+ Reply to Thread
Results 1 to 18 of 18

Thread: Rotor Thickness?

  1. #1
    Moderator Ooooner is on a distinguished road Ooooner's Avatar
    Join Date
    Mar 2002
    Location
    Concord, North Carolina
    Posts
    1,135


    Rotor Thickness?

    I just measured the thickness of my front brake rotors after they were turned. One of them is .388 and they other is .370. Harold Collins looked up the minimum thickness for the rotors on GT's and it said the minimum should be .394.
    I was just wondering if you think the rotors are too thin now or maybe they should still be OK until the next time then I would have to replace the rotors. By the book, Harold said that if it was under .394, the rotors should be thrown away. These numbers seem to be close enough for at least one more use.
    Roy Bell
    1973 Opel GT
    74 Manta Rallye
    Concord, North Carolina
    Carolina Opel Club
    OMC

  2. #2
    Tennessean hrcollinsjr will become famous soon enough hrcollinsjr will become famous soon enough hrcollinsjr's Avatar
    Join Date
    Jan 2003
    Location
    Chapel Hill, TN
    Posts
    2,675
    hrcollinsjr has made a donation to the forum!

    Roy,

    I forgot to ask you, did someone turn them for you? If so and lack of brakes can be blamed for your demise, keep the receipt. I have an answer to, "Whos yo Daddy?" Roy Bell is! I always wanted to have a little extra income and not have to work for it.

    Harold

  3. #3
    Senior Contributor markandson is on a distinguished road markandson's Avatar
    Join Date
    Oct 2002
    Location
    Kent Lakes, NY
    Posts
    2,001


    Got figure that the Opel engineers had a margin of safety built into that minimum number, so I would say go for it. The result of the too thin rotors will be increased fade on hard stops and possible rotor warpage.
    Jeff

    '73 GT,5spd,Recaro,EDIS4 2.2 EFI by MegaSquirt, Ali Flywheel w/S10 Clutch, Electric Fan, Roller Rockers, Venolia Pistons, 6 Cyl Intake w/ Custom Injection, 15" Wheels,Lecarra,F&R Sway Bars,Custom Exhaust,1" Sport Spring,Koni Reds,Big Brakes,3 Core Ali Radiator,Hse of Colors Kandy Pagan Gold.
    123 WHP @ 6800 RPM

    '64 VW Karmann Ghia
    '08 BMW M3

  4. #4
    Tennessean hrcollinsjr will become famous soon enough hrcollinsjr will become famous soon enough hrcollinsjr's Avatar
    Join Date
    Jan 2003
    Location
    Chapel Hill, TN
    Posts
    2,675
    hrcollinsjr has made a donation to the forum!

    Seriously, Jeff is probably correct, especially if your driving style doesn't include practicing for autocrosses everytime you get behind the wheel.

    Harold

  5. #5
    Moderator Ooooner is on a distinguished road Ooooner's Avatar
    Join Date
    Mar 2002
    Location
    Concord, North Carolina
    Posts
    1,135


    Jeff and Harold,
    That's about what I thought. I'm not going to be driving on a race track any time soon so I thought it would be OK. Doesn't hurt to ask... Thanks for your inputs!
    Roy Bell
    1973 Opel GT
    74 Manta Rallye
    Concord, North Carolina
    Carolina Opel Club
    OMC

  6. #6
    Member 1000 Post Club Paul is on a distinguished road
    Join Date
    Mar 2002
    Location
    Ft Smith, Arkansas
    Posts
    1,489


    The other POTIENTIAL problem thin rotors can cause is the caliper piston coming out of the bore when the pad wears down to the backing....

    So keeping these issues in mind, no hot and heavy braking or letting the pads wear completely down, you should be okay...
    Paul

  7. #7
    Senior Contributor markandson is on a distinguished road markandson's Avatar
    Join Date
    Oct 2002
    Location
    Kent Lakes, NY
    Posts
    2,001


    Quote Originally Posted by Paul View Post
    The other POTIENTIAL problem thin rotors can cause is the caliper piston coming out of the bore when the pad wears down to the backing....

    So keeping these issues in mind, no hot and heavy braking or letting the pads wear completely down, you should be okay...
    I think you are talking some serious cheating in order for this to happen
    Jeff

    '73 GT,5spd,Recaro,EDIS4 2.2 EFI by MegaSquirt, Ali Flywheel w/S10 Clutch, Electric Fan, Roller Rockers, Venolia Pistons, 6 Cyl Intake w/ Custom Injection, 15" Wheels,Lecarra,F&R Sway Bars,Custom Exhaust,1" Sport Spring,Koni Reds,Big Brakes,3 Core Ali Radiator,Hse of Colors Kandy Pagan Gold.
    123 WHP @ 6800 RPM

    '64 VW Karmann Ghia
    '08 BMW M3

  8. #8
    Member 1000 Post Club Paul is on a distinguished road
    Join Date
    Mar 2002
    Location
    Ft Smith, Arkansas
    Posts
    1,489


    Quote Originally Posted by markandson View Post
    I think you are talking some serious cheating
    Oh what are you refering to... the HOT and HEAVY?
    Paul

  9. #9
    Opeler Lindsay
    Join Date
    Jul 2003
    Location
    San Diego, CA
    Posts
    524


    Brembo Rotor Spec

    Just checked old rotor that is stamped 10 mm (.394 in) min.

