Pressing new pinion bearing on the pinion shaft

Discussion in 'Fox 5.0 Mustang Tech' started by Kdubslugga, Apr 23, 2007.


  1. Kdubslugga

    Kdubslugga Active Member

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    Pressing new pinion bearing on the pinion shaft, Ive heard of freezing the pinion and heating the pinion bearing up to 200 degrees and it will go on, now my friend and i are having a debate, he says there there was a shim he put on before he pressed the bering on the pinion is this right is there a shim to go on before the bearing is pressed on that just doesnt seem right at all
  2. Mike92GT

    Mike92GT Founding Member

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    Yes, there is a shim that goes between the pinion gear and the pinion bearing. The shim determines your pinion depth. It is usually pretty thin, around .025. Technically you should use a pinion depth checker to figure out the proper shim size.
  3. Kdubslugga

    Kdubslugga Active Member

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    Another specialty tool?? Good lord, Will i be safe just putting a .025 shim behind there??? I had my 4.10s installed professionally like 2 years ago. I left the pinion bearing and a shim back there towards the yoke, do i really have to measure pinion depth or will it be ok with just a .025 shim behind the pressed on bearing?
  4. Mike92GT

    Mike92GT Founding Member

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    If your last set of gears was professionally installed you should be OK re-using whatever size shim was on there originally. I wouldn't recommend guestimating on what size to use, it can vary some.
  5. Kdubslugga

    Kdubslugga Active Member

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    problem is i have no idea what size they used i took out my 4.10s and sold them to a friend there already in his car now
  6. Mike92GT

    Mike92GT Founding Member

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    Oh, OK. You would be better off measuring for proper pinion depth then. Thats the only way to do it right in my opinion. Otherwise you run the risk of having noisy gears, or premature failure.
  7. Mike92GT

    Mike92GT Founding Member

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  8. cobradvm

    cobradvm New Member

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    I doubt you could use the freezing/heating method for the pinion bearing. That method will work fine for putting the ring on, since once you have it started, you can pull it on with the ring bolts. You really should use a press to get the pinion bearing on. With regards to the shim ideally measure your pinion depth - I hadn't seen that depth checker before - wonder how well it works? Anyway conventional wisdom says if you are using FRPP gears, you can reuse the old pinion shim and you most likely will be fine. I did on my gears, and they were fine. Any other gears you should measure.
  9. Kdubslugga

    Kdubslugga Active Member

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    well i guess the next question is what is the propr pinion depth, i didnt measure it before i took it off because i did not know i was supposed to,
  10. Mustang78

    Mustang78 New Member

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    you want to check backlash after everything is assembled, i "pressed" on the pinion bearing with a brass punch and a 3lb mini sledge..worked great IMO just watch for flying chunks of brass in your eyes..i would install a .025 shim, put it all together with the differential then check bashlash with a dial indicator

    ~Mark~

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