Serp. belt tensioner bolt

[trinity_gt]

The serpentine belt tensioner on my 02 is retained by a single bolt. According to my shop manual, this bolt is TTY (torque to yield): tighten to 89 in-lb, then an additional 90-degrees.

I've gone to a Ford dealer looking for this bolt but they didn't stock it and said I had to buy a bag of 4 of them. The only stock he could find was in the US (I'm in Canada). Evidently, Ford service departments aren't replacing this TTY fastener.

What's your take on this? Just re-use the old bolt? If so, what are you torquing the bolt at? Any replacement bolt recommendations aside from a bag from Ford?

Oddly, the two idler pulleys are to be tightened to 18 ft-lbs (not TTY). Sometimes I don't understand Ford...

 

[joshjwc9]

I'd just go to ACE and find another Grade 8 in that same size. Locktite and supersnug. I've replaced mine on my GT before the blower and it saw roughly 35k miles with using the same hardware. But that is with my '99 Windsor motor with a three bolt tensioner. I cannot find any hardware to replace it. Even at AutoParts stores and Mustang websites..

 

[trombonedemon]

I'd just go to ACE and find another Grade 8 in that same size. Locktite and supersnug. I've replaced mine on my GT before the blower and it saw roughly 35k miles with using the same hardware. But that is with my '99 Windsor motor with a three bolt tensioner. I cannot find any hardware to replace it. Even at AutoParts stores and Mustang websites..

Why do you need to replace the bolt, is there something wrong w/the actual bolt?

 

[trinity_gt]

Why do you need to replace the bolt, is there something wrong w/the actual bolt?

It's torque-to-yield (TTY) which are only supposed to be used once because they are stretched permanently. If re-used, TTY bolts will stretch further and weaken. I don't want to risk the bolt snapping both because I don't want to lose the tensioner and belt (and power steering and power brakes) but also because I don't want to have to extract a broken bolt from the front cover.

I like the idea of finding a "normal" bolt. I'll do some searching around here for a suitable replacement.

 

[Dustys'99]

Are you SURE its a TTY bolt. Just because you turn it an additional 90 degrees doesn't mean its a TTY bolt that needs to be replaced after one use. Some flywheel bolts on the deisel (duetz) engines I work on reguire a specific torque then turn 60 degrees, then another 60 degrees after that and these bolts can be used up to five times. I know, I know it's two totally different applications but the principle is the same.

 

[trinity_gt]

I'm assuming it is because of the degree specification. The two idler pulleys are spec'd to be torqued to 18 ft-lbs and that's it. This one is 89 in-lbs and then 90-degrees. Why the difference?

In my experience, any fastener used on a Ford engine that specifies a degree value is TTY. I'd love to have my assumption proven wrong by someone definitively tell me "No it's not." Until then, I'm going to assume it is TTY.

 

[joshjwc9]

I think you are just overanalyzing something that isn't necessary. This isn't a head bolt that sees extreme pressure or a balancer bolt that is vital to the engine running...I've replaced my balancer using the stock hardware like I said above and I haven't had any issues...how many other guys here are running PD blowers or Thumper Tensioners don't even come with hardware to install them actually ever seen any issues? Just grab a new bolt at ACE locktite and torque to spec.