toddalin

The other day the alternator on our '91 L98 died and I don't see any reason that I can't change it myself. It looks to be that I just need to disconnect the battery, unconnect the appropriate plugs on the alternator, release tension on the belt, undo the three metric mounting bolts and remove the alternator. Replacement looks to be the opposite.

My question is how to release/replace the tension on the belt. There looks to be a bolt on a tensioner on the lower passengers side of the engine that was obviously used for this purpose (nicks in paint on frame). Is it just a matter of loosening the bolt to release tension and using a pry bar/extension to hold tension on the belt while tightening the bolt, (sort of like the C2s and C3s I've done), or is the procedure different, and if so how?

I usually work on my older Vettes myself and leave the '91 to my mechanic, but it looks all too easy.

Thanks guys

Z51JEFF

On my 84 the tensioner has a square hole in it for a breaker bar,standing on the pass side insert breaker bar and pull back.It takes about 5 seconds to throw the belt off.I would venture to say that the exposed bolt is pretty much the same thing.Try putting a socket on it and pull up,if it moves your in business.

Tranzor

You can put a breaker bar in the square hole on the tensioner itself and pull up, like what was suggested above. You can also push down on the tensioner and get the same results... just be careful with your hands in there, the tensioner can smash a digit pretty easily, which is why I definitely would use a tool to accomplish the job.

toddalin

Thanks guys, I now see the square hole being referred to. So, it looks like, I loosen the nut on the rounded piece(?), put a breaker bar into the the hole and pull up to release the belt tension.

When I put it back, I assume I just reverse the process. Is this thing spring loaded, or will I have to tension the belt?

Thanks

BTW Tranzor, ours is also a turquoise '91 coupe (bought new) with automatic and all available options. Ours has run a best of about 14.1 at 97 mph.

Tranzor

Yeah, it's pretty much spring tensioned... when you want to put the belt back, line the belt up with all the pulleys and the tensioner, then release the tensioner... it'll pull itself back into place and tighten the belt to where it was before.

Hey that's cool to see another '91 turquoise... I bought mine a few weeks ago, and I too had to change the alternator after having it about a week. It has 76k miles on it, and doesn't have a whole lot of options... leather seats (no power seat though), power windows, locks, etc. Mine also has just has the base suspension and 2.59 rear gears. That's why I was surprised mine ran as fast as it did at the track... figured a car with 2.59s would be good for 14.4s tops.

c4cruiser

Don't loosen the bolt!! That is what hold the tensoner assembly to the accessory bracket on the front of the motor. Just insert a 1/2 square drive ratchedt or breaker bar in there and pull as mentioned. Installing the belt is just as easy; route the belt according to the diagram and put pressure on the tensioner pulley with the tool and pass the belt over the last pulley and then release the pressure on the tool.

If you have an AutoZone close by, you can rent a belt tool by simply giving them a deposit and you get the deposit back when you return the tool effectively a free rental.

I wound up buying a belt tesnioner tool as the kit is pretty much universal for both a square drive hole or a bolt. Worth the $20 I paid for it at Sears.

toddalin

That works! I went to AutoZone today to order the alternator which is due tomorrow.

GIJoe

I always used a crowbar and pushed down heh.

We had one of those tensioner pulley tools though at my buddy's house that I used. Came in really handy.

toddalin

Alternator was from Kragen and they don't loan the belt release tool because they sell it for $33. Still, my old click-stop torque wrench squeezed in there and did the dirty deed.

I don't recommend using a torque wrench for this if you want to keep it in calibration, but it really wasn't all that much effort; probably less than 50 foot pounds. My click stop is way out of calibration so gets abused like this. My beam wrench is on the money.

BTW, my mechanic (Steve LuVisi of Overhaulin' fame) has his torque wrenches professionally calibrated twice yearly. I take mine over and calibrate it against his. If you are cozy with your mechanic, you may want do the same.

The alternator charges great now. Thanks guys.

Macabee18

THANK YOU!!!!! You saved me with posting.

Pyepye

i just knocked the pin out of a 1/2 inch swivel, then bent a screw driver just enough for it to go between the two tangs of the male end of the 1/2 inch swivel. Put the swivel in the male end in the square hole and push forward, no problem.

Macabee18

I replaced my alternator. It is the first time I have attempted a repair on my 90 vette! It was this forum that aided me! Thank you Corvette Forum! You are AWESOME!

65Z01

I recently replaced the serp. on my '88 and the hardest part of the task was working the new belt in between the crank pulley and the frame cross-member.

Hot Rod Roy

That's a sign that your motor mounts are getting tired. The engine is sagging, so the space below your crankshaft pulley is smaller than it should be.

I use a 1/2" drive breaker bar to loosen the belt tensioner on my '84. Works like a charm! (Don't loosen any bolts for this simple job!)

65Z01

Actually it was a clip on the center of the cross-member that required me to slip the serp. on edge down to under the crank pulley.

mfowler

One piece of advice. I had a buddy release the pressure from the tensioner and when I took the belt off the alternator I squeezed it together and put a squeeze clamp on the belt. This holds the tension on the other pullies and keeps the belt from slipping off. Sure does make things easier because you don't have to worry about putting all that belt back!