Bob K's HINO RB

[Dot]

Ha ha we also have to replace a couple of those studs (all of them actually) and gasket replacement... also wanting to have the clutch looked at.

[jon_d]

Bob,

if there is some thread left, there is a tool which is sort of like this:

Imagine a piece of solid rod. One end screws on to the remaining stud. the other end is a pilot hole size.

The allows you to drill out the stud while keeping the centre perfect.



Also, look up thread whisperers; it's a method of undoing nuts and studs etc. It's basically like this: very fractionally, you rock a nut back and forth, very gently almost with no perceivable movement. The rocking breaks the rust. Sometimes, it needs to be done all the way to the end.

[bobk]

Good morning Dot and Jon, unfortunately the studs appear to be broken off at the surface so no grip. I am hoping I don't have to remove the exhaust manifold completely with the attendant peripherals like the exhaust brake etc. I would then have to come up with a different method of guiding the drill bit to keep the hole centred and true. I'm not sure if my plan will work yet, it's just a guess, and I really don't want to start on the engine until the defect items from the vehicle inspection are done, as the vehicle would not be mobile. Dot, lets hope it is not a clutch plate failure, that would be a big job.

[T1 Terry]

The easiest way to remove sheared off exhaust studs unfortunately requires the manifold removal first. Either a mig welder or stick welder with someone operating the power point switch. Rest the electrode against the broken stud, get an arc to deposit a bit of metal from the electrode onto the stud. This piece will usually break off when you try to turn the stud but it will then leave some clean parent metal to weld another knob of electrode material. Now hang a nut over this weld blob and fill the inside of the nut with weld attaching it to the blob on the stud. Let it cool and the broken stud will simply unscrew. The heat/welding actually expands and then shrinks the broken stud breaking the rust on the threads and making it loose in the hole.
Replace all the studs, if one broke the others are about to break It is caused by the movement stress of the manifold caused by the exaggerated heat generated by the turbo within the manifold and the studs actually crack around the last thread entering the head, that is why they always break off flush with the head.

T1 Terry

[Busman]

I can attest to the heat shrink method.
VP needed some front axle studs to be removed for caster adjustment.
Guys at wheel align place used 1" rattle gun, no result.
Went home, heated each head until red, then sprayed with cold water, 1/2" rattle gun got them out with ease.

[supersparky]

The method that T1 has posted is the simplest I have seen so far. Just make sure that you don't use a stainless steel welding rod as it may attach to the cast iron.

[Dot]

Any of you able to do the job with assistance from G, D, & B ? for a start we can't weld...

[bobk]

Hmmm, verry interesting. I can weld some in a very amateurish way, and I do have a welder (in fact I have two stick welders, mask etc) but don't think I would have the confidence for that job. If I can't do it my way I guess I will have to go to a qualified person. Thanks for the input. There are certainly some clever people on this forum.
BobK

[Dot]

yes but they are not anywhere near us

[T1 Terry]

If the job can wait until we are back in Mannum and you can drive the rig up here, I'm sure between us we can get it sorted. Once you see it done a few times you will realise it's not near as hard as it sounds and works for removing any broken bolt, seized in wheel brg cup and even removing dry cylinder liners from an engine block. Quite an eye opener just how much shrinkage a bead of weld causes and helps to understand why certain techniques are required when welding materials such as cast iron and why jigs and pre/post heat treatment is used for complex assemblies

T1 Terry