How do you replace the A/C tensioner pulley??
 

The tensioner pulley on my A/C tensioner is cracked and I need to replace it. I purchased a new one but I am not sure how to go about taking the old one off... I have the hydraulic kind.. i think. There is an 8mm hex port in the middle of the pulley to retract it but I dont see any way to take the pulley off to replace it. Also, I can't find anything in either my bentley or chilton manuals. Thanks!

What kind of car do you have?

Oh, Sorry. It's a 1992 325i 4dr. And the only reason I'm not sure if it's the hydraulic kind of tensioner is because it might be a spring loaded type thing if they ever made those, but it's definitly not the mechanical type adjusting one.

The pulley should just come off when you remove the bolt....

There is no bolt though.. it's not like the tensioner mounted on the alternator. This one has only a 8mm hex insert in the center of the pulley and nothing else that I can visibly see. Is there another bolt that I can not see? Do I have to take the hydraulic tensioner assembly off in order to remove the pulley? Sorry about all the questions. I've been doing so much work on my car but for some reason this one thing just really has me stumped and I can't find references for the procedure anywhere - probably because it's something simple that I'm overlooking... Thanks again!

Can you get a picture of it?

I've got to go off to work right now but I'll be sure to post it when I get home. Thanks for all your help!

From the diagram on my ETK it appears that the ac adjusting pulley has a cover in the center that must be removed to reveal a bolt. The bolt is called a "screw fillister head"

Apparently fillister head means a cylindrical head like on most allen head bolts. Based on the diagram I would say this is proably a allen head bolt like the E36 and E46 brake caliper guides.

Re: How do you replace the A/C tensioner pulley??
 

There's a plastic cap over the pulley hub. Take a small screwdriver and pop it off. This will expose the bolt holding the pulley on. Hold your hand over the cap when you pop it off or it will go inside your fan shroud and get tossed who knows where when the RPMs get up.

Ok, well I'd just like to let you all know that the 8mm hex bolt that you turn to relieve tension is also the bolt that holds the pulley on. However, you have to disconnect the hydraulic tensioner BEFORE removing the pulley. Without thinking I just started to unscrew the hex bolt and it bent the hydraulic tensioner and popped it apart. If you just undo one of the mounting bolts for the tensioner before taking the hex bolt out you'll be fine. Just think before you do this. I didn't think and now I need a new tensioner. It's only the A/C one though so I'll wait till next summer to replace that

I'm not sure I understand. Looking back at the posts maybe we took something for granted. You have to remove the BELT first, then remove the pulley.

To remove the belt you pull the tensioner back using a long breaker bar, ratchet or pair of box/open wrenches looped together. I've never done a BMW belt but the Bentley instructions are typical for most cars. Sorry, I didn't have my Bentley with me on my first post.