Am going to bring my M (non-PHP) into a dealer soon to look at rotors. Have recently developed a very noticable shudder being felt in the brake pedal (and steering wheel) upon application of braking force. Car ('00) has about 47k miles (mostly city driving), front pads have plenty of meat on them (front rotors had no measurable wear at the time), rear pads replaced a few months ago.
(I took the wheels off and looked at all rotors - no nasty gouges or scores on any surfaces, no stones caught in the pads, etc. This couldn't be some problem with ABS - could it?)
When I asked service dept (over the phone) about resurfacing or turning the rotors, I sensed some resistance to the idea. Guy even went so far as to say that the rotors are "throw-away". I'm definately getting the vibe that they'd rather replace the rotors rather then turn them.
Is rotor replacement one of those things that dealer service garages push unnecessarily or am I over-estimating the durability (or re-workability) of factory rotors?
And if I'm going to spring for new rotors, are there better aftermarket types available for the M? Mopar Performance vs oem replacement?
Whether or not the rotors are a throw-away item will depend on a few factors:
1) There is a minimum thickness allowable (I think even by law???). And there is a "machining thickness" (amount of material which is removed during the machining process).
As a theoretical example... Let's say your rotors measure 0.900 inches, and are warped. The mechanic puts them on the lathe and machines them "flat", and to do this, he has to take of 0.010 inches on each side of the rotor. This leaves your rotors with a measurement of 0.880 inches. If the minimum allowablw thickness is specified at
0.875 inches, then the mechanic can re-install the rotors on your car. However, you wont be very happy! Since there is so little meat left on them, the thinner they get, the worse they are at disappating the heat that is generated while braking. This will tend to cause them to warp again - and fairly soon. Most shops would recommend replacing the rotors at this point because if you dont, you will be paying them the labour to do the job again soon anyways!
But if the minimum thickness allowable is 0.890 inches, then you have no option - they must be replaced.
2) The other major factor is design. I used to own a 1987 Olds. The "Heavy Duty" brakes in that car were so thin to start with, that by the time you detected shudder due to the rotors being "out of flat", that they were already past the point of no return! This contrasts with my 1979 Chev that went 250,000 kms on the factory rotors! But these babys were HUGE, and the car was rear wheel drive. :)
It has been my experience that many of the rotors in todays cars are deliberately designed to be throw away.
Now on my GM car, GM wanted almost $200 PER ROTOR to replace them!!! What complete and utter horse shit! The local brake shops varied between $80 and $130 depending upon brands.
But I found a "jobber" who carried "United Brake Parts", and ony wanted $25! ???!!
When I asked the shops about them, I was told they "were not good quality, and would wear out quickly!"
Well let's do some quick math... My brakes were only lasting about 1 year. So at $25 for a rotor, presuming I replaced them with NEW ones EVERY YEAR, then I could buy new rotors for EIGHT YEARS at dealer prices, or FOUR YEARS at "brake shop" prices.
I put in the cheap ones. They lasted TWO YEARS, just like the factory ones!
Now I do not have extensive experience with Chrysler on this issue, but I do have a 1994 Grand Caravan with the 3.3l engine. As cars go these days, it is fairly heavy. I do NOT have ABS. But the brakes work very well. I purchased the van with about 130,000 kms, and now have about 150,000 kms. When the wheels were off recently at my favorite shop, they looked at the brakes (they also inspected the vehicle before I purchased it). They said that the brakes had hardly worn at all! :))))
Before I went in to a dealer with a blank cheque, I would have the car inspected by at least two reputable brake shops. Most of them will provide an inspection/estimate for free. THEN go in to the dealer. You can then decide if your dealer is gouging you or not. There are some very reputable good quality brands of rotors - such as Wagner - which should be as good or better than Dealer parts (Keeping in mind that companies like Wagner often do "OEM" parts for companies like Chrysler!).
As to the specifics for your model, I have to defer that to others with direct experience.
