Older FGs and rubber components...

[WhereisFranklin]

Perhaps it's obvious to some, but I'll pass on my experiences...

I have a 2000 FG637. Travelled only 86000k. Ex Aust Army. I hadn't fully considered the effect of age on some key rubber components. The vehicle has not had a tough life.

1. Just holed up nr Winton Qld waiting for a replacement crankshaft pulley. It failed about 160k from here. Required a 160k, mainly dirt tow to get back to Winton. The pulley uses rubberin its construction to mitigate shock apparently. New pulley (triple) and seal around $400

2. Cab bushes for the tilt mechanism are also based on rubber components.
I had these replaced prior to this trip after enduring contact issues under the cab. Bushes around $500 for both sides plus labour.

Apart from suspension bushes, these seem to be the critical areas where rubber degradation can cause significant issues. Worth checking on older vehicles before a trip or perhaps replacement. We were fortunate to be travelling with friends in an NPS and they saved us a significant recovery bill by towing us to town. Would have been well in excess of the cost of preventative replacement. Hope this helps.

 

[yabanja]

Interesting. I have the same year FG639 with similar miles. The rubbers on mine seem quite good. Will keep an eye on that crank pulley though. May replace it premtively. Thanks for the heads up.

 

[kerry]

99FG here. Hadn’t considered the possibility of a crank pulley failure (fairly common on the 6.5 GM diesel). What were the symptoms? And suggestions on how to assess its condition? Was there visible damage?

 

[WhereisFranklin]

99FG here. Hadn’t considered the possibility of a crank pulley failure (fairly common on the 6.5 GM diesel). What were the symptoms? And suggestions on how to assess its condition? Was there visible damage?

Hmmm, I'm actually quite sensitive to out of place noises in vehicles but I didn't pick it up conclusively until just prior to failure. Trucks are really noisy around the motor. It may present a little differently in each case I suppose.

There was some wear against the timing gear case but not enough to need further action. The outer pulley Vs and the inner section were actually in good shape, the connecting 8mm or so of rubber was largely absent. A few decent spot welds could maybe connect them permanently and avoid my problem. Dumb engineering I say.

I'm no mechanic so not sure how to assess progressive deterioration but be assured it is a show stopper when it occurs so try to get it properly checked.

 

[steve66]

That piece of dumb engineering is called a harmonic balancer, it's performs an important function and all engines have them, some last for many years, some, like the $700 one in my wife's car, about 3years max. There really isn't much warning of impending failure.

A mate was stuck on the side of a highway once in his converted bus, he had a spare part for almost everything, except this balancer, took 4 days to arrange a spare to get dropped off by a passing greyhound bus, the nearest tow truck big enough was 500 kms away.

Hope it all works out ok, cheers

 

[John M.]

Mine is 17 years old. I guess an inspection is order!

 

[kerry]

On a 6.5 GM diesel, the indication of a bad harmonic balancer is a clunk as the engine is shut off and comes to a stop. Maybe an inspection camera stuck up in the vicinity of the pulley would provide evidence of the condition of the rubber.

 

[WhereisFranklin]

Replaced the part today and put radiator etc back in place. Seems to be fine after a few short runs.

 

[kerry]

How easy was it? Some harmonic balancers/pulleys have large nuts with hundreds of pounds of torque which require stopping the engine from turning somehow.

 

[WhereisFranklin]

How easy was it? Some harmonic balancers/pulleys have large nuts with hundreds of pounds of torque which require stopping the engine from turning somehow.

Back in reception... Correct, about 590 Nm (435 ftlb) I think. It was unscientific. Friend of mine is a retired mechanic and guided the replacement process. We did not have access to rattle gun or torqueing tools. Best we could do is put truck in 1st and tighten by hitting the breaker bar and attached 36mm socket with heavy hammer after the slack was taken up. So far so good after about 1000k. Will try to get it checked at some point.