Sunday, August 16, 2009

Changing the Alternator Belt

During a recent drive, I noticed a strange humming noise coming from the engine compartment. I'd describe it almost like the humming of an electric motor. It was most noticeable sitting in the back, with my head leaning over the engine compartment. The problem was, as soon as I opened the lid, the noise from the engine was too loud for me to pinpoint the source of the humming. I received advice on how to identify the cause from the IAC web site. It could be a number of things, but to test the alternator belt, I just had to spray a little WD-40 on it.

I ran back to the bus, applied some WD-40 along the length of the belt, and fired up the engine. The noise was gone, so I ran back inside to order a new belt (068903137D) from the Bus Depot. To save on shipping, I tossed in a couple other items. Within a week, the package arrived and I was ready to change my first fan belt.

Although I have four different repair manuals, I couldn't find instructions with enough details to help me with this process. I found a few posts on TheSamba describing the process of replacing the belt, here's my interpretation (Thanks to Amskeptic for filling in the important details):
  1. Remove the three 10mm bolts that hold the fan cover.
  2. Remove the fan cover and timing scale (behind the fan cover).
  3. 3 = cover plate, 4 = 6mm alternator hex bolt
  4. Carefully pry the plastic alternator cover plate off by using a screwdriver at the top.
  5. Carefully loosen the 6mm hex bolt on the alternator. Do not remove the bolt or the back will fall off.
  6. 5 = 13mm alternator pivot bolt
  7. Loosen the 13mm pivot bolt on the alternator, accessible from under the bus, in line with the oil dipstick. It took me a while to find this bolt until I used a flashlight.
  8. To loosen the belt, move the alternator to the left, pushing by the 6mm hex bolt. I had to carefully use a large screwdriver to apply enough pressure.
  9. Remove the old belt.
  10. Install the new belt. I found it easier to start by placing the belt on the alternator, and then slipping over the air intake fan.
  11. Tighten the belt by moving the alternator back to the right. I had to carefully use a large screwdriver to apply enough pressure. The belt should have 9/16” movement when pushed in the middle with your thumb.
  12. Tighten the 6mm hex bolt to no more than 10 ft. lbs. Do not overtighten this bolt.
  13. Tighten the 13mm pivot on the alternator to 15-20 ft. lbs.
  14. Replace the alternator cover plate.
  15. Replace the timing scale and fan cover, and then tighten the three 10mm bolts that hold the cover. Do not over tighten them or the timing scale or fan cover could crack.


  1. Can I change the alternator without removeing the engine?

  2. That's a good question. I haven't tried to remove the alternator myself. According to the Bentley and Haynes manuals for the VW Transporter, it is possible to remove the alternator, without removing the engine. I don't think it would be an easy process, and the Haynes manual even mentions that. It's a tight fit and I even had to struggele a bit to change the belt.

    Let me know how it works out. Good luck!

  3. I have a 1978 Westfalia. The belt keeps slipping off. It seems I need a special tool to loosen the alternator, then after putting the belt back on, pull the alternator further to the right. Question: Where do I get this tool? Is my plan to loosen it, put the belt back on, then tighten it further to the right correct? Forgive me, I don't know cars.


  4. Thanks this made the belt swap super simple- took me 10 minutes.

    1. Great news Jonathan, I'm glad that you found this post helpful. Good luck with your bus!

  5. Thanks for sharing this with us. This is really helpful to everyone. You made a difficult task to a very simple one. You explain all the things in very good and easy way. I really liked it and give rating as well. Eager to read your next blog.


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