Delamination Question

Topic: Delamination Question (Read 2186 times) previous topic - next topic

Re: Delamination Question

Reply #75 – April 05, 2020, 06:58:43 pm

No tag axle.

Re: Delamination Question

Reply #76 – April 06, 2020, 10:34:27 am

It sounds like you're not in a spot where you can work on it. If this is the case would suggest not checking torque on bolts, they will almost certainly break. Were it me, I would ease down the road to my shop, avoiding rough or unpaved roads. If separation increases too much, some emergency welding might be called for. I would expect there are other possible emergency solutions, possibly chains and load binders to keep the two ends of the bus pulled together. I think it's safe to say some repair is called for.

Re: Delamination Question

Reply #77 – April 06, 2020, 10:56:18 am

An aluminum shop might be investigated to make overlapping sheets to cover the belly after the repair is done. Our Sac shop has a big shear machine to make any size needed.

Pierce

Re: Delamination Question

Reply #78 – April 06, 2020, 11:20:27 am

Quote from: Chuck Pearson – April 06, 2020, 10:34:27 am

It sounds like you're not in a spot where you can work on it. If this is the case would suggest not checking torque on bolts, they will almost certainly break.

In inspecting many, many bulkheads over the years, I have found this to not be the case. These are grade 8 bolts. Torquing to 15-20 ft lbs doesn't come close to their stretch/break point, even if not at OE strength.

And, from torquing many hundreds of them, I have NEVER broken a Rolock. What I find is that they either torque up or are ALREADY (the critical part) broken with the end badly rusted (vs clean metal break). The break is generally 4 or so threads in where the bolt starts into the closest wall of the box beam.

I have seen many many people tell me all their Rolocks are just fine (looking at the bolt heads). It can absolutely give a very false sense of security.

Let me state it a different way-- if a bolt will not torque to 15 ft-lbs, it is not doing you much good holding a 30,000 pound coach together.

Re: Delamination Question

Reply #79 – April 06, 2020, 12:01:58 pm

I have broken several Roloks trying to torque them. I've even broken a couple when I tried to remove them. They would not move so tried to tighten/loosen a tiny bit and then repeated this several times before they broke. Yes, the bolt breaks just where you said. They have two primary places to rust in place, in the threads just on the far side of the angle iron in the threads into the tubing and at the far end where they are threaded into the tubing again. So, in trying to remove them, you are fighting the rust at two places in the threads and also a fastener weakened by the reasons below.

While Roloks are somewhere between grade 5 and 8 when new, rust and hydrogen embittlement plus rust jacking weakens them from a smaller amount in a bulkhead in great shape to ZERO in a rusty bulkhead. The only thing holding them in the worst case scenario is the rust between the body of the bolt and the angle iron. In other words, few Roloks in older coaches are anywhere near their original strength.

Roloks were never intended to be used in this application but rather in quick metal building construction where there is no moisture. They have zero rust proofing/coating and were a TERRIBLE choice that Foretravel made for this use. This whole design along with the way it was implemented is the achilles' heel in our coaches.

Replacement with hot dipped galvanized or stainless fasteners is the only way to make the joint half way secure. Even then, moisture behind the angle iron will create more pressure against the fastener. Spraying the area with sealer is not an answer either. Forcing the angle iron away with a flat chisel and then mechanically removing the rust and then coating the back side with something like spray galvanizing followed by a specialized frame paint should do the job the factory didn't.

Pierce

Re: Delamination Question

Reply #80 – April 06, 2020, 12:18:40 pm

Pierce. You are absolutely correct. But this was a design flaw know and repeated without any build design changes. All metals can be properly sealed to prevent corrosion, yes they must also be maintained. This type of fastener was easy and quick. The box they go threw should of been sleeved for every fastener. More money. IMO the corrosion preventative measures could of been much better. Lapping two Major structures together with self tapping bolts is not correct. It's easy. Properly sealing structure takes time, money, and preventative maintenance for the life of the coach. Hum maybe we have extended beyond what a builder would want. No end date. No new sales. Acid etching, epoxy primers, powder coating costs. We are not building them, we're maintaining our investment and attempting to use some of there useful life during ours. IMO
Scott

Re: Delamination Question

Reply #81 – April 06, 2020, 12:27:37 pm

Quote from: dsd – April 06, 2020, 12:18:40 pm

But this was a design flaw know and repeated without any build design changes. All metals can be properly sealed to prevent corrosion, yes they must also be maintained.
Scott

Totally agree with this assessment. But, with "care and feeding" (mostly keeping water out) and replacing the occasional broken bolt by thru bolting they can last many decades.

Neglect them and we have all seen what can happen-- even to where coaches separate when driving, fuel tanks fall out on the ground (front bulkhead failure) etc.

Re: Delamination Question

Reply #82 – April 06, 2020, 12:57:07 pm

I may be off but I think if I had to rebuild the bulkheads and frame instead of bolting the fiberglass bottom on why not urethane foam the whole bottom. It's a better insulation then Styrofoam and it would completely stop any water from the bottom and it would
insulate the steel tubing's. I have used urethane foam under coaches before and even in wheel wells and it wears really well. It's
just a thought.

