How often to tighten your (accessory) belts?
08-26-2005, 12:45 PM
#1
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How often to tighten your (accessory) belts?
No, not your timing belt or your jeans belt (tighten I wish) but your pwr steering, altenator, a/c compressor and air pump (if you still have one) belts.
When I recently removed my air pump I adjusted all the belts and noticed a considerable difference in power steering. Not sure about the a/c or the alternator performance change other than all is working well.
So, how often do you do yours?
When I recently removed my air pump I adjusted all the belts and noticed a considerable difference in power steering. Not sure about the a/c or the alternator performance change other than all is working well.
So, how often do you do yours?
Last edited by Randy V; 08-26-2005 at 01:27 PM.
08-26-2005, 02:56 PM
#3
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Like the timing belt, most accessory belts will need an adjustment at 1000-1500 miles to account for any initial stretching, and wear-in of the friction surfaces if it's a V-belt. After that they pretty much stay the same length unless they are tired or close to failure.
I did the T-belt job at 66k (second t-belt, thank you) and decided that the accessory belts were all due based on age. After another 1200 freeway-to-Devek-and-more miles, t-belt really needed some help, as did all the accessory drive belts. T-belt needed almost half a turn (that's a lot...) and the accessory belts were noticeably stretched. So they all received a little touch of the wrench. The belts are now at the "finger pressure equals one belt thickness of deflection" stage, which is tight enough to prevent slippage and jumping, loose enough to preserve the various bearings. Running belts too tight also contributes to premature stretching, and a never-ending cycle of tighteneing that always results in premature failure. The correct tension for a belt is really "just tight enough".
I did the T-belt job at 66k (second t-belt, thank you) and decided that the accessory belts were all due based on age. After another 1200 freeway-to-Devek-and-more miles, t-belt really needed some help, as did all the accessory drive belts. T-belt needed almost half a turn (that's a lot...) and the accessory belts were noticeably stretched. So they all received a little touch of the wrench. The belts are now at the "finger pressure equals one belt thickness of deflection" stage, which is tight enough to prevent slippage and jumping, loose enough to preserve the various bearings. Running belts too tight also contributes to premature stretching, and a never-ending cycle of tighteneing that always results in premature failure. The correct tension for a belt is really "just tight enough".
08-26-2005, 11:22 PM
#4
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Are the accessory belts easy enough to adjust without having to remove stuff to get at them? I had all new belts put in about 600 miles ago, and I'm getting what sounds like some bearing noise coming from just below and in front of the intake plumbing. I wonder if the alternator belt is too tight or loose. I'm a 928 noob and I have no idea what I'm doing inside that engine. Is it something I should be able to do with regular tools and no experience? And no belt tension tool, I might add...
08-27-2005, 01:12 AM
#5
Drifting
I'm suprised that you lasted 600 miles on new belts. I had to readjust my new replacement set after about 150 miles.
They are all adjusted from below, so you need to get the car up on a lift or jackstands. On the S4, to gain access to the adjustments, you need to remove both the rear and front belly pans.
Other than that, it's pretty easy to do.
They are all adjusted from below, so you need to get the car up on a lift or jackstands. On the S4, to gain access to the adjustments, you need to remove both the rear and front belly pans.
Other than that, it's pretty easy to do.
08-27-2005, 02:29 AM
#6
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Originally Posted by borland
I'm suprised that you lasted 600 miles on new belts. I had to readjust my new replacement set after about 150 miles.
They are all adjusted from below, so you need to get the car up on a lift or jackstands. On the S4, to gain access to the adjustments, you need to remove both the rear and front belly pans.
Other than that, it's pretty easy to do.
They are all adjusted from below, so you need to get the car up on a lift or jackstands. On the S4, to gain access to the adjustments, you need to remove both the rear and front belly pans.
Other than that, it's pretty easy to do.
Adjusted mine ('89 S4) at 1000 miles. Not too loose, but needed some help. Only needed to pull the front (engine) belly pan. Why did you pull the rear pan? I only tightened the belts on the front of the engine...???
08-27-2005, 03:38 AM
#7
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Originally Posted by dr bob
Adjusted mine ('89 S4) at 1000 miles. Not too loose, but needed some help. Only needed to pull the front (engine) belly pan. Why did you pull the rear pan? I only tightened the belts on the front of the engine...???
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08-27-2005, 09:59 AM
#8
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Porsche recommends adjusting the ribbed alternator belt on the later cars using the timing belt gauge. The timing belt is set to 5.0 of whatever those units are, while the alternator belt is set to 9.0. That is TIGHT!
08-27-2005, 10:33 AM
#9
On an older car, tightening the belts doesn't just kill the belts, it is hard on bearings as well. Tight enough is just enough, and should be ok with one adjustment. I like to clean off the front of my alternator and air pump and put a drop or two of Mobil One on the shafts while spinning it with my hand to work it in. It reminds the grease in the bearings that it is grease. This also works well for tensioner bearings, And I have done this on many makes of cars over the years. I had 200K on one of my trucks, and never had a problem with any of the bearings. I have also done this to the bearings on 10,000 RPM industrial sanders, some of which are now over 20 years old, so I know it works. YMMV Yes, I do it to timing belt tensioners as well, provided that they have no play.
On a new bearing I have been known to put a little CV joint grease on the outside of the seals before assembly. I believe dryness and heat are what kills seals. Again, YMMV
On a new bearing I have been known to put a little CV joint grease on the outside of the seals before assembly. I believe dryness and heat are what kills seals. Again, YMMV
08-27-2005, 12:25 PM
#10
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Thread Starter
[QUOTE=dr bob] I only tightened the belts on the front of the engine...???[/QUO
Too funny.
You can adjust the pwr steering belt from above, the alternator and a/c belts from below. The air pump belt is adjusted from below as well I think; dont really know, its on the shelf with the pump.
Now where's the xmission belt?
Too funny.
You can adjust the pwr steering belt from above, the alternator and a/c belts from below. The air pump belt is adjusted from below as well I think; dont really know, its on the shelf with the pump.
Now where's the xmission belt?
08-27-2005, 05:49 PM
#11
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911Dave
"Bearing noise from just below and infront of the intake plumbing "
reads to me like you mean the water pump area or the T Belt area. If so this deserves further investigation. Failed WP bearings will cause premature demise of the TBelt with expensive consequences.
"Bearing noise from just below and infront of the intake plumbing "
reads to me like you mean the water pump area or the T Belt area. If so this deserves further investigation. Failed WP bearings will cause premature demise of the TBelt with expensive consequences.
08-27-2005, 06:59 PM
#12
Drifting
Originally Posted by dr bob
Why did you pull the rear pan? I only tightened the belts on the front of the engine...???
That's one of my complaints about the aluminum front replacement pans. They are designed to the original dimensions. They could have easily modified them to allow installing the front pan last.
