My mod hell story - how two screws cost me $1500
Cadillac
 

Cadillac Forums | Help Us Help You | Advertise | Cadillac Parts | Cadillac News | Cadillac Classifieds / (Old System)

Cadillac Technical Archive | Cadillac Dealers | Cadillac Reviews | Cadillac Dealer Reviews | Cadillac Vendors

CadillacForums.com is the premier Cadillac Forum on the internet. Registered Users do not see the above ads.
+ Reply to Thread
Page 1 of 3 1 2 3 LastLast
Results 1 to 15 of 41
Like Tree6Likes
2004-2007 Cadillac CTS-V General Discussion Discussion, My mod hell story - how two screws cost me $1500 in Cadillac CTS-V Series Forum - 2004 - 2007; Thought I'd share a story and contradict something I've read almost everywhere - think those little set screws on your ...
  1. #1
    jclayc's Avatar
    jclayc is offline Cadillac Owners Fanatic
    Automobile(s): 2005 Cadillac CTS-V
    Join Date
    Sep 2008
    Location
    Essex Co., NJ
    Age
    41
    Posts
    392

    My mod hell story - how two screws cost me $1500

    Thought I'd share a story and contradict something I've read almost everywhere - think those little set screws on your rotors don't matter? They do. Feel free to disagree but this is my experience.

    I bought a set of fancy Coleman 2 pc rotors for the front for my 05, which I track more than I drive on the street. When they arrived, I noticed there wasn't a hole for the little torx set screw that holds the rotor against the hub. I searched for people's opinion online and even called the supplier and both responses were that, nah, those little screws don't do anything - forget about it. So I did as they suggested and just made sure my lugs were torqued to spec (100 ft lbs)... but started noticing a bad shake in the steering wheel when under heavy braking from 60+.

    After a few weeks and track days and mysterious amounts of heat being generated (smoking after sessions & multiple sets of melted dust boots), I went ahead and pulled the rotors off and checked them - rings and hats are warped. Crap. About that time, I had a chance to pick up a set of Girodisc 2pc rotors as well, so I started running those. Even though they do have a spot for the set screw, by that time, I didn't have any and still didn't think it would matter. You guessed it - a few weeks later and they warped too. $900 for the Colemans and $600 for the Girodiscs shot to hell.

    So I bought a cheap-ass set of iron rotors and happened to find a misc torx screw in the garage and decided to put it on one of the rotors to see if the shake was reduced. It was. Pulling the rotors back off to inspect them, here's what the (not correct) torx bolt looked like:



    To me, this is proof that the set screw has a purpose and the kind of stress that they prevent from being telegraphed through the brakes/driveline. I now run the right set screws (GM part 11570339) with anti-seize on them and the shaking and heat problem seems like it is solved.

  2. Remove Advertisements
    CadillacForums.com
    Advertisements
     

  3. #2
    FuzzyLogic is offline Banned
    Join Date
    Mar 2011
    Posts
    2,048

    Re: My mod hell story - how two screws cost me $1500

    Wouldn't over-torquing the wheel studs have the same positive effect? I'm not disputing your point--vibration between the rotor hat and the hub could certainly cause localized heating, but ARP 100-7709 (or even Raybestos 2093b) wheel studs can handle much more than 100 ft-lbs.

    Also, where did you get a set of Girodiscs for $600, and do you recall where those threads were regarding the modifications necessary to run larger rotors for the 6-piston V2 calipers?

  4. #3
    AAIIIC's Avatar
    AAIIIC is offline Moderator
    Automobile(s): '05 CTS-V
    Join Date
    Aug 2007
    Location
    Where the Navy takes me...
    Posts
    3,633

    Re: My mod hell story - how two screws cost me $1500

    Strange.
    '05 Stealth Grey CTS-V, Hyper Silver Linea Corse Venetos w/Continental ExtremeContact DWs (summer), black Team Dynamics ProRace 1.2 wheels with 275/35-18 R-compounds (track), Hyperblack Rota Torques (winter), KW Variant3s, V2 front brakes, Hotchkis rear sway bar, EPS cam, TEA-ported 243 heads, FAST92 intake w/LS2 TB, JBA Camaro/G8 1-3/4" shorty headers w/JBA cat pipes, Corsa exhaust, UUC motor and tranny mounts, UUC shifter, MAPerformance trailing arms, Specter cradle bushings, etc...

  5. #4
    jclayc's Avatar
    jclayc is offline Cadillac Owners Fanatic
    Automobile(s): 2005 Cadillac CTS-V
    Join Date
    Sep 2008
    Location
    Essex Co., NJ
    Age
    41
    Posts
    392

    Re: My mod hell story - how two screws cost me $1500

    I never torqued over the 100 ft lbs if all else because I've been having a hard time with lug nuts seizing on the studs and snapping them (still trying to find open ended ones that don't seize up - nothing from summit is immune so I'm starting to look at mucho-expensive ones now)...

    I bought the girodiscs from Luke - they were probably closer to $700.

    I've seen the thread on upgrading to the v2 calipers but I'm running v1 calipers at present - not sure of your question there.

    I wish I could figure out that I'm just a dummy and I've been doing something wrong to cause the rotor/brake/lug nut problems and I'm definitely up for suggestions - it's probably important to note that my alignment has been good, wheel hubs are new and all wheels have been balanced during these trials

  6. #5
    crankedupforit's Avatar
    crankedupforit is offline Cadillac Owners Connoisseur
    Automobile(s): 05 CTS V 07 ESCALADE
    Join Date
    Feb 2007
    Location
    Cheese land
    Posts
    1,596

    Re: My mod hell story - how two screws cost me $1500

    Weird. I've run 6 weekends with those Girodiscs without the set screw.

  7. #6
    jclayc's Avatar
    jclayc is offline Cadillac Owners Fanatic
    Automobile(s): 2005 Cadillac CTS-V
    Join Date
    Sep 2008
    Location
    Essex Co., NJ
    Age
    41
    Posts
    392

    Re: My mod hell story - how two screws cost me $1500

    I'll be down at NjMp tomorrow and will know _for sure_ if the problem is fixed under track conditions but testing locally suggests I've solved everything with true rotors and set screws

    I'm with you guys that it all doesn't make sense

  8. #7
    FuzzyLogic is offline Banned
    Join Date
    Mar 2011
    Posts
    2,048

    Re: My mod hell story - how two screws cost me $1500

    Quote Originally Posted by jclayc View Post
    I never torqued over the 100 ft lbs if all else because I've been having a hard time with lug nuts seizing on the studs and snapping them (still trying to find open ended ones that don't seize up - nothing from summit is immune so I'm starting to look at mucho-expensive ones now)...

    I bought the girodiscs from Luke - they were probably closer to $700.

    I've seen the thread on upgrading to the v2 calipers but I'm running v1 calipers at present - not sure of your question there.
    In other words, what needs to happen to install the V2's larger front rotors on the V1?

  9. #8
    jclayc's Avatar
    jclayc is offline Cadillac Owners Fanatic
    Automobile(s): 2005 Cadillac CTS-V
    Join Date
    Sep 2008
    Location
    Essex Co., NJ
    Age
    41
    Posts
    392

    Re: My mod hell story - how two screws cost me $1500

    To install the larger v2 rotors, I'd just need the calipers, drill out the caliper bolt holes a bit and add larger rotors with the 6 bolt pattern either drilled in or made like the ones at racingbrake

  10. #9
    AAIIIC's Avatar
    AAIIIC is offline Moderator
    Automobile(s): '05 CTS-V
    Join Date
    Aug 2007
    Location
    Where the Navy takes me...
    Posts
    3,633

    Re: My mod hell story - how two screws cost me $1500

    Quote Originally Posted by FuzzyLogic View Post
    ... do you recall where those threads were regarding the modifications necessary to run larger rotors for the 6-piston V2 calipers?
    I think you're looking for this thread. In the last couple pages of that I get into what I did to make the V2 rotors fit. Basically, redrill the bolt pattern and enlarge the center bore a bit.

    Quote Originally Posted by jclayc View Post
    I'm with you guys that it all doesn't make sense
    Like I said, strange. I haven't run the little set screws (on the street or the track) since the first time I swapped rotors a few years ago. The holes on the RB center hats aren't even located right, so the set screw wouldn't fit even if I wanted to run them.

    Are you running extended studs, or why do you want/need open ended lug nuts?
    '05 Stealth Grey CTS-V, Hyper Silver Linea Corse Venetos w/Continental ExtremeContact DWs (summer), black Team Dynamics ProRace 1.2 wheels with 275/35-18 R-compounds (track), Hyperblack Rota Torques (winter), KW Variant3s, V2 front brakes, Hotchkis rear sway bar, EPS cam, TEA-ported 243 heads, FAST92 intake w/LS2 TB, JBA Camaro/G8 1-3/4" shorty headers w/JBA cat pipes, Corsa exhaust, UUC motor and tranny mounts, UUC shifter, MAPerformance trailing arms, Specter cradle bushings, etc...

  11. #10
    jclayc's Avatar
    jclayc is offline Cadillac Owners Fanatic
    Automobile(s): 2005 Cadillac CTS-V
    Join Date
    Sep 2008
    Location
    Essex Co., NJ
    Age
    41
    Posts
    392

    Re: My mod hell story - how two screws cost me $1500

    yes, I'm running extended ARP lug studs b/c, once, I put on open-ended lugs and noticed that the factory stud was barely as tall as the lug. people even commented on it. Seeing "just enough" threads to go through a standard lug nut didn't inspire confidence - granted, it's probably academic

    and it can't be that I'm such a beast of a driver that I'm exerting forces on the car that no one else is

    ----------

    I have to say I'm shocked no one has joked about ~two screws for $1500~

  12. #11
    Junior1's Avatar
    Junior1 is offline Cadillac Owners Racer
    Automobile(s): 2005 CTS-V Racecar, 2011 Escalade ESV
    Join Date
    Jun 2008
    Location
    About to pass you...
    Posts
    1,209

