Page 2 of 3 FirstFirst 123 LastLast
Results 11 to 20 of 25

Thread: 4th gen rear brake knock back....need solution

  1. #11
    Senior Member Carroll Shelby
    Join Date
    Mar 2006
    Location
    College Station, TX
    Posts
    4,578
    Quote Originally Posted by Supercharged111 View Post
    Now this has me wondering if the rear is to blame on my car too. The last couple events have been horrible, I had to left foot tap after every corner of every race. Found a loose bearing up front so swapped it for junkyard fresh and it was less bad, but still no good.

    A few years ago with Misty's pink car, I went so far as to cap the rear brakes and drove the car around TWS for a couple laps without hitting the brakes (had free access during the week because she ran the place). I pulled into hot pit and went for the brakes and there was minimal knockback. This was with the old factory OEM hubs. We eventually went with the Dulaney adapters and SKF bearings and saw better results but still had to maintenance tap after every hard turn. Granted we were running 315 wide DOT R's. Eventually, I put an eaton HD in the car and that fixed some of the problem and then we put a 9" with tapered roller bearings. Problem was gone except it never had a very good pedal. The car we have now has a GREAT pedal. Far better than he old one she had even with a new MC. I can push/pull the axles in/out quite a bit. I've done all the typical stuff to make sure the calipers slide but after talking to Patterson, I had not though about the torsen causing some knockback with the way it is designed. That will be coming out and it will be getting an Eaton again. I still have the 9" housing but it requires you cut up the floor to get it in.

    has anyone ever installed a rotating piston caliper from a Mustang? I realize there is some "custom" fabrication to do it but I have a milling machine and a ton of mustang junk laying around. Never had this problem on the mustang even when I had .135" and .180" of axle wear on the inner ends. Probably going to be my next attempt at curing this on this car over the off season.
    Ah, fugg it.

  2. #12
    Senior Member Carroll Shelby
    Join Date
    Mar 2012
    Location
    Houston
    Posts
    1,449
    Blog Entries
    2
    You're on the right track

    But again like I said eliminating end play is key.

    Can you try make thicker c clips to take your end play down to near zero?

    My brakes are feeling pretty good right now with new c clips alone, but want to try take end play down to almost zero too.

  3. #13
    Senior Member Carroll Shelby
    Join Date
    Mar 2012
    Location
    Houston
    Posts
    1,449
    Blog Entries
    2
    Also if your running a torsen consider buying a new center thurst block and measuring it against what you have.

    Maybe that's worn too. I replaced mine last season after I had to cut out a stripped pin bolt.

  4. #14
    Senior Member Carroll Shelby Supercharged111's Avatar
    Join Date
    Jun 2014
    Location
    Colorado Springs, CO
    Posts
    1,149
    I just had an idea, why not weld a bead on top of a Dorman clip that's never seen oil, then flatten it back out with a sanding flapwheel on an angle grinder until it fits?
    RM CMC Director

  5. #15
    Senior Member Carroll Shelby
    Join Date
    Mar 2012
    Location
    Houston
    Posts
    1,449
    Blog Entries
    2
    I spoke with the guy that makes the thicker clips, and where the critical part is hardening

    He's willing to make a set for us if I can get a few guys to commit

    Need to talk to Al and see if I can get the blessing for this to be a test run for a 2020 RCR, but the single best thing I did to kill knock back is replacing worn c clips

    If I can further redurlce end play by .01 on each side it will be mint.

    All the bullshit around axle end flex and caliper springs pales compared to simply taking out end play with thicker or not worn c clips

  6. #16
    Senior Member Carroll Shelby Supercharged111's Avatar
    Join Date
    Jun 2014
    Location
    Colorado Springs, CO
    Posts
    1,149
    I just ordered some Dorman clips off of Amazon, nobody had any in town. We'll see what the car does on Feb 24th cheatin bastard practice day.
    RM CMC Director

  7. #17
    Junior Member Rookie
    Join Date
    May 2009
    Location
    Eureka, Il
    Posts
    29
    I had success by welding a small bead on the end of the axle and grinding or "tuning" it so size allowing a small amount for heat expansion. Ran those axles for years.
    Bob
    Bob Denton
    CMC #67
    Great Lakes Region

  8. #18
    Senior Member Carroll Shelby Supercharged111's Avatar
    Join Date
    Jun 2014
    Location
    Colorado Springs, CO
    Posts
    1,149
    Quote Originally Posted by Den34 View Post
    I had success by welding a small bead on the end of the axle and grinding or "tuning" it so size allowing a small amount for heat expansion. Ran those axles for years.
    Bob
    Uncanny. Ryan just mentioned the same thing to me. I measured .029" play on the right side and .044 on the left, and .007" on the diff pin where the axles have been smooshing into it.
    RM CMC Director

  9. #19
    We'll have to measure the play on mine since it has c clip eliminators and I have plenty of knockback.
    Al Fernandez

  10. #20
    Senior Member Carroll Shelby Supercharged111's Avatar
    Join Date
    Jun 2014
    Location
    Colorado Springs, CO
    Posts
    1,149
    Dorman clips came in today, they measured .159" thick. My old ones were .152" and .153", so definitely thicker. That plus a rosette weld on the axle end should have me good to go here. Going to leave a .010" gap per side, or as close as I can get. That'll eliminate.053" of end play. Along with new rear pads and tighter front hubs should be a more confidence inspiring car.
    RM CMC Director

Bookmarks

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
  •