been told that you have to open up the brake bleed screw to change out the brake pads

if i don't do that then the abs would be fubar'ed, is that true or not???

 

thats bs. to change the pads just take out the old ones push the caliper back put in the new pads make sure the slides and contact points are lubed with brake grease.

 

Yeah, no point in that.

 

you may want to remove to top of you master, when ya push the caliper you may blow the top off & make a BIG mess!! brake fluid WILL TAKE THE PAINT OFF ANYTHING!!! just use a C clamp & go slow pushing it back.

 

The idea behind loosening the bleeder is that the fluid being displaced by pushing the piston back into the caliper will exit the system and not be pushed back into the ABS/master cylinder. This supposedly keeps contaminates out of the ABS/master cylinder.

I am not sure how contaminates would get into the fluid at the calpier considering they are sealed well enough to hold enough pressure to stop the car.

I don't think it's really needed, and I bet 95% of dealer service techs don't bother.

 

i don't think its a 95% that don't i'd say its more 100% that don't i'm a toyota tech student and they never mentioned anything like that to us in brakes class. other thing to consider at a dealership time is money to a tech getting the job done fast is what they want to do. when i worked at acura all we did was just push the pistons back into the caliper. if containments happen over time which is why you should still have you fluid flushed. usally vaccumed out with a special tool then refilled at the master.

 

The bleed screw method is more popular in BBK applications with a fixed caliper where you cant easily get to the pistons to compress them. The trick is to open the bleed scre and push the pads back. Since you cant easily get leverage in the tight spots it makes pad swaps a lot easier. Also, in racing applications, brake bleeding is being done constantly as fresher fluid in the calipers are less likely to boil.

Heres a pic of one of our 4 piston calipers that shows how hard it would be to get to the pistons with a clamp: