Bobcat 753 clanking under load?

[Cstraley]

Ok, sorry, clanking was the best way to describe it. My 2003 low hours (950) 753 has started making a rapid clanking noise under load during operation, not sitting still. Its subtle but I know its different. I've had the cat for about 3 to 4 years and never noticed it. clank clank clank real rapid and not super loud. More as the machine gets warm and is pushed harder. I'm wondering if this is normal or a sign of either wear or thin hydro fluid. It seems directly related to the hydraulics when they are in use during lifting or fast forward motion. I change the motor oil way more than it needs to be, every 50 hours, and filter, but have not changed the hydro oil or filter. The machine had 780 hours on it when I got it and I've put less than 200 hours on it. Mainly used for maintains my property and helping friends and family. I'm the only operator and I am very conservative with it. I don't ram it around. Do you have any thoughts on this and what about the hydro fluid filter change? Thanks!

 

[antfarmer2]

Is your aux hydro stuck on?

 

[OldMachinist]

Is your aux hydro stuck on?

Where does it sound like its coming from? The engine bay or under you in the chain case.
If its coming from the engine area check the drive belt idler pulley. The bearing may be failing.

 

[Cstraley]

Where does it sound like its coming from? The engine bay or under you in the chain case.
If its coming from the engine area check the drive belt idler pulley. The bearing may be failing.

Thanks for the suggestions. As for the sound I honestly can't pin point the origin. Its subtle and I noticed it more over the summer when it was hot out. I don't use the loader often and I consider it to be in tip top shape. It looks brand new. It's just personal use by me for my very small landscaping business and maintaining my dirt road. Of course people find out you have it and I end up doing small odd jobs here and there. Since it isn't alarming or real bad I won't focus or obsess on it too much and just monitor it. I usually use headphone style ear protectors and the day I noticed it I was doing a small job for a friend and forgot them, so I heard everything. Fully enclosed cab btw. What are your thoughts on the hydro fluid anyone? Does it thin out or ever need replacing? How about hydro filter, how often to replace? Thank you, Chris

 

[reaperman]

Thanks for the suggestions. As for the sound I honestly can't pin point the origin. Its subtle and I noticed it more over the summer when it was hot out. I don't use the loader often and I consider it to be in tip top shape. It looks brand new. It's just personal use by me for my very small landscaping business and maintaining my dirt road. Of course people find out you have it and I end up doing small odd jobs here and there. Since it isn't alarming or real bad I won't focus or obsess on it too much and just monitor it. I usually use headphone style ear protectors and the day I noticed it I was doing a small job for a friend and forgot them, so I heard everything. Fully enclosed cab btw. What are your thoughts on the hydro fluid anyone? Does it thin out or ever need replacing? How about hydro filter, how often to replace? Thank you, Chris

On the inside of the back door, there should be a maintenance schedule chart. I believe the hydro fluid is suppose to see a change at 1000 hrs.

 

[Cstraley]

Is your aux hydro stuck on?

Antfarmer, I have never used my auxiliary hydraulics. They are on the hand grips which control all of my motions since I switched over from the foot pedals. I wouldn't know how to tell if they were on or off. My 2003 model has some buttons and switches that have to be activated I guess but I have yet to rent an auger or anything. I want to though. I think they started calling my machine S130 or something in 2004 but I've seen them and it is 100% identical to the last year 753. I may need advice on properly activating and using the auger attachment when I drill a few holes I need. I have a gate to install at the end of my driveway. A big long galvanized two piece gate my brother gave me. Used, free. Now I need some heavy posts.

 

[Cstraley]

Antfarmer, I have never used my auxiliary hydraulics. They are on the hand grips which control all of my motions since I switched over from the foot pedals. I wouldn't know how to tell if they were on or off. My 2003 model has some buttons and switches that have to be activated I guess but I have yet to rent an auger or anything. I want to though. I think they started calling my machine S130 or something in 2004 but I've seen them and it is 100% identical to the last year 753. I may need advice on properly activating and using the auger attachment when I drill a few holes I need. I have a gate to install at the end of my driveway. A big long galvanized two piece gate my brother gave me. Used, free. Now I need some heavy posts.

Ok the machine is coming up on 1000 hours soon. Running great but probably should plan on a hydro fluid change. 970 or so hours on it now. How much fluid is that going to take and what might that cost? Something I can do? I work on my own equipment when possible and have a nice shop but obviously have not gotten a shop manual for this 753 yet. My bad. Thus far oil and filter changes pretty simple.

 

[Cstraley]

Ok the machine is coming up on 1000 hours soon. Running great but probably should plan on a hydro fluid change. 970 or so hours on it now. How much fluid is that going to take and what might that cost? Something I can do? I work on my own equipment when possible and have a nice shop but obviously have not gotten a shop manual for this 753 yet. My bad. Thus far oil and filter changes pretty simple.

https://www.dropbox.com/sc/vhrlbwskig6l6ub/D3QCmgg4zg

 

[frogfarmer]

Low hours in good condition and used for its intended purpose. I would not worry about an odd noise and let it develop. It may be nothing and pass with time. I would be concerned with moisture contamination of the fluid on a 10 year old machine. Unless the machine is stored in a climate controlled environment the fluids will draw moisture. Change the fluid and filters and watch for anything strange in the fluid or filters. Also make sure the chain case has proper and adequate lube.

 

[dwyersm]

I had a friend with a 632 and he had a subtle clanking sound. He thought it was cavitation in the hydraulic circulation, After he pulled the whole machine apart he discovered it was the parking brake disc's loose enough on the sprockets and clanking around and banging on the big solid metal block that retains them! I dont know the parking brake setup on your machine, but your problem may be mechanical instead of hydraulic perhaps. Shane, Australia

 

[Tazza]

I had a friend with a 632 and he had a subtle clanking sound. He thought it was cavitation in the hydraulic circulation, After he pulled the whole machine apart he discovered it was the parking brake disc's loose enough on the sprockets and clanking around and banging on the big solid metal block that retains them! I dont know the parking brake setup on your machine, but your problem may be mechanical instead of hydraulic perhaps. Shane, Australia

That isn't a bad idea actually. I'm working on a 743 that has worn park brake discs like this.