Mine has had a slight shudder for many miles. I ignore it. New rotors may do the same fairly quickly. Apparently pad material can leave residue embeded in the surface that can cause the shudder according to posts here last year.
New thickness is 1.019- 1.029". Minimum thickness (stamped on the rotor, and yes it is by law - it is illegal to turn them if they are below that thickness) is 0.960".
Besides true warpage, the problem could also be pad material not filmed evenly on the rotor surface, as Art mentioned, causing different friction at different points. Also, it could be uneven wear so that there is a thickness variation rather than a true warping. If the latter is the cause, then having the rotors slightly thinner (from wear and turning) will not contribute to the recurence of the problem. Thinner rotors would contribute slightly to tendency to warp because there's less mass to absorb a lot of heat at one time (but surface area for cooling is, for all practical purposes, not diminished more than a fraction of a per-cent).
It is a gamble either way re: get new vs. turn the existing ones (assuming the thickness is not down close to the legal limit). On the same car, one person may have the warped rotors turned and they do fine, another person may buy a new pair and the new pair give problems.
If you get new rotors, I suggest NAPA's P/N 86777, which is the PHP rotor, at $47 each. For some reason, the non-PHP is $60 (they are physically interchangeable). But I can't promise you they won't warp too. It's a design issue. The best you can do is get a replacement that has as good a materials and manufacturing proceses as you can get - but that in itself can't fix a marginal design issue (and as has been pointed out, many manufacturers are grossly guilty of that on brakes these days). Short of going with come exotic mod which would cost several thousand dollars for the M, there has not been a magic bullet aftermarket solution on these cars, that is, a brand that has been found to be problem free (because it is a design issue). There has been some discussion on the 300M ezBoard about some available stainless steel rotors, but even they cost over $700 the pair - IOW - forget it (and I don't know that they solve the problem either).
BTW - don't worry about the rear rotors on your M - they may last the life of the car due to not much heat and wear on them. Your problems are the front - focus on doing the best you can for those. IOW - don't get the rear rotors turned or replaced - put your money in the fronts - that's where the problems are.
Bill Putney (to reply by e-mail, replace the last letter of the alphabet in my address with "x")
When/if you replace your rotors, make sure you get QUALITY rotors. Buy CANADA/USA parts ONLY. The China/Japan/India/etc. parts that are on the market do not hold up the same.
I see that many have responded and provided excellent advice so I will only add a couple of new thoughts. First, if you do not have one already, invest in a good torque wrench and use it to reset the torque evenly on all your lug nuts after you have removed the wheels or had work done by others. From my personal experience, this seems to help reduce/eliminate warped rotors and brake pulsing. Second, you got advice to buy quality US/Canadian made rotors. I've had very good luck with the Raybestos brand as opposed to the Chinese imports in the generic "white box". Lastly, do either re-surface or replace the rotors whenever you are changing your pads as this helps to increase pad wear life.
Some rotors are now so thin from the factory that after you turn them once they will quickly warp again. Combine this fact with the cheap price of rotors these days (they can be had for about $35 each for your car (your cost from the parts store)) and you see why they hesitate to turn them. Cost you a little more up front but then they don't have to deal with you coming back unhappy.
If you can't do the work yourself you might want to consider taking it to a couple of other brake places to get estimates first. Dealer charges are higher than other places for brake work and there really isn't anything that they can do better than your average shop in this case.
Could be just bad luck but the only good brake jobs I've gotten were at my Chrysler dealer. Whenever I go to a brake shop I have to bring the car back for one reason or another and the brakes never feel as good as new.
I verified that the new thickness is 1.019 and the min. thickness is .960 (verified by independant brake shop - not the dealer garage).
Measured > I just had my rotors turned on my '03 300M. I have 43K miles and
Around here, the going rate (independant shop) is about $60 ($44 USD). The dealer wants more like $80.
I was thinking that taking the rotors off was a pain (involving taking the big nut off the hub, releasing the bearings, etc). Guess I was thinking it was a lot like taking off the front drums off an old MoPar. Now that I realize the rotors basically slide off, I'll call around and see what the cost is if I bring them in somewhere.
