M680HD fuel bleeding procedure

[circled]

Good Afternoon All,

In the near, warmer, future I intend to clean out my diesel/water separator. I have read quite a bit on here about the difficulty of bleeding the fuel system after reinstalling due to unclear manual directions. I have included the directions from my 6800 manual and was hoping someone might be able to steer me correctly or point out the problem with the directions. Thanks in advance!

 

[priberc]

I am not seeing any problems with these instructions. Straightforward and easy to understand IMO. Pretty much a carbon copy for "bleeding" the air out of anything these days or yesterday really.
Find and familiarize yourself with the a ,b ,c and d. Locate the 1-4s. follow the procedure. I will say the instructions might not stress how important it is to have pressure as you "pump the fuel pump 3" The instruction use the word "firm"....stiff or hard might be better terminology IMO
A quick look on YouTube and there are some vids on there that may help you
Can I ask why you are "cleaning out" the water separator? can you see water in it? If you cant see water in it.....likely no water in it. "If it is not broken don't fix it"

 

[seville009]

Agree with Priberc - I've never taken apart/cleaned the water separater on any of my diesel equipment. I also know that if I fix stuff that doesn't need fixing to begin with, then things will likely go downhill quickly......

if you see that something is wrong with it, then obviously fix it. Otherwise may be better to just quietly back away......

 

[circled]

I am not seeing any problems with these instructions. Straightforward and easy to understand IMO. Pretty much a carbon copy for "bleeding" the air out of anything these days or yesterday really.
Find and familiarize yourself with the a ,b ,c and d. Locate the 1-4s. follow the procedure. I will say the instructions might not stress how important it is to have pressure as you "pump the fuel pump 3" The instruction use the word "firm"....stiff or hard might be better terminology IMO
A quick look on YouTube and there are some vids on there that may help you
Can I ask why you are "cleaning out" the water separator? can you see water in it? If you cant see water in it.....likely no water in it. "If it is not broken don't fix it"

Thanks for the reply Priberc. I have had the tractor for a little over a year. Part of my going through it was treating the fuel with bioBar and fuel injector cleaner. As it has sat for the last 3 months, while looking around I saw some sediment/crud in the bottom of the bowl. No water, ring is still pretty much on bottom. Just gonna clean it out but as I said, read bleeding per the instructions could be a bear. Maybe the instructions I have are newer or improved? Just thought I'd check in to see what other owners were doing ... hints or tips.

 

[priberc]

Thanks for the reply Priberc. I have had the tractor for a little over a year. Part of my going through it was treating the fuel with bioBar and fuel injector cleaner. As it has sat for the last 3 months, while looking around I saw some sediment/crud in the bottom of the bowl. No water, ring is still pretty much on bottom. Just gonna clean it out but as I said, read bleeding per the instructions could be a bear. Maybe the instructions I have are newer or improved? Just thought I'd check in to see what other owners were doing ... hints or tips.

A little crud in the sediment bowl....personally I would not worry about it. Thats what the sediment bowl is for. When you change fuel filters is the time to clean it. Did you check out YouTube?

 

[big bubba]

good advice from Priberc, the separator bowl is there for a reason, very easy to view & service if necessary. i don't do it very often. on mine, there is a red felt ring in the bowl. water accumulation makes it float & an easy visual when to service. if you get your diesel from a high volume dealer, & you treat fuel, shouldn't have to do very often

i am not of the school of thought to leave it alone. wise on your part to post question & service.
imho the M6800 & M9000 are among the best M series prior to the XX40 models. cheers
btw i'd surely change the fuel filter @ the same time

 

[circled]

Good Afternoon All,

In the near, warmer, future I intend to clean out my diesel/water separator. I have read quite a bit on here about the difficulty of bleeding the fuel system after reinstalling due to unclear manual directions. I have included the directions from my 6800 manual and was hoping someone might be able to steer me correctly or point out the problem with the directions. Thanks in advance!View attachment 734106

OP here. Weather permitted so I attempted to clean the water separator today. Didn't even get to the bleeding portion as the on/off lever (diagram 1) will not turn. I did notice a phillips screw on the end of it, do I need to loosen that to turn the lever? If it's not one thing it is another, feeling pretty stupid. Thanks!.

