743 chain replacement, axle, bearing, and other questions.

[Fefanatic]

any pics brah>?

Here is a picture of what I will use to torque the axle bolts. I plan to weld that socket to the center of the 1/4" strap.

Here are some pics of the debris field in the chain case and the chains. All chains are being replaced with heavy duty chains.

This is a pic of the new chain for the left rear. The bulk chain will be the same quality.

This is the front chain guide on the right side. They will get replaced also

These are pictures of the damaged right rear chain. The left chain got lodged under the right chain after it broke.

This is the damaged driven gear on the left rear.

 

[Fefanatic]

Here is a picture of what I will use to torque the axle bolts. I plan to weld that socket to the center of the 1/4" strap.

Here are some pics of the debris field in the chain case and the chains. All chains are being replaced with heavy duty chains.



This is a pic of the new chain for the left rear. The bulk chain will be the same quality.

This is the front chain guide on the right side. They will get replaced also

These are pictures of the damaged right rear chain. The left chain got lodged under the right chain after it broke.

This is the damaged driven gear on the left rear.

Everywhere I said left or right in the above post is just the opposite of what they should have been. It was the right rear that gave it up. It's been a long day. Why I did that I cannot say.

 

[Madbobcater743]

Everywhere I said left or right in the above post is just the opposite of what they should have been. It was the right rear that gave it up. It's been a long day. Why I did that I cannot say.

Hey man Looks awsome. I like the plate you hooked up. How much have you spent $$ wise? Great pictures. Thank you, I'm very excited to see the rest of the project.

 

[Fefanatic]

Hey man Looks awsome. I like the plate you hooked up. How much have you spent $$ wise? Great pictures. Thank you, I'm very excited to see the rest of the project.

Without looking at the receipts I know I have $450.00 in chains, $200.00 in bearings, $50.00 in seals, $50.00 in wear sleeves, and around $18.00 in gaskets. Add another $100.00 in oil and probably another $100. in incidentals and this part will be done.
As far as the wheel torque tool goes I would have made it a little cleaner if I were in the business of using it all the time. Hopefully it will be used only four times.
I figure if I get out of this project for $1000. I will be happy.

 

[Fefanatic]

Without looking at the receipts I know I have $450.00 in chains, $200.00 in bearings, $50.00 in seals, $50.00 in wear sleeves, and around $18.00 in gaskets. Add another $100.00 in oil and probably another $100. in incidentals and this part will be done.
As far as the wheel torque tool goes I would have made it a little cleaner if I were in the business of using it all the time. Hopefully it will be used only four times.
I figure if I get out of this project for $1000. I will be happy.

Shocker. I called Bobcat this morning to inquire about the chain guides and was told they are $8.00 each. For that money I have new ones on the way. It looks like the reassembly will be the end of the week or the weekend. I will be glad when it's done.

 

[Madbobcater743]

Shocker. I called Bobcat this morning to inquire about the chain guides and was told they are $8.00 each. For that money I have new ones on the way. It looks like the reassembly will be the end of the week or the weekend. I will be glad when it's done.

I don't blame you. I really admire your garage. As crazy as it sounds I'm still installing irrigation systems. I haven't had time to even think about bobcat repairs. Dealer=Devil.

 

[Tazza]

I don't blame you. I really admire your garage. As crazy as it sounds I'm still installing irrigation systems. I haven't had time to even think about bobcat repairs. Dealer=Devil.

The sprocket doesn't look too nasty, possibly rub the sharp bits off with a flap wheel on a grinder
I'm amazed the guides were only $8 each, I'd have suspected a lot more.
Really not loving the metal particles, good thing you are re-doing it.

 

[Fe Fanatic]

The sprocket doesn't look too nasty, possibly rub the sharp bits off with a flap wheel on a grinder
I'm amazed the guides were only $8 each, I'd have suspected a lot more.
Really not loving the metal particles, good thing you are re-doing it.

Well, I have it back together. It was a chore without a second set of hands to help but I managed to get the job done. It seems to be OK but now I have other issues to attend to. The tool I made to adapt to the axle to torque bolt worked well. Instead of using the cut bearing race to press the bearings into the axle I used the split bearing press tool to drive the seals in when I drove the axles. I clamped the split bearing tool tight to the axle so it acted like a collar. I checked axle end play and the worst was .007 and well within specs. Changing the inner races was a little pain because again, I didn't have that second set of hands to help. I had a bearing race tool kit and I threaded it will some allthread rod and pulled the races into place from the outside of the axle. I had to turn the nuts 1/2 turn and then tap the race tool on the inside. It was slow but worked. Installing the chains was done apart and then I installed the master link. Leaving the torque wrench on the axle end and letting it hang there gave enough tension on the sprocket and chain that it allowed me to link the chains without a stretch tool. I couldn't find a link press so I spot welded the master links. I feel confident that they will hold OK. I especially liked the foam top cover gasket that I got from Bobcat. It seemed to work better than cork. Over all the job took quite a bit of time but wasn't that difficult. The total cost of parts were a little over $1200.00 including seals, bearings, races, chains, and oil. I have it running and now I have a leak at the auxiliary hydraulic spool valve stem. It looks like I may have to pull the motor to get to it. If anyone has any suggestions before I start that project I sure would like to hear them. Once the leak is repaired this should be a pretty good machine. Hopefully it won't continue to have problems.