Re: Delamination Question

Reply #83 – April 06, 2020, 01:50:37 pm

Quote from: oldguy – April 06, 2020, 12:57:07 pm

I may be off but I think if I had to rebuild the bulkheads and frame instead of bolting the fiberglass bottom on why not urethane foam the whole bottom. It's a better insulation then Styrofoam and it would completely stop any water from the bottom and it would
insulate the steel tubing's. I have used urethane foam under coaches before and even in wheel wells and it wears really well. It's
just a thought.

I had thought of that and you are quite correct that a spray insulation company could insulate the bottom nicely. I was thinking of a rigid waterproof foam only because the spray foam would make future maintenance more difficult if any welding, etc. had to be done.

As our coaches age, this becomes more the rule rather than the exception. For many, the coach they have purchased has already seen several owners. It then becomes difficult to determine what maintenance the coach has had, where it was driven, etc. So, this sudden delamination or bulkhead problem comes as a ugly surprise when the coach seems otherwise to be in great condition.

As the forum grows with new members, it's especially important to have them aware of the potential problem and how to check if their possible or existing purchase has the problem or the extent of it in these veteran coaches. If bulkhead work was done previously, was it rebuilt carefully like Don did or a shade tree patch job as seen in some of the old posts.

Pierce

Re: Delamination Question

Reply #84 – April 06, 2020, 01:58:02 pm

I should have said that when you remove a Rolok that you think you may have broken, if the broken surface is all rusty, it had previously failed and was only held in place by rust on the angle iron. If it shows any fresh metal, it failed when you tried to torque it or remove it. I had a couple with a little shiny metal at the broken end.

Pierce

Re: Delamination Question

Reply #85 – April 06, 2020, 02:00:27 pm

Pierce,
An idea how much torque you are applying on the ones that have broken?

Re: Delamination Question

Reply #86 – April 06, 2020, 02:43:13 pm

Quote from: wolfe10 – April 06, 2020, 02:00:27 pm

Pierce,
An idea how much torque you are applying on the ones that have broken?

That was about 10 years ago. I had 3 or 4 missing total. A couple on the curb side, both in front and back. Several others were held in place by rust and showed the classic rust jacking failure with rust on the broken surface. I had the idea that I would remove the rest and just replace with long all thread stainless. When I tried to remove them, they would not come off so I shot liquid wrench around the head. When they still would not move with a little force, I tried to tighten and then loosen. This was with a 3/8" ratchet so not a torque wrench. Anyway, this worked on several and they came off but others broke off with not that much effort and showed the fresh metal at the break.

To check how strong the tubing was, I found a section of rectangular tubing up by the fuel tank on the passenger's side where there was access at both sides of the tubing. I drilled it out to 3/8 and installed a grade 8 bolt, flat washers and locking nut and torqued it to grade 8 specs to see if there would be an deformation in the tubing. As I remember, I torqued to 33 ft lbs for the coarse threaded bolt with no discernible distortion in the tubing. This is almost twice the recommended torque for grade 8 in 5/16"

To be honest, I had no idea what the bulkhead structure looked like or the tubing between the bulkheads. I had several ideas that once I actually looked at the construction, were not going to work. Those of you that have been on the forum for a long time probably remember the huge amount of rust behind just a couple feet of the angle iron that I removed with a Sawzall and metal blade once I forced the angle iron away from the bulkhead with a flat chisel and single jack. All in a coach with no visible rust on top or bottom of the big angle iron and a HWH six pack that looks like it was installed perhaps a year before. I had also looked inside with a borescope/endoscope and had no interior rust in the tubing.

That is the reason I would like to have a removable bottom in sections on the belly of the beast so it would be easy to make any kind of inspection or replace any fasteners. You just don't know what is happening until you take a careful look.

Pierce

Re: Delamination Question

Reply #87 – April 06, 2020, 02:46:38 pm

My point in suggesting the op not check torque on rolocks was since he is unable to work on it at present location, and has to drive it to the shop...there's no percentage in doing so at this time. Better to hope inertia prevails for a bit more.

Re: Delamination Question

Reply #88 – April 06, 2020, 03:58:06 pm

Pierce I agree that spraying is hard to get off and yes I would only do that with a proper rebuild that was meant to last as you said
like Don did.

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Re: Delamination Question

Reply #75 – April 05, 2020, 06:58:43 pm

Re: Delamination Question

Reply #76 – April 06, 2020, 10:34:27 am

Re: Delamination Question

Reply #77 – April 06, 2020, 10:56:18 am

Re: Delamination Question

Reply #78 – April 06, 2020, 11:20:27 am

Re: Delamination Question

Reply #79 – April 06, 2020, 12:01:58 pm

Re: Delamination Question

Reply #80 – April 06, 2020, 12:18:40 pm

Re: Delamination Question

Reply #81 – April 06, 2020, 12:27:37 pm

Re: Delamination Question

Reply #82 – April 06, 2020, 12:57:07 pm

Re: Delamination Question

Reply #83 – April 06, 2020, 01:50:37 pm

Re: Delamination Question

Reply #84 – April 06, 2020, 01:58:02 pm

Re: Delamination Question

Reply #85 – April 06, 2020, 02:00:27 pm

Re: Delamination Question

Reply #86 – April 06, 2020, 02:43:13 pm

Re: Delamination Question

Reply #87 – April 06, 2020, 02:46:38 pm

Re: Delamination Question

Reply #88 – April 06, 2020, 03:58:06 pm

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