How do I replace the serpentine belt on cummings 350 isc

I take a picture of path of belt, and then remove belt with tensioner. Old seems to come off easier than new goes on. I had to ask for help from wife while I held the tensioner loose.

Different engine but when I change the serpentine belt, I use one of the 1" ratchet straps to pull and hold the breaker bar on the tensioner. This frees both hands to route the belt and then I can release the ratchet strap and I'm done.

I posted about changing my serpentine belt and A/C compressor belt with photos here.

I've changed my belt a couple of times. I do it from underneath. I can get my 1/2 inch ratchet on the tensioner easier from down there and have a little more room since from the top, I have to crawl across the engine with not much room.

I agree with krivanj on the a/c belt. Loosened the bolts then I use a tire iron on it to bring it back into adjustment. Hold the tension and retighten the bolts.

You are using a 1/2" drive in the tensioner to move the spring, right? Ac belt needs all four bolts on compressor loosened, then stretch the belt adjustment with a pry bar.

Not sure there is a "secret" to adjusting the A/C belt. If tension was proper before removing it to replace the serpentine belt, use a piece of tape above the adjustment area to mark where you want to return it.

With just moderate tension on the bolts securing the compressor, use whatever means you have to return it to its original position. I use water pump pliers. But, a couple of screwdrivers, bolts, etc in the adjustment area will allow you to pry it back to its proper position.

BTW, you have a Cummins.

I agree with wolfe. Find a strong friend to help you. The tensioner is a bear. I changed one and it took me and my son (hes a big guy) more than 20 minutes to get the belt on. As for the a/c belt, I never adjusted one on a Cummins

Assume you have verified that you have to correct belt.

Most belts with automatic belt tensioners (usually 1/2" square drive) are pretty tuff to rotate. But, you should be able to do it-- even if you have to use a short pipe/cheater bar.

Now, if this is a rear radiator, access is a lot more difficult and goes much better with someone below and someone above.