 

[priberc]

mmmm IMO you should not need use much force on this. It might just be "frozen/seized". So if you have not twisted it very hard try again with some more oomph behind it. The Phillips screw likely just attaches the lever. Is that lever plastic? Can you get a set of pliers on it some how to help/add some extra oomph without putting all the torque through the lever and breaking it. Try watching some you tube vids if this fails

 

[circled]

Thanks for the reply priberc! Went the pliers route, not moving. I don't think it is seized. I may try just loosening the lever screw tomorrow and see if it makes any difference. The lever and housing is metal. I have looked at YouTube but the videos I've found involve newer or smaller tractors. Just different enough to not really apply! I'll see if any one else chimes in, if not I'll give the lever screw a try. Thanks again!

 

[priberc]

Thanks for the reply priberc! Went the pliers route, not moving. I don't think it is seized. I may try just loosening the lever screw tomorrow and see if it makes any difference. The lever and housing is metal. I have looked at YouTube but the videos I've found involve newer or smaller tractors. Just different enough to not really apply! I'll see if any one else chimes in, if not I'll give the lever screw a try. Thanks again!

How old is it? Did you buy it used? Do you know the last time the filter was changed.....if ever. On other equipment I have seen fuel shut offs and petcocks seize up because they were never used. How much fuel is in the machine? Can you drain the fuel ,remove and take apart the valve?

 

[circled]

Been away for a few days, sorry. Through Messick's parts library I verified there is a set screw. I included a picture. I loosened the set screw and the on/off lever turned freely. I'll let you know how the rest goes in a few days.

 

[RjCorazza]

My current and previous tractors did not have a set screw like yours... Good call, and glad to hear that your patience paid off! I would have snapped it off for sure.

 

[priberc]

Been away for a few days, sorry. Through Messick's parts library I verified there is a set screw. I included a picture. I loosened the set screw and the on/off lever turned freely. I'll let you know how the rest goes in a few days.

I have never run into a set screw on any fuel shut offs......I can think of a time or two when one should have been in place in an old valve with shrunken seals. Usually just a detent ball of some kind or a spring pull and twist. Glad to hear you got it sorted
Good luck

 

[circled]

Sorry for the delay finishing up post. Warmed up tractor for about 30 minutes before doing all this. Replaced set screw with same size fine thread hex. Easy access to loosen now, just no room to get a phillips on the original. Turned separator fill to off. So removed separator, red float ring and spring and o-ring and element. Used a rubber strap wrench to loosen bowl retaining ring. Cleaned bowl of gunk and debris. Installed new element and lightly lubricated new o-ring with engine assembly grease. Dropped spring and red float ring back into bowl. Filtered a small bottles worth of diesel with a filler neck strainer and filled bowl almost to top. Carefully mated bowl back to housing, excess diesel went into bucket. I was hoping that the overflow during this part would ensure the bowl was filled. Tightened everything up, opened separator fill and tightened set screw (bolt now), checked for leaks started tractor at about 2300 RPM. No hesitation, stuttering or anything. No issues now after about 20 hrs. As previous owner has changed fuel filter approximately 120 hours before, and the gunk was not in separator when I purchased, I did not change fuel filter. I attributed the gunk in the separator to my treating the fuel and possibly cleaning out the system. The element in the water separator is a quite fine mesh. It is a strong first line defense from the tanks to stop debris from getting in system.

So no bleeding necessary in this case, fuel filter replacement will indeed require bleeding as filter is oriented 180 degrees opposite separator - no pre-filling possible. Hope this may be of use to someone.