Author Topic: 1970 Deville Front Rotors  (Read 693 times)

Offline colorado4x4

  • Posts: 52
  • CLC Number: 59187374
  • Name: Nicholas Lundberg
1970 Deville Front Rotors
« on: September 26, 2019, 12:19:15 PM »
Per the 1970 FSM the minimum front brake rotor thickness is 1.230 inches.  What is the thickness of a brand new rotor? 

When a rotor is turned, how many thousandths of an inch is removed?

I have an opportunity to acquire some used rotors at a boneyard and they measure above the minimum thickness, and would likely get them turned to clean them up,  but I am wondering what the starting point thickness of a new rotor would be.
1970 DeVille Convertible Chateau Mauve Firemist
1970 DeVille Convertible Lanai Green Metallic

Offline savemy67

  • Posts: 1364
  • Name: Christopher Winter
Re: 1970 Deville Front Rotors
« Reply #1 on: September 26, 2019, 12:57:57 PM »
Hello Nicholas,

Are the boneyard rotors from a '70 Cadillac?  How were the rotors measured?  Were they measured in multiple spots on the rotor?

I don't own a '70 so i cannot tell you what the thickness was when new.  In the case of drums, there may be a few ten thousandths available for machining.  If the shop manual indicates a minimum thickness of 1.230, then it is not unreasonable to expect a new thickness of 1.250 giving .020 for machining.

How much material is removed is a function of the condition of the rotor.  Many used rotors will have some warpage, so it is unlikely that a consistent, uniform depth of cut will true the rotor.  Usually, a warped rotor will require a deep cut.

Respectfully submitted,

Christopher Winter
Christopher Winter
1967 Sedan DeVille hardtop

Offline cadillacmike68

  • Posts: 3438
  • Still crusin'
  • CLC Number: 15823
  • Name: M Santos
Re: 1970 Deville Front Rotors
« Reply #2 on: September 26, 2019, 11:24:51 PM »
I know that whenever I change pads, I have to back the piston(s) ALL the way in or the caliper will not go over the rotor.

Take a caliper off, put New pads in it and back the piston all the way in. Measure the distance between pads and subtract .010 or. That will be close to a new rotor's thickness.
Regards,
"Cadillac" Mike

Offline Cape Cod Fleetwood

  • Posts: 2523
  • CLC #31411
  • Name: Laurie Kraynick
Re: 1970 Deville Front Rotors
« Reply #3 on: September 27, 2019, 12:51:03 AM »
Watch O'Reilly autoparts... they had new rotors for sale last year, for like 2 days before they sold out. That's when
I got mine. Pads are everywhere. If you need new rotors I know John Abend hogged a bunch from O'Reilly during that
sale, find him on Facebook "The 1965-1970 Cadillac Collective".

\m/
Laurie
There are 2 kinds of cars in the world, Cadillac and everything else....

The Present -1970 Fleetwood Brougham

The Past -
1996 Deville Concours
1987 Sedan De Ville "Commonwealth Edition"
1981 Coupe De Ville (8-6-4)
1976 Sedan De Ville
1975 Sedan De Ville

The Daily Driver and work slave -
2008 GMC Acadia SLT *options/all

Offline colorado4x4

  • Posts: 52
  • CLC Number: 59187374
  • Name: Nicholas Lundberg
Re: 1970 Deville Front Rotors
« Reply #4 on: September 27, 2019, 08:45:52 AM »
Thanks for the replies, the boneyard rotors, if I spend the time to wrench them off of the verhicles that they are on,  would be off of two different 1969 deville convertibles. I measured them in two different spots, they are 1.236 thick, so if they were to get turned perhaps would end up being under the 1.230 minimum.   

