliper is in the slides, where the actual piston housing mounts in the bracket to the spindle.
Check the outer pad. If it is loose in its mounting to the caliper, there are two tabs, one on the top and one on the bottom that bend over and hold the pad. A few "adjustments" with a drift and a hammer will bend the tabs down to tighten them to the pad and limit its movement.
Remove the U clip that goes through the pads and caliper. Remove the clip in the lower half of it to get it to come out. After you get the stone shield that goes on with it off, reinstall just the U clip and put it in until the clip bottoms out. Mark the clip where the rotor passes beneath it on the center of the rotor. Pull the clip back out until your mark is lined up with the outer edge of the caliper. Insert a screwdriver in the clip from the outside and bend the clip toward the front of the car so the mark you made is in the center of a u bend you are putting in each arm of the clip. Reinstall the clip fully. It will require a small hammer after you bend it to get it through all the holes/pads. Make sure you didn't bend it enough to rub the rotor. If so, adjust it a bit with the flat screwdriver to get clearance on the rotor . The stone shield fits under the arms of the clip so make sure there is enough room for that too. Insert one of the stone shields arms under the upper arm of the U clip and pop the lower one in with the screwdriver.
Look at the clip behind the outer pad that touches the U clip. The small clip should hook over the ears of the tabs you first bent and go to the outside of the U clip. Pay attention to this when you insert the U clip.
Now see how much play the caliper has, if the U clip was bent enough, all the play should be gone and the reverse noise stopped. No parts and about 15 minutes time.