I have a CAT 304C CR S/N OFPK02672 that blows oil out of the flat plate where the return filter goes. I have installed new CAT o ring with grease to retain it. When you operate the machine it blows oil out from the under the o ring and plate. The oil level is on the lowest mark on the sight glass. What can I do to correct this? Thanks in advance.
I have attached a picture of the filter cover in question.
Is the filter clean and the correct part? If in doubt, install a new one. Also check that the filler cap is the correct part and in good order.
Regarding oil level in the sight glass. Are you putting the equipment in the correct position before you check the oil level in the tank..? See below. The level should be measured with machine parked on level ground and with the oil cold. The oil tank cap is critical. If the pressure in the air above the oil can't be released when the oil gets hot it will find the place of least resistance to get out. Has it been replaced at any time..? Also the return line filter. When you changed it did you fit a Cat filter or aftermarket..? Maybe it could be generating excessive back pressure if it's not a genuine filter.
Nige pic for level is not ok need to be this
Well how do you like that? Since the dawn of time, every Cat HEX has had the hydraulic oil checked with the stick vertical and then they go and change it. Nice one!
Its in omm
I don't care what it's in - it's fcuked ....... As Cmark rightly points out since the dawn of time EVERY Cat excavator has used the same procedure for checking the implement hydraulic oil level - the illustration I posted above. Now some clown brings out a new procedure just for one product line. You couldn't make it up could you......? Another Cat Design Feature - designed to fcuk you up. Thanks for pointing it out though. It may still be relevant in the case of the OP's problem.
Nige check this out Media Number -SEBU8021-12
I'm not disputing the fact it's in the O&M for that particular model, I'm arguing against the principle that for the last 40+ years the procedure for checking the hydraulic oil level on any Cat excavator was always the same, as per my post #4 above. Now someone has thrown a spanner in the works by changing it, and I'm betting it's only on this particular line of "lawn care" machinery. I'm sure that the rest of the excavator line will be unaffected. But my question is why a procedure that has worked perfectly satsfactorily for that number of years suddenly has to be changed in what appears to be a situation where the left hand doesn't know what the right hand is doing. I would imagine it has something to do with the fact that the 300-series HEX product line is built in Aurora IL and the mini-HEX line in Clayton NC. My guess would be that the 2 manufacturing facilities don't talk to one another.
200 Series have another procedure to do level check bucket close stick out implemts on the ground 300 Series if u have VA boom its another procedure same with MH UHD boom Anyway normally u have a decal next to level how to put the implements
Yes it is a CAT filter. The o ring is a CAT part. I did install a CAT hydraulic thumb and as I was pressure washing I noticed that the hammer valve was in the hammer position, NOT the double acting position. I swithed it to double acting.
Which mark on the sight glass is correct with the machine in this position?
Post a photo of the sight glass so we can see the marks.
The middle with cold old Top mark with warm oil
Ok guys I am sorry to take so long to reply as I have been out working until dark. I took pictures tonight but my phone died on the last pic so I will post in the AM. Thanks for the help so far.
It looks like all cylinders fully retracted.
Apart from the boom cylinder I'd agree with you. This would mean that if you put the implements in any other position and fill the tank to the marks on the sight glass the tank will tend to be over-full when the cylinders retract during operation. This could possibly be why it's blowing oil out of the cover for the filter element. However on the flip side if it's started doing this suddenly and you've made no changes to the way you check/top up the hydraulic tank then the root cause of the leak could be something else. Sorting out the oil level issue should certainly be the first step in the process.
OK so it's a Cat filter, but is it a NEW Cat filter? That leaking seal is on the pressure side of the filter so the most likely causes are either the filter is blocked or the mating surfaces between the tank and the lid are distorted. The filler cap theory is probably a distant second.
View attachment 304C CR hydraulic tank and filters.pdf I have attached pictures of the sight glass, hammer valve, hammer valve diagram, and hydraulic tank and filter arrangement drawing. Yes both the filter and o ring were NEW CAT parts bought from my local CAT dealer. I will have to re post the drawing. For some reason it did not up load.
View attachment 304C CR hydraulic tank and filters.pdf For some reason the pdf wont upload
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.
Pictures of the oil level sight glass and position when checked.
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.
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.
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.