    For some reason Bembo paper spec. is different?
    Brembo Solid Brake Disc: buybrakes.com
    Brembo 25002 Rotors:
    Type: Solid Disc
    Overall Diameter: 238mm
    Minimum Thickness: 8mm (.315 in)
    Overall Height: 55.5mm

  10. #10
    Old Opeler GTJIM will become famous soon enough GTJIM's Avatar
    Join Date
    Jun 2003
    Location
    New Zealand
    Posts
    5,690


    Liability .....

    There - that horrible, fearsome word again ......

    If you have an accident and cause damage or injury and the insurance companies find out you knowingly used rotors turned undersize .....

    Say no-more ....

    Start looking for some NEW Opel disc rotors - they are remarkably inexpensive and by far the best way to go with stock brakes.
    GTJim
    Opel Owner since last Century!

    Copyright © 2000-2009
    J D Henry
    All Rights Reserved

  11. #11
    No....its not a Buick.... yellaopelgt is on a distinguished road yellaopelgt's Avatar
    Join Date
    Feb 2005
    Location
    IL.
    Posts
    1,042


    I think Parts america has them(Brembo)....I replaced mine a year ago and it was like $70.00 for both. And to have them turned down around my neck of the woods was like $16 or $18 bucks a side. I opted to just replace them and not worry about it for quite some time. But...to each his own I guess. After all, I've got SOOO much money sunk into this car I'm not gonna start getting cheap especially with the brakes!!! BTW new rotors and a set of Green Stuff pads, STOPS ON A DIME!!!!
    Joe
    What ...we got here...is........failure......................... to communicate....
    Some men,you just cant reach...so you get what we had here last week...which is the way he wants it.
    Well, he gets it...I dont like it, any more than you men...


  12. #12
    No....its not a Buick.... yellaopelgt is on a distinguished road yellaopelgt's Avatar
    Join Date
    Feb 2005
    Location
    IL.
    Posts
    1,042


    Almost forgot.... its a good time to clean off all the 35+year old grease and re-pack those bearings with some GOOD quality high temp stuff while your in there!!!Replace that old cotter pin too................
    HTH Joe
    What ...we got here...is........failure......................... to communicate....
    Some men,you just cant reach...so you get what we had here last week...which is the way he wants it.
    Well, he gets it...I dont like it, any more than you men...


  13. #13
    Tennessean hrcollinsjr will become famous soon enough hrcollinsjr will become famous soon enough hrcollinsjr's Avatar
    Join Date
    Jan 2003
    Location
    Chapel Hill, TN
    Posts
    2,675
    hrcollinsjr has made a donation to the forum!

    Quote Originally Posted by yellaopelgt View Post
    Replace that old cotter pin too................
    HTH Joe

    With another metric cotter pin. If the old one is loose you can bet it is an SAE cotter pin. If they call it a "carter pin" you might not want to ask about a metric one.

    Harold

  14. #14
    No Access briarrose is on a distinguished road
    Join Date
    Jul 2007
    Location
    at home
    Posts
    31


    What kind of greese did you use? I was reading about that in the emergency kit stuff and all we have doesn't look right to me. The can reads kluberlube nbu 18 but it looks like lard or something and is kinda white. Is this the right stuff? Sorry if this isn't right, but was reading the one about emergency kits and was looking at what we have here.

  15. #15
    Tennessean hrcollinsjr will become famous soon enough hrcollinsjr will become famous soon enough hrcollinsjr's Avatar
    Join Date
    Jan 2003
    Location
    Chapel Hill, TN
    Posts
    2,675
    hrcollinsjr has made a donation to the forum!

    Quote Originally Posted by briarrose View Post
    What kind of greese did you use? ... it looks like lard or something and is kinda white. Is this the right stuff?
    Sounds like you have a can of lithium grease. It's used for a lot of things, hinges and linkages come to mind but NOT wheel bearings.

    Harold

  16. #16
    Moderator soybean is on a distinguished road soybean's Avatar
    Join Date
    Nov 2002
    Location
    Reidsville N.C.
    Posts
    2,150


    Brembo, isn't listed at Parts America anymore, which is where I got mine too.
    Beck/Arnley and Raybestos Brake Rotor: PG Plus are listed now. Raybestos has the following listed : New Surface Thickness .43".
    Discard Thickness: .396"
    Beck/Arnley has no specs listed. Hth, Jarrell
    Last edited by soybean; 07-12-2007 at 07:36 AM. Reason: URL link doesn't come up
    You lose your dreams, you lose your mind. (The Rolling Stones)

  17. #17
    No Access briarrose is on a distinguished road
    Join Date
    Jul 2007
    Location
    at home
    Posts
    31


    On the canister it says it's a high temperature high RPM synthetic grease made in Germany. So this isn't the right grease to use? I just want the emergency kit to have all the right things if we ever go on a long drive in it.

  18. #18
    Member 1000 Post Club Paul is on a distinguished road
    Join Date
    Mar 2002
    Location
    Ft Smith, Arkansas
    Posts
    1,489


    Wheel Bearing Grease

    You can't go wrong with RedLine CV-2 Synthetic...

    Racer Parts Wholesale Home Page
    Paul

+ Reply to Thread

Thread Information

Users Browsing this Thread

There are currently 1 users browsing this thread. (0 members and 1 guests)

     

Bookmarks

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts