743b strange things

[earmuffs]

i just picked up a 743b that drives good but you cant put down pressure on it. it may even try to go up when you push down.it will lift up fine but going down is not working right . the last guy had a lift cylinder off to weld on it, so i checked to see if that side was hooked up backwards,was ok. the bucket cylinder works fine. if you push the aux on when going down with the arms it will fall fast. thoughts?

 

[Tazza]

It could be a load check issue in the control block for the lift section. As you say lift is fine, its only down. Find the segment thats for lift and remove the load checks, make sure they are still in good shape.

 

[mrfixitpaul]

It could be a load check issue in the control block for the lift section. As you say lift is fine, its only down. Find the segment thats for lift and remove the load checks, make sure they are still in good shape.

Make sure the auxiliaries aren't engaged

 

[earmuffs]

Make sure the auxiliaries aren't engaged

it lifts and lowers fine until you attempt to put down pressure at any height.

 

[earmuffs]

it lifts and lowers fine until you attempt to put down pressure at any height.

i found the problem. the nut came off inside the left lift cylinder.

 

[Tazza]

i found the problem. the nut came off inside the left lift cylinder.

That would do it. It was probably worked on my the previous owner who didn't put loctite on the threads which allowed the nut to come loose. There is a reason why they tell you to do it in the service manual