My friend changed the original rotors off his 07 z (60k miles) yesterday, (didn't open any bleed valves, no lines came loose or popped off or anything) and now his brake pedal is spongey he says.. didn't bleed the system because he thought that was only necessary when a brake line came off or soething. Does he need to bleed thesystem? Wht's causing the spongy pedal? If he does have to.bleed the system, what's the best brake fluid to use? Oem, etc??

 

If you didn't also install new pads, and properly bed them in, that is likely your issue. The pads wear to match the rotor, so old pads will not be making ideal contact with new rotors.

 

so would new pads solve the issue more than likely?

am i right when i say there is no way air could have gotten into the system with what i did?

 

Yes, to both.

 

thanks for the help! last question though.. is there any chance the pads may like re-form to the rotor or anything within the next week or two?

 

^This You can change pads whenever but when rotors are changed it suggested that you put new pads on as well.

 

try new pads but while at it, it won't hurt to bleed them. get a motul power bleeder to make it way easier.

 

thanks guys.. will the pads re-form to the current rotors by chance? or does he for sure 100% need to replace them?

 

Old, heat-hardened pads may only glaze the rotor and make things worse. You can try one thing, though. Get some very coarse sandpaper, like a 40-grit, and lay it grit side up on a very flat surface, like a piece of glass, or a countertop. Take each pad, friction side to the sandpaper, and evenly rough it up until all the glaze and ridges are gone. Might take some effort. Reinstall the pads, and see if they'll bed to the rotors. Might work, but for all the effort, it's really easier and better to get new pads. You don't have to spend big$$$ - just get whatever premium ceramic type pad Pep Boys, or Autozone, etc. happen to have on sale.

 

Well since you were changing the pads you might as well had bled the brakes being an 03 and all. Who know what kind of sediment is trapped in your system

 

It's an 07 not an 03. If the rear pads are only 2 weeks old you think maybe they will reform and I will be safe only changing the fronts?

 

There was probably air in the system and when you pushed the caliper pistons back in the air moved and is now trapped in the master. Just do a quick bleed of the system.

 

Didn't even push the pistons back though? They fit without having to do so but it was extremely tight and a rubber mallet assisted in get the caliper back over the rotor

 

that action is enough to push it back in. bleed them