alternator decoupler replacement for a 986 (02)

[Sputter]

What's the difference between a fixed pulley vs a freewheeling pulley? Does this apply to a 02 Boxster S?

Jim

[Tool Pants]

From my memory. There was a problem with the belt coming off/being damaged on the early cars. In 2000 Porsche went to a freewheel pulley for the manual transmission cars to avoid this problem. But the tiptronics transmission cars continued to use a fixed pulley, just like the 1997-1999 cars.

Your 2002 has a freewheel if it is a manual transmission.

The first picture shows the freewheel pulley. The second shows a fixed pulley with a nut that needs to be removed to get the pulley off.

The third picture is a rebuilt alternator you can buy from any parts place. They sometimes do not come with a freewheel or any pulley. But if you have the correct tool you can remove your freewheel pulley and put it on the rebuilt.

[abbiy]

Has anyone ever replaced a decoupler pulley on the alternator for a 986 Boxster 2002. I just replaced the VR on my alternator. It had this hissing noise when i backed off the RPM, before i pulled the alternator out. Had it checked out by auto electrician to see why it was not charging. The VR was replaced, bearings seemed fine but hissing noise is still there!.

All the other pulleys are fine...none have play or roughness or any type of movement. The noise is coming out form the alternator pully.

If someone has replaced this pulley....could you please tell me how it is done...and what to look out for. Do i need to take the alternator out again? . When i remove the black plastic cover on the pulley i can see a spline with another splined grub screw in the centre. I have a TORX bit to fit the centre screw. Car has done 52,000 Kms. Thanks for any info.

Edited September 18, 2008 by abbiy

[Tool Pants]

I have not replaced one but I have the tools to do it. You should double check the shaft because I do not think it is a torx, but a 10 mm triple square/XZN. Count the number of splines. Torx is 6 splines. Triple square/XZN is 12 splines. You need the triple square bit to keep the alternator shaft from rotating while you remove the freewheel pulley, or if you have a fixed pulley to remove the nut for the pulley.

The black tool has 33 splines and a hole in the middle for the triple square bit. With the black tool you unscrew the freewheel pulley while keeping the alternator shaft from moving with the bit. You do not need the black tool if you have a fixed pulley.

[Sputter]

Awesome, that actually answers my next question about swapping the pulleys.

Jim :cheers:

[abbiy]

I have not replaced one but I have the tool to do it. You should double check the shaft because I do not think it is a torx, but a triple sqare/XZN. Count the number of splines.

I think you are right! Good stuff i will try and buy a that tool and i think i will be able to remove this decoupler with taking the alternator off!.Thanks for that ....i will keep you informed....abbiy from Brisbane , Australia.

[Tool Pants]

I merged today's alternator pulley topics, so they are a bit out of order.

First picture is the Hazet version of the tool(s) to remove the freewheel pulley to give you the idea how it works. I did not want to pay Hazet prices and I already had a 10 mm triple square bit, so I bought a Twain version of the black 33 spline tool for $8 from ebay.

Second picture is for people with a fixed pulley. You need the 10 mm triple square bit, and a deep offset box end wrench to unscrew the pulley nut. On my car the nut is 24 mm.

I think you will find that it is actually easier to remove the freewheel pulley while the alternator is in the car..