[Archived]

Jon – Need to identify the years, I couldn’t answer that, it’s for the newer coaches with the split charge air coolers not like my 02 that is stacked.

[Chad]

I did not try to identify the years because it might affect all. That is why the service bulletin link will be posted. It might only impact coaches with the CAC alongside of the radiator but until we know the full scope of the problem a couple of minute inspection will verify if a coach is affected.

---

1984 96" with 8V92TA

(remodeled Liberty Coach)

Greenwood, MO

[Dan]

My 02 chassis does not have the problem. Fan clutch was replaced earlier this year and these is at least a 1″ gap where yours was rubbing. Thanks for pointing it out to me in WPB.

[Deleted User]

New fan clutch 9/17. 2” gap, sweet.

[Davy]

New fan clutch installed 5/17. No problems so far…

[Archived]

New fan and fan clutch 10/2016. Will have check, our Coach is in Indio CA, we are at home until next week.

[Brady]

Jon,

Thank you for providing this information. You are a scholar and a gentleman.

Jim

[Art]

I’m pretty sure we’ll find this is the for the later coaches with the side by side radiator and charge air cooler.

[Archived]

When the belt is in place it is difficult to see and appreciate what is happening. The very subtle clues that something is happening is there appeared to be a slight amount of rubber dust and the edges of the belt started to show some fine threads along the edges.

When the belt really started to destroy itself it happened very fast and I am guessing that at least three ribs were gone within 600 miles from a belt that was completely intact except for the thin fibers along the edge becoming visible.

[John]

I have a very similar problem but for different reasons but with a slightly different outcome also resulting in the loss of the cooling fan belt.

The following is the list of parts replaced by Prevost along with the OEM parts.

Qty 1 – 052476 fan clutch supporting bracket (new replacement number)
Qty 1 – 550966 fan clutch assembly (new replacement number)
Qty 1 – 550836 or Y2-0540-02 (OEM Fan Clutch Assembly number)
Qty 1 – 052588 (OEM Fan Clutch supporting bracket)
Qty 1 – 531469 Silicone Hose
Qty 1 – 531471 Charge Air Cooler Hose
Qty 1 – 24190616 Hose clamp.

The fan clutch and supporting bracket on my coach were replace with the new part numbers due to the failure of the fan clutch. Subsequently the 052670 pivot pin/bolt bent down during normal driving causing the tensioner roller bearing to be slanted or out of the same plane as the two pullys (for no better way to describe) fan clutch and gear drive. Not being in the same horizontal plane resulted in the fan clutch belt to partially (1/2” – 3/4” of the belt) ride off to the side of the tensioner roller bearing scoring and cutting or shredding that much of the belt resulting partial and complete loss of the belt. Of course I had a spare belt on board so I trimmed the belt down to 1” wide and positioned the belt to one the side of the fan clutch and gear drive pullys such that it remained on the tensioner roller bearing enough to get me back on the road and back into Mira Loma Prevost Service Center. My concern is that if there is weight difference between the OEM parts and the replacement parts the OEM pivot/bolt will not support the higher weight. The pivot/bolt was replaced and fan belt is running correctly but this could happen again due to the weight difference if there is one.

I do not recall if I checked the actual pressure of the air bag that tightens the tensioner but believe it was the correct pressure. It the air bag was for some reason under inflated perhaps that allowed the entire assembly (fan clutch, gear box, and pivoting tensioner to bounce excessively going down the road (terrible Califoria roads) putting added strain on the pivot bolt.

I have reached out to Prevost to try and get the weights of the new parts replaced to determine if there is in fact a weight difference and will recheck the air bag pressure.

If it is a weight issue this would be big concern for Prevost Owners who experience fan clutch replacement.

[Archived]

Jon’s mention of his air bellows pressure reminded me that I should disclose what might be significant.

I have eliminated the air bag tensioners because on my coaches with them I spent far too much time dealing with leaky fittings, replacing air bags, chasing leaks in the regulator and valve and generally offsetting any time savings in belt replacement with added maintenance. My replacement was a home made jack screw system. The reason I mention this is because I am certain that part of my success at keeping the flat belt between the fan clutch and the gear box on my 2006 XLII is attributable to being able to raise the fan belt idler pulley higher than is possible with the air bellows insuring both belt tightness as well as a higher angle at the bracket to keep the belt from hitting the bracket.

Anyone coming to Petoskey or our October seminar can look and see what I have done and how my belt issues have been resolved.

[Patrick]

Jon and others……….

I made this entire issue regarding the change to the fan clutch and how all of this relates to belt wear and potential damage to Prevost.

I was assured there was a service bulletin. There is not. I asked for some advice from Prevost, and specifically a service bulletin so this entire problem would be known and corrective measures taken if needed. So far nothing has been issued.

If it seems like I am a little bitchy you are correct because problems of this type will shut a coach down. My sense that this needs attention is in part driven by the fact I spoke to a couple of Prevost technicians about the problem relating to clutches and fan belts and both are not only aware of the potential problems, but both told me how they have to grind and modify the clutch support to prevent issues with the belt. And yet I have seen nothing in writing from Prevost.

[Art]

Jon

With the new/retrofitted fan clutch I do not or have not had an fan belt rubbing on the mounting bracket problem. The initial belt alignment after the fan clutch retrofit was proper and operated for several hundred miles but then for some reason I have not yet fully determined the pivot pin bent down causing the roller bearing to be slanted, not flat, not parallel, not on the same plane as the two fan belt pullys (fan clutch and right angle gear box). Either more physical weight with the new fan clutch and mounting plate or not enough pressure in the air bag I believe caused this to happen, because I believe of bouncing up and down due to the terrible highways here out west, especially California where roads are the worst in the nation. That pin bending randomly after 10 years and 100K miles just does not make sense The ONLY thing that changed was the fan clutch replacement. ??????????

Does that make sense to you AND has anyone reported or have you heard of this bent pivot pin/bolt issue and what my have been determined to have been the problem????

[Rob&Sue]

That “pin” that holds my roller bearing is a 5/8″ (maybe larger) bolt. If it was tight after the clutch and belt were reinstalled I cannot understand how it is remotely possible it could get bent.

I don’t know if you observed the clutch replacement but the fact the idler pulley has a bent pin suggests to me you are dealing with the same issue that caused my coach to eat a belt. First, understand a direct replacement clutch exactly like the original allows the belt to be removed just by releasing the pressure on the bellows. But when the new clutch was installed on my coach the belt could not be replaced because it would not go over the pulleys as it did with the original clutch. The solution was to remove the idler pulley, then install the belt and then replace the idler pulley. I was there when this was happening and it should have sent me a strong signal something was wrong. My brain did not process the problem however.

When my belt failed I had replaced my air bag belt tensioners with my jack screw arrangment but since my concentration was on designing, making and installing my tensioners I failed to notice the belt driving the new fan clutch was hitting the bracket. When I noticed fuzzy edges on the fan clutch drive belt I started to did into it. That is when I realized all that was transpiring.

A longer belt than the original solved the problem completely for me and now I do not have to remove any idler pulley to change a belt. All I have to do is loosen the belt tension. I am pretty sure your pulley was removed and was not reinstalled tightly. If Prevost did the clutch replacement it is probable the techs knew of the issue with belt contact with the bracket and automatically ground the bracket area where the belt passes so you do not have that problem. But unless you have a longer belt you cannot remove or install the belt just by releasing the air to the air bags, something you can easily verify.

[Will]

With a larger fan belt pulley does that mean the fan turns at a slower speed?