Track Motors

[Dave177]

We have a lazy track on our 2008 CAT 8 tonner, It has been getting slowly worse over the last few months. I have tried changing the oil in the gear side to no real difference. Is there anything else to check before I take the motor off and get it rebuilt such as valves, etc etc. There are no hydro leaks from behind the motor and although dirty and smelly no swarf or bad things in the oil that was changed.

 

If it is a rebuild any ideas of places to send it, I'm happy doing the gear side just not too comfortable with the hydraulic motor.

 

Thanks

[highland dave]

Are you sure it's the track motor that's at fault? Could be worth checking the rollers are ok. The track pins can get stiff or seize if it's been standing for any time. Both these problems can cause the machine to crab. Just a thought before you start stripping down the motors.

[aspenarb]

Pressure gauges are your best bet, one on each side and see what you pressure you get as the track levers are engaged. You will need to nose the machine against something to stop it tracking, a lower reading on one side is either a pressure problem or a track motor passing too much fluid ( fecked ) If they are equal look elsewhere.

 

Bob

[aspenarb]

Forgot to add that there will be test points for this somewhere so best check the manual.

 

 

Bob

[Dave177]

so if they are equal pressure it would be something like track rollers or links, unequal would be a hydraulic problem or knackered motors? Its coming back to the yard on Monday so will have a good clean and check over

[sjs5060]

Take the plate off under the cab below the track levers, sometimes **** can build up stopping levers from moving fully, I've known a few like that over the years.

Worth checking

 

Ste

[Breezeblock]

to check track motors pull off the back covers look at the hoses there will be 2 direction hoses 1 x 2 speed travel hose and a case drain hose take it off and check the amount of return flow when the motor is stalled you can do this by putting the blade into a stump etc the return flow should be similar if you don't have a spec. check each pump spool is stroking fully if i am correct the cat has cable operated travel i just done a 302.5 last week that the links were worn on the spool, check the pressures each way and take note of them check the pressures on dipper in as this should bring in all pumps and i think there is summation between the two if the pressure on one side are low swap the service line relief valves round about then recheck if its still the same swap the direction hoses on the centre post and try it again if it transfers the problem one of your motors is on its road out if the pressures are the same but the motor is still slow it could be the pump or straight travel valve thats faulty.this is a general guide to checking motors on most excavator types hope it helps i forgot to add check the return filter for metal on the magnet and bits of seals the brass from the motors won't stick to the mag but will be lying in the filter or the bottom of the tank check that the machine has a case drain filter thats the place to look for brass from the rotary group

Edited May 12, 2016 by Breezeblock

[Dave177]

Thanks for the advice so far, got it back to the yard, and gave it a good clean checked the rollers, nothing siezed or bad, cleaned out the levers, no problems there. They go straight into the travel block so no linkage to worry about. I swapped the hoses over on the bottom of the travel valve block and the same track is slow so it points to a worn motor in my opinion. I am waiting for someone from CAT to give me a call back with hyd pressure in the motor so hopefully I can take some readings this afternoon just to be sure. Seem logical to people on here?

[Breezeblock]

swap over the hoses on the bottom of the centre post to make sure everything else you've done points to a worn motor but it doesn't rule out bypassing centrepost seals