View Full Version : Alternator Replacement Question

02-26-2009, 10:39 PM
Hey guys,

I can see that its fairly simple to replace this, but my Bentley manual says that I need to torque the V-belt to 7Nm when putting it back on. SO, is it ok if I just torque it by hand to what just 'feels' tight? Or do I REALLY need to torque it at 7Nm... because the Bentley manual asks to torque everything to something which i find excessive lol (dont have a torque wrench obviously)

kinda noobish I know, but thanks for the help!


02-26-2009, 11:40 PM
when its tight, you should be able to depress the belt i think 3/8" at the most, at its longest point between pulleys. it shouldnt vibrate when the car is running, that means its too loose.

too tight and you'll wreck the bearings in the alternator.

02-26-2009, 11:44 PM
^^^This infoes is the righteousness.....Just don't forget to pull the battery or it can make for a small spark show if the +12v touches any metal around it. Other that that its pretty straight foward.

02-27-2009, 01:01 AM
wicked, thanks for the info guys! *th-up*

02-27-2009, 01:11 AM
1 more thing, don't rely on the gear nut to apply the tension, you'll want to pull back on alternator too.

02-27-2009, 02:13 PM
The tension depends on a number of factors, how many pulleys there are, how long the belt is... etc. I generally stick to 1/4" deflection for the alternator. Put a ruler up to the belt and press down with a finger, the belt should 'deflect' about 1/4" I'd say absolutely no more than 3/8".

If it squeals you'll know.

Btw don't do what all noobies do and strip the hell out of the tensioner bracket. Every bloody car I've seen has stripped bracket teeth.

There are 3 bolts to loosen. #1 the pivot bolt at the bottom of the alternator, it's a 13mm. #2 the tensioner arm/plate bolt, it's another 13mm bolt near the timing belt cover. #3 The main bolt. 19mm on the adjustment side and 13mm on the back side.

Loosen them all, then the adjustment bolt is rotated (19mm) and this is what tightens the alternator... Then once you have it in position snug up the 13mm bolt on the back side of that 19mm adjustment bolt. Finally tighten the other 2 bolts, then come back to the tensioner bolt 19 and 13mm and get that nice and tight.

Chances are, some idiot played with it and you'll wonder why the bloody alternator can't be adjusted/tightened properly. - go buy another tensioner bracket with the 19mm bolt/gear. shouldn't run you more than 12$ or something.

Good Luck!