[Mark]

Some coaches will throw a belt if the belt tensioners do not have air. To avoid the issue some owners run the aux compressors to add air to the chassis accessory system, turn the key and wait a few seconds to allow the accessory air pressure to fill the belt tensioners and then start the coach.

I never had that problem because I would never go off slow idle until my engine ran for a while, but I eliminated the pneumatic belt tensioner system because if it wasn’t the valve leaking, it was the regulator, or the push in fittings or the mini-air bags. If they were all OK it was the check valve.

Now my belts are always tight and if I have to replace one, all I need is 2 15/16″ open end wrenches and about 2 minutes and I can have the old belt off. Not as quick as the turning of a valve, but in 31 years of owning buses I have never had to replace a belt while traveling.

[Archived]

If I remember, and if it’s leaking and valve has a 1/4″ female open pipe port it’s leaking from, plug it. If you have to change belts pull the plug. It’s regulated for air pressure and wasn’t leaking there. A few years ago called Prevost Houston and that’s what they told me to do to get her in. Been 2 years and haven’t replaced leaking valve yet. . If cylinders leak Prevost has a parts kit for those. I have 2 and need to install one.

[Jeff]

OK replaced our belt tensioner regulator we got from Mira Loma. Of course then it needed to be set. We added a dial gauge and have regulator set at 52. Arriving yesterday from Valve Check in Minnesota were new 6203-1MM-1NPt check valves. Got an extra one as spare.

Arriving today wAS our 3A-74 single belt which is 1.88 inches wide which has 3 V grooves on underside to replace the triple AX-74 belts going on the triple pulley on engine to Junction box for radiator fan and A/C dash compressor

Looked great until I started the bus. How much wiggle or untrueness in a belt is acceptable. Seems to me, the belt should be truer. With Triple AX-74’s all runs smooth. The wider belt I was told was better at staying on when air tensioners are flat. Part of the experiment freshly starting engine, I released the air I added from our garage compressor to see how the belt traveled. It bagan to ride up on the junction box side of system Hit rear stop button shutting motor down. Took belt off and reversed it by repositioning 180 degrees and reinstalled Same out come. Wanted to climb up off pulleys HMMM frowny face

I was hoping to do away with the triple AX-74’s Now maybe not. Napa had to special order the belt from Tennessee last week, from another supplier so I had to pay freight

[Bill]

I tried the single belt on several of my buses and there was just too much vibration.

[Glenn]

I replaced the 3 single belts with the same single combined belt you have any there have been no issues and no vibration. I’ve not seen any unusual movement when the air bag is deflated.

[AL]

Heres a video i hope attaches

[Deleted User]

C’bus, email it to me and I’ll put it up.

[Bill]

I’ve been running the single-triple belt for a year without issue. But I never start my engine with slack belts.

[Rick]

I usually have slack belts at startup and the single triple belt has never jumped off, even when I forgot to let it air up to 90 # so the air bags would inflate. The smaller fan clutch belt did jump off (OOPS!) but the main belt was fine.