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  1. #1
    Saab Enthusiast XLR99's Avatar
    Join Date
    18 Nov 2014
    Location
    Medina, OH
    Posts
    113
    Saab(s)
    '04 9-5 Aero Wagon, '90 900
    Thumbs Up:   2

    Replacing the Voltage Regulator

    I haven't seen any photographic evidence of how to replace the VR on a 9-5. I just did this as part of my 04 Aero Wagon's mid-life refresh. Removing the alternator is an adventure of it's own which has already been documented; two 8mm Allen bolts (seems simple enough, right? ). We found that the combination of an 8mm allen socket and an 8mm ratcheting wrench allowed us to spin off the upper bolt 'easily' .

    I decided to just change the VR rather than replace the alternator for two reasons. One, the bearings still felt fine, and two, I'm cheap. A rebuilt 140amp alt is ~200, while the VR was under $40.

    Once the alternator is out, and on the bench, you have this:


    I soaked all the fasteners in PB blaster overnight before taking it apart, as everything looks a bit crusty.

    To disassemble, first remove the large 13 and 15mm nuts, and the single phillips screw holding the cover on.
    For the phillips screws, use one of these:

    Hand impact driver, inexpensive and very useful.

    After the cover is off, you can see the entire VR, here comparing the old and new VRs:


    To remove the old VR, there are three more phillips screws, and it will slide out.
    Here are the old and new VRs, showing how much the brushes wear over 175k miles of use:


    And here's a side view of the commutator:


    Before installing the new VR, I cleaned off all of the connections with a stainless wire brush, and cleaned up the alternator with electronics cleaner spray. I then used dielectric grease on the connections when reassembling to help prevent corrosion on the contacts.

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  2. #2
    Saab Enthusiast
    Join Date
    19 Jul 2015
    Location
    Charlottesville, VA
    Posts
    218
    Saab(s)
    1997 NG 900 SE
    Thumbs Up:   40
    Interesting write up. I've replaced C900 VRs before while the alternator was in place. Common practice, as that is the wear item. Not the same with 9-5s, as everyone replaces alternator. Do you think the 9-5 VR could be replaced with the alternator in place?

    Sent from my C6725 using Tapatalk

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  3. #3
    Saab Enthusiast XLR99's Avatar
    Join Date
    18 Nov 2014
    Location
    Medina, OH
    Posts
    113
    Saab(s)
    '04 9-5 Aero Wagon, '90 900
    Thumbs Up:   2
    I thought about it after the fact; I did at least one in a 9000 with it in place. If the fasteners come off without needing the impact, you could do it in situ from underneath.
    That's the big if, though, and I'm not sure there would be room to get the impact driver in there.
    I'd definitely try it for starters in hopes that I'd get lucky and not have to pull the alt.

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  4. #4
    Saab Enthusiast
    Join Date
    19 Jul 2015
    Location
    Charlottesville, VA
    Posts
    218
    Saab(s)
    1997 NG 900 SE
    Thumbs Up:   40
    From what I've seen there is no way to fit an impact driver in. On C900s, I've used an offset Phillips to get the VR, and it was tight but doable. If/when I have to do mine, I'll try it. It looks too tempting not to try.

    Sent from my C6725 using Tapatalk

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