Bad Crank Pulley? (1 Viewer)

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Sep 28, 2012
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Has anyone ever heard of or seen a crank pulley go bad on an FZJ80?

When you first start my 80 it makes a bit of a growling sound coming from the belts. It seems to go away fairly quickly. When you engage the A/C when it's cold it makes alot of noise. Sounds like a bad idler or compressor. As the RPM goes up or after a few minutes it goes away.

I have replaced the belts with factory belts. Replaced both idler pulleys and lastly replaced the A/C compressor. Really thrilled after I replaced the compressor to find the noise still there. Again, it goes away after a minute or two and only happens after the vehicle sits awhile.

I have noticed when it occurs, I see what looks like movement or a wobble in the crank pulley. My theory.. this week.. is that the rubber in the pulley is getting soft or coming apart. The tension from the belts pulls the pulley slightly off-center when it sits awhile. When it starts, it's wobbling and making noise and then it eventually centers itself after a few minutes? Is this crazy?

Any thoughts? I'm running out of parts to replace....

Chuck
 
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I don't believe there is any rubber in the crank pulley. I would find it really difficult to believe one of those would get warped.
 
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You believe wrong then :)

And we're talking the harmonic balancer...

cheers,
george.

I shouldn't post when i'm tired. There is a small rubber ring in there just outside of where the big bolt passes through, correct ? I remember it now from my rebuild before I painted over it.
 
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I shouldn't post when i'm tired. There is a small rubber ring in there just outside of where the big bolt passes through, correct ? I remember it now from my rebuild before I painted over it.

Correct, and yes, they do go bad.
Not an expensive part and not hard to replace…
cheers,
J
 
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The crank bolt is tight. I was assuming the outer ring of the pulley and the belt part was separated from the center hub by a rubber ring. If I take a big screwdriver I can pry between the timing cover and the pulley and see the outer part move around. No idea what is normal though. I'll see if I can make a video.
 
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The crank bolt is tight. I was assuming the outer ring of the pulley and the belt part was separated from the center hub by a rubber ring. If I take a big screwdriver I can pry between the timing cover and the pulley and see the outer part move around. No idea what is normal though. I'll see if I can make a video.

It's simple, you should not be able to do that. Be careful, on the diesels the timing cover is aluminum (don't know about the gassers) and breaks easily, when pried against. Then you have a bigger problem.
 
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The pulley should not significantly move in relationship with the hub, if it does, it's bad, time for a new one. Not common, but have seen a few fail.
 
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Things were quiet for awhile then the truck threw both alternator belts on the way to work. A close look revealed that the outer part of the crank pulley was up against the timing cover on the motor. Looks like the rubber finally let loose. Perhaps it was the 8deg weather. When I crawled underneath I could pry the pulley away from the motor about 1/4" w/o alot of force. Needless to say, a new pulley is on order as well as a crank and oil pump cover seal. Just with the local dealer would have matched the online prices so I could get the parts faster.

Chuck
 
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Sure enough the crank pulley came apart. There is a 1/4" thick rubber part between the inner hub and the outer sheaves. The bond between the rubber and the outer part of the pull separated. So when you keep tightening the belts and they still squeal when cold, check your pulley. here's a picture of the pulley. I just slid the inner out with my fingers. It's actually sitting in two pieces on my bench now. Once I tool the belts off, you could just slide it apart without the tension.

20141124_193753.jpg


20141124_201251.jpg


You can see where the pulley was rubbing the timing cover. Since I didn't see any leaks from the oil pump O-ring, I left it alone.

20141124_193713.jpg


Luckily they changed the crank seal design to add a lip to it.

20141124_194959.jpg


The lip works perfectly to hold a piece of 2" PVC pipe coupling in place to use as a seal driver. You need to trim about 1/2" or so off the coupling to get some room to swing a hammer. I used the side of a 3 lb sledge to get it in.

20141124_201251.jpg


Not bad. All fixed. I only had to replace the belts twice, both idler pulleys and the A/C compressor before it finally failed and I figured it out....
 
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Interesting about the pulley rubber coming apart. Does it look like the rubber between the inner and outer sections were molded all as one piece when it was manufactured, or does it look like it had been two separate pieces glued together??

FWIW I noticed a small crack in the rubber all the way around my crank pulley after I took it off using the starter bump method, but don't know if that crack was there previously.

So knowing that the crank pulley can come apart I wonder if we need to rethink the starter bump method of loosening the crank pulley bolt?? Does the torque on the pulley by the moving belts fight against the pressure of the bolt pushing in on the center section of the pulley when these are bump loosened? IDK
 

Dave 2000

Not all Land Rovers are useless!
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Seen this quite a bit on modern cars as well as older 80's. When servicing them I run a line of typex across the pulley sections, drifting out of phase will be easy to spot.

regards

Dave
 
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Interesting about the pulley rubber coming apart. Does it look like the rubber between the inner and outer sections were molded all as one piece when it was manufactured, or does it look like it had been two separate pieces glued together??

FWIW I noticed a small crack in the rubber all the way around my crank pulley after I took it off using the starter bump method, but don't know if that crack was there previously.

So knowing that the crank pulley can come apart I wonder if we need to rethink the starter bump method of loosening the crank pulley bolt?? Does the torque on the pulley by the moving belts fight against the pressure of the bolt pushing in on the center section of the pulley when these are bump loosened? IDK


No, the procedure using the starter to bump it loose does not cause this. It actually prevents it. A frequent cause of this is someone using a strap wrench on the outside of the pulley when loosening or tightening the crank bolt. Occasionally the rubber can be broken down by excessive oil leaks or excessive heat. Hopefully you have already removed your belts before you are attempting to break this bolt loose with your starter. BTW, the breaking the bolt loose with the starter did not work for me. I had to lock the flex plate for both loosening as well as tightening. (14MM impact socket)
 
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It's just another part that degrades after 200k + miles in dirt, heat, cold, wet, dry conditions. No big deal.
 

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