i got an udp today i tried to put it on but couldnt get the orginal pulleys bolt loose is there some trick to this?then i put my original belt back on and now the tensioner is squealing loud is it too tight or loose?

 

This Might help you...
http://www.greghome.com/Greg's%20Garage/1999%20Nissan%20Maxima%20SE/Underdrive%20Pulley.htm


Since the new pulley is smaller than the stock pulley you will need to get new shorter length belts. You cannot reuse the stock belts. I went to a local US-1 auto parts store and bought the exact belts recommended by Unorthodox. They are Gates belts, numbers K-060408 and K-040292. I tried Pep Boys and Auto Barn, but neither of those stores carried Gates belts. The price of both belts together was $31.44. You can buy the belts from Stillen directly, but their price was $54.00. I recommend getting the belts locally. Follow the factory procedure to put the new belts back on, and tighten them to factory specs. Now you can torque the crank pulley bolt to 140 ft-lbs. Again - follow the same procedures you used earlier to secure the flywheel from rotating. Torquing this bolt properly is very important - USE A GOOD TORQUE WRENCH. The last thing you need is to have your crank pulley come flying off the engine during spirited driving. I also cannot stress enough the importance of belt tension. FOLLOW THE FACTORY MANUAL. For a new compressor belt the deflection should be 3.8-4.1 mm, and the power steering belt should be 6.5-7 mm. If you do not tension these belts properly they will squeak like a stuck pig!!