friend has a 91 accord ex who blew his front right tire while going 90 mph...almost lost total control...well now when he backs up the wheel seems to "lock" itself...meaning it wont back up any further by itself unless you press gas, but pressing the gas causes a bad vibration...his calliper moves freely ( a little bit) and is also leaking...my guess was that the calliper was causing the wheel to lock itself while backing up....when driving forward it is fine...what do you guys think? thank you

 

Look for damaged suspension parts. Maybe he blew the tire by hitting a pothole & broke something - allowing the entire wheel to move aft & rub against the fender??

Along with a leaking caliper - sounds like he probably has more than one problem.

 

he didnt hit a pothole or anything...the tire was very worn out already...i was looking at the suspension parts and were fine...wheel bearing is probably out too...

 

A wheel bearing could cause what you are talking about, free rolls one way and binds in reverse, I've seen that in just playing with old bike bearings and such.

 

thank you sir im off to check it out...will let you guys know

 

looks like the brake was stuck to the disc and had to basically pry them off the disc...caliper was also missing a bolt...after all that, car was perfectly fine