possible purchase noob question

[jethrobolas]

Hey all, New here. Of course my first post is a question. A little history about myself. I work in demolition. Been running bobcats and cat skidsteers for 12 years. I have done basic repairs in the field when necessary such as hoses and bobtach pins. I am mechanically inclined, have a basic understanding of hydraulics, have a good selection of hand tools, and am not afraid to use them. I can fix just about anything mechanical with success (and I wind up doing it more often than I like) Looked at a 753 yesterday, asking price is 6000. Sounded ok, 4775 hours. Lift and tilt were strong and smooth. Good pushing power foreward but left rear had almost no go. After about 10 minutes running, left rear would occasionaly jerk with what felt to be proper power (quick jerk, less than a second). What do you all think this is? Bad drive motor? Something in the pump? I read a post on this site with similar symptoms and it was suggested that it may be a small part located on the top of the pump under the centering mechanism (o-rings and such, possible contamination). Hydraulic fluid looked good although just under hash marks on the dipstick. Hyd. Filter looked newer and according to the marker scribbles was replaced about 60 hours ago. I believe the machine was from a concrete company. The current owner is an older gent retired 150 repairman who claims to know almost nothing about this particular machine. He flips them at auctions. Fresh paint and decals that look nice but do not hide the shallow scars on the steel. No cracks that I could find but obvious welds on the frame in the corners up front by the operators knees. I plan to use this machine for maintaining and changing my mx track, driveway maintance, snow removal and odd jobs if I can find some. Sorry for the long post but I figure more info equals better senders. Thank you.

 

[jethrobolas]

Meant to say "more info equals better senders"

 

[jethrobolas]

Meant to say "more info equals better senders"

Answers

 

[Bobcatdan]

Answers

If I under stand right, on only the left wheel is not working? Only thing it can be is a busted chain. Small chance the sproket cracked, but is pretty rare on the mid frames. $6000 sounds like good price to me, but drive train problems can be spendy. Jack it up and check for axle endplay, if it was used hard enough to wreck one chain, the others are probably close and axle bearing to boot. If your handy enough, go for it, but a dealler could easily quote upwards of 30 hours of labor.

 

[jethrobolas]

If I under stand right, on only the left wheel is not working? Only thing it can be is a busted chain. Small chance the sproket cracked, but is pretty rare on the mid frames. $6000 sounds like good price to me, but drive train problems can be spendy. Jack it up and check for axle endplay, if it was used hard enough to wreck one chain, the others are probably close and axle bearing to boot. If your handy enough, go for it, but a dealler could easily quote upwards of 30 hours of labor.

Left foreward works perfectly. Left reverse is very weak. The pump barely whines when the left stick is pulled all the way back and the wheels on the left side have almost no torque applied to them from the drive motor. I'm just trying to figure out if the problem is in the pump or the drive motor on that side. I'm sure the chain and/or sprocket is not the issue. Didn't know to check the play in the wheels when lifted off the ground when I looked at it, learned that there shouldn't be more than about 3 degrees of play in the rotation in the wheels. I learned that searching this site after the fact. I'm more worried about the cost of parts than I am about the labor. Most drives on fleabay are fetching close to $1000. Suppose even if I needed a drive motor I could live with that, just hate to buy one and not have that be the fix. Not sure if the pump is supplying the pressure because I wasn't about to cap the lines and dead-head the pump at the seller's house.

 

[jethrobolas]

Left foreward works perfectly. Left reverse is very weak. The pump barely whines when the left stick is pulled all the way back and the wheels on the left side have almost no torque applied to them from the drive motor. I'm just trying to figure out if the problem is in the pump or the drive motor on that side. I'm sure the chain and/or sprocket is not the issue. Didn't know to check the play in the wheels when lifted off the ground when I looked at it, learned that there shouldn't be more than about 3 degrees of play in the rotation in the wheels. I learned that searching this site after the fact. I'm more worried about the cost of parts than I am about the labor. Most drives on fleabay are fetching close to $1000. Suppose even if I needed a drive motor I could live with that, just hate to buy one and not have that be the fix. Not sure if the pump is supplying the pressure because I wasn't about to cap the lines and dead-head the pump at the seller's house.

Thanks a lot. Tons of great replies. Very helpful.

 

[Tazza]

Thanks a lot. Tons of great replies. Very helpful.

It could be a drive motor issue, if you swap them from side to side, see if the problem moves. If it does, feed it a new seal kit.
If you swap motors, you will have to swap fittings too.

 

[jethrobolas]

It could be a drive motor issue, if you swap them from side to side, see if the problem moves. If it does, feed it a new seal kit.
If you swap motors, you will have to swap fittings too.

Ok, passed on the problematic machine for 6k. Picking up a 743 with 1900 hours. Good tires, grapple bucket, straight bucket, tooth bucket, snow plow, and trailer all in vgc. 10.5k for the lot. Kinda far away, but just couldn't pass it up. I would like to thank the 2 kind strangers who posted here to help me.

 

[Tazza]

Ok, passed on the problematic machine for 6k. Picking up a 743 with 1900 hours. Good tires, grapple bucket, straight bucket, tooth bucket, snow plow, and trailer all in vgc. 10.5k for the lot. Kinda far away, but just couldn't pass it up. I would like to thank the 2 kind strangers who posted here to help me.

The 743 machines are very good, parts are all available. Not as good as the newer ones for starting when cold, but they will get there. All mechanical, very little to go wrong.
I'm sure you'll love your new toy.