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914 Alternator Replacement

Pelican Technical Article:

914 Alternator Replacement

Dave Darling


5-6 hours






Floor jack, jack stands, wheel chocks, safety glasses, torque wrench, degreaser, shop rags, flathead screwdriver, Phillips head screwdriver, flashlight, punch, hammer, metric socket set and metric wrench set, metric Allen key set, a helper or two

Applicable Models:

Porsche 914 (1970-76)

Parts Required:


Performance Gain:

An electrical system that charges fully for your Porsche 914

Complementary Modification:

Replace the battery
Foreward by Wayne:

     Dave sent me this neat article on replacing the 914 alternator, something that I've actually done a long time before I ever started writing these articles.  Dave asked me to take some pictures of the procedure to accompany the article, and they will be appearing in the (hopefully) near future.  In the meantime, you can refer to our 914 parts diagrams that give a clear indication of what Dave is referring to when he describes what needs to be removed.

Alternator Replacement

     You can’t get the red light to go off? Voltmeter reading low? 914 won’t start because the battery never charges? Gee, that’s too bad. Sounds like you need to replace your alternator.

     First: Make sure that the alternator is really the problem. This is a big enough and expensive enough job that you really don’t want to do it for no reason. Clean and check all the wiring connections, including the ground strap on the transmission. See if there is any voltage difference between the alternator case and the battery ground. If there is, then there is a bad connection somewhere. Make sure your voltage regulator is OK. Check the tension on the alternator belt. Try to isolate the problem to the alternator itself.  [Check the Pelican Parts Alternator Troubleshooting Section for more info on diagnosing your alternator]

     This procedure involves working from both the top and bottom sides of the engine. You need to be able to get underneath the car, and have at least a little bit of room to move your arms. If you have to lift the car to do that, support it securely—jack stands are a MUST; a hydraulic jack is NOT enough! If you lift the car, you will probably need to stand on something to be able to reach into the engine compartment from the top side. Make sure you have something stable to stand on. In at least one place, it is very good to have a second pair of hands so that you can get to both the top and bottom of the motor at the same time.  Also, make sure that you disconnect the ground strap from the battery.  Neglecting to do so may damage both you and your alternator.

     The first steps are done from the top of the motor, so you can do these before you lift the car. Unplug the alternator harness from the relay board. This is the 3-pin connector. Remove the two plastic covers from the engine tin so that you can access the altnernator pinch bolt. Using an Allen wrench, loosen and remove the pinch bolt. You may be able to extract the nut for this bolt from the top side, otherwise it will fall on the ground. Slide the alternator up and to the right to loosen the belt; remove the belt from around the alternator pulley.

     You will also be removing the left-front corner of the engine tin. You can start this process from the top. There are at least three screws accessible from the top, where this front-piece joins with the shrouding that goes over the cylinders. These are slot-head screws with VERY large slots. I used the largest Craftsman screwdriver I could find—the normal-sized ones chewed up the screw-heads pretty badly.

     Also loosen the hose clamp that holds the hose from the heater fan onto the left-side heat exchanger, and pull the hose loose from the pipe.

Now lift and support the car.

     From underneath, remove the nut that holds the BIG black wire onto the end of the starter. There is a smaller red wire on that same stud; remove that wire. Poke that wire through the rubber gromet back into the engine compartment.

     Remove the air ducts from the area. There is a "bottom warm air guide" that goes above (side-shifter) or below (tail-shifter) the rear shift rod. It is also held on by those big screws. It can be difficult to wiggle past the shift rod on a side-shifter; so you may be able to just slide it aft. Remove the J-shaped pipe that goes to the heat exchanger. And then remove the S-shaped duct that runs from the fan shroud to the heat exchanger.

     Back to the top: Take the alternator wiring harness, including the big red wire, and push it back down through its hole in the engine tin. There is also a small bolt that goes through the sheetmetal in front of the alternator into the fan shroud. Remove it. It is thin, but pretty long.

     From underneath: There are at least two more screws holding the front-left corner piece onto the fan shroud and the rest of the engine tin. One is at the bottom of the fan shroud, along the seam where the two front pieces of tin join. The other is farther up along that seam, toward the front of the car. This one may be difficult to use the large screwdriver on. That should be all of the screws, so try wiggling that piece out. It will, with patience and lots of cussing, eventually drop out the bottom.

     Use a flashlight and possibly a mirror to find the clamp that holds the cooling air boot onto the alternator. Use a Phillips-head screwdriver to loosen this clamp, and slide the boot off of the back of the alternator.

     Now you’re ready to actually remove the alternator. Remove the nut from the pivot bolt. Use a punch, a long bolt, or whatever you can to push the pivot bolt forward out of the alternator. When you get it far enough, use one hand to hold the alternator up, and the other to pull the bolt completely free. The front piece of sheet-metal will then hang from the alternator pulley. Wiggle it free, then let the alternator down. You will probably have to twist it around to some unlikely angles to get around obstructions in the area—most notably, the rear shift rod. (Note: I do not know from my own experience if the alternator will go around the tail-shfter’s shift rod; I’ve only done this on my side-shifter.)

     Now it’s out! You can overhaul it yourself, take it somewhere for testing or rebuilding, or replace it with a new, used, or rebuilt one.

     While the alternator is out, it is worthwhile to clean up the mounting bracket and the bolts that hold it onto the fan shroud. The alternator grounds through the bracket, and dirt, corrosion, etc., will all hurt its ability to charge. It might even be worthwhile to add a separate ground strap in this area, if you think you are having ground problems. It is definitely worthwhile to check the condition of the alternator cooling air boot. If it is cracked, broken off, or missing alltogether, replace it. (Try pulling it out—if it doesn’t come out, it may be necessary to remove the engine cooling fan to access the front half of it.)

     For the most part, to install the alternator, you just go backwards through the removal steps. There are a couple of tricky parts. Getting the alternator up into place can be tricky, as can putting the front piece of sheet-metal on. Re-attatching an old cooling boot probably requires some care. But the part where I needed the extra pair of hands was to get the pivot bolt back in. I was underneath the car, holding the alternator in position and moving it, and a friend was on top of the car, pushing the bolt in. It may be possible to do this by yourself, but it won’t be easy.

     After you get the alternator back in and everything back together (AND all the wires hooked up; don’t forget the big red one!), set the belt tension.

And that should be that!

Comments and Suggestions:
Evan Comments: doe sthe voltage regulator ahve to be replaced after switching out your alternator? I've already changed mine since trying to problem solve and dont want to waste the money on another new one if I dont have to.
September 20, 2011
  Followup from the Pelican Staff: If it is working, no, you can swap it over to the new alternator. I would suggest replacing it though. - Nick at Pelican Parts  

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Page last updated: Sun 3/18/2018 02:17:29 AM