1970 442 Rotor Help

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Jan 14, 2015 | 11:10 AM

Cincinnati Rick

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From: Cincinnati, Ohio

1970 442 Rotor Help

I have two different styles of rotors. One has a groove in the center of the machined face and the other one does not. The one with the groove has a number on it (38505R). The one without a groove has no number. Does anyone know if the one with the number is a stock rotor?

Rick

Jan 14, 2015 | 03:18 PM

davebw31

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From: crawfordville, florida

Rick I think that is a Raybestos part number

Jan 14, 2015 | 04:15 PM

oldspackrat

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From: Indianapolis

pretty sure all the factory rotors had that groove in the center. That was a wear indicator when there was no more groove it's time to replace the rotor. Someone correct me if I'm wrong?

Jan 14, 2015 | 06:40 PM

Cincinnati Rick

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From: Cincinnati, Ohio

Quote:

Originally Posted by oldspackrat

pretty sure all the factory rotors had that groove in the center. That was a wear indicator when there was no more groove it's time to replace the rotor. Someone correct me if I'm wrong?

Scott,
Do you have one of the grooved type?

Rick

Jan 14, 2015 | 06:56 PM

oldspackrat

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From: Indianapolis

I think I just sold my last set a couple weeks ago, but might have one left in another building. Will find out soon.

Jan 14, 2015 | 08:05 PM

nsnarsk65cutlass

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From: Grass Valley Ca

Quote:

Originally Posted by oldspackrat

pretty sure all the factory rotors had that groove in the center. That was a wear indicator when there was no more groove it's time to replace the rotor. Someone correct me if I'm wrong?

I believe that is correct.

Jan 14, 2015 | 09:17 PM

Moe145

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From: Houston, TX

I still remember these friggin' part numbers

That's amazing!!

Jan 15, 2015 | 02:57 AM

1970cs

Lansing built

Joined: Nov 2011

Posts: 3,330

From: Grand Ledge, MI

I guess I can tell mine is a low mileage car! Still has the groove in both rotors and original T-3 bulbs across the front.

Pat

Jan 15, 2015 | 01:29 PM

Octania

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Posts: 7,286

Quote:

Originally Posted by 1968_Post

GM used 2 rotors back in the day... the numbers were 1852722 and 1971247. Both show up occasionally on eBay (there's a few on eBay right now of both numbers). They were superceded back and forth for a while, and we used either number, depending on which we could buy cheaper from our Delco supplier.

The scary thing is I haven't been a Bowtie parts guy since the early 70's and I still remember these friggin' part numbers (plus a bunch more...). Definitely a bunch of useless information stuck in my head!

http://www.ebay.com/sch/i.html?_from...2722+&_sacat=0

I didn't know you could use those for brake rotors

Jan 15, 2015 | 01:57 PM

#10

oldspackrat

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From: Indianapolis

Rick,
I found 2 decent to good looking originals.

Jan 15, 2015 | 02:06 PM

#11

Cincinnati Rick

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From: Cincinnati, Ohio

Quote:

Originally Posted by Octania

http://www.ebay.com/sch/i.html?_from...2722+&_sacat=0

I didn't know you could use those for brake rotors

Yeah,
I don't think those are going to work. In all fairness, I guess I really didn't specify that I was looking for brake rotors. Still pretty funny!

Jan 15, 2015 | 02:08 PM

#12

Cincinnati Rick

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From: Cincinnati, Ohio

Quote:

Originally Posted by oldspackrat

Rick,
I found 2 decent to good looking originals.

Scott,
I'll check them out Sunday. Hope the weather cooperates.
Did you get my revised...revised parts list today?
Rick

Jan 15, 2015 | 03:09 PM

#13

1968_Post

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From: Tennessee

Quote:

Originally Posted by Octania

http://www.ebay.com/sch/i.html?_from...2722+&_sacat=0

I didn't know you could use those for brake rotors

LOl... Duh! That was pretty stupid! Yeah, they'll stop a car dead, but in quite a different manner.

I have no clue what I was thinking... I think I'll go hide in the shadows now.