DANGER....INSPECTION REQUIRED

[Jon Wehrenberg]

Over the last several years I have been aware that the electric box in the rear of our coaches may break away and drop down onto the engine.

Let me repeat that for purposes of emphasis. The big box in the rear over our engines with all the electrical connections can come loose from its fastenings and drop onto the engine. This is a serious hazard that should be considered unsafe until the mounting is reinforced or new fasteners are used.

I have monitored my electric box mounting integrity routinely, as recently as upon arriving in OKC, and when I got home I realized the mounting rivets had failed and the box was sitting on top of the air intake tube.

On my box there are two terminals extending from the bottom and they were both in contact with the metal air intake tube, but as near as I can determine there was no electric short as a result.

The photos below show the attachment brackets. The failure was of the four pop rivets in each brakcket. The brackets remain secured to the rear bulkhead, but the rivets attaching the brakets to the box failed in tension, not shear as I would have expected. The failure was due to galvanic corrosion.

If the box on your coach is secure I recommend leaving it as it is and secure the box to the top of the bulkhead using an angle or to the sides of the box and bracket using flat strips. The electrical mounting panel appears to be a piece of masonite and it is at least 3/4" off of the back of the outer electrical box so any screws you use to secure the box can extend into that area.

[Orren Zook]

Thanks for the heads up on this, Jon

[lonesome george]

THANK YOU JON!! I'll be scheming on a countermeasure this evening. And did I say Thank you?

[truk4u]

I forgot all about that deal, but will be reinforcing mine ASAP. Thank's for the up close and personal reminder Jon.

[phorner]

WOW! That is scary stuff! I'll be checking mine in the morning.

Thanks, Jon for the heads-up.

[dale farley]

I'll be checking mine also. Thanks for the heads-up.

[GDeen]

Thanks Jon - glad to hear there wasn't a serious problem as a result.

Would be handy to have a section on the forum dedicated specifically to these type of issues that need to be checked periodically to prevent a trainwreck. 2 other threads in the last couple of days of similar stuff - the hydraulic hoses and Hector's door problem come to mind. A separate index from all the other discussion to make it easy to keep up with. Just sayin...

[Kenneth Brewer]

"the electric box in the rear of our coaches may break away and drop down onto the engine."

Stupid question: I don't really know if this is a problem on H3s. I don't seem to recall (not parked here at home) any box over the engine itself. I think just the flat floor over the block, and everything else either in the compartments on either side just ahead of the engine, or behind it. Would you be able to say, Jon? Thanks.

[Jon Wehrenberg]

I can't say if this issue is related to H3 coaches, or even the XLII for that matter.

For those that intend to check the integrity of the box mount, I checked mine at OKC and 880 miles later found it sitting on my engine. My practice was to grab it and tug a little. Obviously that was not a reliable way to check the fastenings. In retrospect if I did manage to cause the box to come loose by tugging on it I don't know how I would have dealt with it at OKC if it did come loose.

To reattach the support brackets to the box I had to remove a lot of minor stuff like the oil pressure gauge and sender and drop it out of the way. cut a lot of cable ties so I could flex the box down further to access the rear, I had to get the air intake tube out, and ironically I had to remove the hoses from the header tank (see the thread about replacing those) so the box could be reoriented. I spent several hours to get the brackets reattached and the box back in place and I had the luxury of my garage and all my tools. Out on the road such as in the OKC campground the problem would not have been easily resolved.

I now have new pop rivets holding the brackets in place and I went to larger screws to secure the brackets to the bulkhead, but now I have to make additional parts to do a better job of securing it because I now know the pop rivets will fail again in a decade or so.

My point is I don't think it can be checked. Assume it will fall, and use your imagination to create additional supports to secure the box to the bulkhead so you are not relying on pop rivets as the sole means of support.

The design of this method of supporting the box is very poor and I am willing to bet that over time every single box in the entire Prevost fleet is going to drop down.

[tdelorme]

Well great, you wait until we're 500 miles into an 1800 mile one way trip and then you post two new issues for me to worry about. If those hoses break or the damn box falls off, it's your fauld, A1!!
Yes dear, I know it's hot and scary sitting on the engine and holding the box, but just a few more miles and we'll be at Jon's house.