Alrighty, so Saturday I had picked up my '69 L46 Coupe and on the way home I had noticed that the belt would squeak above 2500 RPM. I get home and run out to the parts store and get a new belt for it. As I was putting it on I noticed that the alternator pulley was about 3/8" behind the water pump & crank pullies. I thought, well I'll put it on and see what happens.

Sure enough the squeak went away and all was great.....for the day. Driving it last night the squeak came back, same RPM and all. So tonight I put some washers between the alternator bracket and the block & header where it mounts and now the pulleys are all in line. While inspecting the pulleys I noticed that the water pump pulley had what felt like a rubber-like film in the grooves, so I cleaned that out with some simple green, good to go. Throw the belt on and go for a drive, the squeak isn't as bad as it was but it's still there, just now it starts at 3000-3200 RPM.

Two things I'd like to point out are that the car does not have the smaller belt that runs between the crank and water pump. I've heard that helps take some of the load off of the other belt. The other thing being that my fan does rotate independently of the water pump pulley if I hold the pulley and push the fan. Does this automatically mean that my fan clutch is good or can it also be the culprit here?

Thanks in advance!

 

Found this thread, what do you think about going with a slightly wider belt? At the moment the top of my belt sits even with the top of the pulley edges.

 

Clean pulleys not just alt pulley and use a top cog belt .

 

I had the same issue with my '73. Since I had removed the A/C, there is only one belt driving the water pump and alternator. The belt would squak when I would rev the engine. I ended up adding that short belt between the water pump and crank pulleys, where the A/C belt used to go. Fixed problem. Don't remember off hand what belt number I used for my 350 (now 383) small block (L48), but I remember it was a royal pain to get it on. I can look for belt number tonight and let you know tomorrow if you like. I'm at work now, so i can look tonight.
Dale in Badgerland.

 

Purchase the 69 assembly instruction manual (AIM); the AIM has diagrams for all the stock belt routing, pullies, etc, and lists the original GM part numbers for the stock belts.

You should not have to use washers to align pullies. Has the AIR been removed?

 

If you don't have A/C definately put on the extra crank to water pump belt. That solved the problem for me.

But, as Easy Mike says, it should not be necessary to use washers to allign the pulleys. Something is wrong.

 

You need to add that other belt. Too much load for just that one belt.

 

Sorry for the delay in getting back to you, sounds like the smaller belt is a winner. I'll dig through my AIM to see what it takes to put it on. While I'm at it, I'll remove the washers I used to shim the alternator bracket once I have the smaller belt on, can't stand looking at them!

Thanks for your advice, I'll let you know how this goes.

 

I agree that you need to add the water pump belt, but don't stop there. Make sure that you have the right pulleys, as well as the correct alternator brackets. If you have the correct pulleys and brackets, the pulleys should all be aligned properly,.....without using washers to align them.

 

due to the tight radius the top cog belt will perform better.i tried both so i know what i am saying.unfortunately i could only get it in a dayco.gates makes a better belt.i am not running stock pulleys so i will not give a size.you do not, and should not remove any pulley to put this belt on.you do not need a special tool to do this but it may help if you have the one suggested by a respected forum member.you will not stretch or in any way damage the new belt by pulling it over the rotating pulley.do not crank the engine to put it on,this is dangerous and may result in collateral damage.if you put a thin piece of aluminum foil around the section of belt about to be flipped on,it will slide over easily.to put a pulley on with belt tension on it is a big mistake and may lead to improperly torqued pulley bolts.why make a simple job tough.

 

Well I had installed the smaller belt and sure enough, the sound went away! The belt I used was 33-1/2" and was able to get it on by removing the water pump pulley, took all of 10 minutes to do. I did try the aluminum foil trick and the belt was too snug for that to work. Tomorrow I'll take the washers out that I used to shim the alternator bracket and see how she does. Thanks for your help!

 

glad you got it resolved.go back and check the pulley bolts after running a bit for safety.if it loosens over time switch to a top cog.