Automotive Tool Question, quick answer needed??

[TopCatGr58]

Hey Folks,

Okay, I'm going to be helping a coworker replace his timing belt on his '04 Subaru BAJA with a flat four, DOHC. WE have a manual, but we know how they are not the greatest written material at times!

The instructions say to use a Chain Wrench with a piece of old belt to grasp the crank pully to secure it to then use a breaker bar to get the 22mm main pulley bolt loose. IT also says NOT to use an impact wrench or damage may result to the pulley or bolt??? WTF ???

I'm heading to Harbor Freight NOW to get one for tomorrow morning's mechanic work, but can any AUTO mech tell me why the manual would say that? I can possibly understand for tightening it, but for loosening it??

Also, will it be a regular thread...righty tighty lefty loosey?? The diagrams do not show the direction of rotation, I'm wanting to assume that it's clockwise as looking directly at the engine from the front? I know I can just bump the starter to check...doh! But hopefully they wouldn't use a reverse thread on this thing to prevent it working loose against the spin of the engine/crank??

Thanks in advance, will check back in about an hour...I need the chain wrench for other projects anyways!!
T.C.

[ccogswel]

Hey T.C.

That does sound funny. You'd think that the chain strap would do just as much damage. I'm like you with the thought of using the impact for removal. You may take a hammer and tap the bolt to see if it sounds like its a good grade bolt. Maybe look for some markings on the head of it. It should be regular threads. I couldn't see it being reverse threads. But you never know. All ways a first for everything. If it were me I'd use a impact on it to remove it with. I'd recommend using a 6 sided socket to get it loose. Should be safe.

And just for kicks. Whats the torque settings for it? That should give you an idea of how tight it is in there. Just a thought.

Good Luck!

[Montreux_Blue]

Here is a step by step with PICTURES!!! Different car but DOHC 4 cylinder.

http://my.is/forums/f87/diy-timing-belt-water-pump-348511/

[TopCatGr58]

Hey Blue,

I appreciate the link. I have done this a few times! I (Swmbo's car actually) had a wonderful Ford Escort with a straight 4, luckily after they redesigned the valve clearances so that WHEN(not if) the timing belt broke, it didn't eat valves! It was to be checked at 30K and replaced at 60K, but I had to replace it every 30k. It died first in her work hospital parking lot and I did the repair right there. I drilled a hole thru the right wheel well to access the tranverse mounted engine/crank pulley bolt. Used an old trick of wedging the wrench against the wheel well/frame and tapped the engine over to break it loose, and YES it was a REVERSE threaded bolt! Had to do this 2 other times, got it down to about 2 hours! We ended up putting over 90K on that machine, never had to tear the head off, it never bent valves even though the belt would break several teeth right at the crank, crank would spin, cams would not!

This BAJA is actually a flat 4, but with a cam on each sideways head. I just looked thru the entire manual, no diagram of engine rotation!! The crankshaft pulley bolt is only 130 ft/lbs....yes, not NEWTON/Meters! Should be fun!
T.C.

PS, HF actually had the vicegrip style chain wrench, less than $10.00!

[Ivan]

In general, it is ok to remove the bolt with an impact, although most of them are tight enough it really isn't effective.

Pull all the spark plug boots, find something that will support the load of the break over bar without screwing anything up, and bump (just a bump!) the starter. That usually breaks the bolt loose. I have never done that trick on a subaru, but I would imagine it works. I have never seen a left handed thread on a crank either, but who knows on a subaru.

The important thing to remember is that you CAN NOT use the crank bolt to push the pulley back on. This will burn you. Get a "Harmonic Dampener Pusher" to do this work. Usually they can be rented at autobone or some place like that. If not, borrow one. You really don't want to be hammering that on. it can bend and cause all kinds of hell with the belt. If you use the crank bolt, chances are good that you will gall the threads and render the crankshaft useless. Not cheap OR easy.

As far as tightening the bolt, for some reason they will tighten themselves really tight. You just need to get it snug. What ever mysterious force it is will take over and tighten the bejesus out of it.

[TopCatGr58]

Alls well that ends well!

Well, it's done!

Started at 9:00 am, and was done by 11:15! The chain wrench worked like a charm, took flexing the 140 lb torque wrench to it's max to break the 22mm headed bolt loose, but got it..standard right hand threading. The pulley actually just slid right off the crankshaft, it's not any kind of pressure fitting.

I have to praise the Subaru engineers that made access to it relatively easy. Didn't have to drain the radiator, or remove any radiator hose, just one power steering return hose, and the radiator overflow hose/chamber. The two radiator fans, and the two outer drive belts, the AC belt tensioner and PWS belt tensioner. Had a little scare with the right cam/sprocket....after removing the belt, just slightly touched it and it spun 90 degrees due to one of the valve springs were under tension!

Gently/carefully rotated it back into position and it stayed long enough to get the new belt in place and the timing marks aligned!! He drove it away at 11:30. Thanks again for all of the advice, ideas.