New rotors ordered - 986 Forum

Bob O · 10-04-2007, 06:28 AM

Since my car now has roughly 57K miles and I've never checked the rotor thickness, I went to Cummins Tools on Tues, bought one of their micrometers, the C clamp type (for all of $10!!), and measured front and rear rotors. Fronts were 21.4 and 21.2 arrrrrrrrrrrrr, but rears were still within tolerances at approx 18.5 mm. (With a 2mm wear allowance they've still got 25% wear left!!) I checked around and ******************************** Arizona had the best prices I could find, plus no shipping charges. Ordered fronts, Zimmerman, for $148, not bad.

They should arrive on Monday. New pads, new rotors, new brake fluid...yahoo. I should be all set for the DE at Heartland Park in a couple of weeks. I've never changed rotors but in looking at the various instruction guides around, it should be a piece of cake. I've changed pads and fluids numerous times, and it certainly doesn't look intimidating at all. OH DARN... I forgot to order new caliper bolts. Guess I'll be heading off to the dealer for four new bolts. RATS!

Can't wait to see how much pedal difference they make. Since they wear so slowly, its difficult to remember where the pedal was back when. Pedal doesn't feel low but then again it might be. We'll see.

Bob

djomlas · 10-04-2007, 07:24 AM

nice, full brake overhaull.
i got new pads and fluid as well, but need new rotors soon.

do you really need new caliper bolts?

Bob O · 10-04-2007, 07:47 AM

Most everything I've read says you "should" replace the caliper bolts. The minimal cost is probably worth it.

blinkwatt · 10-04-2007, 07:47 AM

Quote:

Originally Posted by djomlas

do you really need new caliper bolts?

Which bolt are you referring to? The two that physically hold the caliper,or the one that holds the spring in place?

If your referring to the springs one you don't really need to replace the clip,retaining pin & caliper bolt.

I've reused mine w/o an issue to date. Just coat the bolt with some type of anti-seize agent.

Bob O · 10-04-2007, 08:43 AM

no no.. not refering to the springs.. but to the bolts that physically attach the caliper in place. Its probably not entirely necessary to replace them, but, when we're talking about brakes, I guess one can't be too careful. I've reused the springs and other hardware several times.....whenever I've replaced the pads. But I've never removed the caliper, and my research just indicates that you should replace those attachment bolts, due to them stretching and weakening from torquing. Porsche recommends changing them with each caliper removal. hmmmmm Does Porsche make a lot of money on parts? of course. Is it absolutely necessary to replace them? probably not. Would I feel better if I replaced them? sure. (I know they're only torqued to 63 lbs, and the stretching of this bolt would be insignificant, but still.....)

djomlas · 10-04-2007, 11:33 AM

Quote:

Originally Posted by Bob O

no no.. not refering to the springs.. but to the bolts that physically attach the caliper in place. Its probably not entirely necessary to replace them, but, when we're talking about brakes, I guess one can't be too careful. I've reused the springs and other hardware several times.....whenever I've replaced the pads. But I've never removed the caliper, and my research just indicates that you should replace those attachment bolts, due to them stretching and weakening from torquing. Porsche recommends changing them with each caliper removal. hmmmmm Does Porsche make a lot of money on parts? of course. Is it absolutely necessary to replace them? probably not. Would I feel better if I replaced them? sure. (I know they're only torqued to 63 lbs, and the stretching of this bolt would be insignificant, but still.....)

just replace them then, its only a few bux.

Bob O · 10-04-2007, 12:28 PM

I know. I will.

djomlas · 10-04-2007, 01:20 PM

Quote:

Originally Posted by Bob O

I know. I will.

btw, with that rasoning, would u replace lug bolts every time you take the wheels off? i mean...they get torqued as well pretty good

Bob O · 10-04-2007, 06:59 PM

It isn't my reasoning, it's Porsche's. But, to answer your question, no. As I understand it... not only is the torque a minor concern, but the vibration and intense heat cycles associated with the caliper would weaken or make brittle the bolts over time. Not so (as much) with the lug nuts. Vibration yes. But they're far enough away from the heat source so as not to undergo the extreme heat cycling the caliper bolts do. Hey.. I don't make the rules. I just (sometimes) try to follow them!!! And the only reason this came up is someone asked a question. sheeeeeeesh.

djomlas · 10-04-2007, 08:23 PM

Quote:

Originally Posted by Bob O

It isn't my reasoning, it's Porsche's. But, to answer your question, no. As I understand it... not only is the torque a minor concern, but the vibration and intense heat cycles associated with the caliper would weaken or make brittle the bolts over time. Not so (as much) with the lug nuts. Vibration yes. But they're far enough away from the heat source so as not to undergo the extreme heat cycling the caliper bolts do. Hey.. I don't make the rules. I just (sometimes) try to follow them!!! And the only reason this came up is someone asked a question. sheeeeeeesh.

no its fine man, im not attacking you in any way hehe, just asking

ill be doing my rotors soon as well, so good info

Bob O · 10-05-2007, 05:29 AM

ok.. no prob!