743 U-joints

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ytr1903

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Hi everyone, I just discovered your website and am very excited that there is a resource like this forum out here on the internet. I gave up a couple of years ago trying to find something of this nature and was not successful. Here is my question. I have a 1983 Bobcat 743 that I have put minimal hours on since purchasing it in 1999. I have done all my own maintenance over the years and the 743 has been problem-free. While reading my service manual and then my operator's manual, I came across the fact that there are U-joints somewhere that need to be lubed every 250 hours. I am approaching that milestone with my Bobcat and am very curious as to where these are located. I have had the cab tilted up, and the engine door open trying to find these U-joints. Can anyone help me? What job do they perform? Thanks, Tom
 

Tazza

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They are on a very short driveshaft from you engine to the hydrostat pump.
Ken
They say to grease them, but no normal person can gain access to them!!!
As ken said, they are attached to the engines fly-wheel that joins to the back of the hydro pump. The only real way to get to it to grease is to pull the engine out. If the engine is aligned correctly the U joints do not move.
 

ytr1903

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They say to grease them, but no normal person can gain access to them!!!
As ken said, they are attached to the engines fly-wheel that joins to the back of the hydro pump. The only real way to get to it to grease is to pull the engine out. If the engine is aligned correctly the U joints do not move.
Thanks very much for the prompt replies. I will no longer consider them an issue. No worries.
 

Luthor

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Thanks very much for the prompt replies. I will no longer consider them an issue. No worries.
I grease my 743 U Joints regularly using a long, small diameter, flex hose attatched to my grease gun, not easy, but can be done in a few minutes.
 

Tazza

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I grease my 743 U Joints regularly using a long, small diameter, flex hose attatched to my grease gun, not easy, but can be done in a few minutes.
How on earth do you find the grease nipples? I take it you have someone on the outside to twist the engine to line up the grease nipples to attach the grease gun hose.
I gave mine a good grease before i re-installed the engine, i think i will leave it alone for a while.
 

WebbCo

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How on earth do you find the grease nipples? I take it you have someone on the outside to twist the engine to line up the grease nipples to attach the grease gun hose.
I gave mine a good grease before i re-installed the engine, i think i will leave it alone for a while.
Those joints are very important to grease! If they are not greased and break, the engine must be removed to replace. They dont come cheap.
Yes you must almost be double jointed with eyes on your hand, but that will keep you from visiting me at the parts counter!
 

jmatt20

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Those joints are very important to grease! If they are not greased and break, the engine must be removed to replace. They dont come cheap.
Yes you must almost be double jointed with eyes on your hand, but that will keep you from visiting me at the parts counter!
bobcat parts mamager is right , if they go out and you don't figure out what the knocking noise is fast enough they can take out the seal and bearing of the rear hydrostatic pump and possibly the entire rear hydrostatic pump. it is a pain to grease them but i only did it about every third oil change on my 843 and i never had one go "out". a buddy of mine had his go out and it did take out the seal and bearing while he loaded the machine to take it to the shop.
 

crowne

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bobcat parts mamager is right , if they go out and you don't figure out what the knocking noise is fast enough they can take out the seal and bearing of the rear hydrostatic pump and possibly the entire rear hydrostatic pump. it is a pain to grease them but i only did it about every third oil change on my 843 and i never had one go "out". a buddy of mine had his go out and it did take out the seal and bearing while he loaded the machine to take it to the shop.
Are there U-joints on the 763? if so, how many am I looking for?
 

WebbCo

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also do I grease it from the back or have to lift the cab up?
No u joints on the 763, it has a transferse mounted engine and uses a drive belt. You just have to watch the idler and the tension on your machine. The pesky idler arm used to come with a brass insert and it corroded, locking up the idler and making a h*ll of a sound!
 

skidsteer.ca

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also do I grease it from the back or have to lift the cab up?
Crowne
Any of the machines that have the motor in sideways are driven with a tripple or quadruple v belt and don not have any U joints.
See “belt tension failure” post and inspect your drive belt instead
Ken
 

skidsteer.ca

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Crowne
Any of the machines that have the motor in sideways are driven with a tripple or quadruple v belt and don not have any U joints.
See “belt tension failure” post and inspect your drive belt instead
Ken
Mark
Do the new tensioners use something besides the brass bushing that I had trouble with?
Ken
 

Tazza

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I havent sold a brass one in years! You will know when the things sounds like a pig squeeling!
Crowne
The only way you can hope to gain access is by lifing the cab. There are no access points from the rear of the machine. The small hole in the front of the blower housing is small enough! You will need to feel your way round to find them. I have no hope in doing mine on the machine, it was hard enough greasing it when the engine was out!!!
Good luck with it!!!
 

Tazza

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Thanks, all new to this, service manual 1 is on my list.
The service manual doesn't cover this unfortunatly.
They are very handy though, i do recommend you get one but it doesn't cover some things.
 
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