If I go the new rotor route, do they include the inner and outer bearing cups? (the picture on the Oreilly site looks like they do), and can and/or should I use my existing inner and outer wheel bearings?
1970 DeVille Convertible Chateau Mauve Firemist
1970 DeVille Convertible Lanai Green Metallic

Offline Cape Cod Fleetwood

  • Posts: 2523
  • CLC #31411
  • Name: Laurie Kraynick
Re: 1970 Deville Front Rotors
« Reply #5 on: September 27, 2019, 01:32:59 PM »
Thanks for the replies, the boneyard rotors, if I spend the time to wrench them off of the verhicles that they are on,  would be off of two different 1969 deville convertibles. I measured them in two different spots, they are 1.236 thick, so if they were to get turned perhaps would end up being under the 1.230 minimum.   

If I go the new rotor route, do they include the inner and outer bearing cups? (the picture on the Oreilly site looks like they do), and can and/or should I use my existing inner and outer wheel bearings?

Change the bearings, they usually come with the rotors.
There are 2 kinds of cars in the world, Cadillac and everything else....

The Present -1970 Fleetwood Brougham

The Past -
1996 Deville Concours
1987 Sedan De Ville "Commonwealth Edition"
1981 Coupe De Ville (8-6-4)
1976 Sedan De Ville
1975 Sedan De Ville

The Daily Driver and work slave -
2008 GMC Acadia SLT *options/all

Offline The Tassie Devil(le)

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  • CLC Number: 18992
  • Name: Bruce Reynolds
Re: 1970 Deville Front Rotors
« Reply #6 on: September 27, 2019, 08:41:04 PM »
If I go the new rotor route, do they include the inner and outer bearing cups? (the picture on the Oreilly site looks like they do), and can and/or should I use my existing inner and outer wheel bearings? 
New Rotors come fitted with bearing cups, but you have to purchase the cones separately.

If your own bearings are known to be good, then simply remove them, with the cups, and put them into the new rotors.

One thing to be very careful of is not to purchase new rotors that are made in China.   I would prefer to use old US made ones, machined, than new Chinese, and that includes the bearings as well.

Bruce. >:D
'72 Eldorado Convertible (LHD)
'70 Ranchero Squire (RHD)
'74 Chris Craft Gull Wing (SH)
'02 VX Series II Holden Commodore SS Sedan
(Past President Modified Chapter)

Past Cars of significance - to me
1935 Ford 3 Window Coupe
1936 Ford 5 Window Coupe
1937 Chevrolet Sports Coupe
1955 Chevrolet Convertible
1959 Ford Fairlane Ranch Wagon
1960 Cadillac CDV
1972 Cadillac Eldorado Coupe

Offline Cape Cod Fleetwood

  • Posts: 2523
  • CLC #31411
  • Name: Laurie Kraynick
Re: 1970 Deville Front Rotors
« Reply #7 on: September 28, 2019, 03:28:17 AM »
New Rotors come fitted with bearing cups, but you have to purchase the cones separately.

If your own bearings are known to be good, then simply remove them, with the cups, and put them into the new rotors.

One thing to be very careful of is not to purchase new rotors that are made in China.   I would prefer to use old US made ones, machined, than new Chinese, and that includes the bearings as well.

Bruce. >:D

EVERYTHING IS MADE IN CHINA BRUCE
The 2019 Cadillac rotors are made in China.
So were my new ones for The Ark, and the bearings. Michael didn't grumble when he inspected them
before he installed them. "They're fine", etc.
I just had him put the cheapest pads and rotors on my SUV, $100 for the pair at Rock Auto.
Made In China. They're fine.

There are 2 kinds of cars in the world, Cadillac and everything else....

The Present -1970 Fleetwood Brougham

The Past -
1996 Deville Concours
1987 Sedan De Ville "Commonwealth Edition"
1981 Coupe De Ville (8-6-4)
1976 Sedan De Ville
1975 Sedan De Ville

The Daily Driver and work slave -
2008 GMC Acadia SLT *options/all

Offline cadillacmike68

  • Posts: 3438
  • Still crusin'
  • CLC Number: 15823
  • Name: M Santos
Re: 1970 Deville Front Rotors
« Reply #8 on: September 28, 2019, 01:49:03 PM »
Change the bearings, they usually come with the rotors.

