Traction Bobcat travel problem

tylertown · Nov 10, 2013

Hi my name is Tyler, im a new member to this site and was hoping I could get some experienced info on a issue of mine with my bobcat 331. here goes, my machine is a 99 bobcat 331 and haven't owned the machine very long but no major problems the only thing wrong with it is i have a slight hydraulic leak at the base of the boom coming from the cluster of hoses. but my main concern is the travel part of the machine. when i press both levers to move the machine forward or in reverse it tends to act like the left travel motor may be weaker than the right. it wants to pull slightly to the left... but when i engage the machine into high gear for faster travel everything is fine and the problem no longer exists... what might cause this??? please help.

SSdoxie · Nov 10, 2013

This should have been posted in Bobcat Construction Equipment so don't be surprised if it gets moved.

There are several possibilities that could cause this, most require pressure gauges, special test fittings, and schematic of the system to check properly. But there is one easy check to make. Look on your gear pump at back of the engine, there are 3 gear pump sections and between the middle outlet section and the end section there is a square block with 2 hex plugs, these are check valves. First make sure 1 of those is not leaking (fix it needed), remove both and swap them, putting back in opposite holes. Try operating and see if the right side motor seems weaker. If so replace them both.
In low range the middle pump feeds the right motor and end pump feeds the left and both check valves are closed. When in high range the front pump sends oil through these check valves to feed both pumps, so a check valve not seated tight could cause your problem.

tylertown · Nov 10, 2013

thanks a lot!! I am about to try this

tylertown · Nov 10, 2013

one more thing too... my left travel stick is tighter than the left. could this be because a previous owner tried to adjust it or is it adjustable like that?

SSdoxie · Nov 11, 2013

Travel control is system of mechanical linkage with ball joints and adjustable rods. Check for lubrication and wear on all the linkage for both levers. If the controls don't move same amount freely, that may be your drive problem..