We have all read the posts on here about the "Serpentine Belt I got was too short". Many of us have run into this, including me this past week. We have all seen that it's too short, but I think I know WHY it's too short (and no, not because it's not long enough) for you jokesters out there.......
A bit of the back story of how I came to this conclusion..... Last Thursday, the Oldest Boy and I (it's his truck) were headed to the local Pull-A-Part for some parts for a vehicle I have been working on for an acquaintance, and a couple cosmetic things for my 07 P71. The previous Sunday, we noticed the pulley on the A/C was starting to squeak, so we have been keeping an eye/ear on it. So Thursday, we headed to the local fuel stop and were topping off the tank, I came out of the store, I noticed blue smoke coming out from under the truck, and little black "worms" were falling out of the bottom of the truck. I had him shut it off, we popped the hood, and saw the belt was starting to get torn up, the A/C Pulley smoking, and while we were standing there, we watched the belt melt/burn in two because of the heat from the pulley.
I pulled the belt out with a set of pliers, and told him, lets get ready and get as close to home as we can. We fired it up, and he drove and I watched the temp gauge. Just as we entered out neighborhood, the temp started to climb, so I told him to turn the corner, shut it off and let it coast as far as it would go. Fortunately, we were able to get it off the main road (US-40) and on one of the neighborhood streets. So we walked the rest of the way home, I grabbed the IH Cub Cadet with the snow blade on it and we headed back to the truck. I pushed the truck home with the tractor, and we parked it in the drive, switched all the tools into my P71 and headed out. We picked up the needed parts for the truck while we were out.
One we got home, he had to go to work, so he left, and I headed out to fix the truck. I had the A/C Compressor Bypass Pulley (Thank You @towcat for that tip in the past) and the replacement belt for the "Non-ambulance/non Leese-Nevil alternator from the local Autozone. I pulled the A/C Compressor loose an moved it to the side, and installed the bypass pulley in it's place, got everything lined up and started to fish the belt into place around the 47 pulleys the IDI seems to have. Finally got the new belt to lay on all the pulleys, grabbed the breaker bar and 15mm socket...... D@MN IT, I can't get this belt over the tensioner pulley. I try several different ways, move the bar, etc and not having any luck. So I have the thought, the vacuum pulley is smooth, and I can get to it easier, so I will put it on the idle, and slip it under the vacuum pump pulley. I try this a couple of times and still no luck. At this point, my hands, arms and fingers are getting tired, so I decide I want to take a short break, so I put the belt over the TOP of the vacuum pulley and relax everything so I can give my hands and fingers a rest. What I notice is, when I relax, and the belt is on all the other pulleys correctly, but over the top of the vacuum pump, the tensioner drops right where it should in the range........
After this sinks in for a second.... I have an AH-Ha! moment...... That's why the belt is too short. Whomever spec'ed out the length of the belt, didn't pay attention to the pulleys and didn't take in account the vacuum pump pulley is smooth, which means it should be on the back side of the belt. If the vacuum pump pulley were grooved to run on the front of the belt it would be the exact right length.
That being said, I was able to get the numbers off of the belt that failed, which was the correct length, ran under the vacuum pump, and allowed the tensioner to be in the correct spot.
The numbers were for a Dayco Belt, with the part number for the "Ambulance Package" IDI's. Looking at the specs for this belt, it is ~113 inches in length. The "non-ambulance" belt from Autozone is ~110.5 inches long. Looking at the difference, and "how much belt I need" for it to fit properly, I need 2-2.5 inches.......
The vacuum pump needs to be replaced, so at this point, I have the belt running across the top of the vacuum pump (which works just fine, even if it's not "right") until the replacement comes in, and I get the ambulance package belt. I will report back with the results, but I think everything will land right where it needs to.
So, sorry for the long post, but know I think I understand WHY the belt was spec'ed too short......
