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Username Post: The Final Word on 1969 - 1970 Impala Rotors        (Topic#334460)
bry593 
Contributor
Posts: 828

Reg: 10-07-13
04-02-16 05:07 PM - Post#2619156    

Okay guys and gals, prepare to be happy. It is no longer impossible to find 1969 - 1970 Biscayne, BelAir, Impala and Caprice disc brake rotors.

I recently had O'Reilys turn my original rotors and upon installation, noticed a squeak, squeak, squeak. As it turns out, they did not have the rotors square on the machine and this resulted in .025" of run-out. It also used up all my machine stock and the rotors measured the minimum 1.210" limit. These are now relegated to the scrap bin.

I began to research my options. The original rotors are discontinued and not available through any parts house. As an alternate, many people use C3 corvette rear rotors on Impala drum brake hubs with longer studs.

I remembered seeing that Centric offered a rotor for 1967-1970 four piston calipers, but this was not said to fit the single piston caliper of 1969 and 1970. Centric did list a few dimension, and these looked comparable to the single piston rotor. I decided to take a gamble.

Well, as it turns out, the four piston are nearly identical to the single piston rotors! I guess no one knew since GM never offered single piston rotors individually, but rather as an assembly integral with the wheel hub. Being that these assemblies are different between the four piston and single piston, everyone assumed the rotor was different. Guess it was only the hub due to different outboard bearings?

There is one difference and that is the new rotors don't have a diametral groove at the center of the pad. That's okay by me. Seems kinda dumb to put a groove there anyway. It just gets hung up on the pads when you try to remove the caliper.

That said, you will need to use 180 grit wet sandpaper to knock groove off the brake pads if you intend to reuse them with the Centric rotors. I used a formica countertop as a flat surface to put the sandpaper against. Be sure to sand with water so as not to create any dust.

The Centric part number is 120.62066. As mentioned, it will say 4-piston only, but I've proven these work perfectly with single piston as well.

Original versus the Centric rotor. Note that the Centric hub is already painted, and the rotor grind pattern looks great.


A view from the side. Note how nice the cooling fins are compared to the original GM. Casting patterns have come a long way since 1970.


Here it is mounted on a 1970 Caprice spindle:


A view from the side showing that it aligns perfectly with the original brackets and pad thickness:


I hope this information will save you all some cash and grief.

Moderators, it might be a good idea to sticky this one....






Edited by 427SS65 on 04-05-16 12:10 PM. Reason for edit: make this a sticky

 
Ecklers AutoMotive
bigbowtielover 
Valued Contributor
Posts: 2546
bigbowtielover
Loc: Surrey British Columbia
Reg: 09-01-13
04-03-16 12:21 PM - Post#2619312    
    In response to bry593

Very interesting. I was told years ago that the offset of the disc surface was different between the 4 piston and single piston type.



 
427SS65 
"15th Year" Platinum Supporting Member & Moderator
Posts: 14664
427SS65
Age: 73
Loc: St. Louis, MO
Reg: 12-11-03
04-05-16 12:09 PM - Post#2619713    
    In response to bigbowtielover

Thanks Bryan. I'll move it to sticky, then make it into a document later for the Reference Material area (with your permission).

Tom 65-70 Full Size Team Moderator

View My Photos Here

65 Impala SS Tahitian Turquoise


 
bry593 
Contributor
Posts: 828

Reg: 10-07-13
04-06-16 06:13 PM - Post#2619964    
    In response to 427SS65

Tom,

That works for me and is why we have this forum, dissemination of knowledge into the public domain.

And to make it official: I release any copyright claims of both text and pics for the 1969-1970 rotor documentation, for use as reference material in the Chevy Talk forum.

-Brian



 
Impfan 
Senior Member
Posts: 571

Loc: Ontario
Reg: 01-10-05
04-15-16 07:48 PM - Post#2621967    
    In response to bry593

Thanks for the Eureka moment, bud. These Centric rotors are a far cry from the $100 per repops floating around out there for this application



 
Ned27 
Forum Newbie
Posts: 70
Ned27
Loc: N. Orange County,Ca
Reg: 09-07-14
04-23-16 11:27 AM - Post#2623820    
    In response to Impfan

This is such great news.....
This is what makes the forums awesome.
I have the " '70" setup on my 68, was wondering what was gonna happen later.

