Yeah, I know, who needs a write-up for something this easy?
Well, not everyone on the board does SAS on their Broncos on the weekends. Some people just might want to wrench a little on their DDs. This is a simple thing to get them started, and my first attempt at a write-up.
So, here we go:
When I changed the belt on my 5.0, I noticed that the tensioner didn't return very strongly or smoothly. The idler pulley was sticky as well (though I didn't notice this until I was doing the tensioner swap already.) I also occasionally have low voltage at idle, so I figured replacing these old parts wouldn't hurt anything, and might help my belt tension stay a little more constant.
I picked up the new tensioner from Ford, but got the idler pulley from a local shop this weekend. I'd rather have a steel pulley like the tensioner, but this'll do. At least it was cheap.
First step is to disconnect the negative terminal on the battery. You *really* don't want the engine starting while your hands are in the fan/belt area.
Second step is to remove the belt. Using a 15mm socket on the tensioner pulley bolt, rotate the assembly counter-clockwise to relieve the tension, and slip the belt off the idler first. Then you can just pull the belt out of the way.
Third step, remove the tensioner. It takes a T50 Torx bit, and it has a normal right-hand thread. I had to put a wrench on the pulley bolt again to break loose the mounting bolt.
New vs. old
Here's the mount on the engine. The blurry tab sticking out is what the tab on the body of the tensioner presses against (where you can see the non-rusty vertical scratch).
Here's a shot of the new tensioner part-way on. You can see that the tab on the body of the tensioner is against the tab on the engine.
Here's the tensioner all the way on. Tabs are more obvious here, and the spring has been pressed together like the old one was.
I needed to extend my little breaker bar a bit to get the bolt loose on the idler, so I used my jack handle. This is usually a *bad* idea, and you can break tools really quickly doing this, but in this case it was exactly enough to make it really easy to break the idler bolt loose. This bolt is also a normal right-handed thread. I used a T50 Torx bit, which worked, but I'm not certain that was the right size, it seemed a little loose. I had to clean a lot of sand out of the head of the bolt as well.
Old and new. You re-use the bolt.
Here's the mount for the idler. Just screw in the new one with the old bolt. (and ignore the coolant seepage) Then you can put the belt back on (again, relieving tension with the 15mm socket on the tensioner pulley bolt). Read your manual or the sticker under the hood if you can't figure out or remember how the belt is routed. Tip: smooth pulleys get the smooth side of the belt against them, ribbed pulleys get the ribbed side. And if you find yourself trying to get the belt to go around the fan blades, you're probably doing it wrong.
Here are the two new parts installed. Prettier, no?
I gave a small blood sacrifice to the knuckle god, so this was a pretty normal wrenching session for me. Total time, if I hadn't been taking pictures, 20 minutes.