[RMeehan]

I have a 77 280 with a broken fan belt, the one that goes around the alternator. To replace it, it is necessary to take off the other fan belt so as to put the new fan belt behind the pulley of the other. I have unscrewed the long bolt on the center pulley believing this would relieve the tension on the belt and be able to remove it. It did not. So, I'm stuck as to how to remove the fan belt. Interesting, I have several Z books, but none deal with changing or replacing a fan belt. Suggestions please.

RPM

 

[silver77280z]

There is a bolt that conects the alt. loosen that and slide alt. up and you can slide new one on in about 5 secs.

 

[RMeehan]

Thanks for your reply. But my problem is not moving the alternator to get the belt on. I can do that. Its the other fan belt that prevents me from getting the alternator belt on. I have to get behind the other belt in order to get the Alt.belt on, and it is that one I don't know how to remove.

RPM

 

[MTP78Z]

another bolt to loosen

You have to take the a/c compressor fan belt off to get the alternator fan belt on or off. To loosen up the compressor belt there is an adjustable pulley between the water pump pulley and the compressor which I think is blue. You have to loosen the bolt in front of that pulley and then you can loosen the long adjusting bolt to lower it and reduce the belt tension.

 

[Tony D]

MTP Correct.

You must first loosen the bolt in the center of the pulley for the A/C tensioning pulley, then screw out the other bolt you mentioned.
You don't have to loosen the pulley center bolt all that much. Tap the other bolt with a wooden stick or something, and it will work past the grunge to let the pulley de-tension the pulley and belt so you can remove it.
You can thread the alt belt on over the fan a blade at a time until it's in position. lever against the water outlet to tighten the alt belt. remember there are three bolts on the alt that should be loosened/tightened when attacking this belt.

BEFORE you install the alt belt, wiggle the fan/clutch assemble and see if you detect ANY wobbling of the pulley on the end of the waterpump! If it moves, the bearings are on the way out, and you need to get a new water pump soon! Running like this can result in a helicopter revue as your fan lifts off the broken pump shaft and decides to eat your radiator!

Replace and tighten the A/C belt afterwards by tightening the other bolt first, and then the nut in the center of the pulley.If you wish to minimize dowwntime, you can stow an extra belt for future use, but it gets really dirty, and I carry tools with me, so changing it isn't a big problem.

All better, on the road again!

 

[RMeehan]

Re: MTP Correct.

Hey, thanks much for your help. Everything you wrote makes sense, and I'll get it done. Again thanks.

RPM

 

[Tony D]

Tawas Area High School?

If Meehan, then reply. If not Meehan, then disregard.

 

[jcool78 2plus2]

Re: Don't...

Don't try to tighten the new fan belt too much. You'll only over stress the water pump bearings. Get the tension tight enough so that the new belt won't squeal. Then. after about 100-500 miles, re-tighten it.

 

[Tony D]

Finger test.

If you can spin the alternator fan with your finger, the belt is too loose. If you can't, or just get a slight turn before the belt grabs, that's just about a loose as you can run it and still get decent charging/accessory operation without excessive squealing at startup. Using this method, you must recheck frequently, as this is running the belt towards the loose end of the applicable scale, but results in the longest life of the H2O pump bearings. Tho I've seen the seals go in 6K miles with everything correct. The new Nissan Coolant works better than the "silicone-silicate" formula conventionally used for the past 40 years...
Those silicone silicates eat the seals on a Z. The new Nissan Coolant is backwards-compatible, and does not have the silicone-silicate compounding. It is designed with Aluminum engines in mind, as opposed to the old formulation that was for cast iron with incidental aluminum contact...