bobcat 763 cooling fan tensioner removal/repair

[nshoregrappler]

Noticed that the tensioner spring was no longer keeping tension on my cooling fan belt. The spring and arm will only move when i physically pull on the idler pulley to increase tension on the belt. Because the spring and arm are not moving freely it allows me to keep tension on the fan belt. I want to replace or rebuild the spring tensioner mechanism.
The tensioner is held in place by a 1/4 inch hex head bolt. I am able to turn the hex head bolt counter clock wise and get the tensioner arm to move until it rests against the hydraulic pump drive belt pulley, i can move the bolt about a quarter turn in both directions. I am unable to get the bolt to "unscrew" any further, I assume that getting the arm to move counter clockwise is really unscrewing the bolt. The ultimate question is how do I avoid breaking the bolt in the housing? I understand that it (the hex nut) must be removed to "fix" this problem and replace the spring and bushings on the tensioner arm. I also realize that if the hex nut "breaks" in the "housing" I will probably have to pull the engine and pump to repair "my damage". I"ve sprayed with penetrating oil multiple times but seemingly still not budging any further. Any thoughts or suggestions would be appreciated. Ps. I've broken two 1/4 inch hex drive sockets and the the bolt is still in place. Heat at this time is out of questions due to space. Help!!!!!!

 

[nshoregrappler]

thank you for not responding. I really sometimes wonder what am i doing working on a bobcat, for "fun". I just realized how old age can effect one's brain. Think I had a brain ****. going to cut the tensioner arm in place, $75.00 part new. I now realize that the tensioner arm or bushing is fused on to the bolt and not going to allow me to turn the hex bolt! Since I'll probably just replace most everything anyway cut anything stopping it from coming out. What ever happens, I'll post to perhaps help someone with a senior moment.

 

[SSdoxie]

I think you are correct, bolt/bushing siezed to the arm is stopping the turning more so than threads siezed. FYI; I have heard of drilling and installing a grease zerk in the new arm, so it can be greased ocassionally to prevent future siezing.

 

[nshoregrappler]

Done. Yea frozen solid to hex head bolt. Had a tear in my eye as i cut thru that tension-er arm knowing it was adding $75 to the parts bill, but glad it was off. Removed relatively easy, cutting with an electric cut off wheel. The new arm comes with plastic bushing already installed i coated every moving part and threaded part with never seize. thought about grease zert but with aluminum opted to hope for the best. Old one since 97. Parts everything new without belt, $190. guess i saved $270 labor estimate. LOst a day.

 

[SSdoxie]

The anti-sieze will last a long time. Now that you are aware of it, part of the annual service could include removing that bolt and recoat it.

While working on it, did you happen to remove the plug in the fan drive and check or add gear lube to the housing?

 

[nshoregrappler]

Did try that, but have penetrating oil on the plug trying to break that free now. Letting it soak for a few days, while on a trip out of town. That is my next project. Boy, my honey do list just got longer, this is cutting into my fishing time,
To think I do this for fun! If ever I would "make" a skidsteer the motor and pump would "slide out as one unit. ANY other suggestions please feel free to add tothe list. Napa fan belt for cooling fan was #25.9400 ALTERNATOR BELT outside:45.98 in. inside 43.90 metric 9mmX13mm