68' Impala SS 396 Coupe , Matador Red , Pearl White Int ,Corvette Rally wheels...(second Impala coupe owned)
https://www.youtube.com/watch?v=mMiJmJpwiAI


 
wheelman 
Valued Contributor
Posts: 3638
wheelman
Loc: Long Island--New York
Reg: 04-14-07
04-29-16 11:20 AM - Post#2624995    
    In response to Ned27

So glad to hear, I've been looking at them for a year but have been leary as to fitment and qyality. There's no O'rielly's in my state and have only found them occasionally on ebay... Is there a way to order them directly ? I have original 70' set up on my 68 i bought from a texas junkyard in '07 were sitting on a shelf since 1970 as car was wrecked when new, I could still read stamped numbers on pads my rotors have never been cut as I change my pads before they reach 50% wear. but will be nice to have options .

1968 Impala Sports Coupe
2004 Jeep Grand Cherokee
Save a Classic - Crush an Import
[url=https://www.facebook.com/greg.leonovich [/url]


Edited by wheelman on 04-29-16 11:30 AM. Reason for edit: No reason given.

 
62sedan 
Very Senior Member
Posts: 4076
62sedan
Age: 68
Loc: Above the red Texas dirt
Reg: 08-12-02
04-29-16 11:35 AM - Post#2624996    
    In response to wheelman

Wheelman,

RockAuto has them listed at $55.99 each.

See them here >>>> http://www.rockauto.com/en/partsearch/?mfr=CE NTRIC...



Chuck






 
jktucker92 
Silver Supporting Member
Posts: 308
jktucker92
Loc: West Richland, WA
Reg: 02-05-17
02-20-18 08:18 PM - Post#2725046    
    In response to 62sedan

Since the original photos were lost because of Photo Bucket, I thought I'd post some that I just took. I have a set of original '69 rotors that I could have had turned, but I don't know of a shop I could trust. For the price at Rock Auto, I decided to buy new instead of having mine turned. After measuring with a digital caliper, I can confirm that there's no significant difference between the two. Other than the OP's comment about the missing grove in the new discs, the only other difference I noticed is a chamfer in the new rotors that isn't present in the originals. The only measurement I took that wasn't right on was the total thickness. Not surprisingly, the original '69 rotors were 0.030" thinner.

Attachment: MVIMG_20180220_154920.jpg (1.03 MB) 53 View(s)




Attachment: MVIMG_20180220_154927.jpg (719.28 KB) 36 View(s)






 
69chevyguy 
Member
Posts: 143

Loc: Kitchener, Ontario
Reg: 12-15-05
05-27-19 12:43 PM - Post#2767188    
    In response to jktucker92

Jumping on an old thread, I'm about to do this right now. One key piece of information not included in the OP is...how the heck do you get the hub off the rotor without destroying it?

I have my rotor/hub off, all studs pressed out. Cannot separate. Because the rotor goes UNDER the hub, only surface to press against to push it out is the bearing seal/bearing race area, and that wall is less then 1/4" thick. It won't take much to distort that at all...then it's junk. This is from a car that's never seen winter but the hub and rotor have been together for 50 years...

Also - any drive ability/wear issues after the fact? OP was several years ago, wonder how it held up?

www.1969chevy.com

69 Impala LM1 M38, C60, F40, N33, J52
41 Chev Master Deluxe Coupe


 
bry593 
Contributor
Posts: 828

Reg: 10-07-13
07-07-19 11:48 AM - Post#2770115    
    In response to 69chevyguy

To separate the hub from rotor, you need to press the lug studs out. If you plan on reusing the studs, install a lug nut over the end to protect the threads and whack with a brass mallet, or better yet, use a press to press the knurled shank free. The new studs can be pulled into place using the lug nuts and a wrench or impact.

