genuine GM vs aftermarket parts

racer0175 · July 8, 2002

i have had people tell me that aftermarket stuff is out of spec, or just plain garbage

when i did the intake manifold on my 97 venture i bought all gm dealer stuff...they didn't even sell the gaskets at napa, so i went to the dealer for everything...

but take for example rotors for my 99 silverado

there like 180 bucks from chevy, 140 from napa, and at murrays there like 50 bucks...whats with that...are these garbage, out of spec, a company with a large national chain just being fair???

what do you guys think...

carguru · July 9, 2002

A lot of times it depends on who makes the parts. Parts made by reputable manufacturers will be tested as the OEM parts. Some of these are OEM parts. Many aftermarket guys just build a replica part and sell it without much testing. A lot of the cheapie overseas parts are junk. The parts tolerance are much looser than the OEM parts. Many of the large chain stores stock reputable manufacturer parts and the cheapie parts. But on the other side of the coin, the dealer has huge markups on parts. The only way you could win out is to find a dealer that discounts the OEM parts or buy reputable manufacturer parts from the chains. If you go with the chain store parts, just make sure that they match the OEM quality.

MoJo · July 9, 2002

First, brakes are the last place you want to go 'cheep'! That being said, there are good aftermarket rotors out there that do meet OE specs. Kelsey Hayes and Century ARE OE manufacturers. You'll find their products reboxed by Raybestos, EIS, Wagner, NAPA etc.

There are other mfgrs such as KVR, Brembo etc, etc that have a good reputation as well.

BTW, the OE rotors on the HDs and 4X4s are quite beefy. There is a spec for min thickness cast right into the rotor. If this is not exceeded, there is no problem if you have them "turned". It's much cheaper and just as safe.

Lots of luck

:blush:

racer0175 · July 9, 2002

i understand about getting the rotors turned i have done it for all my cars and if i can i will. what i am saying is how can u tell(or can't you) if something is oem on your own...i mean if i walk into napa and buy a set of raybestos rotors i know i am getting good quality stuff. Napa was also selling cheaper rotors and the only thing they could say about them was that they were from overseas...i bought those because i was hurting for cash and when i got home it said they were made in canada...thats where napa said the raybestos were from

they have been on my wifes van for about 8 months, with no pulsation what so ever...i have never bought the rotors from murrays and i don't know who makes them...they are way cheeper (in price) than the ones napa sells..a friend of mine buys the middle of the road rotors from there and hasen't had any problems.

what i am getting at is how much different can they be....my OEM chevrolet rotors on my 99 silverado lasted a whopping 34000 miles before they were rusting to sh*T. and they cost 185 bucks

also i have noticed big price differences in semi-metallic pads...they look the same, (To me) and alot of times you pay like 20 bucks more for those little stainless clips that the pads ride in, when the old ones are fine.

carguru · July 10, 2002

I usually stick with brand name companies such as Raybestos, Bendix, etc. They usually do the OEM parts. Some of the store brands or no name ones aren't manufactured to the same specs. The manufacturing process and testing involved has quite a bit to do with the parts cost. For example, you may be able to buy the lowest priced brake rotor and not have any problems. But because of the manufacturing process and quality control, there is no guarantee that the parts might not fail prematurely in a given situation. A friend of mine put cheapie rotors and brake pads on his truck. He had pad rivet failures on 3 sets of pads. Then he drove through standing water and warped the front rotors. He lucked out because the store warranted those parts. However, soon after this, the store carried a different cheapie brand. To me, it just isn't worth it to go through the hassle of worrying whether the parts will fail me or not. If you decide to go the cheapie route, good luck.

racer0175 · July 10, 2002

well i usually don't buy that stuff as i haven't bought anything at murrays, i used to shop at forest city though and the stuff seemed to be good. I started going to places like napa because of the intelligence of the people working there. I used to go to Nationwise and i knew more than anyone i met there.

thanks for the info.

