Cat 311B Front Idlers

[RobMonk]

My Cat 311B has had bad idlers since I bought it but until recently I didn't have the money to replace them but now I am ready to go and a few days ago one of the axles on the wheel broke clear and now it is time that I replace both of them. It still waddles along ok but I am about to have my operator dig a foundation and that wouldn't be any amount of fun.

The questions I have are:

1) What pieces will need to be replaced? The track mentioned seems to be fine, in fact everything seems to be fine other than the wheels and the axles (and presumably some kind of bushing). That being said I was under the impression that the idler came as a group. If someone could shed some light on that I would appreciate it.

2) Are there any things I should note when removing/replacing this part so I don't screw something up in the process?

3) Are parts like this available after market? And on a similar vein, are they the same on other machines?

MAchine serial #8gr00697

 

[Nige]

If the wear has been so much that the shaft broke when you tear it apart you will probably find that everything is junk and you have to replace all the parts (idler inc. bush, shaft, hardware) plus most likely the 2 brackets that connect the idler to the tensioner because the worn idler will have been rubbing against the inside of them.

The same idlers fit pretty much all models of 311, 312, 313, & 314.

 

[RobMonk]

Thanks, good information.

I looked at the "forks" that hold the wheel to the tensioner, they seem to be grooved by the edge of the wheel a little bit but not too bad IMO. Is there anything I should look for to say that it is destroyed? Is it hard to remove the pieces that hold the idler wheel on? I'm sort of thinking it might be not too much more to buy the whole idler group anyhow.

Are there any internet shops to buy undercarriage parts like this that anyone is aware of?

 

[Nige]

The "forks" are #8 in the above diagram. On each side they are where one half of the metal face seal #4 mounts. If there has been no oil in the idler (you fill it via plug #1) then the face seals are probably long gone. The metal-to-metal contact between the idler and the forks will have torn them up completely so you will have nowhere to mount your new seals. Building them up with welding and having the seal grooves remachined in them would be an option as opposed to complete replacement

I'm sure someone will be able to come up with an aftermarket supplier for these parts. Genuine Cat the complete assembly (with forks) as shown in the diagram above will run you $750 each.