Dilavar, broken stud removal ?

[avro-6]

Dear all,
i am having trouble removing a broken head stud. I have tried using a heavy duty stud removing tool but the stud is to strong for the tool to grip onto, all it does is flatten the serations on the tool ! Its that Tough!! Anybody have any ideas.

I should just mention that i am a mechanic of 30 years , but this is new to me. Thanks in advance Chris....

[cstreit]

Hi Chris,

Those studs are loctited in pretty good. The best way is to get a good amount of heat in the case area around the stud to melt the loctite. It should turn out easily at that point. I like to use propane with a good tight flame. You can use oxy-acetylene too, but with great care so as not to melt or distort the case!

The Snap-On stud remover works really well, though it helps to have it on the threads. I've also had luck just welding on a nut to the broken end, works well too.

What I do is get a good hot flame played around the base of the stud while keeping pressure on the stud, maybe 30-40ft-lbs or so. (that's what my elbow-torque clicker sez) and then let that flame heat it up. It can take 3 or so minutes to get the case hot enough, but then the stud will slowly start to turn. Works every time.

[john walker's workshop]

just keep the flame off the stud. heat inside the cylinder spigot, over where the threads would be.

[avro-6]

Thanks for your reply cstreit,
I have tried the heat but with No Threads to use, the removal tool was the next option, but it does not GRIP the stud tight, to be able to turn Heat or no Heat it just Skids round ! Any thoughts..

[john walker's workshop]

i use one of those 3 roller 8mm remover tools on the broken ones, along with heat. 8mm, not 10mm, because it fits the stud shank nicely.

[avro-6]

In reply to john walker's workshop, its the gripping of the stud thats the problem -- Before any heat is applied. Its hard stuff this DILAVAR !!!

[avro-6]

Just to add The stud does not --Compress --unlike say STEEL, to allow any grip to be applied.

[john walker's workshop]

all i can say, is i've been using that 8mm roller tool on broken dilivars for years and it works fine for me. it's an AST brand, 100-8, made in USA. i guess you need a better tool.

[avro-6]

OK will try your recommended tool and give it a try . Thanks chris .....

[Eagledriver]

I just weld nuts on the end. The heat from the welding seems to loosen them right up. I got 12 studs out in about 1 hour that way. By the way that is the extent of my welding capability!

-Andy

[casperlabs]

You did not say if you have an aluminum or mag case. Magnesium can develop a self sustaining fire if it gets hot enough. While I have not seen a mag Porsche case fire, I have seen mag fires in turbine engine gearboxes. I once saw one on fire while it was being machined (chips can be ignited without a flame, a spark will set them off). This is an extremely scary, intense, purple fire that can only be stopped by dumping sand on it (sand pulls heat off and gets the metal below its self ignition temp.). Water makes it rage. Believe me, the experience is unforgettable. Needless to say, I never put a torch to a mag case for any reason. If the case stud is accessible we put a fire blanket around the case and tig weld a nut to the stud shank after shortening it to 1.5 inches (long studs act like torsion bars). The welding heat is usually enough to turn threadlocker to carbon. After the stud cools, it usually comes out. If not, we split the case, and put it in the mill for carbide tool drilling.

Good luck, and be patient!

Bill Ryan
Casper Labs, Inc.

[rlane]

while you wait for the new stud remover try Dremel-ing flat edfes to the stud down about 2 cm above the case, heat as described and with a good pair of Visegrips attached at the flat areas torque it off....low tech but it works