743B grease zerk replacement and hydraulic question

[Sam_French]

Hey guys. I am trying to replace the grease zerk in the rear boom lift cylinder on the right hand side. It has been painted in. Would heating up with a small propane torch and WD40 work? It is hard to get to. Machine has 11 hours on rebuild. It was running a little sluggish I checked the spy glass hydraulic fluid was on the bottom. It was full when I took delivery I filled to the top of the spy glass. It is now about 1/4 inch from the top. I see NO fluid anywhere not on machine nor where it is parked also has no hissing when running. I was "told" it is just working the air out. From an outside party. Operational wise it is very snappy. I am guessing I poured in around 2-3 quarts. Hard to guess when using a 5 gal bucket. What I did was raise the bucket and put two bricks beneath it. I got about 2 in of clearance wouldn't a slow leak bleed off and put the bucket sitting on the bricks? Thanks in advance.

 

[Fabricator]

Grease zerk: Can you get a socket on it? Should be able to twist it out with a socket. Using an open end wrench is more liable to slip. I wouldn't apply heat. Possibly carefully cut through the paint with a razor blade around the zerk.

Hydraulic oil: Usually you know if there is a leak - not by sound but by the pool of oil you find somewhere. On the ground. In the engine bay. Running down the side somewhere. Possible that it is just working air out if everything was drained for a rebuild recently.

Leaking off: Even without a leak to the outside of the system, it is possible for the bucket or arms to "settle" if left up slightly as the fluid leaks past the seals and valves. But more in the realm of at least overnight or over the course of a few days if everything is relatively tight. Even a machine with some wear will usually hold pressure for a few hours.

 

[jerry]

If you have hyd oil disappearing check your chain case oil level to make sure you don't have a drive motor leaking into it. The level should be just up to the check plug in the front of the chain case behind the bucket. If you take the plug out and oil flows out check again after a few hours of operation if more oil flows out you may have a motor problem.

 

[Tazza]

If you have hyd oil disappearing check your chain case oil level to make sure you don't have a drive motor leaking into it. The level should be just up to the check plug in the front of the chain case behind the bucket. If you take the plug out and oil flows out check again after a few hours of operation if more oil flows out you may have a motor problem.

If you *must* remove the grease nipple, you can lift the arms up and block them, put a jack under the rear to prevent it from tipping back as the arms lower down. With the arms up a little, you can pull the lift ram out by removing the pins and sliding it forward, this will give you access to swap the grease nipple.
Yes, the system will self bleed, it may take a little time, but it will go. Mine dood a few weeks on a full re-build of using it for a few minutes a day. Drive it around lift tlit then sit. Be patient.
The rams will slowly leak down, this is generally control block wear or piston seals in the rams. I think a few inches an hour without a bucket is acceptable by Bobcat.
As Jerry mentioned, if you have no external leaks and the oil level is dropping, you have a motor leaking into the chain case. As you have a 743B i suspect you don't have a reduction box on the chain case, your motor is a direct connection to the chains. You may need a new seal on the bearing carrier assembly. Check the oil as Jerry said, if its indeed leaking into here i can give more details about the seal.

 

[Sam_French]

If you *must* remove the grease nipple, you can lift the arms up and block them, put a jack under the rear to prevent it from tipping back as the arms lower down. With the arms up a little, you can pull the lift ram out by removing the pins and sliding it forward, this will give you access to swap the grease nipple.
Yes, the system will self bleed, it may take a little time, but it will go. Mine dood a few weeks on a full re-build of using it for a few minutes a day. Drive it around lift tlit then sit. Be patient.
The rams will slowly leak down, this is generally control block wear or piston seals in the rams. I think a few inches an hour without a bucket is acceptable by Bobcat.
As Jerry mentioned, if you have no external leaks and the oil level is dropping, you have a motor leaking into the chain case. As you have a 743B i suspect you don't have a reduction box on the chain case, your motor is a direct connection to the chains. You may need a new seal on the bearing carrier assembly. Check the oil as Jerry said, if its indeed leaking into here i can give more details about the seal.

Thank you all for replying. Here is what I have learned this week. I did not have bucket high enough when I pulled lift cylinder pins. I pulled the front pin out of cylinder on other side. I tried to jack up the bucket but kept raising the whole front of the machine up. I called Mike person who rebuilt it. He said put some blocks under the back to keep machine from pivoting. I put some blocks under the engine door frame. Had cylinder out in 2 min. Grease Zerks I used a 7 mm to take out zerk then 12mm to take out the main zerk body. Metric NAPA zerks are different from Bobcat. Threads are cut different also NAPA zerk is threaded deeper and will screw deeper in the pin. So I ordered new zerks from Bobcat of Antioch TN Zerks on the machine are painted and will not take grease so I am replacing ALL of them. If I can't grease the machine I WILL NOT run the machine. As far as hydraulic fluid is I will top it off and run it a little while. I will pull the chain case plug just to and check fluid level just to be safe. I am using AW-68 as Mike put in it. How hard would it be to raise the cage and pull the seat out so I can look deeper in the chain case? Again thank you all very much

 

[Tazza]

