1960s Squeaking belts on '61 Deville

[ZGJim]

The belts on my non-AC Deville squeak loudly when they get warmed up.  Have tried belt dressing and cleaning the inside of the pulleys with emery paper and scotchbrite. No improvement.  The belts are new and correct according to the listing at O'Reilly's.  The belts are the notched style. Gates belts #7550 and 7575.
Has anyone found a cure for this problem?

Thanks,

[Cadillac Jack 82]

Chalk.  Rub a piece of white chalk against the belt while running.  Problem solved.

[Big Fins]

I'm going to say tension isn't tight enough, or...the driven item, IE: water pump, P/S pump, generator is binding more than it should. Remove the belts and manually spin the driven items feeling the amount of effort needed. It is minimal on all of these. They should easily spin a few revolutions after you spin them by hand. Even the generator fully loaded at 35 amps shouldn't make a belt squeal that at the proper tension.

[Jon S]

These notched belts suck and look ugly. I use bar soap on the belt with the engine off. I suspect one of your belts needs a little more tensioning.

[bcroe]

The gen pulley can tend to slip after starting,
trying to put back the charge the starter used. 
Check its dia, they are small but vary in size. 
The larger the pulley, the less likely to slip. 
Bruce Roe

[TJ Hopland]

I have found that modern automotive V belts for some reason take 2 or 3 re tensions over a few hundred miles before the seem to settle in and stay where you set them.  Industrial or lawn and garden belts don't seem to do that.  Dunno why.

[Big Fins]

Look at the make up of the mower belts. You can see much more fabric or Aramid(sp) cord in them as opposed to automotive belts. When engaging a pair of 22"+ blades, it puts a hurting on the rubber. Think about how many times you stop/start a mower and engage the blades.