In short my brother replaced the t.b.'s on his 88' wagon 2WD this summer. The just went again today. I want to know why? Anyway, if anyone has a theory on what went wrong let me know. Is there anyway to prevent it from happening in such short order again?

 

cheers,

 

Dave

Just a tought.....did you happen to replace the tentioners at the same time???? If not that would be my guess ( and expierience)..... Later, Tim

Ya, replace the tensioner too. Mine was way 'dry' (ie noisy).

Were the belts properly tensioned (i.e., with a torque wrench and an apropriate adapter)?

Either they were cheap non-OEM belts or they were not installed with the proper torque. I have seen them get chewed up in 3k miles because the persone tensioned them like you would a V-belt.

That's funny, mine just went today on my way to school! Mine died from old ade though. The one that broke was BADLY cracked and the other side was beginging to crack. So, tomorow I will get new ones and install them. So much fun!

I replaced my sister's timing belts three months ago with NAPA's belts and her's are still in tack. Funny, same side too. hmmmmm....

let me gues driver's side went? Driving the oil pump and the distrib. put a bit of extra load on it.

 

Hmmm ... how should the timing belt be tensioned? Yeah, his idlers were good. He's a machinist so he just replaced all the bearings in the idlers.

Another reason for timing belts failing is faulty front seals; oil gets on the timing belts and they don't last very long. Generally speaking, belts should be replaced every 60K miles. Every 2nd belt change replace oil pump, water pump, and seals in addition.

Per '85 FSM, the cam sprocket should be torqued to 24-25 N·m ( = 2.4-2.6 kg-m = 17-19 ft-lb) if both timing belt and head gasket are new; or 14-16 N·m ( = 1.4-1.6 kg-m = 10-12 ft-lb) for conditions other than those (undoubtedly to allow for belt stretch and/or head gasket relaxation). Per '85 FSM.

 

Below is photo of a tool I made to adapt a torque wrench to the cam sprocket (instead of the special Subaru tool #499437000). Welded in the center of the tool is an all thread rod coupling (just like a hex nut, only longer). (FYI - The little thing to the right in the photo is a flywheel stopper I made).

 

After using it a few times, I could probably tension the belt properly without a torque wrench (within the variability that you'd get with a torque wrench due to adjuster stiction and other variables). It's moderately taut, but bbitner is correct - it's definitley not nearly as tight as you'd tighten a V-belt.

 

(A word of caution - make sure your torque wrench works in the CCW direction - some of the cheap click type ones only click in the CW direction - after all - how many times have you torqued a left-hand thread? - I didn't realize this the first time I used my adapter tool and it's a wonder I didn't break something because I kept pulling harder and harder on the wrench because it never clicked before I finally figured out it wasn't going to click in that direction. BTW - nothing wrong with click-type torque wrenches - I prefer them - my point was the *cheap* ones may only work in one direction)

 

thnaks bill. I think I'll be heading up to my bro's place to help him with his belts tonight. I suspected one of two things when I heard his belts had gone and one of them was oil.

 

Cheers,

 

Dave

You're welcome!

Archived post, well done all.