Re: Bulkhead Separation - Planning for the Worst Reply #20 – December 12, 2014, 04:57:19 pm I guess I will chime in about part of the quote attributed to Wayne of FOT... I think that the idea of separating the ¼" angle iron from the bulkhead by 3" to 4" is just nuts. It could be done, but is simply not necessary or even desirable in any case I can imagine. An inch to an inch and a half is more than adequate to get the area cleaned out and even coated with a rust preventative. As far as the risk of delamination in the sidewalls above the bulkhead joint, it is highly unlikely to be caused by the bulkhead joint separating in the usual manner. I puzzled about this issue because of the separation in the rear bulkhead of our coach had me scratching my head in how that could happen without being transmitted to the walls above that area. The answer is that the bulkhead will hinge at the top just below the floor where it is attached to the drivetrain carrying longitudinal framework (which is supported by the horizontal frame members through which the top of 'H' frame of the suspension and air bag assemblies support the sprung weight of the coach). Anyway on our coach, the rear bulkhead (defined as the sheet metal partition which separates the basement compartments from the drivetrain area behind it are tied to this heavy engine and tranny framework by a total of four 2"X2"X¼" vertical pieces of angle iron which are tack welded to the sheet metal of the bulkhead and structurally welded to the 3"X3"X¼" transverse angle at the bottom and the heavy longitudinal 3"X5" rectangular tubing of the drivetrain carrying subframe. The bulkhead assembly (which I will define as the sheet metal partition combined with the heavy 3"X3" angle and trailing arm mounting shackles etc.), is put under tension at the bottom by the trailing arms with every bump and dip and by application of transmission retarder or engine brake. The basement is what keeps the rear axle located in the vertical plane and is capable of resisting the tension as long as the fasteners are in good shape and the basement framing is not compromised. When the fasteners and/or basement floor framing are compromised by rust, whatever the source, the angle iron pulls the bulkhead assembly away from the basement. the reason that the structure above the floor typically isn't adversely affected is because the four 2"X2"¼" vertical pieces of angle iron crack where they are welded at the top and the bulkhead as a whole hinges away from the basement at the bottom. The fenders are flexible enough to give and bow outward when the bottom of the bulkhead assembly pulls away from the basement floor. when I redid my the utility compartment portion of the basement framing and repaired the bulkhead joint on our coach, I fabricated some heavy 3"X"3 rectangular tubing with integral gusseting welded to the longitudinal drive train carrying framework and to the vertical pieces of angle iron which were cracked.The act of separating the bulkhead joint and controlling the gap (on the rear bulkhead only) is fairly simple and doesn't involve prying it apart or using a come-along. I am not recommending that anyone take this on but just describing how it can be done based on my experience on our own coach. Raise the coach as high as possible with the HWH air system. Place your four safety stands in front and behind the rear wheels (You do use four stands per axle, don't you? ). Dump just enough air to make contact with the safety stands and pin them in place with the weight of the coach. Place an appropriately sized bottle jack (the harbor freight 12-ton air assisted bottle jack just fits and makes this much easier) in front of the rear wheel next to your front safety stands if you have room, or replace them if you don't. With no fasteners between the transverse angle iron (having already been either broken or removed), work on each side's bottle jack alternately to apply downward pressure to the"H" frame near where the bottom of the air spring is attached to the suspension "H" frame. The suspension "H" frame will then act as a lever (think Teeter-totter) with the wheels as the fulcrum to pull the joint apart via the trailing arms. I can't stress enough that the rear safety stands are crucial to control and limit the amount of separation at the bulkhead joint. If you have a slightly separated bulkhead joint and your vertical angles are not cracked at all, you need to determine what has moved before starting this process. Personally, I wouldn't let fear of cracking the vertical angles keep me from cleaning out the joint and to be able to protect it. The reason that I wouldn't is that, in my opinion, the vertical angles by themselves don't serve as a structural joint (at least not a strong one). The way I read it is that these vertical angles are mainly there to stiffen the sheet metal bulkhead which also helps support the sides of the waste or fresh tanks. They also help support bulkhead while the coach is being built before the basement is bolted in place. That said however, with the semi-monocoque design of the Unihomes