Belt slipping
05-01-2016, 11:47 PM
#1
Belt slipping
Ok, so I've been chasing this ghost for over a year. Several gray hairs later and countless shots of whiskey, no resolution! 74 corvette 454 4-speed with power steering and factory A/C. Motor was rebuilt about a year or so ago, decided to powder coat all of the pulleys except for the PS pulley. I've been chasing a squealing belt issue and cant resolve the problem. I've installed new belts, powder coated pulleys, sanded powder coating off, installed new fan clutch, alt pulley, re-powder coated pulleys, I'm at a loss. A GM mechanic recommended I install the original Idler pulley GM # AQ 3952332, said it would resolve the issue, funny thing is, it wasn't on the car a few years ago and I didn't have this problem. I need help before I become an alcoholic!!! 
05-02-2016, 12:02 AM
#2
Can you narrow it down to which pulley is squealing? A/C, Steering, alt? I had this issue once and what I did was spray a bit of water on one pulley at a time. If it still squealed I moved on to the next pulley until I got the squealing to stop or reduce greatly for a minute until the water was gone. In my case it was the alternator pulley. I then removed the alt. pulley and use a very coarse emory cloth to rough up the belt surface of the pulley so that the belt had a more aggressive surface to grab. It worked for me.
This is all assuming you dont have an alignment issue or bad bearings in a water pump, alt., a/c compressor.
This is all assuming you dont have an alignment issue or bad bearings in a water pump, alt., a/c compressor.
Last edited by L Holmes; 05-02-2016 at 12:04 AM.
05-02-2016, 12:12 AM
#4
Can you narrow it down to which pulley is squealing? A/C, Steering, alt? I had this issue once and what I did was spray a bit of water on one pulley at a time. If it still squealed I moved on to the next pulley until I got the squealing to stop or reduce greatly for a minute until the water was gone. In my case it was the alternator pulley. I then removed the alt. pulley and use a very coarse emory cloth to rough up the belt surface of the pulley so that the belt had a more aggressive surface to grab. It worked for me.
This is all assuming you dont have an alignment issue or bad bearings in a water pump, alt., a/c compressor.
This is all assuming you dont have an alignment issue or bad bearings in a water pump, alt., a/c compressor.
05-02-2016, 12:31 AM
#5
The A/C belt is a 15490, the P/S pump is a Gates 9440, and the Alt is a Goodyear 17325. The problem is, the depth of the pulleys seem different therefore a thicker belt will ride differently coming from, say, the water pump pulley to the power steering pump pulley.
05-02-2016, 09:10 AM
#6
Team Owner
There are differently designed belts, too. They have differently angled sides. If the belt design doesn't match the pulley design....SCREECH!!!
Recheck the belt and P/S pulley to make certain they match properly. Then, use a piece of 150 grit sandpaper to scuff the sides of the P/S belt. With all that screeching, the belt is likely glazed and will easily slip.
Recheck the belt and P/S pulley to make certain they match properly. Then, use a piece of 150 grit sandpaper to scuff the sides of the P/S belt. With all that screeching, the belt is likely glazed and will easily slip.
05-02-2016, 09:55 AM
#7
Le Mans Master
The A/C belt is a 15490, the P/S pump is a Gates 9440, and the Alt is a Goodyear 17325. The problem is, the depth of the pulleys seem different therefore a thicker belt will ride differently coming from, say, the water pump pulley to the power steering pump pulley.
05-02-2016, 11:37 AM
#8
That was something I've considered, I have a NOS idler pulley but had never decided to use it. The motor has been modified, could that, plus the absence of the idler cause the belt to fail under load?
05-02-2016, 11:42 AM
#9
There are differently designed belts, too. They have differently angled sides. If the belt design doesn't match the pulley design....SCREECH!!!
Recheck the belt and P/S pulley to make certain they match properly. Then, use a piece of 150 grit sandpaper to scuff the sides of the P/S belt. With all that screeching, the belt is likely glazed and will easily slip.
Recheck the belt and P/S pulley to make certain they match properly. Then, use a piece of 150 grit sandpaper to scuff the sides of the P/S belt. With all that screeching, the belt is likely glazed and will easily slip.
05-02-2016, 12:30 PM
#12
Le Mans Master
Paging forum member LS4 PILOT......he changes his '74 454 belts every 5 years.
Look at the LS5 belt configuration in the diagram. It also shows the idler pulley pressing against the crank to water pump belt.
Look at the LS5 belt configuration in the diagram. It also shows the idler pulley pressing against the crank to water pump belt.
Last edited by 71 Green 454; 05-02-2016 at 02:05 PM.