Reuse pads with new rotors?
 

Quick question. Is there any reason I shouldn't reuse the existing brake pads with the brand new rotors I just installed on my car?

Yes. If the pads are not perfectly flat due to ridges in the wear surfaces you will get hot spots in the new rotors. The ridges will drastically reduce the contact patch putting more pressure on the contact area resulting in higher temperatures. If the pads are relatively flat and you break them in gently you will probably get away with it, but it doesn't seem like a good gamble. The payback (cost of new pads) does not justify the risk (cost of new pads plus cost of new rotors).
In the old days we used to sand the pads flat, but I don't really recommend that either.

If your pads are thick and beefy, I would reuse them.

If the surface is not level you can use a file to clean them up, but be careful not file them at an angle. They have to be parallel to the rotor surface.

Sammyg2,

Just curious, why not sand the pads flat?

I understand the hot spot issue that can arise from only partial contact but sanding my nearly new pads flat on a bench sander seems like a halfway decent option. Does your experience dicate otherwise?

Not trying to be cheap, just trying to understand the issues.

Absolutely you should replace them. What's another $48 when we've already spent thousands on these things... :)

And save the old pads. Why? Because when you rebuild your calipers and you need to scooch out the pucks after the rebuild you'll want to use pads just *slightly* narrower in width than the new pads you put in. Press pedal, pads go to rotor, then you remove old pads, scooch pucks back in *just* enough, and put in new pads.

Saves you from the squishy brake pedal problem.

John

I would use some 80-150 grit sandpaper and a flat serfice insted of a power unit, It won't take much work to get the riges off and keep them flat just my .02

I've re-used pads with new rotors before. No big deal. Plus, it's not just "another $48" for some of us....front and rear pads are running me $270 these days....

As long as the pads don't have anything *obviously* wrong with them, I'd re-use 'em.

Mike

I've been told that pads harden in use and should therefore not be used with brand new discs. The discs should last longer if they are installed with new pads.

I've sanded pads before, but I'm not about to recommend someone doing it on this board for obvious legal reasons.
I'm not sure what all of the materials they are putting in brake pads these days but I'm sure they are not good to breath so if you do it make sure to wear the right protection. Also make sure to keep the pads flat and parrallel so you don't have a problem with contact on the leading edge or they will squeal and chatter. We used to put a small bevel on the leading edge for just this reason. It can be done right and it can be done safely, or it can be screwed up royally, even to the point of damaging the rotors and maybe even causing an accident if they pull hard one way under panic stopping. Some things I like to experiment on, some things I like to be frugal on, braking systems don't fall into these categories any more for me at least.

Soooooo, if it were my car and I needed to get it running and I didn't have the money to buy new pads, I would consider sanding them.
If I could afford them I would buy new ones.
BTW, unless we are talking about exotic racing pads, they are only $40 for front and $39 for rear, prices taken out of an add in Panorama, it says pads, original Textar, Jurid, or ATE. I haven't checked with our host, but I bet they have good prices also.

If we are talking about racing pads, that changes lots of stuff.

Point taken. Since I was planning on just going with stock or slightly better pads I'll probably buy new ones. Any recommendadtions for a good, economical street pad that could handle a couple of DEs a year and maybe some autocrossing?

My wife and I just had a "budgetary clash" last week due to the purchase of 4 new rotors, new SS lines, caliper rebuild kits, new rear wheel bearings, caliper paint, turbo tie rods, bump steer kit, hood struts, Mityvac and a replacement rear hub that was ruined by a bad wheel bearing. All this in last couple of months. All of these were authorized purchases but the tally was a little higher than she'd hoped for. I was just trying to avoid more fuel on the fire.

For an answer on this I would go to an expert. From Carroll Smith's Prepare To Win, page 82, "It is best not to run new discs and new pads together because either scoring of the disc or heavy pickup on its surface will result." and "When re-using old pads, install them in their original positions."

Sanding the pads is probably a bad idea because there is no way that some of the sandpaper's abrasive won't be embedded in the pads surface. I wouldn't go and do an serious track events until the rotors have gone through some heat cycles. Once the rotors have been broken in and the pads are happy with them then you can go beat on them.

If you aren't going to really lean on the brakes and put major heat into them, I wouldn't worry about any of this. The question should be, "Have you ever faded the brakes pads other then during initial bedding?" This will tell you how much care and feeding of the brakes you should be doing.

On the question of pads, I personally like Porterfield Engineering's R4S compound. They work very well when cold and are very hard to fade. As a bonus they are rather affordable, especially compaired to the Pagids. $79 fronts, $69 rears.


Wayne