12ht camshaft pulley came loose

[rideglobally]

has anybody had an experience with camshaft pulley coming loose? my engine was rebuild 7,000 mile ago it is possible that it was not torque down. but if it was torque down what would cause the nut on the camshaft pulley to come loose.

i am hoping to leave tomm for a trip to Baja California, my plan is to put loc tight on the bolt and tighten it down, since i am going on this long trip i want to make sure it does not come loose again. is there any thing else i should do. i do not have a puller to pull the pulley all the way out to inspect it, but i could maybe locate one if necessary. thank

 

[blis]

I cant see it coming loose if it was torqued up to spec... but on the other hand, i've never heard of one coming loose either... Just punch a mark on nut or use loctite and it should be good to go...

 

[rideglobally]

the nut is very difficult to get out.

 

[doug720]

Are you talking about the cam shaft or crankshaft pulley? On a 12ht, I thought the cam was gear driven?

If it's the crankshaft nut that is loose, you should have enough room to tighten the nut. I would clean the threads well and apply "Red" lock-tite.

Torquing it to spec is the best way to insure it won't come loose in the future, but I know many people who have used an impact.

I would make sure it's secure before heading off to Baja.

Doug

 

[amaurer]

12HT cam has a gear, not a pulley; is held on with a bolt, not a nut; and the gear is keyed to the shaft AND hidden behind the timing cover.

So we're probably talking crankshaft pulley rather than camshaft. And the 6 cyl in a 40-series is probably a lot less fun to access the pulley than on a 3B, for example.

Still, solution is the same - retighten the bolt. Use some loctite. Try going from underneath the truck.

 

[bloc]

Personally, I'd NEVER put red loctite on a bolt that big (cam or crank). Red LT on a bolt of that type, and you'll probably never get it loose again.

Blue loctite, applied correctly, and torqued to spec should be more than enough.

 

[rideglobally]

thanks everyone, it was the harmonic balancer coming apart on the camshaft pulley. thankfully Spector off road had one so we are on out way to Baja Californian leaving at 5am. Specter say he has not seen one come apart like this. has any one have experience with this. here is a picture of the camshaft pulley. if i am able to post on expedition portal i will post the link here to share with you our trip.

 

[amaurer]

I've seen it on mud a couple of times now.

 

[lostmarbles]

That rebuilder probably had to use an oxy-torch to loosen the CRANKSHAFT pulley bolt after some dude had previously applied red loctite to its threads (cooking/destroying the rubber in the harmonic balancer in the process).

 

[FJRanger]

I had this happen just after rebuilding a 22re. The kit I used had plastic time chain guides, after a few weeks one of the bolts backed and I took the front apart again. That's when I noticed the harmonic balancer. Mine didn't looked that bad but the rubber was separating and my timing marks had rotated.

Had a machinists teacher of mine warn us that it can happen with age and when it happened on my truck I was still a bit surprised.

 

[TLC Norway]

This just happend to me too. I just noticed oil drippings after a few hours drive back home.
Its a 2h, im talking about the big nut on the main pulley on the main shaft. Think its a 44mm nut.
Had it torqed to specs after seal replacement last year.
Seems the pulley has gotten loose on the shaft, moving a couple mm to the front.
Found the nut on the skid plate underneath!
Ill probably remove the pulley and check for issues. Now that the bolt is off most of the job is already done.

 

[Stephen835259]

All,

If I order the crankshaft pulley, will the harmonic balancer automatically come with it? Do they come together when ordered? I'm looking at this engine breakdown and all I see is the crankshaft pulley, and I'm hoping it has the harmonic balancer within it. I'm looking at part 13471.

 

[Gengis]

Nut is 46mm. In this case it was the harmonic balancer but that nut does come loose, often. I believe mainly because guys repairing or rebuilding them don't have the correct torque wrench or the right 3/4 socket , so it just gets made as tight as possible with whatever comes to hand.
325ft-lbs or 4500 kg-cm is the correct torque. Does your wrench go that high. Concerning Loctite, then get hold of you local rep, they seem well trained and can advise accordingly at least here in sunny South Africa.

Getting them loose? Socket and tee bar. slip an extension pipe over the tee bar and rotate engine until the extension rests on the top of the left-hand frame rail. Chuck a sack or bit of canvass over the bar and hit the starter button. Works like a charm, but probably not endorsed by the armchair brigade. Please get observers and helpers to stand back during this and don't try to video it.

 

[Slow]

Nut is 46mm. In this case it was the harmonic balancer but that nut does come loose, often. I believe mainly because guys repairing or rebuilding them don't have the correct torque wrench or the right 3/4 socket , so it just gets made as tight as possible with whatever comes to hand.
325ft-lbs or 4500 kg-cm is the correct torque. Does your wrench go that high. Concerning Loctite, then get hold of you local rep, they seem well trained and can advise accordingly at least here in sunny South Africa.

Getting them loose? Socket and tee bar. slip an extension pipe over the tee bar and rotate engine until the extension rests on the top of the left-hand frame rail. Chuck a sack or bit of canvass over the bar and hit the starter button. Works like a charm, but probably not endorsed by the armchair brigade. Please get observers and helpers to stand back during this and don't try to video it.

Do you know what tread is on the nut? Happen to came loose completely and I’m without the nut and almost destroyed fan when the pulley moved forward quite a lot. I’m located in BC, Canada. Thanks for help.

 

[bladedog]

Do you know what tread is on the nut? Happen to came loose completely and I’m without the nut and almost destroyed fan when the pulley moved forward quite a lot. I’m located in BC, Canada. Thanks for help.

Is this Zee? Did you get this sorted? I've got a socket and torque wrench to tighten it back up.

 

[Slow]

Is this Zee? Did you get this sorted? I've got a socket and torque wrench to tighten it back up.

Hey! Yes it is, France right? It was the mission of the time, but yes, all back together and slowly exploring finally around It was little bit worse than just what I thought loosen nut. The harmonic balancer cracked, and needed to get another one. Luckily guys in Edmonton had one for me on the yard, to avoid buying new one for at least 3 times more the money ) Thanks for reaching me up!