Serpentine belt...how do you get it on?

[96f250psd]

hey I have a 96 7.3l and My Idler pulley blew up and now I cant seem to get it back on...yeah for rain and darkness. Can anyone explain what I need to do to get that back on. Thanks for your help.

[pipelayerjdh]

Do you still have the diagram under the hood? Put a wrench or pull handle on the tensioner pulley and twist it enough to get the belt on. You have to pay attention to routing, because I think there is a way to rout the belt so that almost fits, but doesn't.

[tmcdaniel]

Not sure about your year, but for a 99, simply insert a 1/2 inch socket wrench or breaker bar (just the square driver part) into the square hole on the tensioner and pull toward the passenger side of the vehicle. That will release the tension and allow you to put the new belt over the last pully. I find it easiest to route the belt and so that the last pulley is the idler. Also, if you are using a short 1/2 socket wrench, then you might need to grab the end of it with vice grips to get the necessary leverage. I would highly recommend checking the belt tensioner so see if it is starting to come apart. I just replaced mine, as the belt kept getting eaten on the edges. The first time that happened the frayed portion acted like a whip and tore off my upper radiator hose and a good deal of the insulation from the bottom side of the hood. Hope this helps.

Oh and before I forget, my 99 has a belt routing diagram under the hood.

[USAFdieselman]

I am not sure if the OBS truck are like the SD's, but you have to pull the upper rad hose too.

[tmcdaniel]

USAFDieselMan is correct. The factory shipped my truck with an upper radiator hose that goes through the serpentine. When it comes time to replace your hoses, you might consider buying the slightly more expensive hose that routes above and to the right of the serpentine and rides in a perfectly sized half moon groove on the alternator bracket. I did just this when I had my mishap. I also took a portion of the old serpentine, cut it off and placed if between the hose and the 2 zip strips that I used instead of a hose clamp where the hose rides in the half moon cutout on the alternator bracket. Call me paranoid, but I prefer fishin to fixin.

[CELAYORK]

Originally Posted by 96f250psd

hey I have a 96 7.3l and My Idler pulley blew up and now I cant seem to get it back on...yeah for rain and darkness. Can anyone explain what I need to do to get that back on. Thanks for your help.

In the OBS you dont have to disconnect the upper hose, and there are not the square hole on the tensioner, instead there are only a 18mm IICR, bolt in the pulley of the belt tensioner that is left hand threaded, you put a breaker bar with the exact size of the bolt and pull toward the passenger side of the vehicle.

[Frank 93L]

idler flung off my truck too....going down the highway with a 14k+ pound isuzu NPR dump bed full of gravel on the back in pouring rain from a severe thunderstorm.

wasn't my favorite experience

[tubzz]

Originally Posted by CELAYORK

In the OBS you dont have to disconnect the upper hose, and there are not the square hole on the tensioner, instead there are only a 18mm IICR, bolt in the pulley of the belt tensioner that is left hand threaded, you put a breaker bar with the exact size of the bolt and pull toward the passenger side of the vehicle.

this correct but for some reason i'm thinking it was 15mm.

for crank to the passager side
under the crank,WP (back side of belt), tensioner,alt,idler(back of the belt),AC,VP(back of belt),PS then back to the crank

get around everything but the top idler then put the sockit on the tensioner and install it on the idler

i hope that make sence and i didn't forget a pully in that mess

[CELAYORK]

Originally Posted by tubzz

this correct but for some reason i'm thinking it was 15mm.

for crank to the passager side
under the crank,WP (back side of belt), tensioner,alt,idler(back of the belt),AC,VC(back of belt),PS then back to the crank

get around everything but the top idler then put the sockit on the tensioner and install it on the idler

i hope that make sence and i didn't forget a pully in that mess

You are right, in the stock tensioner it is 15 mm and and aftermaket with upgraded arm (like mine) is 18 mm.
If you have a problem routing it. There's (or should be) a sticker with a diagram showing the routing in the engine compartment.

[CELAYORK]

Or better here is an squematic:
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