DO NOT use the cheap a$$ bearings that come with the rotors. get a set of Timken bearings from RockAuto or somewhere.

Get the Ceramic pads. The pads for RWD Full size are the SAME from 1968 through 1996. Look it up on RockAuto if you don't believe me.
« Last Edit: September 28, 2019, 05:08:49 PM by cadillacmike68 »
Regards,
"Cadillac" Mike

Offline Dr. John T. Welch

  • Posts: 119
Bone yard rotors
« Reply #9 on: September 28, 2019, 02:07:30 PM »
Bone yards can be a good source of usable rotors especially here in the desert southwest. Warpage is a problem independent of the amount of stock remaining to effect a proper resurfacing. I use a Van Norman brake lathe for rotor resurfacing.  It is a true machine tool that is very different than the units used at auto parts stores. After mounting the rotor on the machine spindle, the rotor is turned slowly  against an index pointer affixed to a dial gauge and run on both sides of the rotor.  A rough indication of warpage is then readable on both sides of the rotor.  I always listen to the machine as the initial cuts are made.  The sound of the cutter against the rotor is indicative of the degree of any warpage. With this machine it is possible to remove different amounts from each side of a rotor to obtain a satisfactory usable rotor that otherwise might be discarded. The caliper piston can accommodate the slight difference in side to side rotor thickness.   
John T. Welch
 CLC   24277

Offline cadillacmike68

  • Posts: 3438
  • Still crusin'
  • CLC Number: 15823
  • Name: M Santos
Re: 1970 Deville Front Rotors
« Reply #10 on: September 28, 2019, 05:10:44 PM »
There is a thread here somewhere that shows you how to use 1972-76 rotors on a 1968-71 Full size RWD (all except Seville).

I also have one  NIB 1968-71 rotor if anyone is interested.
Regards,
"Cadillac" Mike

Offline The Tassie Devil(le)

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  • Posts: 12409
  • CLC Number: 18992
  • Name: Bruce Reynolds
Re: 1970 Deville Front Rotors
« Reply #11 on: September 28, 2019, 08:49:58 PM »
G'day Mike,

Thanks for bringing that up.   It was myself that did the conversion, and wrote it up on the Modified Chapter.

http://www.modifiedcadillac.org/articles/onepiecediscswap/onepiecediscswap.html

Bruce. >:D

PS.   Not sure why it comes up in blue, which makes it very hard to read.   See if the attachment makes it easier to read.
« Last Edit: September 28, 2019, 09:07:10 PM by The Tassie Devil(le) »
'72 Eldorado Convertible (LHD)
'70 Ranchero Squire (RHD)
'74 Chris Craft Gull Wing (SH)
'02 VX Series II Holden Commodore SS Sedan
(Past President Modified Chapter)

Past Cars of significance - to me
1935 Ford 3 Window Coupe
1936 Ford 5 Window Coupe
1937 Chevrolet Sports Coupe
1955 Chevrolet Convertible
1959 Ford Fairlane Ranch Wagon
1960 Cadillac CDV
1972 Cadillac Eldorado Coupe

Offline cadillacmike68

  • Posts: 3438
  • Still crusin'
  • CLC Number: 15823
  • Name: M Santos
Re: 1970 Deville Front Rotors
« Reply #12 on: September 28, 2019, 11:48:44 PM »
G'day Mike,

Thanks for bringing that up.   It was myself that did the conversion, and wrote it up on the Modified Chapter.

http://www.modifiedcadillac.org/articles/onepiecediscswap/onepiecediscswap.html

Bruce. >:D

PS.   Not sure why it comes up in blue, which makes it very hard to read.   See if the attachment makes it easier to read.


I did the same thing. 1972-76 rotors are half the cost of 1968-71 and the inner bearings and seals cost the same, and if I do come across a 1968-71 rotor it will fit right in (with the correct inner bearing and seal). I went 1 step further and put the 1970 one piece steering knuckle on the car as well.
Regards,
"Cadillac" Mike

 

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