72' Front Disk ?'s

[z7199]

I have a 72' C20 and I went to change my brake pads the other day and noticed that there was a big groove on both sides of the rotor and on both rotors. My question is this is that groove suppost to be there or not. I went to AZ to look at a new set and they had no grooves. I thought maybe it was a new design. However when I bought the new pads the did not have a (hump) in the to fit in the grooves like the old ones did. (I think old ones just wore in to the grooves)

[dyingdeadman]

my front rotors look just like that, they have that groove. I think some brands of rotors are made that way. not sure which brand I have.

[ezernut9mm]

mine also have the groove. i don't like it. it seems there would be more drag with this design.

[NPilot1975]

The groove or grooves are from the front brake pad rivets. Your trucks have been driven at one time or another until there was no more pad. My dad always said it was good for airflow. (Not really, it will trap air in the center of a good set of pads.)

[mrein3]

Originally Posted by NPilot1975

The groove or grooves are from the front brake pad rivets. Your trucks have been driven at one time or another until there was no more pad. My dad always said it was good for airflow. (Not really, it will trap air in the center of a good set of pads.)

The guy at NAPA said the groove was from the brake pad rivets - the last time I ever went in his store.
In 1971 GM put grooves in the center of the rotor. I don't know what for but all the stock ones I ever saw had the groove.
The replacements for my Monte, which are now on my Chevelle, did NOT have the groove.

If the groove is obviously machined, it was there from the factory. If it is sort of rounded out somebody ran the pads past to where they should have been replaced.

[Stocker]

Mrein3 has it right. While rivets can obviously create a groove, I believe you are looking at grooves that were machined into the rotors. My OEM (yup!) rotors have a machined groove on each side about midpoint on the braking surface.

[71C/10]

the o.e. rotors were designed like that. aftermarket rotors do not have the groove. you know it is amazing how many of us still have the o.e. rotors on our trucks. the rotors they make today would never last this long..too much sand in their construction.

[GloryHound]

71C/10: It also has to do with the pads we use today. Not as much asbestoes in them if any. The old pads were made not to wear the rotors as bad. You had to replace pads more often but the price of pads compared to good rotors?

[z7199]

Originally Posted by NPilot1975

The groove or grooves are from the front brake pad rivets. Your trucks have been driven at one time or another until there was no more pad. My dad always said it was good for airflow. (Not really, it will trap air in the center of a good set of pads.)

Yeah I thought that it could not be from the rivots in the pads because of how perfect it was and the exact same on both side and both rotors. I guess I have the o.e. parts kinda cool I think Now on another note is there anywhere to get the same rotors with the groove

[rico_bob]

I had a '70 Chev C-10 And I recall it did have grooves in both front rotors.

Now if you notice what they are doing with rotors now days... drilled and slotted (for extra cooling) Who knows what GM was up to? Anyway my point of view is that they were machined that way (for whatever reason) And no rivet is going to do that in the same place on so many OE rotors (Ya Think?)

Any who that is my two cents worth for what that is worth... rico_bob

[BubbaGreen]

Those original stock/groved rotors are much better in quality than most (if not all) available rotors today....keep'em as long as you can. They usually dont warp, most likey still have lots of "metal" before they hit the discard thickness, etc. Plus, with the groove, you know they are stock. Mine is a '71 and they are grooved like that as well.

[Longhorn Man]

I've always been told they are like wear indicators.
But in all reality, it helps gasses to escape.

[tmcgrawlookalike]

from what i have been told about the groove from some older gm mechanics,the groove`s were machined to be some kind of an `alignment`groove after the pads started wearing into the rotor,which i can see maybe it having some sort of effect on keeping the pad `in track`with the rotor.anyone else????

[rico_bob]

sooner or later someone is going to read my post and say that Chevy did not put disk brakes on the C-10's until 1971.

Well, I agree - except that I had a weird '70 C-10. It had a 1970 Title.

BUT the grille was a 1971 as was the front bumper. Now since I was not the original owner who is to say...it could have been a rebuild? But I spent a lot of time on that truck, and never found any indication of body damage or re-painting? So was my truck a late build 1970 that became a Hybred at the Flint Plant? Hmmm "weirder things have been known to happen".

Like the time a guy who I worked with bought a brand new 1979 GMC. When he went to show me his truck he was mad as Hell ... I said whats up? He said "look at this"

So I looked where he was pointing and right there on the steering wheel of his GMC was a Bowtie Horn Cap. Now if that were not bad enough ...

On the Drivers side it had GMC Emblems and hubcaps ... and you guessed it, on the passenger's side the emblems said "CHEVROLET" and the hub caps were Blue BowTies!

NO KIDDING! I am telling the truth. I was LMAO .... but he was a "die-hard" GMC buyer and he was Totally Ticked-Off!

Another day at the factory in 1978! Ha Ha! my 2 cents worth, rico_bob