Belt broke, forced to limp home...help.

[Shed]

I was on the way home this morning at o dark thirty and suddenly the battery light comes on and I have no power steering/brakes...

Pull over and find a shredded belt. Problem is we had heavy fog and I'm on a county 2 lane road. I feared a serious collision, so the truck was running and the gauges were all ok with the exception of the charging system. I decided to limp it home 5 miles. kept it slow(35 mph) due to lack of steering and brakes. Truck ran fine and did'nt over heat or anything out of the ordinary.

My questions.... Did I hurt it limping home? How hard is it to change a belt? I am NOT a mechanic and have limitedabilities. There are no mechanics anywhere near and I hate to pay a tow bill for 35 miles.:(

Thanks for any help.

[DmaxMaverick]

You didn't hurt anything. The Duramax engine was designed to run an extended distance w/o the acc. belt. The water pump is gear driven. As you've noticed, only the power assist and alternator were absent. While in a cooler climate, you could have driven it until the batteries got too low to run the electronics.

The belt is easy to replace. There is (was) a diagram sticker above the radiator showing the belt routing. Study it, and the pulleys. You'll need a 15mm wrench to engage the tensioner (on the tensioner pulley bolt head). A long breaker bar or ratchet (with a cheater) works best. Grooved pulleys engage the grooved side of the belt, and smooth pulleys engage the smooth side of the belt. Route the belt onto all the pulleys (you DO NOT have to go around the fan like you would with a V-belt, the smooth belt back will engage the fan pulley as you route it over the grooved pulleys), ensuring the belt is centered on all the grooved pulleys, and save the alternator for last. Hold the belt in place near the alternator pulley (use a thumb as a temporary tensioner) and rotate the tensioner as far as it will go with the wrench. Work the belt onto the alternator pulley (keep fingers clear of the belt/pulley, lots of tension gonna happen), centering the grooves. Slowly release the tensioner, watching the belt to make sure it didn't slip off any pulleys. If it is routed correctly, the tensioner should only release a little. All this takes me less than 2 minutes solo. A pair of extra hands will be very helpful, especially the first time. Once you understand the belt routing, the rest is simple. Take your time, study the diagram and be patient. If you can't find the diagram sticker, let me know and I'll dig one up and post it here.

If your failed belt was original, the pulleys were probably also. Now is a good time to replace the tensioner and idler pulley. This is also very simple to do. All you need is a 15mm wrench for both. Use dielectric grease ("tune-up" grease, Permatex brand) on the bolt threads and aluminum mating engine surfaces. Tighten about as tight as you can by hand with the wrench. You can do these later (and will probably have to soon), but it requires R/R of the belt, again. New belt and pulleys should run you about $120 or less at your local parts stores. The dealer will be double that, and doesn't have anything better than the others.

[DmaxMaverick]

Also......

If you don't want to tackle this yourself, charge up your batteries to full and just drive it to your mechanic. 35 miles can be done easily. I don't suggest driving too slow, as lower gears and unlocked torque converter generate more heat, and allow less air through the cooling stack (radiator). 50-55 MPH should get the TC locked once warmed up. Limit your electrical load to necessities, such as no radio, HVAC (heater blower), lights, phone charger, etc. Avoid additional starts or extended idle periods. Get ready to go, start it and just go. You could have someone follow you, just in case. If you run out of juice, you can charge it back up with jumper cables. Or, bring along a generator. It isn't rocket science.

[Shed]

Well, I guess I get lucky sometimes... Thank you guys for the responses. I was worrying that I was hurting the old girl driving it. I had a friend replace the idler pulley/tensioner a couple of years ago because it was making noise, but he said the belt was fine.... I'm headed to the parts store now.

Thank you again!!! Once again all of you and your expertise have helped save my butt again!:D

[EdHale]

If you are replacing a belt on a truck with two alternators are your instructions above still good? I have 103,000 on my truck and have been thinking of replacing the belt just because for some time.

Thanks.

[DmaxMaverick]

If you are replacing a belt on a truck with two alternators are your instructions above still good? I have 103,000 on my truck and have been thinking of replacing the belt just because for some time.

Thanks.
It's essentially the same. Route the belt according to the diagram, and "save" the passenger side alternator for last. Once the tensioner is rotated completely to the stop, the belt should slip over the pulley. The belt-pulley engagement rule is the same: Grooved pulleys engage the groove side of the belt; Smooth pulleys engage the smooth (or back) side of the belt. Also, don't go "around" the fan, like on V-belts. Start at the crank pulley, and work your way up. Make sure the grooved pulleys have the belt centered in the grooves. At 103K, I'd suggest replacing the tensioner and idlers (you'll have a few more than a 2001 LB7). Keep your old belt and stash it in the truck, along with a tool for the tensioner. This way, you'll never have to run w/o a belt.

Also note:
Belts should be replaced at the FIRST sign of deterioration or about 100K miles, whichever comes first. Waiting could be costly. Depending on how they fail, they can destroy many things under the hood (including the hood). A 300+ HP nylon/Kevlar reinforced weed-eater can do a LOT of damage. I've seen aluminum intake pipes shredded by these. Wire looms, hoses and tubing don't stand a chance.

[Shed]

Thanks again for all the help! Belt install was great up until I started the truck! I found out why the belt broke to begin with.... Idler pulley siezed up... So with the new belt it blew the bad idler pulley apart. Now I'm on my way back to the parts store for a new pulley. Fingers crossed.

[Kennedy]

We've been doing belts on most any truck that we have in for injectors or head gaskets just for good measures. Truth be told I can't remember ever having a serp belt fail unless something seized up, but I guess if they get old enough they can go.

Replacement is relatively simple, BUT be sure to look at the diagram. The belt never needs to pass between the radiator and fan clutch. This one tends to get people sometimes.

[Shed]

Tahks everyone! Back on the road and running pretty well right now!!!

[Kennedy]

I might suggest sourcing a new GM pulley. Helper installed aftermarket his on his 2001 with 90k just for the sake of doing it. Something like 900 miles later and in the rain he was putting the old one back on. Both had same bearing mfr, but one was Japan and the other China.