Correct Pinion Seal

Discussion in 'Got gears?' started by rlafash, Sep 11, 2004.

  1. rlafash

    rlafash Well-Known Member

    I have replaced the pinion seal in my 1966 Skylark GS three times in the last year. The whole story is this. When I bought the car it had an open rear. I purchased a positraction unit and had it installed by a qualified mechanic. At his suggestion, even though there was no leakage at the original pinion seal, he installed a new one, NAPA #16500. That seal leaked all most immediately. The Auto Zone replacement, Timkin #2043 was obviously to big. Some how, NAPA #15305 was suggested and installed. It has just begun leaking after about 500 miles of usage. Another parts supplier lists National #8611N as the correct replacement. In looking at it, it appears to be identical to the NAPA #15305. I don't want to go to the trouble of installing this one if it will only last another 500 miles.
    I was able to obtain an original GM #1387449 which is listed in my parts book as the correct seal. It "appears" fine. At the outer edge of the lip, it measures 1.63", while the NAPA #15305 and NATIONAL #8611N both measure 1.50". Any suggestions/help is greatly appreciated.
  2. The Chad

    The Chad Member

    The NAPA 15305 is probably the right seal if it went 500 miles before leaking, so the question is how does the yoke look? if it is pitted or has any groove worn from the lip of the seal if must be replaced. Are the pinion bearings properly preloaded? if those bearings are loose or worn they will knock out a seal.
  3. DugsSin

    DugsSin Well-Known Member

    Dick I have in my notes Alans Gear Works, Clearwater FL (727)784-0452 for rear pinion seals. This name comes up often for the hard to find parts.
    I had no luck on information reguarding your trans shifter issues have you made progress with it?
  4. rlafash

    rlafash Well-Known Member

    Pioion Seal

    Thank you for responding. I will pose both issues to my mechanic. He did say at the time that he installed the current seal that there was no visable ware evident. As for the pre-load on the bearings, I "assummed" that he took that into account when he installed the "posi" unit. Is there anything I might look for with respect to a failure to pre-load the bearings properly? Something visable? Something in the amount of "play" one might expect at the pinion flange end of the pinion shafT? Would you stay away from installing the NOS GM #1387449 in favor of the NAPA #15305?
  5. rlafash

    rlafash Well-Known Member

    Thanks for the information Doug. I'll try Alans today. No luck on the shifter issue as yet. Thanks for asking. The pinion seal leak has become the priority issue for the moment.
  6. mainebuick

    mainebuick Well-Known Member

    I have seen different seals used (pinion). One has a flat area that seats on the shoulder, and the other fits inside the housing, flush. I used napa 16500, and it hasnt leaked yet.
  7. rlafash

    rlafash Well-Known Member

    From your reply and several other pieces of information, I'm convinced that the NAPA (CR seal) #16500 is the correct seal. I believe that the first #16500 may have been improperly installed. I'll be trying again as soon as I get one. Do you have any "tips" on the installation process such as how to properly gauge the "pre-load" on the pinion bearings, the best sealent to use on the seal where it presses into the housing and any other suggestions that might come to mind. Thanks!
  8. mainebuick

    mainebuick Well-Known Member

    I dont use sealant. If everything is clean, you should be ok. Use the manual when assembling the yoke. The nut is tightened , until it takes "x" pound inches to rotate the assembly. Most folks dont have installation tools specific for installing seals. Center the seal, then you can put a small , clean piece of wood across the seal , and tap it in, checking that it doesnt cock to one side. or, using a plastic hammer, gently tap around the seal until seated. Put a little grease or oil around the rubber part that the yoke slides in. Make sure the yoke is clean and has no scars or nicks that can cut the seal. good luck.
  9. gstewart

    gstewart Well-Known Member

    what most people failt to do is to fail to rub a little oil about the rubber portion of a seal . i would also do the same on the shaft . as a result , both surfaces are lubricated for the seal installation .
  10. rlafash

    rlafash Well-Known Member

    Thanks to all who responded and offerred advice. It appears as though the problem is now resolved. The correct seal is NAPA #16500; the correct process for installation is to insure that everything is clean and oil free and to be sure to seal the seating area of the gasket with RTV. Also lubricate both the seal "lip" and pinion flange shaft with gear lube.

    I will now be attempting to fix balance problem with my drive shaft. I will be posting a question in that regard under a new "thread".

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