Thank you all for replying. Here is what I have learned this week. I did not have bucket high enough when I pulled lift cylinder pins. I pulled the front pin out of cylinder on other side. I tried to jack up the bucket but kept raising the whole front of the machine up. I called Mike person who rebuilt it. He said put some blocks under the back to keep machine from pivoting. I put some blocks under the engine door frame. Had cylinder out in 2 min. Grease Zerks I used a 7 mm to take out zerk then 12mm to take out the main zerk body. Metric NAPA zerks are different from Bobcat. Threads are cut different also NAPA zerk is threaded deeper and will screw deeper in the pin. So I ordered new zerks from Bobcat of Antioch TN Zerks on the machine are painted and will not take grease so I am replacing ALL of them. If I can't grease the machine I WILL NOT run the machine. As far as hydraulic fluid is I will top it off and run it a little while. I will pull the chain case plug just to and check fluid level just to be safe. I am using AW-68 as Mike put in it. How hard would it be to raise the cage and pull the seat out so I can look deeper in the chain case? Again thank you all very much

You do need to block or put a jack under the back when the arms are up.
To look in the chain case isn't so easy if you want to get deep in it. Hopefully yours has the removable section between where the steering sticks are, this will allow access to a cover. You can look in the chain case and mop it out, but it will not give you access to the park brake, the pump really needs lifting for this.
Hopefully that will give you an idea of what is involved.

 

[Sam_French]

You do need to block or put a jack under the back when the arms are up.
To look in the chain case isn't so easy if you want to get deep in it. Hopefully yours has the removable section between where the steering sticks are, this will allow access to a cover. You can look in the chain case and mop it out, but it will not give you access to the park brake, the pump really needs lifting for this.
Hopefully that will give you an idea of what is involved.

Been a rough week. Pulled out lift cylinder and had a machine shop remove the old zerk. I have all of the old zerks pulled out. However I can't get any of them to take grease. I noticed on the lift cylinder there is a lot of old grease. I am going to remove the zerks and heat up the pin(joint) and try to soften the old grease up. Is there any way I can get these zerks to take grease? Only joints that have pins still in are the ones in the back and the lower joint for the other lift cylinder and bucket cylinder. Could I pour some diesel in the zerk holes to breakdown the old grease? Thank you for your help,

 

[Tazza]

Been a rough week. Pulled out lift cylinder and had a machine shop remove the old zerk. I have all of the old zerks pulled out. However I can't get any of them to take grease. I noticed on the lift cylinder there is a lot of old grease. I am going to remove the zerks and heat up the pin(joint) and try to soften the old grease up. Is there any way I can get these zerks to take grease? Only joints that have pins still in are the ones in the back and the lower joint for the other lift cylinder and bucket cylinder. Could I pour some diesel in the zerk holes to breakdown the old grease? Thank you for your help,

Are you trying to re-use the old grease nipples? or is this the new ones?
Some will take grease if you use a hige pressure grease gun, but they won't all work. Heat should help with making the grease softer, it can't hurt.

 

[Sam_French]

Are you trying to re-use the old grease nipples? or is this the new ones?
Some will take grease if you use a hige pressure grease gun, but they won't all work. Heat should help with making the grease softer, it can't hurt.

I am replacing all the zerks with new ones. I was told heating the joints with the zerks out would help taking new grease. This sure has been a learning experience. Thank You

 

[Tazza]

I am replacing all the zerks with new ones. I was told heating the joints with the zerks out would help taking new grease. This sure has been a learning experience. Thank You

If they were replaced, you should have no problem with pushing fresh grease though.. Worst case you may need to remove the pin and give it a clean. If the grease has plugged up the hole from the grease nipple to the pin. I have seen some pretty hard grease in them before....
Heat will soften the grease up, but nothing is better than pulling the pin out and cleaning the pin and bushing with diesel or kero then filling it with fresh grease.

 

[Sam_French]

If they were replaced, you should have no problem with pushing fresh grease though.. Worst case you may need to remove the pin and give it a clean. If the grease has plugged up the hole from the grease nipple to the pin. I have seen some pretty hard grease in them before....
Heat will soften the grease up, but nothing is better than pulling the pin out and cleaning the pin and bushing with diesel or kero then filling it with fresh grease.

Had a friend come over got all the zerks taking grease. Checked chaincase oil had water in it. This machine sat a good while so I am guessing water leaked in. Going to change chaincase oil. Is there any tricks? James said let it drain for a few days. I am going to use AW 68. hyd oil. Thank You

 

[skidsteer.ca]

Had a friend come over got all the zerks taking grease. Checked chaincase oil had water in it. This machine sat a good while so I am guessing water leaked in. Going to change chaincase oil. Is there any tricks? James said let it drain for a few days. I am going to use AW 68. hyd oil. Thank You

Hydraulic oil should be replaced at 1000 hour intervals. If you need to change the chain case, drain it and if you can get in the top mop it out with a rag. Pump the old hyd oil into the chain case and put new hyd oil and filter on.
Water often leaks in the top covers from the boom stop smacking the front of the chain case and braeking the seal f the cover. Look for cracks in this area too, and be sure to silcone the covers and tihten them up good.
As for the grease nipples, often when they are plugged, you need to take a pick and dig the hard grease out of the hole the nipple screws into as well. Failing that try some heat or remove the pin.
Ken