I have an 86 Subaru GL wagon with 292000 miles on it. When I got it at 289,000 I replaced the cam seals,timing belts and tensioners.and oil. no oil pump reseal tho.

 

The timing belts worked fine for a few miles then the adjusting bolt for the drivers side pully worked its was loose causing the drivers belt to slip. I replaced it and had a hell of a time getting it to what I felt was tight enough.

I had my bro tap on the top of the tensioner body with an extension and light hammer. I would snug it to what seemed tight enough without striping and give the belt a squeeze and the tensioner still moved untill I tightened it scary tight.

 

It held up to a month straight of driving an 80-100 mile daily round trip up to green bluff and back for harvest with no problem, then on my very last day about 3 miles from home guess what?? the tensioner bolt worked its way out again. now I am shy a running car and a bolt.

 

Plans are to pick up a 1/4drive in/lbs torque wrench reseal the oil pump now that I have all three seals, hardware store(10mm 1.25)?.red lock both tensioner bolts.

 

Any tips on how to get the tensioner tight enough?

Thanks

Get it to where it runs and has minimal deflection. The tensioner will only get so tight before it hits its stop. Get both bolts snug, make sure the car will run. Turn the car off.

 

Back out one bolt. Put lock-tite on it. Put it back in, snug it down (but don't crank on it, you don't want to strip the threads). Repeat with the other bolt. Repeat with the tensioner for the other belt.

The threads in the engine case are deeper than the tensioner bolts are long. Therefore, you can get a longer bolt in the threaded hole.

 

Something like a 1/4" longer than what is from the Factory will do you good.

Which bolt? she slot or the povot? If the thread on the slot is good, then all the pivot bolt has to do is not come out.

 

I once had the idler pulley walk out, causinng a failure. I once had to thread a helicoil to the same pulley on a different engine.

 

I had the same issue with a tensioner as you are describing, and i was just careful with my torque, and used lock-tite. I was able to have it apart and back together a few times with the poor thread without it being worse.

 

If the lock tite fails, i would go for the helicoil (better) or tap it out to a standard size ( 7/16"x14 ), but you might have to enlargen the holes on the tensioner bracket.

...then the adjusting bolt for the drivers side pully worked its was loose........and had a hell of a time getting it to what I felt was tight enough.....and the tensioner still moved untill I tightened it scary tight. .............the tensioner bolt worked its way out again.

properly functioning parts that are properly installed won't have any issues - so something is wrong. many of us have done countless timing belt jobs on these with no issues - properly done they hold 100% of the time, it's really a very simple set up.

 

Any tips on how to get the tensioner tight enough?

properly working threads and bolts work 100% of the time so my guess is your threads are stripped.

 

if the bolt is backing loose then something is wrong - stripped threads, wrong bolt, wrong part....probably stripped threads. a longer bolt, as mentioned by Tom will reach unused threads deeper in the hole - that is a standard 1.25 metric pitch bolt - probably an M8x1.25 bolt, just get one a bit longer (if it's too long use spacers under the head).

 

chasing the threads with a tap to clean them up is a good idea too.

What you have is a fine thread in an aluminum bore, vs a coarse thread in a n iron bore. And for whom so the subaru is an unconventional project, the result is 'hillbilly torque' on these poor aluminum threads.

 

The finer threads take less torque to hold a specific value than a coarse thread.

I've actually stuck a piece of copper wire in the hole, same direction as the bolt. Then screw the bolt in and the copper takes up the slack and its there forever.

I've actually stuck a piece of copper wire in the hole, same direction as the bolt. Then screw the bolt in and the copper takes up the slack and its there forever.

that's awesome, mental note.

Another vote here for trying a longer bolt.

Working fine here.

 

Blow out the bolt hole to be sure its clean.

Mybolt was too long and I need a couple washers.

Edited November 12, 201114 yr by zukiru