Engine stud removal

motoddrob

motoddrob

Hero member
Location
S/W Australia
Need to replace 2 of the M6 case studs along the front of the cases. Those suckers don't want to budge!! Used gentle heat and been applying a penetrene for several hours now.
Any ideas??
 
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Hey Rob

Seeing as you will be scrapping the existing studs how about welding a nut or tee bar to the top so you can apply more torque to the equation.............. Stripping the casing threads is a real risk here as I'm sure you are aware.

But you'd be better asking an expert.

                              Thanks
                                    Matt   
 
dead easy, get an electric arc welder, atach the earth to the cases, then with about 150 amps dialed in touch the electrode holder on the top of the stud, give it a nice "cooking" get the stud nice and hot,and then wait,  30 seconds or so, then turn out the stud,either with a pipe wrench/mole grip, or as mentioned, by welding a short tommy bar, if it drags aluminium with it, then it can be timecerted, which would be a good thing to do anyway, I mean those threads have been under tension for 35 years, so unless they are pefect, Timecert them anyway.
CLEM
 
I don't have much experience with Aluminium Alloy, but speaking as a Power Station clanky fitter I would use a stud extractor/stillsons near the base of the stud to remove it.
If you turn at the top of the stud you are wasting energy twisting it rather than putting the energy below the surface where you need it.
Also you have more chance of snapping the stud if it twists.
 
I destud engine cases on a regular basis to bore top case to 1200 liners or do some other repair to them
these 6mm studs are always tight
Simon is on the right track, if the double nut does not work I use a stud removal tool close to the base of the thread
once they "crack" free they unwind no problem
very rarely strip the thread, maybe once per 50 times

slip an 8mm nut over the stud, sit it down lower on the stud and weld it on
or use stillsons close to the bottom of the stud

no need for heat
 
Once you have got the stud moving don't just wind it out. Wind out a bit then back in - more penetrating fluid, back out a bit more and so on slowly slowly.
If you wind out in one go a chip of swarf may just strip the thread out in one spiral, but if you wind back in the chip may be broken and prevent this.
 
I now know what to do so thanks guys. Reason they're worn like that is from the original Motodd engine mounts. That occured in the first 50,000kays. The mount would also break on the 90? bend where it mounted on that stud. Got tired of welding it so I remade the brackets from a piece of 50mmx5mm angle and spread the load over 2 mounts. Next 50,000km, never a problem. Now that the cases are apart I want to change out the studs.
 
another vote for the welder.
I cut the stud just above the thickness of the nut I'm going to weld on to it (about 20mm) ... the heat of welding the nut to the stud works wonders to free it from the case... and then you have a nice big nut to turn it out with.
 
Unfortunetly my welder isn't on the shelf but in Perth [420km!] so will need to visit a mate to do the job, that means more beer drinking!!
Can't see how the longer nuts will help, I only have limited thread and Simons coment about waisting energy twisting the stud makes sence.
My only stilsons are on the large size so not much help either.
Welding on a nut seems to be the best way to do it. Not about to go buy a stud extracter either.
 
and when you've rounded out the allen hole in a brake rotor bolt... welding a hex head bolt into the hole works the business as well... especially when someone has installed with red loctite..
 
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