and Unicoaches, everything plays a role in the strength of the coach as a whole. I felt strongly enough that I wanted to help the basement resist the pull of the trailing arms, that I went through the trouble to fabricate a reinforcement. I would caution anyone who has a bulkhead separation issue to use your own judgement, or the judgement of somebody you believe capable on how to proceed. What I have done on our coach, and what I have said obviously doesn't constitute a recommendation about what anyone faced with similar issues should do. My purpose of posting this is purely educational and it is my hope that the information might help someone else reach a decision about how to approach solving a problem such as this, either through their own efforts or to help them choose a place to carry out the repairs.DonQuote from: hughes54311 – December 11, 2014, 03:09:39 pmI'm looking at buying a 2003 U320, but have no way to inspect it. I'm concerned about bulkhead separation so contacted Foretravel service for "worst case" planning . . .They'll inspect for free, but I was told that repair could range from 8 to 20 hours (@ $150/hour), depending on the extent of the fix. Ouch!Tech also indicated that DIY repair was possible. I've read about folks doing this, but Bulkhead Separation article indicates that . . . "the most important part of the repair is cleaning the surfaces between the steel pieces at the joint. He [Wayne] said the joint had to be spread 3-4" apart so all oxidation could be removed and a rust preventative be applied. He said that without this work the rust in the joint would just keep expanding, breaking any fasteners. The spreading process is definitely beyond the capability of most of us (with the risk of sidewall delamination!)"So, DIY or Nacogdoches? Quote Selected
Re: Bulkhead Separation - Planning for the Worst Reply #21 – December 12, 2014, 05:23:55 pm I suspect Don will verify, but cleaning the back of the box beam (referring to rear bulkhead) does NOT, repeat NOT insure that "all is well". Particularly with leaks in the wet bay that migrate down into the basement floor (same box beams and foam construction) that will hold water against the unprotected iron box beam, the front of the beam or even the inside of the box beam may be compromised. That is why keeping the wet bay dry is critical to longevity.I have seen something as simple as a bad gasket ($.15) on the fresh water fill that leaked for a long time do serious damage to a bulkhead. Same for water heater drain or water heater pressure relief valve. It is NOT rocket science to keep the bulkhead in good condition for many decades. It is also possible through what I will call neglect, to allow it to fail.I have inspected 25 year old Foretravels with perfect bulkheads and 10 year old ones that have been allowed to fail. Quote Selected
Re: Bulkhead Separation - Planning for the Worst Reply #22 – December 12, 2014, 05:33:27 pm That is correct Brett. In our case, the worst of the rust was in the area between the bottom skin and deck skin of the basement adjacent to the bulkhead joint. This is where the blue Polystyrene insulation lives. The worst of it is the area which was filled with two layers of ¾" plywood that fills a cavity in place of the polystyrene insulation, presumably to give an attachment point for accessories such as water pumps, hose reels, etc. The plywood was close to the outboard edge of the basement floor in four places on our coach. The two that were in contact with the basement side of the bulkhead joint were especially soaked and rotting, therefore holding moisture against the steel framing in direct contact with the pointy end of the Rolok bolts.DonQuote from: wolfe10 – December 12, 2014, 05:23:55 pmI suspect Don will verify, but cleaning the back of the box beam (referring to rear bulkhead) does NOT, repeat NOT insure that "all is well". Particularly with leaks in the wet bay that migrate down into the basement floor (same box beams and foam construction) that will hold water against the unprotected iron box beam, the front of the beam or even the inside of the box beam may be compromised. That is why keeping the wet bay dry is critical to longevity.I have seen something as simple as a bad gasket ($.15) on the fresh water fill that leaked for a long time do serious damage to a bulkhead. Same for water heater drain or water heater pressure relief valve. It is NOT rocket science to keep the bulkhead in good condition for many decades. It is also possible through what I will call neglect, to allow it to fail. Quote Selected
Re: Bulkhead Separation - Planning for the Worst Reply #23 – December 12, 2014, 05:50:06 pm Nac.Get Xtreme, FT and MOT to look at it, pick the one you like the best (Not necessarily the cheapest) I had MOT do mine, and Xtreme or MOT check every time I am in town. Â was less than $1,000 (coach buck) including undercoating.Tim Quote Selected
Re: Bulkhead Separation - Planning for the Worst Reply #24 – December 12, 2014, 09:28:03 pm Wayne at FT did mine-also $1000. Quote Selected
Topic: Bulkhead Separation - Planning for the Worst