Cub 3 No More Knock

Mon Jun 09, 2014 12:50 pm

Took the hood and tank off and put the aux tank on to give the "rod knocker" some diagnostic testing…I had taken the mower off and noticed the hydraulics were operating badly…I pressure washed the tractor and did the broomstick thing…Thinking I needed to address the hydraulics before it was torn down, I filled and bled the TC….Guess what, it took a substantial amount of Hyd fluid and the knock has gone away…The crankcase doesn't seem to be overfull so I guess I lucked out…Just a reminder that the TC being abnormally low will cause a pronounced engine knock…I kinda figured that and I guess I was right….for once…Thought I'd share that….Dave :thumbsup:

Now on to the clutch…..

Re: Cub 3 No More Knock

Mon Jun 09, 2014 1:48 pm

I have never heard of a low TC tank causing a knocking sound before. If it is that low, I would triple check the TC pump just to make sure. There has to be a leak someplace since the TC system is a closed loop system.

Re: Cub 3 No More Knock

Mon Jun 09, 2014 4:50 pm

What tipped me off was it started to squeal a little….The tractor has sit for many years…Last PO just bought it to sell, and before that it had been sitting for who knows how long..I just started it up noticed a knock, drove it across the field to my house and let it sit till yesterday when I put it in the shop..The listening stick told me the occasional chirp and the knock were coming from the front…I have no idea how long the tractor has sit unattended…But its a long time…And occasional parts have been canibalized….Doesn't seem to leak and is not going into the crankcase…Just didn't have any fluid in it..LOL…Anyhow the knock is gone from adding 3 Mickey Dees coffee cups of hydraulic fluid…( I think they were medium…LOL)

Re: Cub 3 No More Knock

Mon Jun 09, 2014 8:24 pm

Was that with cream an sugar! Keep on trucking!!

Re: Cub 3 No More Knock

Mon Jun 09, 2014 11:24 pm

Keep checking the level of the oil in the crankcase as you use the tractor, just to be sure the coffee you put in doesn't end up there. :wink:

Re: Cub 3 No More Knock

Tue Jun 10, 2014 6:23 am

cub 3 wrote:Was that with cream an sugar! Keep on trucking!!
….Nah we drink cowboy coffee here…Black no sugar…LOL...

Re: Cub 3 No More Knock

Tue Jun 10, 2014 6:26 am

Trent M wrote:Keep checking the level of the oil in the crankcase as you use the tractor, just to be sure the coffee you put in doesn't end up there. :wink:
…Will do, and I'm hoping it just wasn't coincidence they both happened at the same time and it starts knocking again... :mrgreen:

Re: Cub 3 No More Knock

Tue Jun 10, 2014 3:03 pm

Hengy wrote:I have never heard of a low TC tank causing a knocking sound before. If it is that low, I would triple check the TC pump just to make sure. There has to be a leak someplace since the TC system is a closed loop system.
….Well we shall see Mike, I hear a faint knock at 3/4 throttle now and have to split it anyway so I may as well plastigauge things and check the engine out thoroughly and go from there…It'll be awhile….I'm in no hurry and got a lot to do this time of year…But its ready to split as I jot this down….

Re: Cub 3 No More Knock

Wed Jun 11, 2014 7:27 am

Could the knock have been from not having a good prime on the oil pump??

Re: Cub 3 No More Knock

Wed Jun 11, 2014 5:42 pm

Buzzard Wing wrote:Could the knock have been from not having a good prime on the oil pump??
Good thought…Never gave that a thought…I'm going to drop the pan tomorrow and check the rod bearings etc before I split it to do a clutch….But you know that does sound like a reasonable explanation…When I was preparing it for splitting I noticed the oil filter outside top was full of oil.(gasket leaking I presume)….It might have just gotten primed….still a subdued knock…You can't hear it at idle…(or I can't LOL)….May as well check it out well as long as its down…Ed suggested I lap the valves while its down also…I think he wants me to break a head bolt…. :lol:

Re: Cub 3 No More Knock (ammended)

Sat Jun 14, 2014 4:42 am

Number 4 rod bearing was the culprit….Nix the hydraulic system comment.. :lol: ….The bearing had moved slightly thus tightening up at the same time I filled the hyd fluid…Thus the screech I heard…And the knock subsided somewhat…( Another Irish guess)... :mrgreen: