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How tight should the alternator, A/C compressor, and power steering pump belts be tightened?
On a recent long drive I noticed a burning rubber smell coming into the cabin. Upon examination of the engine compartment I discovered that the power steering pump had come loose, causing the reservoir to rub on the alternator belt from time to time. The belt itself was intact, but frayed along about 30% of its length where it rubbed against the pump reservoir housing.
So, yesterday I replaced the frayed belt with a new one. In order to replace this belt I had to first remove the A/C compressor belt and the power steering belt. These belts were in good condition, so I re-used them. I also snugged up the power steering pump so that the reservoir would not interfere with the alternator belt.
I tightened all the belts and everything seems fine. But, how tight should each belt be? How critical is the tightness of each belt? I know if they aren't tight enough the belt might squeal, or become glazed from insufficient tension, but beyond that, how tight is too tight?
The 1967 Chassis Manual states that there are specifications for the tightness of each accessory belt listed "in the Tune-Up Chart section". But, I can't find any Tune-Up charts in this manual! Maybe my copy is missing some pages?
I bought a $20 NAPA "V-Belt Tension Gauge" that's supposed to measure the tension of the belt when placed along its lenght. You press down on the device until a 'click' is heard and then read the tension from the gauge. How well do these gauges work? Are they reasonably accurate? There are dial-indicator type belt tension gauges available, but these are much more expensive.
So, what's the best way to verify belt tension, and where do I find out how much tension to apply to each specific accessory belt?
Go to the belt manufacturer's web site, Gates, Dayton, etc. there is guidance there.
In the Nuclear industry there is a procedure that tells how to use the gage.
Frankly (no pun intended on Frankie), I use the thumb and 1/2" deflection on my cars. Be aware that after a week or two of use, the belts WILL STRETCH. Retention them and DRIVE IT.
Go to the belt manufacturer's web site, Gates, Dayton, etc. there is guidance there.
In the Nuclear industry there is a procedure that tells how to use the gage.
Frankly (no pun intended on Frankie), I use the thumb and 1/2" deflection on my cars. Be aware that after a week or two of use, the belts WILL STRETCH. Retention them and DRIVE IT.
Good advice..........
For the alternator and PS, I just pull on it pretty hard by hand......and then tighten the adjusting bolts.
For the A6 AC compressor I use a 18 inch bar to wedge against the engine and compressor to tighten the AC belt. I don't pull on it with all my strength, but I pull on it pretty good. Then tighten.
It is best to have a helper tighten when you are pulling..........but it can be done either way. Your choice.
I have never used a belt tension gage in 50 years on any of my cars, but that doesn't mean it isn't a good idea. Only that it is unnecessary for many of us. PS: I never caused a bearing failure from over tightening a belt and never threw a belt from under tightening it when I was racing.
The pic below is the type of tension gauge used by GM in the plants back in the '60's. In the early days, the assemblers just used pry bars but then the plants developed different types of torque devices for the operator to use and tension was randomly checked by roving process monitors using a gauge. Belt torque became a fairly big deal before the use of tensioners. There were a fair number of warranty problems caused by over-tensioning - especially alternators.
The pic below is the type of tension gauge used by GM in the plants back in the '60's. In the early days, the assemblers just used pry bars but then the plants developed different types of torque devices for the operator to use and tension was randomly checked by roving process monitors using a gauge. Belt torque became a fairly big deal before the use of tensioners. There were a fair number of warranty problems caused by over-tensioning - especially alternators.
That is why I only adjust the alternator belt by hand. It is probably the first to have issues if belt is over tensioned or if a pry bar is used.
06-27-2017, 07:55 PM
Checking "V" belt tension
Maybe my copy is missing some pages? 
PS: I never caused a bearing failure from over tightening a belt and never threw a belt from under tightening it when I was racing. 
That is why I only adjust the alternator belt by hand. It is probably the first to have issues if belt is over tensioned or if a pry bar is used. 
