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Rear axle options

Discussion in 'A Body: Duster, Valiant, Dart, etc' started by saltydog, Sep 18, 2013.

  1. saltydog

    saltydog Well-Known Member

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    So as you know, I have been driving my valiant quit a bit lately(so much fun) anyhow I have noticed a bearing noise coming from the rear of the car. So I took the valiant to a trusted mechanic, he checks it out and believes it needs new wheel bearings. Since it is the original axle (I am sure it's the 7.25) I believe he right. He mentioned to me that it will not cost much more to replace all the wear items in the axle since it will be apart already. So for a complete rebuild I am looking at $800-900 including labor. Does this sound right? And is it worth rebuilding? I am planning to stay with the slant six, maybe just upgrade it a bit.

    Now I know I can do the removal myself, but as for rest of it, I would feel better having some else do it.

    Apart from finding another A body rear axle that is in good shape, is there newer MOPARs that have similar dimensions? Maybe a M body?

    I am kicking myself right now, I had a chance to purchase a 8.75 early A body rear axle for $400.....I should a jumped on that....


    Edit: this would be for my 64 valiant.
     
  2. valiant67

    valiant67 ...

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    The only replacement options are an A body 8.75" or 8.25". The 8.75" would keep the same bolt pattern and requires a driveshaft length adjustment. The 8.25" would have the larger bolt pattern and also requires the driveshaft adjustment.

    I would hate to spend money on the 7.25" as it is marginal behind even a slant. The 8.75" you found earlier would have been a decent deal at $400. I am in the same spot with my 68 Valiant.
    The 73+ A body axle is slightly narrower, but the perches are in the same spot. The M body perch width is different and would require removing and rewelding the perches. here's a good reference:
    http://dippy.org/forum2/index.php/topic,189.0.html
     
  3. CudaPete

    Level 2 Supporter

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    You can pull the axles yourself, not difficult to do, and have new bearings pressed on. The bearings will cost around $50-75 each and it will be around $25/axle to have them pressed on at a machine shop. I have a 7.25 behind a 300 HP 318 for 10+ years and haven't broken it. They are not as weak as people think.
     
  4. saltydog

    saltydog Well-Known Member

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    Thank you for the information! Very helpful, I might just have the current one rebuilt. I dont ever plan on anything but a Slant Six, the original has lasted this long and I am sure it will be ok with the new bearings.

    As for doing it myself, my time is limited so I am too the point of having it done, rather then trying to do it myself. My dad could do it, however he has a new job and no time.
     
  5. Bearhawke

    Bearhawke Things happen for a reason

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    As valiant67 pointed out: any of the A body rear ends will swap in easily under any other A body since the leaf spring mtg points are identical across the board; the only thing that needs to be modified is having the driveshaft shortened about 1.5" and going with different bolt pattern wheels if the replacement assembly has the common 5 on 4.5" bolt pattern. oToH: even the original ca. 1964 Valiant parking brake cables will fit right up to the levers attached to the rear brake shoes on the new diff. :)
     
  6. CudaPete

    Level 2 Supporter

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    The 7.25 axle in the early Valiant had 2.5" axle tubes. The 8.25 and 8.75 had 3" axle tubes. In this case you will have to change out the mounting plates and U-bolts too.
     
  7. Bearhawke

    Bearhawke Things happen for a reason

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    Good catch there.
     
  8. saltydog

    saltydog Well-Known Member

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    Agian thank you for all the tips, this is next in line to repaired. Then some more body work...the roof has some dents and the windshield lip has some very very light rust bubbles around the rubber gasket. So I need to get that fixed. I have a plan, or at least I think I do :working:
     
  9. saltydog

    saltydog Well-Known Member

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    Thought I would update this, I have decide to rebuild the current axle. My dad is helping with, so far we have the axles out and have had the bearings pressed off. The parts are ordered.

    Should have this done soon, making her ready for the trip to Van Nuys.
     
  10. Volunteer

    Volunteer Well-Known Member

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    Just picked-up on this topic. Thanks for info and update. Did you find out which rear bearing likely contributed to noise? - or could it be inside the diff.? I am also the proud possessor of the (questionable) but light 9-bolt unit. No issues for me - so far, but I imagine keeping fresh/clean lube plus good additive can go a long way to extend useful life. I would, however, love to 'upgrade' to a sure-grip unit. They are rare yet available. Please update as you progress or post new topics. thanks. :thumbsup:
     
  11. saltydog

    saltydog Well-Known Member

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    The bad bearing was on the passenger side, so once I have it put back together it should be quite. If not then it may be the differential, it looked good in there when we pulled the cover.

    So keeping my fingers crossed.
     
  12. MRGTX

    MRGTX Well-Known Member

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    Jamie,
    it sounds like you found a solution... keep us posted.

    If the day comes when that 7.25" isn't serving your performance needs, one (semi) popular swap is a Ford Explorer 8.8" axle, shortened on one side to center the diff. It will require a little bit of labor but they are cheap, strong, plentiful, usually have limited slip, frequently 3.73 ratio and they come with disk brakes...also, it's an instant upgrade to 4.5" bolt pattern.
     
  13. saltydog

    saltydog Well-Known Member

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    Update: The new bearings are in and man what a differance! Much quiter! Found myself cruising at 80 mph....I am so used to the noise.

    I am sure this will hold me for some time, as I dont see any engine upgrades coming(not yet anyway).

    Now I think she is ready for the trip to Van Nuys! Woot! :thumbsup:

    Thanks for the info! I would have never thought of that.
     
  14. valiant67

    valiant67 ...

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    I hate the though of spending a single penny on a 7.25" rear axle but the one in my 1968 Valiant is noisy. If it's only the bearings like yours Imay bite the bullet and have it fixed. I passed up a $300 A body 8.75" axle last year and am constantly kicking myself for that. I'm sure I could find an 8.25" but I have too much invested in small bolt pattern wheels.
     
  15. saltydog

    saltydog Well-Known Member

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    I would think it is well worth the money. Altogether there is about a $100 in to it, not bad.

    @ 300 bucks, man that is a good deal, but I understand I was in the same place not that long ago when I passed up on for 400 bucks. I Just would rather spend the money other things for the Valiant.
     
  16. Bearhawke

    Bearhawke Things happen for a reason

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    Side note about 8 3/4" rear ends here: a richer source of them would be under ca. 1965-74 big cars and 5 lug pickups and possibly vans. They're wider than an A body but apparently said donor diffs can be narrowed quite easily as well has have their axles shortened/resplined since their basic shafts are the same diameter from the flanges in........

    5 x 4.5" bolt pattern but, most of the above vehicles had 11" drums.
     

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