Struggling with a sheared stud

[944Scott]

Guys im after some suggestions.

In attempting to fit my de cat pipe one of the studs on the pipe from the turbo has sheared off. As their is some stud left I had thought about halving the thickness of the flange on this side to allow me to use the remainder of the stud except the thread that is left is stretched. I have tried to use a die on it without success and I have even tried making it a smaller diameter for a smaller die but to no avail.

Im undecided on the next course of action, do I try and grind the stud flat then try to drill and tap a hole with it in situ (crossover pipe is also still in place) or do I aim to remove the exhaust pipes off the turbo ( I am loathed to remove the inlet manifold after fixing an inlet leak) sod's law says I will end up yet more bits snapping, when I originally removed the wastegate several bolts snapped []

I would welcome your thoughts.

 

[zcacogp]

Not knowing the details of the particular parts you are talking about, the standard procedure with a snapped stud is to remove the remains of the stud and put a new one in. Doing anything less will probably be weaker than the original arrangement (and a botch).

The stud will probably screw out, if you can get purchase on the remains of it. This may mean you don't need to remove the part it is screwed into. A new stud will be very cheap, if you can get it out easily.

I'd be concerned about the flange which bolts over it - have you thinned it down yet? If not then please don't start ...


Oli.

 

[944Scott]

No not yet. Access is an issue as the crossover is still attached and that in itself appears to be a faff to remove. My thoughts are that if the stud sheared then trying to get the remainder out will be nigh on impossible.

 

[Frenchy]

Been there, done that ! it happened to me last year Scott, i managed to snap 2, even with the crossover pipe off it will be a miracle as the buggers will be well tight, i ended up with a strip down in the end, i replaced every single nut and bolt throughout the system on rebuild, the biggest and timeliest job, was removing the crush ring where the crossover pipe meets the turbo, i left this in-situ as i did not want to start snapping studs at the wastegate end, eventually got it in bits using a Dremmel.
Ended up drilling out and tapping the broken studs when the turbo was off...................................i seriously fell out with the car as it was July and the weather was gorgeous outside and i must have put 40 man hours in.............all sorted now though.
Turbo Off Methinks.....................Sorry Matey just my opinion after having been there !

 

[George Elliott]

What he said....100% true & good advice.

just put the crossover back on mine today - there are no shortcuts with these things - although 30 man hours may be sufficient if you work really hard[8|]
Drill the crush rings with a 2.5mm bit to half depth and then convert a punch to a centre-punch / scriber hybrid.......that gets 'em out.

George
944t

 

[924nutter]

ORIGINAL: 944Scott

Guys im after some suggestions.

In attempting to fit my de cat pipe one of the studs on the pipe from the turbo has sheared off. As their is some stud left I had thought about halving the thickness of the flange on this side to allow me to use the remainder of the stud except the thread that is left is stretched. I have tried to use a die on it without success and I have even tried making it a smaller diameter for a smaller die but to no avail.

Im undecided on the next course of action, do I try and grind the stud flat then try to drill and tap a hole with it in situ (crossover pipe is also still in place) or do I aim to remove the exhaust pipes off the turbo ( I am loathed to remove the inlet manifold after fixing an inlet leak) sod's law says I will end up yet more bits snapping, when I originally removed the wastegate several bolts snapped []

I would welcome your thoughts.

You speak about driiling the stud out which suggests access. The best way to drill the stud out is to assemble the flanges so that you can use the holes as a guide. If the pipe gets in the way then you might consider making up a jig with the correct hole centres. If it is a 10mm stud the clearance hole should be 10.2mm, and the tapping drill is 8.5mm; 8mm is 8.1 and 6.8. Spot drill through the hole with the clearance drill and continue to drill checking very frequently until the tip just starts to cut at full daimeter, which should establish a good, and quite accurate centre. The studs are likely to be a hard due to the continual heat cycling and considerable pressure may be needed to get the drill to cut. Ideally, depending on your level of skill you should consider using a pilot drill of perhaps 5- 5.5 mm hence the need to accurately determine the centre by "spotting through" Use a good gutting compound, or you will lose the cutting edge of the drill very quickly. In my considered opinion, only the very highest quality cordless drills have the necessary grunt to cope. For example I had a 24v cordless bit it wouldn't get close when the wastegate studs sheared on my 924 turbo so I used my 30 year old black and decker mains drill.

 

[944Scott]

Thankfully it easiest one to access, that said though I am going to need some sort of extended drill chuck as I cannot get a drill up there so with the extension chuck I was looking at using one of these (110855785266 copy and paste auction number on e bay) and then hopefully, hopefully i can just replace the stud.

I really cannot be doing with removing the turbo and crossover pipe []

 

[u63af]

Have you got a mig welder? When my stud snapped on downpipe I threaded a nut onto stud and the back filled it with weld. The heat that this produced helped free off the stud and also far me a hex end to get a socket on.

 

[scam75]

I think you will need to strip it all down I'm afraid and do as Frenchy says, replace every stud, nut and bolt in the turbo/exhaust assembly. When I had my turbo and engine rebuild Alasdair replaced every one of them and the ones you are talking about had to be roasted and removed and I mean roasted till the exhaust flange was white hot!

At least if you do this you know that the next time things will come off properly and nothing should shear or break. You probably have about 20 years of heat cycling in that bolt that's causing you grief. I'll bet it won't want to go anywhere in a hurry!

Stuart

 

[sulzeruk]

To remove the crosover pipe means the turbo has to come out as you cannot get into any of the bolts easily and they will be all seized. You will need serious heat to get them out as wel, probably a set of bottles. There is no easy way to replace the studs on the pipe unless you are very, very lucky and can do what Sandy says. You could try and get a massive blob of weld on there and remove the stud. Either that or get in with burning gear to roast them out. You will easily loose a day doing it and the parts are not cheap either, one of the sealing rings is about £15!
Alasdair

 

[Hilux]

ORIGINAL: u63af

Have you got a mig welder? When my stud snapped on downpipe I threaded a nut onto stud and the back filled it with weld. The heat that this produced helped free off the stud and also far me a hex end to get a socket on.

What he says []

 

[944Scott]

I have a mig so I will try this first once the newly aquired man flu has disappeared then If that does not work I will try drilling and tapping, if this does not work then its turbo off.

Time has got away from me on this project and others are backing up, the promax kt and wastegate have been in my possesion over a year now and i want (need!) to get these jobs done.