FatJackDurham 318 #1 Posted July 21, 2018 I just picked up a 520H where the previous owner had tried to replaced the muffler and sheared off the bolts holding the muffler flanges on. I’m thinking drill and tap. Anyone have suggestions for the thread size, warnings? Share this post Link to post Share on other sites
Jerry77 1,218 #2 Posted July 21, 2018 23 minutes ago, FatJackDurham said: I just picked up a 520H where the previous owner had tried to replaced the muffler and sheared off the bolts holding the muffler flanges on. I’m thinking drill and tap. Anyone have suggestions for the thread size, warnings? Along with all the good advice you will be getting, add one more....patience,,patience, patience... 2 Share this post Link to post Share on other sites
WVHillbilly520H 10,369 #3 Posted July 21, 2018 Thread size I believe 5/16"-18, if there is any bolt left sticking up above the port, try welding a nut to it the heat should help release the seized threads as well as something to "wrench" it out with, Jeff. 1 3 Share this post Link to post Share on other sites
lynnmor 6,762 #4 Posted July 21, 2018 You might be able to drill deep enough to completely remove the old bolt and still have enough depth to install a longer bolt. Just be sure that you have a stop collar on the drill bit to prevent excess depth. After drilling, run a tap as deep as possible for the new bolt. If you run a small drill thru first, you will be able to determine if this is feasible. Share this post Link to post Share on other sites
FatJackDurham 318 #5 Posted July 21, 2018 43 minutes ago, lynnmor said: You might be able to drill deep enough to completely remove the old bolt and still have enough depth to install a longer bolt. Just be sure that you have a stop collar on the drill bit to prevent excess depth. After drilling, run a tap as deep as possible for the new bolt. If you run a small drill thru first, you will be able to determine if this is feasible. THanks. Share this post Link to post Share on other sites
R. L. Addison 299 #6 Posted July 21, 2018 Might check you tube, saw some good work on there last night. Share this post Link to post Share on other sites
JAinVA 4,619 #7 Posted July 21, 2018 (edited) All the advice you are getting is good.If you end up having to install helicoils one advantage is that they are made of stainless steel and will act as a barrier to any further corrosion.A lot of folks turn their noses up at a heli-coil repair but in fact every aircraft or space craft has them when new. Edited July 23, 2018 by JAinVA 1 Share this post Link to post Share on other sites
Digger 66 3,476 #8 Posted July 21, 2018 Center-punch it Drill it Soak it Heat it And use a good name brand thread extractor . The center punch is the key here .I always use my angle grinder to knock it down as flush as I can . This way : 1) You are not deceived by the thread and can punch exactly in the center of the original hole . 2) The angle grinder will leave the surface slightly concave which is a benefit as well . If you get as close to dead center as you can , you can use the biggest drill possible . Good luck ! Share this post Link to post Share on other sites
FatJackDurham 318 #9 Posted July 22, 2018 I was able to attach a nut to one of them. Do you really thing welding it will loosen it enough to back out? 1 Share this post Link to post Share on other sites
953 nut 51,540 #10 Posted July 22, 2018 37 minutes ago, FatJackDurham said: I was able to attach a nut to one of them. Do you really thing welding it will loosen it enough to back out? Welding the nut to the stud will cause electrical currant to flow through the corrosion that is holding the old stud in place. The corrosion is a high resistance material compared to the stud and block so it will heat up and break the corrosion down to a powder and allow the stud to be removed. While it is hot you could also apply some paraffin wax which will run into the threaded area and provide lubrication. Share this post Link to post Share on other sites
Digger 66 3,476 #11 Posted July 22, 2018 (edited) 1 hour ago, FatJackDurham said: I was able to attach a nut to one of them. Do you really thing welding it will loosen it enough to back out? Every time I try this , I get good flow to the nut but the head seems to "sink" all the heat away from the stud leaving me with a melted /deformed nut and hardly any adhesion to the stud ( especially an aluminum head ). I'm admittedly no pro welder but it has never worked for me . Good luck though .... Edited July 22, 2018 by Digger 66 Share this post Link to post Share on other sites
cleat 4,936 #12 Posted July 22, 2018 My 2002 F150 had 3 broken exhaust manifold studs and my neighbor welded nuts to the studs and they came out. I think all 3 were below level as well. The weld does not stick to the aluminum. It took a lot of heat as the aluminum kept drawing the heat away. However, in this case I think the bolts were fatigued and not actually stuck. Cleat Share this post Link to post Share on other sites
groucho 1 #13 Posted July 22, 2018 I'm new here so please bare with me, I was wondering if any one would know the belt size of a 1985 series 211-3 transmission drive belt. I don't know how to start a conversation of my own. Share this post Link to post Share on other sites
Digger 66 3,476 #14 Posted July 22, 2018 (edited) 32 minutes ago, groucho said: I'm new here so please bare with me, I was wondering if any one would know the belt size of a 1985 series 211-3 transmission drive belt. I don't know how to start a conversation of my own. Welcome to Red Square ! Edited July 22, 2018 by Digger 66 Share this post Link to post Share on other sites
groucho 1 #15 Posted July 22, 2018 thank you bud!! 1 Share this post Link to post Share on other sites
FatJackDurham 318 #16 Posted July 23, 2018 Groucho - Good luck. Keep trying. Everyone else - OK! I'll break out the TiG welder tonight and try to weld that old nut on. It would be nice if that fixed it. It took just under two hours to drill out that other bolt. I tapped it with a 5/16-18 tap, but I'm wondering if I shouldn't just drill it out and heli-coil it with stainless threads, as suggested. If this welded nut works, then I'll have just one more bolt to drill out. In a fit of optimism, I already ordered the muffler and gaskets. 1 Share this post Link to post Share on other sites
FatJackDurham 318 #17 Posted July 24, 2018 Welding didn’t work, I couldn’t get the bolt head to melt at the same time as the nut. I wonder if it would have worked with a higher quality nut? anyway, nice try but I’m going to have to John McCain it, drill baby, drill. Share this post Link to post Share on other sites
FatJackDurham 318 #18 Posted July 25, 2018 Drilled tapped and coiled. Waiting for the new muffler. What type of bolts should I use? Stainless? Or high grade steel? Share this post Link to post Share on other sites
cleat 4,936 #19 Posted July 25, 2018 I would use a grade 5 with lots of never seize. Stainless is weaker and grade 8 would be difficult to drill out if it broke again. You could use studs and nuts as well. 1 Share this post Link to post Share on other sites
953 nut 51,540 #20 Posted July 25, 2018 On 7/22/2018 at 5:02 PM, groucho said: I'm new here so please bare with me, I was wondering if any one would know the belt size of a 1985 series 211-3 transmission drive belt. I don't know how to start a conversation of my own. Your best bet will be to start a new post for any further information you may need. This manual should be helpful. 1 Share this post Link to post Share on other sites
