Rear end axle shafts different offset after assembly?

Discussion in 'Got gears?' started by StKing, Feb 8, 2021.

  1. StKing

    StKing Well-Known Member

    Hey everyone,

    I had my rear end cleaned up powder coated and reassembled by a pretty well known rear end shop in Los Angeles. Once I got it home I started assembly on the rear Wilwood disc brake caliper kit and quickly found that my calipers won't fit on the rotors correctly. I measured the distances and they're off. The left side axle sticks out .1150 further than the right side. I called back the place who assembled it and they couldn't think of anything or any reason that would happen. They told me it might be the powder coat but I removed the circular bracket that bolts to the axle tube flange and it's the same on both sides so that's not the case. It all fit together before I bought it in and now it doesn't. I'm mostly concerned about what's going on inside the rear end. I can machine the larger brackets to size but I don't want the thing to blow up driving down the road.

    What do you guys think?

    Right Side:
    unnamed.jpg

    Left side:

    unnamed (2).jpg

    Difference:

    unnamed (1).jpg
     
  2. BrianTrick

    BrianTrick Brian Trick

    Looks like you still have c-clips. If that is true,the difference you are finding is likely how much further the carrier is to one side. For an exaggerated example: If the carrier was moved all the way to the passer side. The passenger side axle would stick out a lot further than the driver’s side.
    You don’t have this problem with bolt-in axles.
     
  3. StKing

    StKing Well-Known Member

    I do have C clips correct. I see and would that be something the shop should have figured out before it gave me back my rear end? Should they have added spacers or something of the sorts to make it equal? I bought the rear end into them disassembled but I had everything in separate ziplock bags labeled left and right side. I really don't know much about rear ends so I don't want to blame them for something that's not their fault.
     
  4. Bens99gtp

    Bens99gtp Well-Known Member

    Did you do a gear ratio change on the rebuild. If so as brain pointed out thst could cause the carrier to be jockied to one side more.

    Just a silly question since I can't see it correctly in the 1st picture......is the bracket on the same side of the axle backing plate flange.....one side isn't on the inboard side behind the flange and the other on outboard side side?? I could see that would change the measurement by the thickness of the bracket and backing plate flange
     
  5. StKing

    StKing Well-Known Member

    I did not change the gear ratio.

    I believe you're talking about the circle bracket that the spacer bolts to? They are both bolted on in the correct direction.
     
  6. BillA

    BillA Well-Known Member

    Are the axles interchangeable from side to side? If so swap them. Maybe there is a slight difference in length. This is interesting because I am getting ready to purchase the Wilwood 140-7141 kit for my 12 bolt equipped Skylark and I know the axle offset is a critical measurement.
     
  7. Andrew Sury

    Andrew Sury Well-Known Member

    You need to shim the caliper brackets to center them. That's the gold washer kit that comes with the setup. 1/10th of an inch is completely acceptable.
     
    1973gs likes this.
  8. StKing

    StKing Well-Known Member

    I'm not sure. seems odd they would be different. I'm going to take the rear end back to the shop today and see what they say.


    That would be fine if they were equidistant but this is not the issue in my case. The axle offsets are different, one caliper fits the other doesn't.
     
  9. 436'd Skylark

    436'd Skylark Sweet Fancy Moses!!!!!

    Don't overthink this. Shim the one side and live your life..
     
    DasRottweiler likes this.
  10. StKing

    StKing Well-Known Member

    I'd have to machine the largest shim. It's an option but I'm not a fan of mickey mousing things. Especially when I paid to have a professional do the job right. I'm not looking for opinions on how to build my car or live my life but for reasons why the axle offsets would different when they fit before.
     
    mikethegoon likes this.
  11. BrianTrick

    BrianTrick Brian Trick

    The axle shafts are the same length. It goes back to what I mentioned previously about the carrier position dictating the position of the axle shafts. It is fairly common,in a c-clip application,to shim one side,and not the other because of this exact situation.
    The original flange on the axle tube itself could also be slightly off,compared to the other. There was margin of error back then,and the drum brakes were forgiving for that.
     
    Andrew Sury and StKing like this.
  12. Bens99gtp

    Bens99gtp Well-Known Member

    I had to shim my front calipers different side to side to center them.......just depends how the bearing line up on the spindle.........sometimes you just have to do what you have to do and go on.
     
  13. 436'd Skylark

    436'd Skylark Sweet Fancy Moses!!!!!

    Your working with a housing that was mass produced to a huge margin of error and aftermarket parts. There are a reason why shims are around- to make up for sloppy machine work. Your wheels won't fall off, your diff won't explode. Put it together and be done with it. You can take it all apart and find no two parts are the same that should be.. it is what it is.
     
  14. StKing

    StKing Well-Known Member

    The main point is the fact that my brakes fit on the rear end before I brought it to them.

    The copper shims are fine and normal I understand how to shim the caliper to center it. This is not the problem. After I got the rear end back I had to buy the largest banana spacers available from Wilwood and there still isn’t enough space to clear the rotor let alone shim it. One side fits perfect the other side doesn’t have enough clearance to bolt the caliper on. Something went wrong in their re assembly.

    Make more sense now?

    Brian seems to have the answer of the carrier not being shimmed correctly. Thanks Brian.
     
  15. 436'd Skylark

    436'd Skylark Sweet Fancy Moses!!!!!

    A simple reassemble doesn't necessitate changing any shims.
     
  16. BrianTrick

    BrianTrick Brian Trick

    Do have pictures of the banana spacers that you had to get for one side?
     
  17. monzaz

    monzaz Jim

    YAh...IF the rear was assembled ...then disassemble with OUT ANY CHANGES it should go back together exactly the same. Powder coating etc is NOT going to affect anything it is not that thick of covering.
    SO the only other thing is that they swaped the carrier shims where the carrier is for backlash.
    IF they did the rear is likely to not run right either. Soooo Double check your backlash and see if that is what happened. THAT is the only thing that could have shifted the axles too far one way or the other.
    Check you backlash.... Jim
     
  18. knucklebusted

    knucklebusted Well-Known Member

    C-clip axles will move in and out a slight amount due to the axle being retained by said C-clip and the differential spider gear cross bar. I don't know what the spec is but maybe 0.025 is acceptable. Push them both in and pull them both out and see how much end play you have. If it is excessive, you might a bad spider gear, a missing spider gear bushing or even a worn cross shaft. Without looking inside, it is a guessing game.

    The other thing I see is you are measuring to a backing bracket that is bolted to the housing. Have you tried loosening them to see if they will reorient? If the mounting face isn't perfectly flat on both pieces, it could possibly skew it out one way or the other. Can you check it for squareness to the rear end housing?
     
  19. BrianTrick

    BrianTrick Brian Trick

    A worn posi can also result in more endplay.

    Keep us posted with your progress. Just trying to help.
     
  20. StKing

    StKing Well-Known Member


    The axles don't have play when I push them in and out.

    I tried removing the bracket checking for anything out of alignment and redoing etc. Nothing worked.

    I dropped off the rear end at the shop Last Friday and they said they would take a look. I gave them my spacers and calipers. However, when he called me to tell me it was ready he said they just added more spacers. The spacers aren't the concern, I would like it assembled the way I dropped it off but it doesn't seem like they want to reopen it up to find out whats really going on. The results from this shop are frustrating.

    Once my buddy with a truck is ready I'm going to pick it up and take it down the road to Ramjet Rear End Repair in the SFV and see what they say.
     

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