These have held up fine. I have over 13000 miles on my brake system and it still feels like new. No shimmy, no extra pedal travel.

Be sure to adjust your rear brake shoes as out of adjustment is the leading cause of warped rotors. If the rear brakes are not contacting, the front has to do all the work and overheats. Brake shops never adjust the rear brakes unless directed to do so. It keeps you coming back for more work.



 
Als68396Imp 
Poster
Posts: 59

Age: 37
Loc: Cedar Rapids Iowa
Reg: 08-29-13
07-21-19 08:04 PM - Post#2771257    
    In response to bry593

I'm running 70 swap on 68. So to separate the rotor from hub do I press out the studs?

Alan T.
396 Grotto Blue Custom Coupe survivor getting redone.


 
jktucker92 
Silver Supporting Member
Posts: 308
jktucker92
Loc: West Richland, WA
Reg: 02-05-17
07-22-19 11:26 AM - Post#2771310    
    In response to Als68396Imp

Yes, you need to press out the studs. If you don't have a press handy, you can thread on an old lug nut and use a hammer to drive them out. The trick is to have several threads engaged to share the load, but the lug nut itself is the only thing that is deformed during the process.
Installing is usually done by essentially tightening a nut and pulling it through. They make special lug nuts for that purpose, but some people will just use an old lug nut. I have a hydraulic press, so I chose to press them out and back in. To press them in, I used a old disc from a Camaro to provide support while I pressed them in. One word of caution, make sure you re-torque the lug nuts once or twice after driving it briefly. When you press the studs in, they may not seat fully until they've been stressed by driving, so it's good practice to re-torque them.



 
jktucker92 
Silver Supporting Member
Posts: 308
jktucker92
Loc: West Richland, WA
Reg: 02-05-17
07-22-19 11:32 AM - Post#2771311    
    In response to jktucker92

Note that I have seen a case where the disc and hub were one casting. It wasn't on an impala, so I'm not certain if it was ever done for Impalas. I also believe that they were separate castings when new. However, it's possible an aftermarket application used one casting instead of a separate hub and disc casting, or even later GM parts.



 
69chevyguy 
Member
Posts: 143

Loc: Kitchener, Ontario
Reg: 12-15-05
08-16-19 01:03 PM - Post#2773316    
    In response to bry593

Thanks for the info re separating the hub from the rotor. I did press out all the studs (I have a shop press so this was easy) trouble is with those out I can't get the hubs separated.

I made up a 1/2" steel plate to sit on the bearing seal area without distorting it and applied pressure with the press (since these sit on top of the rotors not behind them). Delivering careful, even pressure, after 5 tons these did not budge. I took them off the press, applied a healthy dose of heat and let it cool (expansion/contraction often breaks a rust bond) and still nothing. I'm actually thinking of having a buddy with a machine shop mill the rotors off, although its a lot of material to hog through...

I had considered buying replacements, did order some from a place on the west coast, they showed up beat to hell (shattered actually) and the bearing seal lip rolled over, hammer marks and all. They were junk and the business owner said "they're fine cause I sell them all that way". yikes...so now I know never to buy anything there again (no, I won't say the business name, this isn't THAT kind of post). Point is, I'd really like to find a way to keep the ones I have that are still in one piece.

www.1969chevy.com

69 Impala LM1 M38, C60, F40, N33, J52
41 Chev Master Deluxe Coupe


Edited by 69chevyguy on 08-16-19 01:11 PM. Reason for edit: No reason given.

 
jktucker92 
Silver Supporting Member
Posts: 308
jktucker92
Loc: West Richland, WA
Reg: 02-05-17
08-16-19 04:45 PM - Post#2773333    
    In response to 69chevyguy

I'd try heat and pressure at the same time. How much heat are you applying? I've often used my oxy-acetylene torch to heat parts up to separate metal items. When I use heat, I generally don't let it cool off before I try to break them free.
Concentrate the heat on the rotor while under pressure and see if that works. If that fails, you can also try to cool the hub with ice with the disc hot. The heat will make the hole in the disc slightly larger, and if the hub remains cool, that often will help them separate.



 
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