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Grease instead of oil in pivotshaft on D8, bad idea?

Per Eriksson

Senior Member
Joined
Oct 24, 2007
Messages
652
Location
Sweden
A customer of ours had a seal tear and is losing the pivotshaft oil rapidly, he want's to fill it with grease instead but I don't think that's such a great idea or am i wrong?
 

Cmark

Senior Member
Joined
Jan 2, 2009
Messages
3,178
Location
Australia
Any lube's better than no lube, but how does he propose to fill it with grease through a header tank?

You could point out that if he allows his pivot shaft to wear, he gets one shot at grinding it undersize and if it goes beyond that, it's big bucks....
 

blitz138

Senior Member
Joined
Jun 22, 2011
Messages
335
Location
Utah
This is a horrible idea! Grease will not dissipate heat, grease will not fill in the voids fast enough when it is displaced from movement. I think the pivot shaft calls for a TO-4 oil? I dont know why you would need a friction modifer in the pivot shaft. The TO-4 oil has the friction modifer for wet brakes/clutches.....

There are anti-leak gear oils that work, you have two different types rheopectropic and theomopectric. One is basically a gel that will shear when exposed to heat or movement turning to liquid and acting as a gear oil at the gears. The other is more in line with an open gear lube, its thick to slow or stop a leak but thin enough to protect the gearing.
 

Nige

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Jun 22, 2011
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29,426
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G..G..G..Granville.........!! Fetch your cloth.
As posted above. No, no, and no. Tear it down and fix it. Pivot shafts are too expensive to screw with.

Blitz, the reason the spec is TO-4 for the pivot shaft is simply that the same weight of TO-4 is used in final drives and recoil compartments (equalizer bar as well if it's oil lubed) so customer doesn't have to use a different oil. You could I suppose ask why a TO-4 is specified for differentials and final drives in OHT.
 

Per Eriksson

Senior Member
Joined
Oct 24, 2007
Messages
652
Location
Sweden
Believe me, I've tried to talk them out of it.

Even more strange that they want to go this route considering I had the machine in less than 2 years ago and was supposed to replace a torn seal and ended up replacing shaft and all bushings, the right side bushing in the frame had less than 2mm material left and it was bone dry and dirt everywhere........it ended up being quite expensive but no lesson learned it seems.
 

blitz138

Senior Member
Joined
Jun 22, 2011
Messages
335
Location
Utah
Makes sense Nige. Per Eriksson I'll send you a link for the anti leak gear oil. If nothing else talk them into using an open gear lube
 

Cmark

Senior Member
Joined
Jan 2, 2009
Messages
3,178
Location
Australia
Believe me, I've tried to talk them out of it.

Even more strange that they want to go this route considering I had the machine in less than 2 years ago and was supposed to replace a torn seal and ended up replacing shaft and all bushings, the right side bushing in the frame had less than 2mm material left and it was bone dry and dirt everywhere........it ended up being quite expensive but no lesson learned it seems.

Sounds like whatever you say Per, the decision's already been made :beatsme

The owner (presumably) knows his own circumstances and his own finances. If he's been down this road before he will be comparing the cost of the repair against the cost of the downtime right now. Maybe if he keeps it running for a couple of weeks, it'll finish a contract early for a big bonus which will more than pay for the damage. Who knows?
 

Nige

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Jun 22, 2011
Messages
29,426
Location
G..G..G..Granville.........!! Fetch your cloth.
Better IMHO to give the operator a gallon can of something like TO-4 SAE60 and have him keep topping up the reservoir for the pivot shaft every hour or so. We di that a few months ago on one of our 10's to keep it going for the last month or so coming up to an overhaul. Shaft was perfect when it came out, seals not so much.
 

Garrie Denny

Senior Member
Joined
Jul 20, 2011
Messages
507
Location
Gin-Gin,Queensland
Occupation
see above
To me this is a No brainer.Manafacturer call for Oil? Owner wants cheap version of grease ? Nige has turned up the Ace card for this post if the owner wont replace properly, rig up a cheap 20 litre container with tap to slowly release required oil until unit can be fixed the proper way.
 

Nige

Senior Member
Joined
Jun 22, 2011
Messages
29,426
Location
G..G..G..Granville.........!! Fetch your cloth.
Garrie, There's no need to even do that. The pivot shaft lube system has a tank that is about 1 gallon capacity IIRC. It's mounted right by the LH cab door in the cowling between and the fuel tank. All the operator has to do is to check the level in the tank every so often and fill up as necessary from a container kept in the cab or strapped on somewhere outside.
 
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