does turning old front rotors make sense with 9mo old pads ?

[fenixus]

hi there,

I was thinking recently what i can do to further improve stopping power (which is great by now haha!) and seems the only thing untouched are rotors.

I kept old ones (didn't turn them) when i was installing new Hawk HPS pads last summer. does it make any sense to take the rotors off, bring to shop for turning and install with old pads (they are barely worn) ?

also, where do you bring rotors for turning ? any local auto repair shop would do ?

thanks for insights.

[Mike Gerber]

If you are not feeling any brake pulsation, I would just leave things as there are for now. The 9 month old pads have seated to the old/unturned rotors a long time ago. Probably within a hundred miles of when you installed them. Save your money on turning the rotors for the next pad replacement.

Mike

[fenixus]

thanks Mike. you're right, no pulsation when braking what so ever. next time will turn them for sure

[uibalnme]

You can "resurface" the pads. Use 80-grit sandpaper lightly on the pads to get down to fresh material, and reinstall with the turned rotors. You can have the rotors turned at any local auto repair shop. Or, can have the rotors turned at a Sears automotive center if you don't trust the smaller shops. I learned that from an ASE certified mechanic. It works, and it's really easy.

[fenixus]

i will consider "resurfacing" both rotors and pads when i get bored
good to know it can be done on pads by hand using a sand paper (80 grit). for now brakes work great, just uneven rotor surface looks bad, though it doesn't do the infamous pulsating ... yet.

[uibalnme]

If those are the original rotors, I'd just replace them with Brembo blanks, or upgrade to drilled/slotted rotors. I have Brembo blanks up front, but I'll be upgrading to drilled/slotted rotors all around when I do the V6 front disc upgrade to match the rear disc swap I just did.

[fenixus]

yeah, i was thinking about upgrade, but i don't quite like the idea of going with blanks when my original rotors look still not bad and were never turned yet.
i'd love to go with slotted/drilled ones, but that's too expensive for me.

i still have original drums with original pads in the rear LOL not planning to touch that yet. all i did was star wheel adjustment on them, they seem to work good, parking brake is also nice tight after 5-6 clicks now.

[73sport]

Originally Posted by uibalnme

You can "resurface" the pads. Use 80-grit sandpaper lightly on the pads to get down to fresh material, and reinstall with the turned rotors. You can have the rotors turned at any local auto repair shop. Or, can have the rotors turned at a Sears automotive center if you don't trust the smaller shops. I learned that from an ASE certified mechanic. It works, and it's really easy.

When and if this is done just make sure the final pad dimension is square in all directions. The brake pad backing plate and the friction material should be parallel to each other.
> Sticky slides on calipers can allow them to wear at odd angles which further makes the caliper slides stick even more.

If they look like cheese wedges (triangle) chuck them and fix the caliper slides so they wear the next set evenly.

[fenixus]

Originally Posted by 73sport

When and if this is done just make sure the final pad dimension is square in all directions. The brake pad backing plate and the friction material should be parallel to each other.
> Sticky slides on calipers can allow them to wear at odd angles which further makes the caliper slides stick even more.

If they look like cheese wedges (triangle) chuck them and fix the caliper slides so they wear the next set evenly.

i fixed sticking top caliper pins by replacing all of them (both bottom and top) with new bushing and new grease. once i take them apart in spare time i will check if new pads stay flat in parallel to the back side. i think there's nothing wrong so far, though it's been a few months since i checked on them.

i will go into rotors resurfacing and stuff once i confirm fuel trims got fixed with clean injectors. i guess i'm looking for another task, since i have a feeling this one will get fixed soon (hopefully)

[uibalnme]

Originally Posted by 73sport

When and if this is done just make sure the final pad dimension is square in all directions. The brake pad backing plate and the friction material should be parallel to each other.

Easily done. Lay the sandpaper down on a table/bench top, and run the pad across the sandpaper a few times with light pressure. 5 to 10 passes across the 80-grit should be enough to get the friction surface down to fresh material, and keep everything even.

[73sport]

^^
Due to the broad audiance, this should prolly stay attached. . .

Quote:

Originally Posted by 73sport
If they look like cheese wedges (triangle) chuck them and fix the caliper slides so they wear the next set evenly.

[uibalnme]

I agree, uneven pad wear warrants new pads. If the pads show even wear, the procedure I mentioned will work just fine.

[djb2]

Turning rotors is old fashioned. Even roughing them up is now disfavored.

Some new pads come with a thin abrasive coating that cleans the rotor without a bedding-in cycle. If your pads didn't, or you are reinstalling used pads, ten rounds of 60MPH, brake hard to 10MPH will remove the old pad transfer layer and start wearing the base metal. Subsequent braking will re-establish a very thin transferred pad material layer that is the basis for long pad and rotor life. (Normal braking is when the pad and transfer layer drag against each other with minimal wear. Only heavy or hot braking will result in pad against metal.)

[fenixus]

Originally Posted by djb2

Turning rotors is old fashioned. Even roughing them up is now disfavored.

Some new pads come with a thin abrasive coating that cleans the rotor without a bedding-in cycle. If your pads didn't, or you are reinstalling used pads, ten rounds of 60MPH, brake hard to 10MPH will remove the old pad transfer layer and start wearing the base metal. Subsequent braking will re-establish a very thin transferred pad material layer that is the basis for long pad and rotor life. (Normal braking is when the pad and transfer layer drag against each other with minimal wear. Only heavy or hot braking will result in pad against metal.)

i'm sure Hawk HPS pads create this thin layer as they carry a special note on bedding in. 3-4 hard braking from 45mph down to full stop and around 10 medium force braking down to a full stop from 30mph or so, then they wrote to park the car and wait until brakes cool down for 15 mins. i think it equals more or less to what you mentioned. i'm too cheap now to get new rotors.

if I ever turn those old rotors (might be a bit old fashioned hehe), i will repeat pads bedding in process, no worries. pads manufacturer claims it's essential for their quiet operation and full stopping potential, etc...

[diddly]

Not trying to jack the thread or anything, but I got a question for 'uibalnme'. If you don't mind me asking: What's the approximate cost to put rear discs on a gen4? Do you have to change or modify (if modifying is even possible) the proportioning valve? I'm assuming the resulting braking is substantially better; yes, no?
I've also got a T100 with rotors that need turning: I've always considered just 'refacing' pads, if they have a ton of meat left on them, yet the brakes pulsate. Maybe I'll try that on the T100: Thanks for the confidence with that!....diddly.