 

[billrbg]

Well, I have it back together. It was a chore without a second set of hands to help but I managed to get the job done. It seems to be OK but now I have other issues to attend to. The tool I made to adapt to the axle to torque bolt worked well. Instead of using the cut bearing race to press the bearings into the axle I used the split bearing press tool to drive the seals in when I drove the axles. I clamped the split bearing tool tight to the axle so it acted like a collar. I checked axle end play and the worst was .007 and well within specs. Changing the inner races was a little pain because again, I didn't have that second set of hands to help. I had a bearing race tool kit and I threaded it will some allthread rod and pulled the races into place from the outside of the axle. I had to turn the nuts 1/2 turn and then tap the race tool on the inside. It was slow but worked. Installing the chains was done apart and then I installed the master link. Leaving the torque wrench on the axle end and letting it hang there gave enough tension on the sprocket and chain that it allowed me to link the chains without a stretch tool. I couldn't find a link press so I spot welded the master links. I feel confident that they will hold OK. I especially liked the foam top cover gasket that I got from Bobcat. It seemed to work better than cork. Over all the job took quite a bit of time but wasn't that difficult. The total cost of parts were a little over $1200.00 including seals, bearings, races, chains, and oil. I have it running and now I have a leak at the auxiliary hydraulic spool valve stem. It looks like I may have to pull the motor to get to it. If anyone has any suggestions before I start that project I sure would like to hear them. Once the leak is repaired this should be a pretty good machine. Hopefully it won't continue to have problems.

Doing the spool seals on the Control Valve isn't easy, but not the worst job down there. Don't bother to remove the engine, that doesn't give you more access where you need it. Figure to do all the spool seals, both ends of each, as you will probably have to remove all the ones above the aux to get to it. Sound fun? Several of us here have "been there", can answer questions.

 

[Fefanatic]

Doing the spool seals on the Control Valve isn't easy, but not the worst job down there. Don't bother to remove the engine, that doesn't give you more access where you need it. Figure to do all the spool seals, both ends of each, as you will probably have to remove all the ones above the aux to get to it. Sound fun? Several of us here have "been there", can answer questions.

I was looking at my spool valve. My unit serial number is above 15000. It is a one piece affair and looks like there are boot seals on the shafts. Looking at the parts diagram I don't see a shaft seal. Does the boot act as the seal? If so it looks like I might be able to make a long screw driver bit and get the two retainer screws loose and replace the boot. Yea, I know, no way it would be that easy..

 

[billrbg]

I was looking at my spool valve. My unit serial number is above 15000. It is a one piece affair and looks like there are boot seals on the shafts. Looking at the parts diagram I don't see a shaft seal. Does the boot act as the seal? If so it looks like I might be able to make a long screw driver bit and get the two retainer screws loose and replace the boot. Yea, I know, no way it would be that easy..

No, the boot isn't the pressure seal. There is another behind the boot, either a lip-type or "quad ring", probably the quad. And, an identical one at the other end of the spool. Yeah, you will get considerable practice using a variety of things to drive a 3/16" hex for those socket-head screws. In the rear, you will have one on a 2' to 3' extension... I urge you to start by draining the hydraulic reservoir so you can remove that big hose connecting the reservoir to the Port Block, and several other hoses. Getting to those spools and covers is miserable, even with all the access you can get!

 

[prowedge]

I need to replace a chain on my 743b, how do I get the master link to stay on? Is there some sort of flaring tool to round off the ends of the pins on the master link?

 

[cdmccul]

It depends on the type of chain.. some brands have a clip that goes on. I've seen a couple types done in chain cases.

 

[prowedge]

It depends on the type of chain.. some brands have a clip that goes on. I've seen a couple types done in chain cases.

The chain I bought came without the retaining clip. Would it be a bad idea to use one with the retaining clip as it would be much easier or are they not as strong?

 

[cdmccul]

The chain I bought came without the retaining clip. Would it be a bad idea to use one with the retaining clip as it would be much easier or are they not as strong?

In my experience they are as strong as they are rated for... But see what others say.

 

[prowedge]

In my experience they are as strong as they are rated for... But see what others say.

Ok, thanks for the reply! The chain also has slightly different link plates than the one I'm replacing although when I ordered it, they said it was the correct one for the machine

 

[Coke-in-MN]

The rating of the chain should be listed by the Mfg. to meet ANSI ratings . If the clip fits onto pins it should work but is best to use parts that are rated for the chain , Side bars can vary in look and strength by different manufacturers but the tensile strength must meet the rating .
Roller chain is made in several sizes, the most common American National Standards Institute (ANSI) standards being 40, 50, 60, and 80. The first digits indicate the pitch of the chain in eighths of an inch, with the last digit being 0 for standard chain, 1 for lightweight chain, and 5 for bushed chain with no rollers.

