Technical Help ID these brake rotors

Doing the front brakes on my 1940 Chevy truck, was told that the front brakes were from a chevelle. I ordered a set of rotors and pads for a 1970 Chevelle, the pads are spot on, but the rotors are different. The new ones are 11” but the old ones are 12” and the studs on the new rotors are smaller diameter than on the original. So I went and got a set of rotors for a 1972 Impala since they were 12” but they’re not right either, they take a way bigger bearing than the original.

Based on the numbers that are stamped on them, can anyone look at these pics and confirm what they might be so I can order the right ones?

 

What is the wheel bolt pattern?

 

5x4.75

 

I can't identify them, but would advise to check the Rockauto site for pictures of any candidates before you order any more.

 

Get the bearing and race #’s then start looking at GM cars wheel bearings on RA, see if you can find the same numbers for a specific car.
I tried that with hub/rotor combo, came up empty but figured out from the wheel bearings what they were off of.

Edit: I might add when I posted a similar question, Alchemy nailed it, but RA confirmed it.

 

Look like 70-78 camaro.

 

Nope, those were 11" 12" with 5x 4-3/4
Is a fairly odd duck. GM B-body maybe.
3rd gen Camaro with HD brakes maybe but they had a separate rotor & hub.

 

12"?
Try 1980-1990 Chevy full size like a Caprice

 

Those do match discard per Rockauto vs other metric rotors.

 

So yeah it’s just a hair under 12”

 

There is a Camaro that uses a 12 inch rotor. It's a hipo version of the 70 to 77 I think
It's that one as I think it uses the same spindle

 

I think it's a 1988 to 92 1LE Camaro 12 inch rotor, speedway sells them
Look at the length of the snout and the step down of the hat. It's the same

 

Caprice are 11.86"

 

S10?

 

So I looked up 70-78 Camaro as was mentioned and found ACDelco 18A3A, but those are listed as being 11.6” and mine are closer to 12”

Any other ideas? I guess those number stamped on it don’t mean anything, I googled them but didn’t come up with anything

 

I mentioned it before, but if those wheel bearings fit a a 1971 gadzook , it would give you a place to start.
Yes, it’s more work/effort involved, but might get you on the right path.

 

Those 1LE rotors also have the 5x4.75 bolt pattern

 

Yeah I was just looking at those 1LE rotors and they do look pretty close. It just sucks that they’re ninety something plus $20 shipping and only speedway sells them apparently

 

https://www.autozone.com/brakes-and...-rotor/p/duralast-brake-rotor-5516/210534_0_0

 

On 78/84 or so rear wheel drive GM big cars incuding Impala, Caprice, Olds 88 What ever you called the full size Pontiac and Buick depending on the package you either got a 5 on 4-3/4 lug pattern or a 5 on 5 lug pattern. First time I ran into it was on my wife's 79 Caprice Ex cop car with the big rotors. I've still got the 5 on 5 chevy pickup wheels with the studded tires on them out by the shed.

Top is the Big rotor for most 78/80 something GM full size rear wheel drive rigs.
11-7/8 diameter with 5 on 5 bolt pattern

The other one is the small rotor 11-1/64 with 5 on 4-3/4 and among a lot of other 78/80 something GM rear wheel drive full size it does fit the later second gen Camaros.

 

Still no luck with this. The brakes were converted to discs in the early 90 and haven’t been touched since, so the rotors have to be pre-1995 GM. Since the motor, rear axle, trans, mc and booster, and rear drums were all from a 70 Chevelle, that’s what I assumed the front brakes were from also, but nope.
I cleaned up the original and took some better photos, hopefully someone can look at this and know exactly what it’s from. The guessing game sucks and return shipping on a pair of rotors isn’t cheap.

 

Is there a reason that you couldn't have them turned?

 

It's funny, if you google 474350 it comes up a rear rotor.

 

When I googled it it said it was for a Mazda

 

Take and post some pictures of the front suspension. Some one on here will be able to identify it then there is a good chance that the rotors where the originals for the front end.

 

I’m going to repeat myself, no worries, my kids understand.
But get the bearing numbers. Then start looking on Rock Auto for bearings for a -pick a car- and see what pops up.
I realize that’s more effort than someone id’ing them for you though.

 

There’s nothing on that rotor that a turning won’t fix. And it would probably be a better quality part than whatever new Chinese rotor you replace it with. Plus, the labor will cost the same as just the shipping of any replacement parts.

 

If that worked for you, awesome, I think you got lucky though. There are way more varying rotors that GM used throughout the decades than bearings. I’d guess for every model bearding there are probably 40 different rotors that they would fit. Not to mention a lot of times these websites use stock photos so I can’t even really tell what I’m looking at

 

Here are some photos of the spindle and bracket assembly, not sure if that will help any but maybe if it’s a common swap kit someone will recognize it