Broken rear end. Suggestions on which direction to go.

Discussion in 'Race car chassis tech' started by Briz, Sep 30, 2023.

  1. Briz

    Briz Founders Club Member

    Broke the rear end and sheared off the lugs on the L side at launch last night's test n tune. Made a post on FB but wanted to get some ideas from the guys that dont go there or are not on my list.

    Staged up at WOT on the 2 step and brake. Let go of the button and there was a loud bang / the shift light came on. Killed the ignition and the starting line guy was holding my lug nuts and studs in his hand. Later after getting it off the line I noted the R wheel was just free spinning and making crunchy noises in its housing.

    Do I rebuild what I have or go with something like a fabricated 9"? Its gonna cost$ either way.
    385046447_10160754659001253_6720195175813074124_n.jpg 385000357_10160754658876253_7903089683914801560_n.jpg
  2. BrianTrick

    BrianTrick Brian Trick

    What rear is under there now?
    Max Damage likes this.
  3. Dano

    Dano Platinum Level Contributor

    Suprising given the passes on it prior & the few you've made.
  4. Skyhawk

    Skyhawk Well-Known Member

    Has a Chevy 12 bolt in it.
    Dano likes this.
  5. moleary

    moleary GOD Bless America

  6. Briz

    Briz Founders Club Member

    I may have the option of a manufactured aftermarket 9" housing available to me on the cheap. Dont know if he still has it or if it will fit under this car. It is narrow so maybe so.

    Will get it out of the trailer later this week. Will have to drop the axle to get the tire off. install a couple new 1/2 studs then remount the tire so it will roll out of the trailer. Both my race jacks are under the car holding up the L side so we could wench it into the trailer without the tire tearing up the glass 1/4 panel.
    Max Damage likes this.
  7. Skyhawk

    Skyhawk Well-Known Member

    Just fix the 12 bolt. If it broke the axle you need an axle.
    Change the gear set to as it is old by now. I used to change it every 200 passes anyway.
    That car don't need a 9 inch.
    If you do a 9 inch I bet it will be 7500 or more to do. You will be getting all new brakes, 4 links set up as well by the time you are done. Then countless hours to set the car back up again.
    Trust me.
    John jr

    Rebuild the 12 bolt and get new heim joints. Wouldn't be surprised if they are frozen and binding from sitting the few years too. That could be causing your issues as well.
  8. philbquick

    philbquick Founders Club Member

    So, when the axle snapped it transferred all the power to the other wheel and sheered the studs?? That track must have been real sticky!
  9. hugger

    hugger Well-Known Member

    If you do decide to go Fab 9....Matt Smith at Performance Fab here in spartanburg makes the best there is for around 2500....then will be another 3500 to fill it....but its a badass looking unit they make the big bearing ends for the GM pattern...rebuilding whats there will be definitely cheaper way to go
  10. hugger

    hugger Well-Known Member

    I would definitely do 5/8 studs this time around
    Tall Deck likes this.
  11. Bens99gtp

    Bens99gtp Well-Known Member

    I agree something is binding after watching a videos of this launching and the way its been hamming the tires and chattering.......something is bound to break. I like the s60 housings better than the 9" they come standard 35 spline and have a 40 option. Not sure how your breaks are on there or with what housing end.

    But if you swap housings it will require alot more suspension setup test time.

    Get a pro gear no matter what you do but they do not live as long as regular
  12. Briz

    Briz Founders Club Member

    So much so I couldnt keep my sketchers slip in shoes on my feet while pushing her back out of the glue.

    As much as Id like to go 9" Im sort of leaning towards just fixing the 12 bolt. Will be less out of pocket and back on the track sooner.
  13. TORQUED455

    TORQUED455 Well-Known Member

    I’d be listening to what John says 100%!!
    Max Damage likes this.
  14. Briz

    Briz Founders Club Member

    Spent the entire day rolling around on the floor of the trailer. Its a complicated process to get the wheels and tires off / on this car. First I had to get the jack under the wheelie bars and lift the rear as high as i could go then put jack stands under the frame fwd the rear end. then let the jack down and add 4" of block / do it again. Once the car was on the stands the nuts/ washers n rubber bushings have to come off the top of the shocks. The builder made a access hatch inside the car for just that reason. They also made up some nifty extender things to screw onto the stud that keeps everything lined up for when you put it back together. Next ya have to let the jack and rear end down until the tires clear the fender lip. Got the tire off and then discovered the "studs "were actually bolts which had their heads welded to the back side of the axle flange. Grinder and cut off wheel , a 9/16 wrench and what was left of 3 of the bolts came out. Now I'm having to find 3-3" 1/2 x 20 bolts on a Sunday. Parts stores... Nope! Lowes has some but they are not fully threaded. Buy the 3 grade 5 bolts and then a tap n die set which has the one die I need. They dont sell it seperate. Go home, fully thread the bolt then find out I have to slide the axle out several inches to thread the new studs into the holes. This requires the brake caliper to come off. No big deal. Get it done, reassemble and mount the tire / wheel. Put enough stuff together to roll the car out of the trailer and to the place where she will sit during the repair / upgrade process. It after 5 and Im now tired.
    Waterboy and Max Damage like this.
  15. Smartin

    Smartin Staff Member

    Good lord.
    Max Damage likes this.
  16. Skyhawk

    Skyhawk Well-Known Member

    Actually to get the tires off is really a breeze once you do it once or twice. If you let the air out of the tires it is easier. The hard part was doing it in the trailer no doubt. You will be back at the track by the weekend.
  17. Guy Parquette

    Guy Parquette Platinum Level Contributor

    It looks like it didn’t do any body damage. So that’s a positive, right?
  18. Bens99gtp

    Bens99gtp Well-Known Member

    Having to remove axle shafts is common on alot of rear ends when using long studs. I think some axles axle used a truth thread in stud instead of just a crazy long bolt or pressed in stud.

    Whos axle snd what spline count are they? I ask because depending on who's they are and spline count I think moser come with like a 10 year warranty......but if you have 33 and they replace they go to 35, 35 goes to it still requires some upgrades

    I think strange is 5 years
    Tall Deck likes this.
  19. Briz

    Briz Founders Club Member

    Probably gonna take a bit more time than that. John suggest to replace the gear set unless you've done it since getting it from him + I dont know yet if it or the spool is damaged. The good L axle is catching on something when I try to rotate it. Could be just the other end of the R axle. BTW... Do you know what pads the Wilwood calipers use?

    Only damage is from moving it off the track and into the trailer with that giant fat tire flopping around in the hole but yes, its minimal and wont show up unless ya look for it. If it'd come apart after launch ... would have tore the 1/4 completely off and I'd be so screwed

    I was expecting a press in and I had 3 all ready to go.. reset and try again!

    They are Strange 35 ct axles. Not sure how old they are or who put them in there. Id like to probably go to a 40 if it will still fit the spool assuming its not damaged. Again that would be a Denny or John question.
  20. Bens99gtp

    Bens99gtp Well-Known Member

    I dont think 40 splines fit inside a 12 bolt spool/carrier

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