Oh, and for ~$40, I recommend anyone with a serpentine truck, keep one of the bypass pulleys behind the seat..... you may be hot in the cab, but you are still moving......
A bit of the back story of how I came to this conclusion..... Last Thursday, the Oldest Boy and I (it's his truck) were headed to the local Pull-A-Part for some parts for a vehicle I have been working on for an acquaintance, and a couple cosmetic things for my 07 P71. The previous Sunday, we noticed the pulley on the A/C was starting to squeak, so we have been keeping an eye/ear on it. So Thursday, we headed to the local fuel stop and were topping off the tank, I came out of the store, I noticed blue smoke coming out from under the truck, and little black "worms" were falling out of the bottom of the truck. I had him shut it off, we popped the hood, and saw the belt was starting to get torn up, the A/C Pulley smoking, and while we were standing there, we watched the belt melt/burn in two because of the heat from the pulley.
I pulled the belt out with a set of pliers, and told him, lets get ready and get as close to home as we can. We fired it up, and he drove and I watched the temp gauge. Just as we entered out neighborhood, the temp started to climb, so I told him to turn the corner, shut it off and let it coast as far as it would go. Fortunately, we were able to get it off the main road (US-40) and on one of the neighborhood streets. So we walked the rest of the way home, I grabbed the IH Cub Cadet with the snow blade on it and we headed back to the truck. I pushed the truck home with the tractor, and we parked it in the drive, switched all the tools into my P71 and headed out. We picked up the needed parts for the truck while we were out.
One we got home, he had to go to work, so he left, and I headed out to fix the truck. I had the A/C Compressor Bypass Pulley (Thank You @towcat for that tip in the past) and the replacement belt for the "Non-ambulance/non Leese-Nevil alternator from the local Autozone. I pulled the A/C Compressor loose an moved it to the side, and installed the bypass pulley in it's place, got everything lined up and started to fish the belt into place around the 47 pulleys the IDI seems to have. Finally got the new belt to lay on all the pulleys, grabbed the breaker bar and 15mm socket...... D@MN IT, I can't get this belt over the tensioner pulley. I try several different ways, move the bar, etc and not having any luck. So I have the thought, the vacuum pulley is smooth, and I can get to it easier, so I will put it on the idle, and slip it under the vacuum pump pulley. I try this a couple of times and still no luck. At this point, my hands, arms and fingers are getting tired, so I decide I want to take a short break, so I put the belt over the TOP of the vacuum pulley and relax everything so I can give my hands and fingers a rest. What I notice is, when I relax, and the belt is on all the other pulleys correctly, but over the top of the vacuum pump, the tensioner drops right where it should in the range........
After this sinks in for a second.... I have an AH-Ha! moment...... That's why the belt is too short. Whomever spec'ed out the length of the belt, didn't pay attention to the pulleys and didn't take in account the vacuum pump pulley is smooth, which means it should be on the back side of the belt. If the vacuum pump pulley were grooved to run on the front of the belt it would be the exact right length.
That being said, I was able to get the numbers off of the belt that failed, which was the correct length, ran under the vacuum pump, and allowed the tensioner to be in the correct spot.
The numbers were for a Dayco Belt, with the part number for the "Ambulance Package" IDI's. Looking at the specs for this belt, it is ~113 inches in length. The "non-ambulance" belt from Autozone is ~110.5 inches long. Looking at the difference, and "how much belt I need" for it to fit properly, I need 2-2.5 inches.......
The vacuum pump needs to be replaced, so at this point, I have the belt running across the top of the vacuum pump (which works just fine, even if it's not "right") until the replacement comes in, and I get the ambulance package belt. I will report back with the results, but I think everything will land right where it needs to.
So, sorry for the long post, but know I think I understand WHY the belt was spec'ed too short......
Oh, and for ~$40, I recommend anyone with a serpentine truck, keep one of the bypass pulleys behind the seat..... you may be hot in the cab, but you are still moving......