Roller Chain | ANSI Drive Chains | Industrial Parts Distributor | MN | SD

ISC Companies & Adams-ISC are distributors of roller chain; self-lube, double pitch, hollow pin, side bow, leaf, silent, plastic & tabletop.

www.isccompanies.com

 

[prowedge]

The rating of the chain should be listed by the Mfg. to meet ANSI ratings . If the clip fits onto pins it should work but is best to use parts that are rated for the chain , Side bars can vary in look and strength by different manufacturers but the tensile strength must meet the rating .
Roller chain is made in several sizes, the most common American National Standards Institute (ANSI) standards being 40, 50, 60, and 80. The first digits indicate the pitch of the chain in eighths of an inch, with the last digit being 0 for standard chain, 1 for lightweight chain, and 5 for bushed chain with no rollers.

Roller Chain | ANSI Drive Chains | Industrial Parts Distributor | MN | SD

ISC Companies & Adams-ISC are distributors of roller chain; self-lube, double pitch, hollow pin, side bow, leaf, silent, plastic & tabletop.

www.isccompanies.com

I bought the chain from bobcat, it's a tsubaki 80HBC. 1inch pitch. I just like to try and use a regular master link instead of the press on one that would require flaring the ends of the pens as I'm going to do it inside the machine

 

[montezuma]

Hi, I have a 743 with a broken chain on the right rear wheel. I pulled the cover, drained the fluid and found the broken chain in the bottom of the case. I jacked the unit up, removed the tires and wheels, and checked end play on all four axles. The axle with the damaged chain has about 1/16" play. I did not measure exactly as it was obvious it was way out of spec. I removed the axle and the outer bearing stayed inside the axle tube as the seal did not come out. I used a porta power to push the axle out. Once out I could see that the race on the outer bearing was scored from debris. I removed the gear from the case and it looks worn but might be serviceable. I already ordered a new chain, seals, and gaskets from Bobcat and they will be here Wednesday. There is so much debris in the bottom of the chain case that I decided to pull all axles to clean and reseal the whole lower unit. Once the damaged axle was removed there was a accumulation of material laying on the bottom of the tube for the full length. If it is in this tube it will be in all the others. The chain case oil was milky from water contamination. There isn't any rust on chain or gears so I am not sure where the water came from. The seals are not leaking so I would think that if it wouldn't allow oil to escape then it wouldn't allow water to enter. I did use a pressure washer to clean this thing before I started working on it but that wouldn't have caused the milky condition. This is the first Bobcat I have ever worked on. I bought this from a relative (I know) and it was represented in better condition than it is. Here are some questions I have in doing these repairs. I am concerned about the outer bearing coming off the axle when the axle was pulled. It is supposed to be pressed onto the axle and it seemed to come off too easy. There isn't any indication on the bearing seat surface that indicates it has been spinning on the axle. Should I be concerned if it doesn't press on tightly? The gear had some nicks but didn't show a lot of wear. Replacement gears would be around $480.00 each according to Bobcat and I am not wanting to dump that kind of money into the machine. What's the opinion on a decent set of used gears? I most likely will replace all bearings on all axles. It seems that I can buy the bearings without races since the Bobcat takes a different race than what is normally supplied with bearing sets. I have been reading the service manual and it calls from some bolts to be tightened to 500 ft lbs. Is that correct or possibly a typo? I also noticed that the broken chain had slid over to the left side and had been interfering with the left rear wheel chain. The chain has mashed spots on the chain ends but it doesn't look damaged to the point of replacing. Should I replace it anyway? Space is at a premium on working on this machine. I was looking at the 20 bolts that attach the chain case to the upper half of the skid steer. Would removing those 20 bolts and removing the hydraulic lines free the whole lower unit from the upper or are there other things attached that would make it not worth the effort? I know that splitting a bearing race can be used to drive a new seal into the axle tube and I already split one for that purpose. I saw the tool that is designed to install the inner races but I am thinking that I might be able to use a porta power to install them. I will have to make a bracket to push against but I think I can do that. This has what I think is Teflon chain guides. Chain deflection on all chains is around 1" or so. The manual says to remove a link if necessary to tighten in. There is not a full link length of slack so removing a link is not possible. I just don't know how much slack is acceptable. Any advice here would be appreciated. My main concern is the axle bearing coming off instead of pushing out the seal. Would that be a problem in the future. The other concern is whether it would be worth the effort to remove the whole chain from the upper section of the loader. Since this is the first time I have tackled something like this any advice will be taken seriously. I want to do this only once. and Wow, this was a lot of babbling here

hi guys any time you have to replace a chain and dont know how long it is put a small zip tie around a chain roller and as you rotate count the rollers until the zip tie appears deducting a link if you want to make it shorter this way you can pre cut the new chain and also you can use half links caution they arent as strong as regular links and here is a bit of chain and sprocket info if a new was always used on a aprocked the sprocket would never wear out as a chain wears its pitch doesnt match the sprockers pitch so inatead of pullingon all the teeth equally the pull is placed on one or two