So , I know this issue has been brought up numerous times previously, but, being new to this,I was just wondering if certain models, chassis ,or years of coaches are more prone to the bulkhead problem than others. Or is it just something to watch and be aware of in all Foretravel coaches. We are headed to "the mother ship" in a few weeks for a full coach inspection, but just for my own knowledge going forward. Again, sorry to beat a dead horse , but I read all the previous posts and could not find specifics addressed... PS. Ours is a 2008 Nimbus 338... thanks again.
The "bulkheads" are an integral part of the Foretravel factory built
monocoque chassis. If a Foretravel coach was (or is) built on a chassis manufactured by another company, then it will not have the "bulkheads".
This is up through 05, correct?
Also, was there something done in 01+ to alleviate some of the issue? I vaguely recall someone mentioning that in passing but don't recall the source
I think FOT started using their own in-house factory built monocoque chassis (which includes the "bulkheads") around 1992 or so. This was the replacement for the GV, OREG/OFEG/ORED/OFED and Unihome GV models being built up to that time.
I'm not familiar enough with the post 2000 models to know exactly when all production was shifted to a chassis built by outside vendors.
FWIW, in the ForeForum Wiki, under the listing of model specs, the last model year that mentions the word "Monocoque Chassis" is the 2001 data.
Foretravel Specifications, Floorplans & Brochures [ForeForums Foretravel... (https://wiki.foreforums.com/doku.php?id=through_the_years:specs)
Monocoque Chassis is akin to Jumbo Shrimp, it can only be one or the other.
Any coach with 8 air bags has bulkheads/monocoque construction. So, for example, a 1988 U280 or U300 has bulkheads.
Brett,
"Also, was there something done in 01+ to alleviate some of the issue? I vaguely recall someone mentioning that in passing but don't recall the source". Do you know anything about this, was there some improvements, perhaps difffrent bolts/nuts or process ?
Sorry, have not opened up a post 2000 coach bulkhead.
Another member best described it as "bridge" construction. Wiki quote: "Monocoque (/ˈmɒnəˌkɒk, -ˌkoʊk/), also called structural skin, is a structural system in which loads are supported by an object's external skin, in a manner similar to an egg shell. The word monocoque is a French term for "single shell".
First used for boats, a true monocoque carries both tensile and compressive forces within the skin and can be recognised by the absence of a load-carrying internal frame.
The term monocoque is frequently misapplied to unibody cars. Commercial car bodies are almost never true monocoques but instead use the unibody system (also referred to as unitary construction, unitary body–chassis or body–frame integral construction),[14] which uses box sections, bulkheads and tubes to provide most of the strength of the vehicle, while the skin adds relatively little strength or stiffness."
In the case of most Foretravels, the bridge construction is limited to the area in the length of the compartments, in our 36 foot U300, about 15 feet in the middle of the coach is the bridge type of construction. A conventional frame construction extends approximately 14 feet to the back from the bulkhead and 7 feet to the front from the forward bulkhead. This is why our coaches flex so much and break windshields, etc. So, in the case of our 36 footer, the bridge construction is only 41 percent of the total length of the coach.
The old GM Greyhounds were semi-monocoque construction as they also had supports riveted to the skin of the bus. This was from the very back of the bus to the nose and gave great strength minimizing any flexing.
Pierce
Follow-up question to BigOil76's upcoming coach & chassis inspection and "assessed" condition in terms of structural integrity. As I understand the issue, failure occurs when the structural skin, and/or structural system frame tubing (the skin is attached to) disintegrates (rusts) to the point of no longer being capable of supporting the load. Other than torquing bulkhead bolts or removing the skin, does an instrument (or other technique) exist that can "view" the underlying condition of the metal structure (without removing the skin)? Like using an x-ray device to exam the bones within a body or using sonar to map surfaces underwater? Just curious...
When Keith Risch inspected mine he crawled around underneath on a creeper tapping the subframe with a hammer.
I used a borescope on ours but the only way to really check how extensive it is means you have to peel the bottom skin off.
Pierce
Elliot: Yep, I recall KeithR mentioned that he has success using a hammer on the bolt heads and listening for a "ping" or "thud" sound.
Pierce: Was a bore scope used to look at a specific area or overall framing? Did you remove the trim below the bay doors and run the scope down each square tube or drill a hole for access? Did it help locate or eliminate structural points of concern?
I drilled a hole at an angle through the big angle iron and into the tubing on the far side on each side of the coach. I wanted to see if any water had penetrated into the interior of the tubing. None had. I'm sure the exterior of the tubing has some rust but the only way to really check is to do a visual on it. I have not checked on the rest of the tubing. It would be nice to have removable panels on the belly so they could be quickly removed to check but I've got too many other projects.
I did have several Roloks fail in both the back and front bulkheads and sistered them with long 3/8" stainless bolts. I used a very long special tap to thread the far side so no hole was made underneath for access. In the propane/fuel tank compartment, I could reach both sides so used a long 3/8" grade 8 and nut.
Pierce
TGordon,
And that is where the myth was created.
P
The other "telltale" of a compromised bulkhead is RUSTJACKING of the box beams.
You should be able, when lying on the ground looking up at the FG underbelly to slightly see the outline of the box beams. Look in the center (fore/aft) of the coach to get a pretty good idea.
If you see markedly more "outline" at a bulkhead, the steel has turned to rust.