Change pads with rotors?

[frankengrant]

I just changed my pads and discovered I need new rotors, do I need to change my pads again, something about pads setting into a rotor....?

Im going to repack the wheel bearing at the same time, and might replace them since they are cheap, I havent decided yet.

[leathermang]

If your car uses ' one time only ' crush washers for setting the tolerance on the wheel bearings be sure to pick them up before you start the process....and dial indicator if you do not have one...

[vstech]

need more information to answer your question.
how long did you drive on the rotors with the "new" pads?
what kind of material/brand pads were they?
how bad are your rotors? warped? grooves? BIG ridge?

[toomany MBZ]

No, you don't need new pads.

[woodboat3]

Originally Posted by toomany MBZ

No, you don't need new pads.

You can't say that without seeing them. If the old rotors had a big grove in them the "newish" pads will no longer be flat. They will cause a funny wear pattern in the new rotors. If the old rotors are simply below spec on thickness but are otherwise flat than I will agree that you do not need new pads.

[frankengrant]

The pads probably have 300 miles on them, they are honeywell brand pads and the rotors have a big lip on them.
thanks!

[vstech]

Originally Posted by toomany MBZ

No, you don't need new pads.

a blanket statement like this cannot safely be made.
NEW rotors are soft material.
seriously warped rotors will put a shape into the pads, and can cause rapid rotor wear if put into place on new rotors.
it's really important to know the condition of the pads.
I'd hate to put hot spot generating pads onto new rotors.
if the pads are smooth, and quality ceramic material. and they don't have deep grooves, or seriously altered shape, they should be ok to use on new rotors.

[frankengrant]

the big lip is from the rotors being worn below spec btw. they are 1 mm below spec

[woodboat3]

Did the big lip put a big groove in the new pads?

[woodboat3]

As a side note unless it is a government imposed inspection forcing the change I would run the below spec rotors and pads until the next brake pad change and change the rotors then. 1mm is nothing

[vstech]

Originally Posted by frankengrant

The pads probably have 300 miles on them, they are honeywell brand pads and the rotors have a big lip on them.
thanks!

the lip will have cut a mirror lip into the pads surface. you will be braking for the next 5000 miles without the outer lip of the new rotor getting friction. slightly reducing the braking diameter of the rotor.
I'd put in new pads.
300 miles of a lip wearing into pads is plenty to damage the pads.

[vstech]

Originally Posted by woodboat3

As a side note unless it is a government imposed inspection forcing the change I would run the below spec rotors and pads until the next brake pad change and change the rotors then. 1mm is nothing

I disagree...
SPEC is too much to keep the rotors, 1mm below spec is beyond safe limits set by MB...
there is no way to know how tall the groove is, or how much damage to the pads were done.
pads are what 50.00?
put new on.

[vstech]

I'm seriously anal about brakes...

[leathermang]

Originally Posted by vstech

I'm seriously anal about brakes...

WHY ????

Are they that important for Safety ?

anything less than the thickness stamped on the rotor should not be used.

How much do new brake pads cost ? With new rotors.... I think is penny wise and pound foolish not to have them start out flat and new together.....
It is not nearly as important that the car be able to GO as it is to STOP.
Since you are taking them off anyway... this is the time to put them back as a pair...

[woodboat3]

original equipment MB rotors 1mm below spec are better than aftermarket rotors made in china that most people put back on their cars. 1mm less will dissipate less readily then new rotors. Where I live this would be a non issue