Joined: May 08, 2012
|Posted: Sat Jun 23, 2012 9:43 pm Post subject: Replacing the Alternator on Mexican Beetle with AC [how-to]
|So, the shop told me they'd have to drop the engine. The PO told me that wasn't necessary. I thought I'd have the alternator rebuilt, but the downtime wasn't promising, so I thought I'd pick up a new alternator and try it myself.
First off, you can get a NEW Bosch AL-82N from Amazon.com for $160. The best price I've seen anywhere. And it's sold BY AMAZON.
So, to get to the alternator on this fuel injected engine with air conditioning was more troublesome than your standard Beetle alternator replacement. The PO walked me through it via text-message and I got it done today, finally. So I thought I'd write up the process for anyone else dealing with this.
First off, dropping the engine on a Mexican Beetle is a little more involved than your typical Beetle, so that was out as a solution. See this write-up here for the process. (Word doc) The injector rails are fragile and in the way, there are more electrical connections, and the A/C hoses also posed a problem.
1 Start by jacking the car up and putting it on jack stands.
2 Disconnect the battery.
Remove the decklid and decklid mounting brackets. Mark their positions before you do this so you spend less time aligning the lid at the end. You will need to disconnect the wiring to the license plate lights and the alarm sensor switch. The license plate light wiring goes to a squeeze-to-release plug as part of the harness along the back of the firewall. Also note the ground strap from the relocated ignition coil.
Remove the air cleaner by loosening its 10mm bolt bracket and disconnecting the hoses. Block up the throttle body with a clean towel to prevent dirt from entering the system.
Remove the alternator connections and the alternator strap.
Remove the front half of the alternator pulley and set aside the shims and nut. Make note of the number of shims currently in place between the alternator pulley halves and use that as a basis for reassembly.
Loosen the A/C idler pulley and unhook the A/C belt from the compressor pulley. Remove the two long A/C mounting bolts, top and bottom. The bottom bolts rear nut is difficult to get to. A flex-head ratcheted wrench is helpful to hold the back-side nut.
Remove the two bolts holding the A/C mounting arm from the base of the alternator stand and set aside all parts and the arm. The left-side mounting bolt is difficult to get to, but an open-end 9/16" wrench or a universal adapter is your friend here. Rest the compressor to the side with a shop towel protecting the body work. Do not disconnect any hoses or wires.
Loosen the throttle cable from the throttle body, remove the throttle cable tube that runs through the fan shroud by pulling it straight out. Clean this out while you have it removed-a .22 caliber cleaning brush should work well. Get under the car and pull the throttle cable back under the car so that it clears the shroud.
Loosen, but do not remove, the 10mm bolt holding the fan shroud on either side of the shroud (two total). You can find these bolts at the bottom left and right sides of the shroud where the intake manifold curves back toward the front of the car. The one on the left is particularly troublesome, as there is little clearance. Use an open-end 10mm wrench or 10mm ratchet wrench.
Loosen any wiring harnesses and hoses connected to–or otherwise in the way of–the fan shroud, as you will be lifting the shroud straight up. This includes electrical harnesses, spark plug wires, and breather hoses. Do not disconnect them from their end-points, just from the brackets holding them to the shroud.
Remove the top two 10mm bolts holding the alternator-fan plate to the shroud. Have a helper lift the shroud straight up so that you can access the two lower bolts previously obscured by the intake manifold. Remove these two lower bolts. That's four in total.
Lift that shroud up as far as possible, but only straight up. You don't want to damage the oil cooler contained therein. You should be able to remove the alternator-fan combination with a little wiggling. It may be tight, as the throttle body and related/attached parts get in the way. Watch out for the wiring harnesses and you should have the whole thing out in no time.
Remove the fan plate, fan, back half of the pulley, and all the goodies from the alternator like your typical Hanes/Bentley/Muir book recommends, replace the alternator with a known good unit, and reverse the above process.
Remember the shims from before? You will likely need to adjust the number of shims to achieve proper belt tension. I ended up going from five to three. Five was too loose with the new alternator. While you're at it, might as well install a new alternator belt.
One thing I hadn't seen mentioned before is that the alternator will have little half-moon metal index wedges inserted into its spinning bits that have to transfer to the new alternator. My AL-82N also required a smaller diameter nut on the B+ terminal than the stock Mexican alternator. I found one lying around, luckily.
Have an extra set of hands available.
Have a multitude of tools available. Some 1/4-3/8 and 3/8-1/2 adapters would have come in handy. Have a universal joint in 1/4 and 3/8.
Mark your decklid mounting brackets in a known good position for reinstallation. What a PITA it is to get these right, otherwise.
I think that about covers it. Thankfully the PO has done this and was helpful in getting me through this.
Feel free to offer suggestions!
2000 Mexican BtlMex Swing Axle 4MT - SOLD