Was looking at aftermarket rotors on the net (only Brembo seems to come up). Stainless steel ($700!) and cryogenic rotors (?).
Around here, Crappy Tire has them at $80 each (unknown brand) - would rather buy Brembo for $60 US. Will try other parts outlets next week.
Did '98 and '99 300M's come with 15" wheels? (saw this many times on various parts-charts on the web). Based on the charts - seems that different years have different rotors (yes?).
Also seems that PHP rotors are a tad (sometimes 15-20%) cheaper than non-PHP. Can someone explain the differences in the PHP/non-PHP rotors? (ie will PHP rotors _really_ fit on a non-PHP car?)
Dealer wanted $340 (CDN) plus tax for new rotors, installed, with new pads (pads have "lifetime" waranty - free replacement (parts+labor)). This is a "package" price. Rotors only (installed) is $10 or $20 cheaper.
Dealer says that in the last couple of years the minivans are coming with rotors that are good for 1 turning so I guess they don't exactly treat them as "throw-aways".
...For 0.008" total. Obviously if they are truly warped, they may have to take off more. But what they told you is probably typical.
Yes - once you remove the wheel and caliper (remove two bolts, and hang caliper on strut spring).
I think some of the earlier 2nd gen 300M's did in fact come with 15" wheels - not sure what percentage.
After '99, there were only two types of front rotors on the M - the PHP and the non-PHP - physically 100% interchangeable. Other than that there is only the third (smaller diameter) rotor for the 15" wheeled LH vehicles (different steering knuckle to locate the calipers/pads further in or out to accommodate the two different rotor diameters).
The only difference is that the non-PHP's are vented on the inside, i.e., they pull air in from the engine side of the rotor, and the PHP's are vented on the outside...they pull air in from the curb side. The visible difference is that there is an open groove for air entrance on the curb side of the rotor, where the non-PHP is solid in that area and has an open groove on the opposite (engine) side. I know there are some photos showing the difference linked from the 300M ezBoard - I will try to find them and provide the URL (ezBoard search engines suck big time).
The factory engineers would probably tell you that the PHP (outside venting) should only be used if the wheels are open construction (i.e., alloy wheels) vs. the more closed off steel wheels. Whether it makes a difference in reality, I can't say for sure.
That's typical of most rotors these days. And if you accept the common line that the risk of warping goes up tremendously because they're thinner after you turn them, then you can be convinced to throw then away without turning even though they could be just fine. I'm not sure it is as drastic an issue as some claim it is. In one sense, you could argue that a rotor that's already warped and truned already has the distortions settled out of it from its earlier history (stress relief from heat). (This also ties in with the possibility that what is often blamed on warping could really be due to uneven wear, i.e., varying thickness, which is not a true warping and therefore not related to heat dissipation issues, and would therefore not be made worse by turning and making a few thousandths of an inch thinner). To replace or turn is a gamble either way. Buying new costs more but takes out some (not all if it's an inferior product) risk.
Bill Putney (to reply by e-mail, replace the last letter of the alphabet in my address with "x")
As promised (link to photos of rotors of Donn Scruggs, a contributor to the 300M ezBoard with normally-aspirated M in the low 14's quarter mile):
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(Single left-click on thumbnails to enlarge individual photos. "Regular Rotor" = non-PHP.)
Here's another photo showing the groove on the curb side of the PHP rotor (these happen to be drilled and slotted rotors, but the venting is the same on OEM PHP rotor):
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photo is by SD Mike (San Diego Mike) - another contributor to, andmoderator on, the 300M ezBoard). The vent groove is perhaps a littlemore obvious in this photo. I know there's another photo somewhere that shows someone sticking their finger in the groove to make it even more obvious, but by now you should have the "picture" (literally). 8^)
Bill Putney (to reply by e-mail, replace the last letter of the alphabet in my address with "x")
God forgive me for siding with Nomen Nitwit, but the "shitty bias ply tires" take a load OFF the brakes, not the other way around. If the tire is slipping on the road, part of the heat of braking is going to the tire-road interface instead of to the rotor-pad interface. He's right in the basic assumption that modern discs are horrendously undersized for their job. Its all done in the name of saving weight. I can tell you firsthand that when you put modern sticky tires on an old car with
20-pound brake rotors and really make them work hard, they STILL last longer than modern car brake rotors. And quite often, the old car stops much better than a modern car too- especially on the 2nd or 3rd hard stop in a row.
