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Serpentine belt nottracking


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The serpentine belt on my 90 4.0 liter (Air, P/S) keeps tracking to the inside of the Crank pulley. I'm sure it's some kind of alignment problem since It still does it with a new belt. The old belt was good. Anyone ever seen this before? I don't see anyway to align the pulleys. I also don't see any that aren't aligned. I can't crank the engine and see the pulleys at the same time, but it doesn't take anymore then one quick crank for the belt to ride out of the track on the crank.

 

A little history. When I bought this comanche the P/O put water in the radiator and when I started it on a freezing day the water pump was frozen and it took out the serpentine belt. I'm guessing that when the belt went it must have pulled something out of alignment but don't see anything obvious.

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The harmonic balancer may be starting to separate, which is causing the belt to detrack.

 

 

I'll 3 X's that :D

 

I've seen it before, take a good hard look at the harmonic balancer, it should be flush with the inter bell / outer pulley, with NO rubber sticking out. If it's not flush, time for a replacement.

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When you check the harmonic balancer don't just look at it. Reach down and move, shake, jiggle it. The HB went out on my '77 J20. For over a week I'm getting funny noises from under the hood. Would eyeball everything and it all looked good. I felt the fan blades, steering pump pully but not the HB.Finally it threw the fan belt. It wasn't untill I was putting the belt back on that I caught on to the fact that the HB was shot. There wasn't a shred of rubber left between the pully and the hub but it looked good just looking at it.

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Thanks guys, judging by the puddle of oil and oil on the swaybar the harmonic balancer is the problem. Doesn't look damaged and I haven't crawled under there yet, but I'm guessing the nut is missing. I have a spare off my parts Comanche if it's the balancer itself.

 

Mac...

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If the Nut is missing off the crank, Don't start / run /drive the truck, if the HB comes off, besides a flying missile, you have a very good chance to snap the crank shaft :eek:

 

Also, there is a seal on the timing chain cover that might need replacement if your leaking that much oil, and the time to change it is when the HB is off.

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I climbed under to have look. the harmonic balancer is separating as many suspected. Now the big question is how to get the bolt off? It's an automatic so I need to keep the engine from turning. I agree this is the time to change the seal.

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The last time I helped a friend change his HB, we put a socket on the nut with a long handle that touched the ground. Then he just blipped the starter to loosen the nut.

 

While this may not be the recommended method, it did work quite nicely.

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That sounds kind of dangerous. What I did was screw a bolt into one of the puller holes then attached the 19MM socket on a breaker bar. I wedged a crowbar between the socket and the puller bolt and squeezed them together. I wasn't sure what a bad HB looked like since I didn't have a good one to comare it to. Here's what mine looked like. There is about 1 1/4 inch offset between the crank side of the HB and the pulley side. There shouldn't be any from the pictures I googled.

 

pulley1.jpg

pulley2.jpg

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