View attachment 304C CR hydraulic tank and filters.pdf For some reason the pdf wont upload
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Cat 304C CR oil leak issue
- Thread starter f311fr1
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Click on the 304C CR hydraulic tank and filters.pdf and the drawing will come up. Gone to put the machine in correct position and check oil level.
Nige
Senior Member
If the oil was cold in the top photo of post #23 then that oil level is bang on.
If the oil was at operating temperature the level would be permitted to go up as far as the upper red line of the sight glass.
Regarding the pdf you uploaded it might be a good idea to have a close look at the cap #2 in the illustration and if it's not too expensive replace it. Do you know if it's the original cap or not, any Cat markings on it maybe..? Could it have been replaced by an aftermarket "will fit" cap at some point in time..? I would not even consider buying the replacement from an automotive parts store because there are too many options of pressure setting unless you can find a specification for it somewhere.
If the oil was at operating temperature the level would be permitted to go up as far as the upper red line of the sight glass.
Regarding the pdf you uploaded it might be a good idea to have a close look at the cap #2 in the illustration and if it's not too expensive replace it. Do you know if it's the original cap or not, any Cat markings on it maybe..? Could it have been replaced by an aftermarket "will fit" cap at some point in time..? I would not even consider buying the replacement from an automotive parts store because there are too many options of pressure setting unless you can find a specification for it somewhere.
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It is a CAT part and with the tank cold (100 degrees here today) you could hear the tank vent when I unsrewed it to top off the oil tank. It took about a quart. I will run it this week and see how it does. If it still blows out I will replace the cap and filter cover o ring. I will let you know.
Still blowing oil. I will replace the tank cap next. Nige do you have the service procedure? I went back out tonight and removed the filter, felt in the bottom and found the locating nipple in the bottom, made sure the filter was seated properly, correctly installed the bypass assembly, and wondered why the sight glass did not come up when I uncapped the return filter. Opened the fill cap and wached the oil level rise one complete ring level. In my before retirement life I was a Certified industrial Hydraulic Specialist. All out tanks were vented to atmosphere fithe a filler breather.
We have identified the problem. The flange under the lid has a dent in it. How it got dented I have no idea. The dent is right under the where the o ring seals. I think I am going to widen the o ring groove to accept a thicker cross section o ring.
We found the corresponding spot on the filter top cover where the dent in the flange was. Filled the dent in the tank flange with some good black RTV and finger tightened the bolts. Worked in the barn on one of the ASV's while it rained. After lunch, and the rain stopped, we torqued the bolts and worked it for a solid 8 hours till dark. No leak.
Nige
Senior Member
Assuming the RTV is a temporary fix just to make sure you can seal the cover plate, is it possible to panel-beat the dent out as a permanent solution ..?
The flange welded on the tank that the cover bolts to is 3/8 to 1//2 inch thick and about 6 inchs OD by about 5 inches ID. It is dented at about 10 o clock position. I would have to hit it from inside the filter compartment which is pretty cramped. Or maybe use a couple of flat bars, one on top and one on bottom and a hydraulic c clamp might do the trick. Since i don't have a pota power c clamp I think a wider o ring groove with a thicker cross section o ring would be worth a try. I have no idea how the flange could get dented short of a hammer blow from the top.