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Dolphin danger!


HTRDLNCN

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While under the rv I noticed the frame above the rear spring support is craked..Under further investigation i discovered that the enitire rear (everything behind the wheels! )of the coach including both grey and black water tanks are supported by some flimsy reinforcements welded all the way up at the spring perch making the rear spring mount the fulcrum point.The entire coach from the wheels back has a measurable slope basically the shell is bending now..This is bad engineering plain and simple. Now I will have to figure out if it is possible to fix the damage and make it safe or just junk it. Great way to start my rv experience..

dolphincrack1.jpg

dolphincrack2.jpg

dolphin.jpg

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That crack definitly looks bad. Would it be possible to jack up the rear frame assembly and then weld the crack back together on the sides and bottom. I would then weld some frame size c channel on the side of the frame rail (drivers side and passenger side) maybe a couple of feet exstending on both sides of the crack. If you can not weld the top of the c channel to the frame you can drill 1/2 inch or larger holes along the top of the c channel and weld the holes to the frame.

Greg

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something like that is what we have planned but its tough to say how long it will hold,,that a lot of weight/length thats waggling around back there.

rearbend.jpg

I dont understand why they cut the original truck frame at the rear axle mount,thats moronic. My Toyota one ton dually box truck had the full frame all the way to the back. Doing a search on the net I found similiar complains from people owning full size Dolphin coaches about too much rear weight and cracked frames..seems like they did the same mistakes with their full size rvs.

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What floorplan is that, the barrel chair and L-shaped little dinette? Also what's the manufacture date of the coach and truck? Does it have a generator installed, looks like it in the pics... I've got a '90 Dolphin that I've only had about 3 months, I'll get under it in the AM and check it out, IRC its frame extensions start about halfway between the rear wheels and the rear of the coach, not just behind the wheels, at least I hope not! :unsure: I'll post in the AM with what I find on mine.

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Mine looks perfectly fine. It's identical to yours in the pictures, but no cracks. I'll definitely be keeping a good eye on it from now on. Are you sure that National RV cut off the frame because I don't think they really did, our 22' Dolphins are much longer than all the 1 ton dually work trucks I see around, I'd say that our original frames end at nearly the identical spot where the dually 1 ton Toyota truck frames end. I'm not an engineer but would it really have been better to have started the frame extension connection and welds behind the suspenion mounts just floating in thin air?? How many miles are on your coach?

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My commerical box truck had the frame go back at least 2 extra feet then had a an extra full size frame grafted to that to the extreme rear. Much better design,it had a 700lb hydraulic lift bolted to the back of the box and felt ten times sturdier than the motorhome. Probably overkill for an rv but I would feel a lot safer if it was built the same. If a car ever rear ends this thing it wont stop till it hits the rear axle!

Yes barrel chair and dinnette.

No generator

See the blocks the rear suspension is bolted to at rear? the normal commercial chassis does not have those either. there is a real frame there to bolt it to at least on the one I had.

Title says 1991 Dolphin but truck is a 90

It has 180K miles

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Same plan exactly as mine, which is a '90 Dolphin on an '89 Toyota. Ours only has 77k, but as I said I'll definitely be keeping a very close eye under there. Is this RV a recent purchase? Keep us posted as to how everything goes with your situation. Good luck with it!

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:o Ok here are some frame pics. My frame has the extension below the level of the truck frame rail. I do not like the design though. It looks weak. Extending the rail and putting reinforcment along side would be stronger. I have considered pulling a very small trailer but the frame would need to be beefed up. Note the steel block sitting on top of the added rail which the coach sits on. I realize mine might be different because its a 4x4. The spring mounts seem to be custom, made bigger. This is a 1986 18 foot 4x4 sunrader.

Note that my extension also begins just past the rear spring mount.

It may be in my case that there was not a 4x4 1 ton chassis so the standard 4x4 was used and modified to make the chassis. That would account for the 5080 lb GVWR sticker instead of the 5500 lb 1 ton GVWR rating.

Look at your stickers and see what it says. You may also have a modified chassis instead of the 1 ton.

frame1.jpg

frame2.jpg

frame3.jpg

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That looks pretty close to the stock one ton design though not exact,that looks a whole lot stronger than mine..My Dolphin has a puny extension maybe 1/3 the size of that extending toward the back..When I post the pictures youll see what I mean..Its a joke..

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Best of luck Ray on your frame fix this weekend, hope all goes good. Its hard to see clearly from the picture but it appears someone has added an extension block under the rear spring mount, makes me wonder if possibly when they removed the original mount from the frame if they cut too deep and created a weak point and with the rear overhang weight over time it started cracking at that point?? just a guess.

Now Greg with your latest pictures I can see more clearly the method to the madness, pretty exotic labor intensive change. They have removed both the front and rear spring hangers from the frame, added the extension blocks to lower the mounts and rehung the axle to gain the lift with the axle mounted on the top of the springs as opposed to having it mounted on the bottom of the spring pack like a normal 4x4 axle. Why it was done that way I can't say unless maybe for tank or camper body clearance.

Does your camper use the standard long bed chassis wheelbase or has it also been extended midway between the cab and frong spring hangers to accomadate the camper length? I enjoy the pictures, someday maybe I'll figure out how ya do it, computer stupid toy nut, what can I say.

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Nolan

I will have to crawl under and see about any extensions. I will measure the wheel base tonight when I get home.

To post a picture you must first have some sort of online service to store your pics. Then when you post a message just above the text box are the code buttons. The one that says "IMG" is the one for adding an image. its then just a matter of entering the URL of where the pic is stored such as

http://www.toyotamotorhomes.com/technicald...s/og_ff_800.jpg

Thats the location of the pic that apears below.

og_ff_800.jpg

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Greg your extensions are way beefier than mine and you have much less overhang than this thing.

here we go,,you can see the crappy work they did,crappy materials they used,skinny crossbar which is way bent from the load,crappy bumper brackets which are basically breaking off,god help anyone counting on that to stop anything from coming up your rear. A monkey could have designed this better..

Sorry for the ranting,I just hate bad engineering..

bottombent.jpg

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Don't take this wrong, because there's no doubt that the rear of our RVs' undercarriage could have been better built. But considering your week old used RV has 170k miles on it, it has held in there. And who knows how that thing was driven and loaded over those 170k miles. National RV has a better than average reputation in the RV industry and there are thousands of very happy owners. I'd imagine that if you got under the rear of most if not all Toyota based RVs you'd fine very similar designs. Just out of curiosity, what did you pay for that thing? Did you have any idea about the frame damage when you got it, because I find it very hard to believe that the previous owner wasn't aware of those frame cracks...

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paid $3500,no generator,water damage around vents and down side wall from awning pulling out side wall,missing cushions ,mechanically sound.

previous owner was a 78 yr old retiree,he only owned it one year,he bought it from a floridarv dealer..I doubt he knew or ever got under to look. he only used it once.

I have read people towing with some toyota based rvs and I am thinking they have to be much stronger back there to be able to tow anything. Mine has a specific label in back warning not to tow anything with this thing. Gregs rv looks to be much stronger and better setup in comparison.

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