    Re: My mod hell story - how two screws cost me $1500

    Hmmm...
    I'm running the same Coleman's on my car and I was starting to think I didn't properly bed the pads in.
    I've got the warp shake on the straight at T-Bolt going from 140 into Turn 1. I thought I pushed it a little too hard too fast as the rotors now have some grooves in them.
    Nothing too bad but it is noticeable under hard braking. I've run another 2-3 full track days on them since. My Giro-Disc's are still in the boxes.
    2005 cadillac cts-v.r #83 nasa st3 . 2011 escalade esv . 2011 sierra denali

  13. #12
    Dan_Gurney is offline Cadillac Owners Fanatic
    Automobile(s): 07 - CTS-V
    Join Date
    Jun 2010
    Location
    Arizona
    Posts
    406

    Re: My mod hell story - how two screws cost me $1500

    I don't buy that the little screw has any effect. the friction created by 6 lug nuts torqued to 100ftlb, is so large that there will be no slipping of that interface. If that interface is not slipping, then an extra screw in there will have 0 effect, once torqued that is a fixed assembly.

    The only thing that screw could do it maintain the clocking during installation, but i just don't see how a slight rotation one way or another before installing the wheel would make a difference.
    barrok69 likes this.

  14. #13
    jclayc's Avatar
    jclayc is offline Cadillac Owners Fanatic
    Automobile(s): 2005 Cadillac CTS-V
    Join Date
    Sep 2008
    Location
    Essex Co., NJ
    Age
    41
    Posts
    392

    Re: My mod hell story - how two screws cost me $1500

    D_G - any thoughts on the cause of bad wheel shake when under braking if it's not the rotor wobbling - and keep in mind, I'm going to near 0 from very high speed. No shakes w/o brakes on

    tests w new rotors and retaining screws at NJMP seems to have eliminated the shakes/heat that I haven't been able to get rid of otherwise (even w new rotors alone) Like I say, I want to agree with everyone's opinion that it doesn't matter but I can't find any other cause and can't deny that the screws helped, if not eliminated, the problem

    Only variation of the thought is that the screw isn't holding the rotor but it does hold the rotor lug holes perfectly aligned to get the lug nut conical base to seat properly... And I've just been really terrible at getting the lugs to seat without the screws...

  15. #14
    FuzzyLogic is offline Banned
    Join Date
    Mar 2011
    Posts
    2,048

    Re: My mod hell story - how two screws cost me $1500

    Brake pins not totally engaged? No brake shims? Caliper bolts not torqued to spec?

  16. #15
    Andringa is offline Cadillac Owners Enthusiast
    Automobile(s): 2004 CTS-V Blk/Blk
    Join Date
    Nov 2009
    Location
    Wisconsin
    Age
    31
    Posts
    752

    Re: My mod hell story - how two screws cost me $1500

    Quote Originally Posted by jclayc View Post
    D_G - any thoughts on the cause of bad wheel shake when under braking if it's not the rotor wobbling - and keep in mind, I'm going to near 0 from very high speed. No shakes w/o brakes on

    tests w new rotors and retaining screws at NJMP seems to have eliminated the shakes/heat that I haven't been able to get rid of otherwise (even w new rotors alone) Like I say, I want to agree with everyone's opinion that it doesn't matter but I can't find any other cause and can't deny that the screws helped, if not eliminated, the problem

    Only variation of the thought is that the screw isn't holding the rotor but it does hold the rotor lug holes perfectly aligned to get the lug nut conical base to seat properly... And I've just been really terrible at getting the lugs to seat without the screws...
    Correlation does not always equal causation.

    You changed more than one variable (You unmounted/mounted the wheels, rotors, calipers to put on rew rotors) and then assumed that the set screw was the thing that fixed it.
    -If you want to test your hypothesis, take off the front wheels and remove the set screws. You should be able to get the shake to come back.
    -If it comes back, then take the front wheels off and put the set screw back in. Your shake should go away.

    Are you correctly bedding these rotors/pads in? Everything I've read online seems to indicate that uneven pad material distribution on the rotor causes the majority of brake pulsing or shaking.

Quick Reply Quick Reply

Register Now

Please enter the name by which you would like to log-in and be known on this site.
If you do not want to register, fill this field only and the name will be used as user name for your post.

Please enter a password for your user account. Note that passwords are case-sensitive.

Please enter a valid email address for yourself.

Log-in

Human Verification

In order to verify that you are a human and not a spam bot, please enter the answer into the following box below based on the instructions contained in the graphic.



Bookmarks

Cadillac Posting Rules

  • You may post new threads
  • You may post replies
  • You may not post attachments
  • You may not edit your posts
Read about Lincoln | Buick | Kia Forte Forum
Need products for your Cadillac? Check out your options at the links below:

custom floor mats | Cadillac Chrome and Black Chrome Wheels | window tinting