Drive belt adjusting bolt

CASTLK · Apr 13th, 2010, 11:04 AM

Hi Guys,
Can anyone tell me where the drive belt adjusting bolt is on my 99 Sentra 1.6L engine. I can't seem to find it and I have to replace the water pump ( leaking out the weep hole) and alternator and need to loosen it so I can get the belts off. I am going to be replacing the belts also while I have it apart and I 'm sure the adjustment is going to be different than the old belts were. Also how much tension should be on belt without ruining the bearings in the new pump and new alternator?

PTXer · Apr 15th, 2010, 06:49 AM

As no one else has replied, I will give it a shot from memory. The tensioner for this belt is on the firewall side of the motor between the crank pulley and the waterpump. It has a lock nut then an adjuster rod/bolt. If you have jackstands, it can even be easaier to get to from underneath. 10mm sticks out in my mind as the head size. Hope this helps.

CASTLK · Apr 15th, 2010, 06:55 AM

The one you are talking about is for the power steering and water pump. It uses a 12mm socket to adjust tension. The one for the Alternator is up front just below the alternator itself. There are two mounting bolts that hold it to the motor, however I can't find the one that allows you to adjust the tension on the belt itself. Thanks for your reply.

NissanPartsDept · Apr 15th, 2010, 12:51 PM

The alternator should move on the upper bracket to adjust the belt.

CASTLK · Apr 15th, 2010, 09:25 PM

Thanks, would you happen to know what the proper amount of tension should be on the belt without putting undo stress on the alternator and water pump bearings? Also how to do know if the tensioner pulley itself is bad? I read that if you loosen the bolt that holds the pulley onto the bracket itself and the re-tighten it you must replace it, it this correct? Should the bolt that holds the pulley onto the bracket be very tight or just snugged to allow the pulley to turn without destroying the bearing inside of it? can it be taken off re-lubed and put back on?

NissanPartsDept · Apr 15th, 2010, 10:44 PM

1/2" to 1" of deflection in the belt with fairly firm pressure is about right.

the bolt does not need to be replaced when it is loosened. It has a shoulder on the bolt so you are not tightening it directly against the pulley. Snug it up good.

The pulley should spin smoothly when the belt is off. it is sealed and cannot be lubed.

CASTLK · Apr 15th, 2010, 11:57 PM

Thanks again, I figured that was about right but just wanted to be sure, don't want to have to do the job twice it's a pain to do just once when you have a bad back. I am guessing the belt deflection for the power steering is the same then just like on most cars.

NissanPartsDept · Apr 16th, 2010, 11:15 AM

You got it. Good luck.

CASTLK · Apr 16th, 2010, 11:59 AM

4 hours to get the alternator and the water pump out of that thing. I couldn't believe that I had to drop the a/c compressor to get the mounting bolt out on the side that faces the engine.

The water pump is no walk in the park either. That actually took longer to get out than alternator. They make it so hard to get your hands and tools into where you need to be to take things apart. If this was my Vette I'd have been done in an hour and half tops. I hope this is a job I only have to do once, it sucks and the starter looks like it's a pain the butt also. Oh well here I go back out there to start putting it all back together.

Jopet · Jul 2nd, 2010, 10:28 AM

Just been doing this. Had to replace my inner belt (A/C, alternator belt). That's the easy part. Thing is you have to remove the outer belt to install the inner belt.
Inner belt - No, you dont have to drop the a/c compressor and no I cant seem to move or pivot the alternator (95 GXE) The tensioner pulley screw is also the lock screw for the belt tesioner. Just remove the pulley and you'll see everything. adjust the tensioner bolt full (loose, ccw) to prepare for installation. I found it more easier to move the from the bottom of the car.
Outer belt - should be the same effort, but, anything you need to do right beside the firewall is hell! Tension bolt should be easy to see. Loosen the lock screw (perpendicular to the bolt), do not remove. Then fully loosen the tension bolt (CCW). the belt will not loosen (at not on mine) when the bolt is completely loose, the power steering pump needs to be pulled or move towards the engine. I had to use a pipe to move it. Then the belt will come loose enough to remove.
intall the belts (install back the idler pulley for the inner belt), tightened the tension bolts and don'r forget to tighten the lock screw as well (for the inner belt that's the idler pulley screw).
Belt deflection shoulbe 1/2 to 1 inch with firm push of the finger

Oh yeah, I had to move the coolant reservoir out of the way (just pull that out) and the plastic mounting (unscrew). To have more space to work with.
If you have no patience you'll not finish this job. Im short and stubby which means my physical attributes is not in agreement with small hard to reach spaces. My arm wrist and hand were bruised and black and blue in some areas. Just a heads up.
Hope this helps