3500 GT rear axle: identifying the right variant by width

Discussion in 'Maserati' started by Wizz, Nov 15, 2017.

  1. Wizz

    Wizz Rookie

    May 24, 2014
    I'm restoring a 3500 GT, and it needed a complete new Salisbury 4HA-001 rear end, which I have bought.
    But is it correct for the car?

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    Mostly it looks right and fits, but for two issues.
    First, the spring mounts are a bit too far apart. That's easy enough to correct, but a bad omen.
    The bigger problem is that is seems too wide overall, by crude eyeballing.
    The 1475 measurement seems too wide for any of the Maseratis that use the Salisbury rear end based on the specifications I have.
    The main widths are 1380mm (e.g. Mistral, Mexico, and I believe 3500 and Sebring too), 1403mm (e.g. QP 107/A and Ghibli), and 1434mm (e.g. Indy) though I am not 100% sure those are the measurements hub face to hub face the same way.

    Unfortunately I do not have the correct wheels yet, so I can't mount them to check the rear track width which should be 1360mm for a 3500 GT measuring from centres of tire patches. I think that spec is probably done using 5.5" wheels and 6.50 tires.

    Maybe someone can tell me (a) if this is the right rear end for my 3500, and (b) if not, what car it's for.

    Is it feasible to do surgery to narrow a Salisbury 4HA rear axle?

    My main question:
    If you have a 3500 GT, configured with splines for knock-offs, what is the correct spline tip to spline tip total width measurement?
    Or the hub face to hub face measurement, which is definitive if we manage to measure to the same point the factory did.

  2. Dr. K.

    Dr. K. Karting

    Mar 23, 2011
    Hi Jim,

    I have an original early Maserati 3500 GT axle, but for the Bimetall Borranis.

    What I can do is taking measurements from middle to middle of the spring mounts.

    Would that help?

    Best greetings
  3. Wizz

    Wizz Rookie

    May 24, 2014
    Thanks for the reply

    Well, first question, is your axle for sale?

    But as for measurements---
    Actually middle to middle of spring mounts won't tell us a whole lot more, since we have the springs and body mounts on the car and know that width.
    It's what's outwards from there that I'm unsure about, as I don't know the correct total width.

    Any of the following would be great:
    * Left wheel hub mounting face to right wheel hub mounting face is the traditional definitive answer for axle length
    * distance from the middle of one spring outwards to the wheel hub mounting face.
    (maybe even middle of spring outwards to the inner face of the drum, or to the outer face of the drum, as a sanity check,
    or to outer face of brake disc, if it's set up for disc brakes)
    * Centre line of *left* spring to *right* wheel hub mounting face would be fine too, if that's easier than full length.

    Anything you're offering much appreciated, the more the merrier.
    Heck, tape a yard stick to it and post a photo : )
    Tip: works best with a zoom lens.

    We have some numbers from some sources, but they don't seem consistent with each other, so if nothing else sanity checks are good.

  4. Dr. K.

    Dr. K. Karting

    Mar 23, 2011
    Hi Jim,

    I will try to give all Info you need, but this axle is an early one for drumbrakes.

    What I can do is taking pictures and measure totally from one end to the other.

    Should I send it per pm?

    For sale yes, but it's in Germany.

    What else do you need?

    Best greetings.
  5. lussoman

    lussoman Karting

    Sep 7, 2008
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    Hi Jim,
    I think you are looking for, but not sure.
    This a salisbury rear dif for a 1963 3500 Sebring which I am pretty sure in the same configuration as the earlier 3500
    It has discs brakes and Borrani wire wheel hubs.

    The distance from the outside surface of spindle to the very other end spindle is 1608 mm
    This is waiting to go back into my car soon - body shell is coming back from VERY long paint job in 2 weeks

    Chris Rose
  6. Wizz

    Wizz Rookie

    May 24, 2014
    Hi Chris
    Sorry, I missed your post for a while.
    Huge thanks for that measurement!

    Yes, I think you're right, I believe the Sebring is probably the same as the 3500 GT.
    If it is possible, could you send a few more confirming measurements?
    My motto is measure twice, cut once. But in this case it's literal, as it looks like we're going to cut and narrow the one we have.

    If you can provide any/all of the following additional numbers it would be great
    Width from one side to the other measuring from inner limit of the actual splines--see image below
    Width from one side to the other measuring from outer face of brake disc--see image below
    Width from one side to the other measuring from outer face of wheel disc where the bolts are--see image below
    For bonus points...
    Width from one side to the other measuring from centreline of spring brackets (centreline of spring, in effect)--see image below
    Width from one side to the other measuring from centreline of bolt hole for shock absorber (I think this must exist, no?)

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    Any other information from you (or anyone else) very much appreciated.
  7. Wizz

    Wizz Rookie

    May 24, 2014
    I guess a great confirmation would be the "inside hub face" measurement as in the photo at the top of the thread.
    I'm just not sure exactly which surface that is, as I didn't do the measurement myself.
    I guess that's the surface that the brake disc mates to?

    If you can do it though, great!

    A prediction:
    If things make sense, then if the overall measurement is 68mm too long on mine, then the inside hub face measurement will be too.
    Meaning if you measure yours the same way, we'd expect to see a dimension of 1407mm.


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