Help with belt

[Skip426]

Originally Posted by bpu699

If the ac compressor clutch bearing fails, doesn’t the compressor just lock up and spin? Meaning, it’s drivable?

If the internal bearing/compressor fails, isn’t it similarly drivable using the clutch bearing as long as you don’t turn the AC on?

I guess I’m asking, unless both the compressor AND clutch bearing fail, why not just change the belt and drive home?

The clutch bearing when failed ( locked up) will prevent the belt hub from turning , so the belt slips on the hub , until it starts to melt and breaks.
Internal failure of the compressor , will cause the the electro-magnet clutch to slip and overheat ; hopefully blowing the power fuse and allowing the belt hub to free wheel on the clutch bearing , before the heat of the slipping takes out the bearing , and locks up the belt hub and breaks the belt .
You'd have to hear the belt squealing and get the A/C shut off to save the clutch bearing , a very short window of opportunity . Slippage of the electromagnet clutch will produce enough heat to destroy the bearing in minutes, often before the fuse blows .
So yes if the belt breaks ; due to internal compressor failure ; and the belt hub still rotates freely , replacing the belt, disconnecting the clutch power , and driving is possible ; but that's seldom the case .

[ernieh]

Originally Posted by Skip426

Sorry to hear about your problems .

But , every Cummins diesel pusher , I've seen; heard of ; up till now, the dash A/C compressor , wasn't driven by the serpentine belt .
The serpentine belt , drives the fan hub ( idler in case of side rad ) and a V belt from the fan hub , drives the compressor. As per pictures below.
The V belt ( yellow arrow) can break and damage the serpentine belt.( green arrow)
But because the alternator and water pump are driven by the serpentine belt , a quick replacement of the serpentine belt , will get the coach mobile ; without touching the A/C compressor .
If your belt routing is different than these pictures . I'd love to see a photo.

I'm guessing that you have never seen a rear radiator FL chassis. Both that I have owned as well as many others have a single belt.

[BillW1]

I was up just outside Lima, Ohio in a new 2014 Thor Palazzo with less than 2,000 miles on it when the engine overheated and shut down. Discovered the serpentine belt broken.
Called 1-800-FTL-Help and they had it towed to the Lima, Oh Freightliner Dealer. Freightliner phone support was excellent, tow truck operator was excellent and Freightliner had it inspected within an hour of arrival at the dealership.
Turns out the A/C compressor locked up and caused the belt to break. Of course they didn't have one but expedited shipment arrived the next day and they installed it as soon as it arrived.
While it was a bad experience to be stranded at the side of a 2 lane road I can't say enough good things about the response from Freightliner Help Line or Stoops Freightliner in Lima.

[RichKimball]

Good service is always great to hear...in the face of adversity as we can be so vulnerable in our big rolling homes.

[Florida Panhandler]

Originally Posted by blang311

So our air conditioner compressor froze up snapped the serpentine belt. On a I SL9 Cummins 400. Mechanic came replace the compressor and now issaying that the serpentine belt that he matched up with the old one for length is the wrong size. How could that be possible anybody ever run into this we are stuck on the side of the road

Good timing. I had the very same experience. Luckily it happened when I moved the coach forward to hook up the truck in my driveway preparing to head south for the winter. AC Compressor on my ISL froze, shredded the fan belt. Called Coach Net, they sent me someone from nearly 70 miles away and after a week, I at least had a new compressor and a new belt and headed south for the winter. I don't have AC for the dash because one of the hoses had so much corrosion, it snapped off the old compressor and is "glued" into the hose. By that point I was so frustrated with the service guy that I just had him strap it up out of the way and I'll fix it later. It would probably have been cheaper and quicker to just call Cummins and have them do a service call at my house because that coach wasn't moving.

Mine was a single continuous serpentine belt which matches the routing on the left graphic that I have seen others submit. The original compressor was a Sanden 4822, ser 4591010470, the replacement compressor was a VAC Mod 7H15, part # CO4822C. The belt was an 8-groove, 1-belt system. Old # 3972263, New #5256769, or NAPA 25-080830HD. Hope this helps.

[PeterFTH]

My 2002 Cummins 400hp uses a separate belt for the AC, not the serpentine belt which runs the alternator and water pump via a tensioner.

