GMC Repair: serpentine belt, crankshaft pulley, serpentine belt

Question
-------------------------
Followup To
Question -
i have a 1988 G-20 305cu.i. van. the serpentine belt tears regularly. i have replaced the tensioner. the belt always tears towards the front of the pulleys. what do i look at next and how? thanks
Answer -
OK, The FIRST thing I need to know is WHAT components have been changed that the belt drives ?.

Alternator ?.
Water Pump ?.
Air Pump ?
Power Steering Pump ?.
Idler Pulley ?
Tensioner ?.
Crankshaft pulley ?.

if ANY of these components were REPLACED and or REMOVED from the engine in order to work on the engine it is almost a certainty that they were NOT properly re-aligned when re-installed.

I have seen this so many times it wants to make me scream.

What I use to re-align the pulleys is somewhat unusual but it has worked for many years on many vehicles who kept grinding up belts every time you looked at it.

I use a RED laser pen and align the second groove from the front of each component to see if the red line lines up EXACTLY with the next closest component from I initially set the laser light line ON. Once this closest one is PERFECTLY aligned, I move the red line to this component that I just checked and then line-up this components pulley to it's closest component and then to the next amd so on.

It takes some time and a good eye, But it ALWAYS works.

Telling someone how to do it sounds dumb, But seeing it done is a different story.

It only takes a 16th of an inch OFF of any component and or a COCKED component or BENT pulley to grind a belt.


autohelp
    THANKS for the reply.  I've only had the van for a short time so i don't know a whole lot about the service history. I have only personally replaced the tensioner. Everything else is as i bought the van. If i use the laser technique and find a pulley out of line, do i shim it up to re-align our is their another way to do it? If i find a bent pulley, can i replace only the pulley or the whole component? thanks for your time. joe

Answer
Yes, You shim the component buy putting flat washers on the bolts between the component and bracket that it mounts to.

Yes, You can ONLY replace the pulley as long as the SHAFT of the component is not bent.

It takes some patience but it works very well.


autohelp
meperganfortis@msn.com