on a side note, i think you will warp any set of rotors if you drive through standing water and they are hot. I know people who have done it with oem parts. I think that is just because of the newer rotors on most vehicles are thinner and throw-away type...(minimal turning)

carguru · July 10, 2002

Yep, the rotors are getting thinner on most vehicles. Because of the thinner rotors, most of the more reputable manufacturers have done thorough testing and FEA analysis to make the rotors more warp proof. But sometimes they will still warp. The knock offs usually just manufacture them business as usual without much testing. The ones that my friend got warped so badly that they were contacting brake calipers. In fact, there were mild stress cracks in the rotor.

racer0175 · July 10, 2002

you got me there.

both my friends had minimal warping...enough to make the brake pedal pulsate.

i think 3 people have asked me about a pulsating brake pedal, and when i asked if they recently drove through standing water everone of them said yes. All of those were newer cars with probably oem rotors.

thats definitely one difference between the oem and the junk...

is "OEM" a standard..what i am getting at is that if it says it then it meets specs. or does it mean that THEY make the stuff for the dealers. i always thought it meant "original equipment manufacturer". so the dealer dictates the standard and the manufacturer follows it.

if i go to murrays and ask if their $50 rotors are OEM and they say yes, and the box is plain white, what would you do?

GreenRado · July 10, 2002

Yeah, definitely agree w/ MoJo and carguru here - depends on who makes them, and what parts it is you're buying. It's nice to find an OEM aftermarket manufacturer like Kelsey-Hayes, Bendix, etc, but it's hard to know sometimes, especially w/ the less common parts.

I've pretty much always found NAPA to be stocking better quality parts, in general. I know some chains like to go the bottom-feeder route, and it's hard to differentiate sometimes. ???

Rotors has always been an issue with me - who knows unless you want to spend $1,000 on a set of Brembos. My Alero likes to eat them (a systemic problem w/ them and Grand Ams) . Even the rears are warping - Rears, for Chr**t sake!!

It may be that NAPA and GM buy from the same OEM for rotors, just a huge dealer markup - but who knows?

carguru · July 10, 2002

OEM stands for Original Equipment Manufacturer. Unless they are just repackaging the same ones from the dealer, or an alternate supplier to GM, they can't really say they are OEM. Much of the OEM parts have the GM or Ford or Chrysler or whomever the manufacturer logos cast into them. I would be willing to bet that those cheepie parts don't. Also, some of the cheepie parts are recycled parts. I have seen rotors that were cleaned up and turned and packaged and sold much like rebuilt alternators and starters. This could be why they would call them OEM. I still would be a bit leary of buying the cheapie parts because of this. Know what your part looks like (logos, min thickness, etc cast into parts). OEM parts sold through parts stores would have the same identifying marks. Reputable manufacturers put their names into the parts too. If there is no name, don't buy.

MoJo · July 11, 2002

In the case of brake rotors, none of the "big 3" make their own. Once you get away from the frame/body and engines/automatic trannys, most stuff is made by vendors such as; Spicer, gears/u-joints; Saganaw, steering and some manual gear boxes; Muncie, Richmond, Melling, TRW, the list goes on and on. Some of these ARE owned by GM, some are not.

As far as the rotors from Canada, some Century rotors are made there. There is a HUGE difference between 'foreign' stuff made in Canada, which can be OEM, and the crap that comes from other places! Firebirds and Cameros are made in Canada but they are not considered "Foreign" or 'Imports'.

Basically, NAPA does not sell junk when it comes to engine, transmission/drivetrain, brakes, ignition etc. You get the picture.

So, if I can buy a Raybestos rotor from PepBoys for $80 and the same application from NAPA for $120, I'm gonna buy the PepBoys part and be fully confident that it meets or exceeds the OEM, SAE and all Federal specs.

racer0175 · July 11, 2002

so basically i should just stick to namebrand stuff. i have almost always bought rabestoes, or bendix stuff, except for the last set of rotors for my van, they were from napa, but were the cheaper set. maybe they were those centry ones you were talking about. guy said those were the big sellers to all the service stations around town, so i went with them. so far so good.

is there any truth to namebrand companies selling stuff (seconds) to the big chain stores? i.e the lower price??

i would think that the oem companies wouldn't want to ruin there good names, but who knows? don't remeber where i heard that, maybe a napa guy...lol