Fan Bracket Problem

[Larry Fisk]

Hey Guys, Just a heads up. As you may remember I just had to spend a lot of money replacing my radiator, charge air cooler, fan, and fan bracket due to my hydraulic motor cooling fan bracket breaking in British Columbia, Canada. I was looking at the repaired cooling fan when I noticed the lower support arms on the bracket were bending in allowing the fan to intrude further into the shroud. This was after only 2,100 miles on the new bracket. I contacted BCS and was told that Radiator Supply House in Sweet Home Oregon made the new bracket and that I should talk to them about it. After e-mailing several pictures and visiting with them on the phone they agreed that this was another disaster waiting to happen and the bracket they made was insufficient for the forces it was dealing with. They are now in the process of making me a new, improved bracket which I will again have to pay to have installed to replace the bad one they sent me. So after spending over $12,000 to get this problem fixed it looks like I will be spending more to correct this new problem. I'm just glad I took a look at it and didn't take for granted that the bracket they made was good enough. So again, check those brackets!

[Larry Fisk]

I would also like to say that the people at Radiator Supply were very pleasent and never made me feel like I was seeing things. There are several more pictures I sent them to show the problem. In their defense they explained that they were just following drawings they recieved from Monaco and the drawings were not always as they should be. They also build these brackets for Monaco and said that our year, 2005 seems to have the most failures of this kind. Anyway I just wanted to pass this on in case anyone else installed one of these brackets because they may have a problem like mine.

[Edward Buker]

Seems like these brackets should be made in the form of a U channel for strength or use rectangular tube. Hope they take the bull by the horns and provide the "Fort Knox" model for you Larry. This does look like poor engineering on Monaco's part.

Larry, could you ask the Radiator Supply House if the would create a kit with a PN, once they have the better design complete, so that the enhanced bracket assembly could be ordered from them. I would think that owners of coaches with this design bracket would want to preventativly make the change given the expense.

Later Ed

[Larry Fisk]

Yes, here are pictures of the original fan bracket and the one that Radiator supply House Built. You can see the the original was channel iron and much beefier than the new one that was built. I sent them several pictures of the original so they could see the difference in the make up and material. A friend of mine who has the exact same coach supplied me with the original pictures since my bracket was destroyed and disposed of after the repairs were complete. As you can see there is a huge difference. Anyway I appreciate the fact that they are going to make it right. It was suggested that they might want to let Monaco know if they sent them any of the bracket designs they sent for my repair. These will not last long is my guess. Mine was ordered thru Beaver Coach Sales, so I did send them pictures and explain my problem to them. I will suggest your idea Ed, that's a good one.

[Edward Buker]

It would have been great to have the original bracket in order to failure analyse the weak point and what actually caused the fail. This is tough duty and the balance of the components involved keeping vibration in check is a prerequesite for having the system last. If you could see the old component it would define the first to fail point (probably a bend or a weld) and that area could be improved in the new design.

Is it possible to get one of these brackets from Monaco? They look beefier by far and a good starting point. What one could envision is taking some flat strap steel of the same thickness and width as the current struts and putting a 90 degree bend on it and welding that bended section onto the flat part out by the bolts and then box welding the u channel down to the flat of the hydraulic motor bracket. That would seem like the next step in improving the strength of this system. I'm not a mechanical engineer or metal fabricator but others who have tinkered here may want to comment.

Later Ed

[Joel Ashley]

Taking heed of Larry's warning, I went out to check my fan setup.  It is quite different than his, and perhaps a better arrangement overall.  I opted to take a snapshot and post it as a consideration, if available or a conceivable rebuild design, or adapt an existing part for other models.  Of course the number of mounting points around the fan shroud impacts the possible design, but the flat perimeter of Larry's seems to offer no limitation there;  the motor side would just need an appropriate bracket.