But again, *modern* automatics have very tall final drive ratios and torque convertors that are very "loose" in the back-driving direction- another way to extend fuel economy further- which means the brakes get more of a workout.
So they took about 43 thou off them (about 1.1 mm).
One thing I noticed was that although the outer surface was pretty flat and had a uniform texture, the back side had pits or depressions that were from 1/8" to 1/4" in area. Basically it looked more like a thin chrome-plated surface that was flaking off and forming pits. The mechanic said that the inner side of rotors typically do degrade more than the outer side.
Can someone tell me what those spring clips (shaped like a "W") are for? They seem to act like springs that hold the brake pads apart but they're a bitch to keep in place when putting the caliper back on.
I called around to see who had new rotors, and found brands like Wagner, Gardian, Dana (Napa) "Trustop" and "Application Engineered". The Wagner brand had listings for 282 and 297 mm diameter rotors, and seemed to refer to one or both of those as "European". The original rotors measure 11 5/8" (295 mm) so I'm not sure what the smaller rotors are for (15" wheels perhaps?). Prices ranged from $58 to $84 and, if I remember correctly, when PHP and non-PHP were both available, the PHP rotors were less expensive. (and yes Bill I did see the links showing the difference being which side the rotors were vented on).
Went out for a test drive and the vibration/shakes were completely gone. But there's still a problem. I suspected I was applying too much pedal during braking and it's still the case. Brakes are too spongy, and during a hard brake when I'm practically standing on the pedal the brakes simply don't bite and the ABS doesn't even kick in.
Either I put on some bad pads when I changed the brakes the last time, or I've got some air in the brake line. Which leads to my next post...
Possibly way overheated for some reason. There's a term for the condition of the metal, but it slips my mind for the moment. There have been a few posts over the years on the 300M ezBoard of that happening to the front 300M rotors. Sticking/dragging caliper?
Yes - they're pad spreaders. Most so-called "professional" mechanics throw those (your personal property) away without even asking when doing a brake job. Some LH's come with them, but most do not - I have not figured out a rhyme or reason as to which options or years they come with - I snooped around a Chrysler lot one time and some new LH's had them, most didn't even though the calipers are the same for all.
You can't buy replacements thru the dealer. The only place I have ever seen posted for a source for those was with a certain brand of pads that someone bought from Pep Boys. I'm not sure how effective they are - possibly they help a little on the CAFE numbers (by reducing brake drag), but Chrysler has no interest in making sure they are available to the customer after the sale.
Dana is the parent corp. for Raybestos and United Brake (which is a Raybestos boxed as United Brake for NAPA).
My guess is "European" = PHP (for the autobahn)
Yes - the Ø282mm are for LH vehicles that came from the factory with 15" wheels (mostly the base model Intrepids and Concordes - possibly later years came with only 16" or larger wheels and the larger brakes). I though I covered that before in this thread.
That can be just needing to wear in a little - but I'll read your other post to see what you say there. Or perhaps your pads are overheated/toasted - not surprising if the rotors were as bad as they apparently were.
Bill Putney (to reply by e-mail, replace the last letter of the alphabet in my address with "x")
Stop working on your own brakes. Change your oil, change your plugs, heck, even rotate your own tires but brakes are too important!
If you don't know what these parts are, don't know about bleeding brakes, and have only this ng as a font of knowledge, you are putting yourself and others in danger.
If you can find somebody that really knows what they are doing, then learn from them, otherwise it is just too dangerous!!!
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