I think I asked this question over a year ago but I didn't get a response. Can anyone tell me (from experience, preferably) what might cause the following:

Often, when I apply the brakes AFTER having shifted from Park to Reverse, there is a loud thud that I can feel in the pedal. It's almost as if the caliper piston is suddenly shooting out. I have a hard time explaining, but it happens after I have put the car into Park, then I push on the brake to release from Park. As I go into Reverse, the car begins to roll backward. I push down the pedal and hear a thud that I can feel in the pedal, almost like the sound the anti-lock brake test makes (I don't have ABS on my car). It is consistent and happens most only when backing up and first applying pressure on the pedal. It happened with my old calipers, and now also with my brand new ones (new pads and rotors too) so I am not so certain it's coming from the brakes but perhaps another part that gets pressure at the same time.

Any ideas???

 

sometimes the pads shift inside the calipers when you go from forward to reverse since the roters are rotating the opposide direction but usually you only hear it clunk rather than feel it.

 

Axle skipping a beat? Does the same thing happen when you go into "D"?

 

inspect your brakes dude. you should be able to tell if anything is awry assuming you've done work to them before.

 

I have done brake jobs before. I don't think anything is awry. There is not much play for the pads to be moving enough to make this sound. The axle would be a good idea, but I don't think it would be dependent on my braking. It's not happening when I go into reverse, it happens when I go into reverse from P or D and THEN brake. I wonder if I am missing a shim? I can't replicate with the system taken apart, obviously, so I am really relying on someone who has had this problem and fixed it...

 

The exact same thing happened to me..I never figured out what the problem was because it just stopped after a while..