-Joel

[Larry Fisk]

From my initial post about this incident I posted a picture of the failure while waiting for the tow truck. The failure seemed to take place where the motor bolted to the bracket. The repair shop said parts of the bracket were gone when they went to remove it. I think it might have helped to send pictures of it to radiator supply house before they built the new one but what happened is the repair shop called BCS at my suggestion and ordered the part from them so we assumed it would be identical to the bracket that broke. I was at work when the job was completed so my wife picked up the coach from the shop and drove it up to Alaska without me. I never got to actually see the repair until I returned home from work. Anyway I was surprised to see the new bracket support arms bending. At first I thought I was just being paranoid after spending so much to get this repaired, so I called my friend who has a Beaver exactly like mine and asked him to see what he thinks. He confirmed my fear and said the fan blades were actually into the shroud 3" furthur on the lower portion of the fan. This was very disappointing news after getting all this repaired. RSH is supposed to send me pictures of the new bracket before they ship it so I can see what I think. Your set up certainly does look better Joel.

[Larry Fisk]

Here is the picture I posted of the original failure. It's hard to tell exactly what happened, but it looks like a weld may have broke where the motor bolts to the bracket.

[Joel Ashley]

If you only have a few brackets actually holding that motor, I'd research if there wasn't another CAT radiator on another Beaver model or even another brand of coach, that uses a circumferential system like mine, and with shroud distances close to yours.  I would assume that a multi-mount circumferential cage distributes loads better than other systems and resists failure or collapse better as a result.

But I realize you already have a fix in the works and a lot of dough spent.  Such a remedy may not be feasible at this point unless the fabricators think it reasonable to do.

Joel

[Larry Fisk]

The design on yours certainly does look more bullet proof Joel. Another thing about it I like is the cage offers some protection if you have your face in there looking in your engine compartment. If my fan were to come apart again parts would be flying as they did before. This could be deadly or at least a serious injury. I have also wondered why they didn't build these with electric cooling fans instead of hydraulic. Well, we will see what new design they come up with. I just hope it last a lot longer than the previous two brackets, the original and the first new one.

[Gerald Farris]

 Larry,
The side radiator cooling fan is hydraulically driven out of necessity. To use an electric fan motor that would pull the amount of air that is needed to provide cooling with high torque and variable speed control, would cause two problems since it will not be a little 20 amp fan motor like your car uses.

The first problem is the weight of the motor. An electrically driven fan motor that would supply the power necessary would probably weigh 4 or 5 times as much as the hydraulic motor and be much larger so mounting it would be very difficult and would require a complete redesign of the cooling system.

The next problem is what do you would use as a power source. If you use 12V DC, the permanent magnet motor will be heavier than an induction motor an require more maintenance (brushes), but a 120V A/C induction motor will require an inverter that is on anytime the engine is running to power it. Also the engine driven alternator would have to have a substantially higher capacity to operate the fan.  

Since a hydraulic system is already necessary to provide power steering, the hydraulic fan is a much better option.

Gerald

[Larry Fisk]

Thanks for the explanation Gerald, everyday is a school day for me, always learning something new.

[Edward Buker]

I'm still thinking, that if it were me, I would try and get hold of the original beefier bracket that Larry pictured and have a good welder box in the arms. The additional bent piece of metal would double the thickness out by the bracket bolts, box the U channel, and then overlaps the motor bracket hub and get welded there. As I look at Larry's photo I think the U channel is just butt welded to the hub which is not a strong joint without some gussets and those joints are prone to fatigue and cracking with vibration over time. There looks like some room for a small second reinforcement plate that would overlap the arm and motor bracket on the fan side of the bracket.

Monaco may have already made some improvements to the original design if they have been involved with some fails so maybe the new bracket would be better.

Joel's design is a lighter hydraulic motor and fan assembly and this design would probably not hold up for Larry's application unless it was designed for Larry's motor and fan size.

This seems like a case, given the expense of the radiator, where you would want to do all you could to have the "Fort Knox" bracket next time around. Just one guys opinion...

Later Ed

[Jeremy Parrett]

Gerald,
  does the 2000 Marquis C12 have a suitably strong hydraulic fan mounting bracket??  I am going to the coach tomorrow and will try to take pics of my set up.

[Gerald Farris]

Jeremy,
The 2000 Marquis was made by SMC and they used a totally different mounting system for the radiator cooling fan on most of their Magnum chassis coaches.

You radiator cooling fan mounting bracket does not mount to the fan shroud like most Monaco built coaches. However it uses 2 straight pieces of 2 inch steel angle iron with a steel plate welded between them in the center where the hydraulic motor mounts. This mounting bracket bolts directly to the frame at both ends. Therefore it can not be compared to the shroud mounting brackets that Monaco used.

Gerald