As I am about to install a revised tensioner I ran across this TSB. http://www.jagrepair.com/images/TSB/...er%20Start.pdf. I was looking at an exploded view if the old one that called for two o rings, number 7 in the illustration. The old one and the used upgraded one don't have these. Are they necessary

?

 

I dont recall #7 in any of the :revised units I have sorted. Very different innards to the original units.

#8 & 9 you will need, unless your old are still usable.

 

The revised tensioner takes a longer shank installation bolt ( s )

To short and you risk stripping the threads

On mine the previous owner had a leak past the hardened large O - ring

So they really cranked down on the 2 bolts in the original pre revised part to no sense

 

Thanks, gentlemen. I will be replacing the O ring EAC 4540 and gasket EAC 4557 and I wondered if those o rings were necessary. Lots of work sorting out an old car, but very satisfying.

 

The old style original has an insert and shaft going THROUGH the tensioner body. It NEEDS the small 'O'ring to seal.

The updated one is CLOSED at the end and does not require the small 'O'ring. (no hole in the eng of the body)

 

I see!