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Alternator rebuild

Discussion in '348/355' started by blue90, Mar 12, 2019.

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  1. blue90

    blue90 Formula Junior

    Dec 15, 2013
    339
    NJ
    Full Name:
    Dave
    #1 blue90, Mar 12, 2019
    One more good day of rain is gonna wash the salt off the pavement! That's what I keep thinking. Installed a new bosch 34r battery which helped the charging system though I'm pretty sure it's due for an alternator rebuild. This seems easy enough to get out but what is the deal with the cheesy looking alternator tensioner? Do they break? My wife's Honda has something similar looking so I wonder if something better is in order ?

    Sent from my Pixel 2 using Tapatalk
     
  2. krazykarguy

    krazykarguy Formula Junior

    Apr 17, 2014
    732
    Fort Mill, SC
    Full Name:
    Matt
    #2 krazykarguy, Mar 13, 2019
    We just completed the engine out service on our '97 355.

    The alternator/water pump belt tensioner bearing in the pulley was noisy and loose. We had the 'older' style tensioner assembly where the bearing in the steel pulley was replaceable - not the newer plastic pulley.

    Upon installation and setting belt tension, the tensioner screw/bolt would not squarely set the pulley, it was cocked upward at a 3-5 degree angle. On an accessory belt, you want this pulley as square as possible for even tension.

    We removed the aluminum tensioner bracket and found that the seating surfaces for both the adjuster bolt and the pulley shaft seat were mangled, and despite our efforts to re-level it, it still wasn't right. Someone had neglected to loosen the pulley nut before cranking the adjuster bolt tight.

    While it is a cheesy design, and a spring tensioner (like your wife's Honda has) would have been a better choice, it is what it is. I strongly suggest that you remove the tensioner bracket and inspect the seats inside for odd wear, as well as cleaning the bolts. Running the bearing at any sort of angle will prematurely ruin it.
     
  3. BT

    BT F1 World Champ
    Lifetime Rossa

    Mar 21, 2005
    15,291
    FL / GA
    Full Name:
    Bill Tracy
    #3 BT, Mar 13, 2019
    The tensioner works okay if you loosen it before trying to adjust it. You can definitely do some real damage if you don't loosen it first.
     
  4. krazykarguy

    krazykarguy Formula Junior

    Apr 17, 2014
    732
    Fort Mill, SC
    Full Name:
    Matt
    #4 krazykarguy, Mar 13, 2019
    No kidding. Ours was likely mangled by the same ape who overtorqued all of the fuel filter fittings and the shift shaft joint.
     
  5. steved033

    steved033 F1 World Champ
    Owner Silver Subscribed

    Apr 12, 2017
    10,332
    Atlanta, GA
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    Steve D.
    #5 steved033, Mar 13, 2019
    As I disassembled things for my major, the only thing holding the AC compressor up was the belt (348), and the pivot bolts. the slotted ear on the bracket was missing, and the adjuster screw had the head broken completely off...

    sjd
     
  6. blue90

    blue90 Formula Junior

    Dec 15, 2013
    339
    NJ
    Full Name:
    Dave
    #6 blue90, Mar 13, 2019
    It looks looks like the tensioner is mangled already so I will have to plan to fix or replace. Appreciate the advice. I really like the alt ps belt twist tensioners on my 944 turbo because they are simple and solid.

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  7. krazykarguy

    krazykarguy Formula Junior

    Apr 17, 2014
    732
    Fort Mill, SC
    Full Name:
    Matt
    #7 krazykarguy, Mar 14, 2019
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    Here's what the outside flat surface of ours looked like. The inside flat surface was much worse - we tried to correct it by 'leveling' it and indexing the corresponding tightening bolt groove at the bottom, but were unsuccessful. The tensioner 'axle' was binding in the groove, too.

    As far as I could tell, the only solution was to buy a new one at nearly $300.
     

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