Dented tank

[Smallfry]

I have a dented hydraulic oil tank that has a hard crease and dent in it. It lives under the bonnet of a Unimog, but I find it unpleasing, so I want to get the dent out. Of course, I could just leave it, but it annoys me.

Obviously cannot get on the inside to beat it out, It is made of 1.5mm steel, so a bit beyond popping it out, or pushing out with a stick. I do not have a stud welder either, so thats out. Could try drilling a hole and using a slide hammer, but its right on a curved corner, so it would not do a satisfactory job.

Annoying thing is, that my old mate George, who was around when I did my apprenticeship, would have looked at it, cigarette in mouth, then looked up at me over his half moon glasses, shook his head, and walked off with it. Half an hour later it would be back, and no one would ever know it had been dented. I do not, and no one I have ever met since, have his metal shaping abilities.

Only way I can think of doing it, is to grind the welded seam, and split the halves. Sledgehammer to crack a nut really, unless anyone has any other ideas ?

 

[winchman]

What about tacking a bolt on and using a slide hammer?

 

[Blobber]

That's stretched the metal too much just to "pop out"
If its liquid tight I wouldn't start cutting into it, just try and tap the side back in a bit and fill the dent

 

[Wildefalcon]

How much is a new tank?

 

[Anguz]

airline to pressurise it.... end up making it a completely different shape, then start searching online for a new one

 

[Morrisman]

Air line, blow torch, cherry red, dent eases itself out.

It’s easy peasy, I saw it on YouTube.

 

[Wildefalcon]

airline to pressurise it.... end up making it a completely different shape, then start searching online for a new one

Air line, blow torch, cherry red, dent eases itself out.

It’s easy peasy, I saw it on YouTube.

I wonder if you made a frame to hold the rest of the tank in shape would that actually work? Presuming it doesn't explode.

 

[CompoSimmonite]

I think cutting section out, straightening dent out on bench and then rewelding the section back in would be the method I'd go with

 

[bricol]

If it really really bothered me . . . I'd shut the bonnet and not look at it - if it isn't leaking, don't fix it.

I might, only might, weld something as a pull tab in the bottom of that crease and start levering, pulling, while smacking the side of the dent in.

Or just smack the side in, while hoping it doesn't split, and fill the rest.

I would be doing the least amount of cutting into and welding back in as possible to reduce chances of leakage later.

 

[Nomad]

Is is a pressurised vessel or just a reservoir?

If not pressurised can you cut an access hole on the opposite side of the tank and use rods / bars / poles to tap the dent out from inside?
Or use a 2x2 timber to support the dent from inside and hammer into shape from outside?
Plate over your new hole when done, the repair doesn’t have to be pretty if it’s out of sight

Plan B: Put a splashguard / heatshield / knitted tea-cosy over it so you can’t see the dent??

 

[julianf]

The question,

"How much is a new tank"

..is important in two respects -


Its not just a case of "is it worth attempting repair when compared with replacement" but, also, sometimes overlooked -

"How much will a replacement cost if this one gets destroyed in the repair process"

If it's 100% functional, but the look bothers you, how about some body filler!?!

 

[julianf]

If it were me, I'd leave it.

If I had to do it, the compressed air and heat "seems" like a good idea but I have no experience of that. I might try or I might not.

Other than that, I think I'd drill a hole in the opposing face, just big enough to get a rod of something hard in, and hammer out the dent like that.

But then we are talking still obviously repaired, rather than perfect.

If it works currently I'd certainly just leave it.

The OP mentions "unimog" so I'm guessing the rest of it won't be showroom?

 

[knighty]

I'd go air pressure and heat

start low and keep turning air pressure up... stop before the rest of the tank bubbles out and hope that's enough pressure to push that out

I think I'd cut into the corner before I cut the seam

might be able to cut 3 sides of a rectangle and bend that up to give enough access to bend the tank back to shape, then bend the flap back down and weld it in

any rust inside?

 

[dave h 2]

Make your own version of this , make some 'keys' weld on and pull.

 

[gordon stephenson]

I have a dented hydraulic oil tank that has a hard crease and dent in it. It lives under the bonnet of a Unimog, but I find it unpleasing, so I want to get the dent out. Of course, I could just leave it, but it annoys me.

Obviously cannot get on the inside to beat it out, It is made of 1.5mm steel, so a bit beyond popping it out, or pushing out with a stick. I do not have a stud welder either, so thats out. Could try drilling a hole and using a slide hammer, but its right on a curved corner, so it would not do a satisfactory job.

Annoying thing is, that my old mate George, who was around when I did my apprenticeship, would have looked at it, cigarette in mouth, then looked up at me over his half moon glasses, shook his head, and walked off with it. Half an hour later it would be back, and no one would ever know it had been dented. I do not, and no one I have ever met since, have his metal shaping abilities.

Only way I can think of doing it, is to grind the welded seam, and split the halves. Sledgehammer to crack a nut really, unless anyone has any other ideas ?View attachment 494664View attachment 494665

Just fill it and spray over the tank, My son used to run 6 Unimogs for his crop spraying business

 

[anto44]

What size is the tank? If you're going to pressurise it fill it with water first, you shouldn't pressurise something like that with air for the same reason you always do a hydraulic pressure test on pressure vessels.

 

[brightspark]

Air line, blow torch, cherry red, dent eases itself out.

It’s easy peasy, I saw it on YouTube.

and the fumes of the oil your welcome unless you steam or clean it out
and heating it localy bit by bit with an oxyacetylene torch just done one on a badly dented cross member on my van quite nicely

 

[wyn]

Pressurise it and heat the dodgy bit.

Used to do this with 2 stroke exhausts and the dents would come out easily enough.

 

[cocker]

Put some acetylene in the tank waive a match round the filler hole and you won't see that dent again !

 

[GRW]

When I did a bit for a guy I did some work for on a Unimog.... the parts prices were truly astonishing!
His air cleaner had rusted the bottom out... its just a big can to hold a large ish air filter element - over £1600
(I cut the rotten part of the cylinder out, rolled dome sheet metal and welded it in, then some black paint... ; even with my iffy talents given its location you'd struggle to spot it).

Dent. A mate dented the corner of his 1980's thick metal Iveco in similar fashion. He welded a bolt on, then rigged up a ratchet strap round the rsj of his workshop and just cranked the dent out. I happened to be there & watched him do it - and it worked amazingly well