Removing seized and sheared bolts.

[ajlelectronics]

2.8 Cologne, water housing on alloy fannymold. Two of the bolts snapped with little effort, one with 5mm of stud left, the other 10mm ish. I have cleaned everything up and wound a couple of nuts onto the remains so it needs welding together now. I would like this to be successful first time and I am wondering about power level? There is one hell of a heatsink there so the chance for no penetration into the stud is fairly high. I use an R-Tech Mig 180 with Argon mix, my assumption is that I will need to go fairly high power and try to aim for the stud rather than the nut and let the heat propogate.

Any comments please?

 

[Dcal]

My approach would be to try the one with the full nut first and see how you get on. If it breaks, worst case, you have a flush stud to deal with.

The one with 10mm of thread - plenty of power and blast the weld into it to get as much heat into the stud as possible, then let it cool a bit before trying to remove.

The one with 5mm of thread I would be inclined to weld a washer on first (to stop arc strikes on the head) then weld the nut to the blob of weld. If necessary use a 10 or 12 mm nut to give plenty of access and weld.
I think it would give a better change to get good heat into the stud.

 

[Shox Dr]

Are you in a rush? If not Alum would eat it out

 

[jordan1]

Why not pre-heat it first?.

 

[Hopefuldave]

Wot they said, plus make sure the nuts aren't galvanised.
Plasticene is alum-resistant if you're trying that, build a little dam around the studlet and get the alum as hot and strong as you can.

Saying that, I always end up drilling the remains out until I'm at the root of the threads then picking it out with a scriber so I can get a pair of needle-nose pliers on and wind it out...

Dave H. (the other one)

 

[Shox Dr]

Wot they said, plus make sure the nuts aren't galvanised.
Plasticene is alum-resistant if you're trying that, build a little dam around the studlet and get the alum as hot and strong as you can.

Saying that, I always end up drilling the remains out until I'm at the root of the threads then picking it out with a scriber so I can get a pair of needle-nose pliers on and wind it out...

Dave H. (the other one)

I’ve not tried it myself. From watching ut videos, agitating the solution and heat speeds up the reaction

 

[gordon stephenson]

As per Dcal above, I would make a 3mm Thick washer, Nice fit on the stud and large enough to get a good fillet weld to the nut, Let it cool and unscrew (fingers crossed) Forward and backwards, A little at a time.

 

[angellonewolf]

dont know if you seen my thread with a snaped bolt flush in a mower engine but i never had any luck with removing mine hope you have better luck

i welded quite a few times and it never bit in to the metal bolt every time it snaped could have been the bolt/ weld was the weakest point as the bolt was chemical welded in to the housing with a steel bolt and ali head

 

[mtt.tr]

Just get the stud as hot a possible with the weld.

 

[angellonewolf]

would have thought you had a good chance of getting the right hand one out ass there a good amount off meat on there to get a good weld

 

[Pigeon_Droppings2]

Mine took several attempts when I did it recently (also a water pump but restricted access). What I learned is that you really need to direct the mig wire very carefully at the stud itself...if it strikes off the nut you might get a cold weld or a void which won't work.

In the end I used a copper plate (protect the pump faces)....and I built the weld up on top of the stud before I then welded a bolt (yes bolt) onto the end of the built up area.

Mine had broken at the surface (like the one on the left)....and there was only room for a head or a torch but not both!

 

[cheb]

Before I had a welder I centre drilled some 6, 8 and 10mm bolts for use when pilot drilling broken studs. As long as there was about 1/2 a turn of thread protruding you could drill the pilot hole through the snapped stud.

 

[8ob]

As per Dcal above, I would make a 3mm Thick washer, Nice fit on the stud and large enough to get a good fillet weld to the nut, Let it cool and unscrew (fingers crossed) Forward and backwards, A little at a time.

The all important bit Once you are happy with the weld and you get it to break back and forth I find a few squirts of wd40 or the like down the back of the washer also help.

Bob

 

[ajlelectronics]

Just had a go, welder flat out and I couldn't get penetration to the stud. So it looks like linishing flush and carefully drilling out. I will have to be accurate on the vertical alignment of course, not easy with the engine in the car, freehand.

 

[many_methods]

Just a thought with the stubby one, if the stud is not getting hot enough before the nut fills up with the weld pool, could you try taking the nut off and instead welding a thin bit of steel bar to the stud itself?

I.e. drill a hole the diameter of the stud into a piece of say 3mm bar, place over the stud and weld on, then use the bar like a spanner to undo the stud once it's welded together. Perhaps a long shot but must be easier than drilling it out.

 

[Dcal]

dont know if you seen my thread with a snaped bolt flush in a mower engine but i never had any luck with removing mine hope you have better luck

i welded quite a few times and it never bit in to the metal bolt every time it snaped could have been the bolt/ weld was the weakest point as the bolt was chemical welded in to the housing with a steel bolt and ali head

On a lot of mower engines (well Brings and Stratton ones) the bolts are self-tapping hardened bolts and like you they are the only ones I've ever had a problem removing by the welding technique.
They just don't like being welded and will break off at the end of the weld. Also they don't like being drilled.
Never had a problem with an 8.8 bolt

 

[Dcal]

Just had a go, welder flat out and I couldn't get penetration to the stud. So it looks like linishing flush and carefully drilling out. I will have to be accurate on the vertical alignment of course, not easy with the engine in the car, freehand.

What size welder do up have?

I'm surprised it can't heat a 8mm stud no matter what size of a heating you have.
Try it on on a bolt in q vice on the bench to get your settings right
The heat is what's really needed to loosen the threads. If it was put together with Loctite you also need the heat to break the bond.
Drilling might work but you could end up needing helicoils.
Tig is by far the best tool for a job like that but mig or stick can be made to work.

 

[Dcal]

Are you in a rush? If not Alum would eat it out

What's Alum?
Will it dissolve the steel but not the alloy?

 

[Pigeon_Droppings2]

I think the key is to do a blob of weld at a time...build it up slowly. I then weld a bolt on the end...a lot less heat required Vs a nut.

 

[Munkul]

What's Alum?
Will it dissolve the steel but not the alloy?

he's taking the mickey - in that over time, the galvanic corrosion will dissolve the steel altogether.

Might take another 20 years though

I've always had good success with both MIG and TIG welding nuts on broken studs - always a first time for it to not work, though. As said above, it's the heat input to the stud that breaks the corrosion bonds... or helps to, anyway!