[Jchemie]

I bought my current coach at 11 years old and 34k on the diesel. Being the mechanic that I am I replaced the two belts on my ISB 300 Cummings right away. Kept the two old ones as a spare in the paper belt holder from the new ones so that I could order replacements. Thus I have an emergency belt of correct size and the correct part number for re-ordering. Plus I keep a tensioner tool with the correct socket for my engine on hand. Does take two to install but person #2 can be anyone who’ll just hold the belt from falling off for a few minutes until I can slip it on while pulling the tensioner.

[Rixthe1]

Call the moho manufacturer. I guess the mechanic is mistaken. Some serpentine belts need to be forced on, even when the spring loaded idler is 100% compressed. I would change the idler pully bearings also, they fail much more often than other components. The compressor scattered metal inside the system. there is a screen filter in or near the receiver/dryer. I was a semi truck mechanic for 20+ years, before I got re-treaded. #Livin the dream in Arizona.

[Fourwinds93]

Originally Posted by blang311

So our air conditioner compressor froze up snapped the serpentine belt. On a I SL9 Cummins 400. Mechanic came replace the compressor and now issaying that the serpentine belt that he matched up with the old one for length is the wrong size. How could that be possible anybody ever run into this we are stuck on the side of the road

I had a similar issue when we first bought our unit. Similar motor, Cummins ISL 400 side radiator. When I brought it home going over different things and was checking the serpentine belt, it was shredded. I had a repair shop come up to fix it and I gave them the numbers off the old belt. Didn't work wrong size. Belt was even different from what was recommended. I bought an extra belt just incase. Hope you have it fixed now. One of my muffler clamps was only holding on by about one inch. Went to Freightliner for a replacement, they looked up the number and I headed home. Clamp was two inches to small. At least I know I have a larger muffler and tail pipe. Can't depend on part numbers.
Mel

[Mile Marker 42]

Originally Posted by bpu699

If the ac compressor clutch bearing fails, doesn’t the compressor just lock up and spin? Meaning, it’s drivable?

If the internal bearing/compressor fails, isn’t it similarly drivable using the clutch bearing as long as you don’t turn the AC on?

I guess I’m asking, unless both the compressor AND clutch bearing fail, why not just change the belt and drive home?

In many cases, when an A/C compressor seizes up, it won't spin at all as it is "locked" up. It will then throw/smoke the belt.

[NIACC]

Originally Posted by blang311

So the part number was not visible, freight liner didn’t know the belt but did send the diagram. It was the same one I had. The tech was not experienced with rv repair and it was looking bleak. He finally went and came back with a handful of belts. He bypassed the new compressor and we were ready to leave, 7 hours and a lot of money later.

I spent hours in an Advanced Autoparts parking lot doing that very thing, bypassing the locked up compressor with one of a handful of belts they had in stock. One, a bit narrower, worked and got me home.

Eventually replaced the compressor and fitted the correct belt from Freightliner.

[427ford]

I have two concerns. 1) is the clutch pulley on the original compressor the same diameter as the new one? Sometimes the new compressor comes with no pulley and you have to press the original on. If the new compressor came with pulley, and it’s smaller diameter, you may not be able to tightened the belt adequately. 2) you’ll want to protect the A/C system from contaminates. The cut lines and the compressor fittings should be covered with something (duct tape, etc). Belt routing is often on a decal under the hood. Hope this problem is behind you soon.

[RichKimball]

Originally Posted by 427ford

I have two concerns. 1) is the clutch pulley on the original compressor the same diameter as the new one? Sometimes the new compressor comes with no pulley and you have to press the original on. If the new compressor came with pulley, and it’s smaller diameter, you may not be able to tightened the belt adequately.

2) Belt routing is often on a decal under the hood. Hope this problem is behind you soon.

You may be mistaken thinking compressors vs. alternators.
Most a/c compressors come with the clutch/pulley assembled. I suppose they can be obtained without maybe. Alternators can come without the pulley however...and is common.
I have yet to see a belt routing sticker on a diesel pusher. Maybe they're out there somewhere.

[Old Scout]

Yup--serpentine belt-driven AC compressors is common on the ISL425, perhaps some 400's too. Agree, AC and belt config is a builder issue so Cummins cant help you. Small chance there is enough slack in the hose to add a new connection--not ideal but hoses can also be spliced....would definitely verify that compressor and pulley size/dia. are for correct for you engine....in this situation, some folks carry a shorter belt to by-pass the compressor so you can continue driving until professional/qualified service can be obtained...