broken Bolts

[wolfie-uk]

Hi,

what is the best method you have found for removing broken bolts / studs.

Last night ( Monday ) i removed the exhaust water jacket from the 85 Charger and 5 out of the 17 or so bolts sheared their heads, water jacket removed and i have about 1/2 inch sticking out of the block, at least something to grab if i can.

regards

 

[jerryjerry05]

Re: broken Bolts

HEAT!!! Is the best.TAKE YOUR TIME!!!!!
I spray with PB Blaster or any penetrating oil.Heat it and tap gently with a hammer.
Do this a couple of times.The start with vice grips and as you heat try slowly to move the screw.Screwing in and out,don't try to just run them right out.
Then reheat and spray and tap.Tapping with the hammer loosens the corrosion.It might take an hour for each stud.Or 5 min.Just don't go too fast or you'll be drilling and tapping.

 

[Frank Acampora]

Re: broken Bolts

For those bolts broken above the surface of the block with enough to grab: I use heat and penetrant, then use a Vice-grip pliers to twist them out---maybe.

For bolts flush with the surface: I re-bolt the exhaust plate back on (snug, not tight, no stainless plate, no gaskets) using as many bolts as are available and hammer a 5/16 by 1 1/2 inch long roll pin into the empty bolt hole above the broken bolt. Using the roll pin as a guide I drill out the bolt with a 3/16 cobalt steel drill bit. If I can clean out the threads, great. If not, I drill deeper and use longer bolts.

 

[sschefer]

Re: broken Bolts

Agree with the heat method and Franks method. There's a right way and a wrong way, you've just been told the right way. If the vice grips aren't getting a good grip and you have a welder you can tack a nut to the exposed bolt and then use a socket. Make sure you remove your electronics from the engine, (switch boxes) if you have them and disconnect the starter and battery. If you break it off again, use Franks method. If it's really, really bad, pull the power head and take it to a shop that has a EDM. I've gone that route on salted up mid sections.

 

[wolfie-uk]

Re: broken Bolts

well the good news is i used the ice and heat method, took 45 mins to remove the 7 bolts that had sheared off,

1st froze them with of all things a old CO2 fire extinguisher ( lucky for me we have just had to change a few at work as out of date) froze them quite good.
2nd let them thaw out for 5 mins
3rd used a MAPP gas burner and got them cherry red
4th then tapped the ends several times
5th warmed them up again and squirted WD40 at them
6th tapped the heads again
7th grabbed them with the grips and worked them back and forth slowly, applying liberal amounts of WD40 as i went

slowly but surely they started to turn a bit more each time, once i got a full turn they just screwed out, then ran a good bolt down each hole with cutting paste, and they are like new.

now next question is ? how many bolts of each type and thread, as i want to fit new, cant see a list in my clymer manual of sizes, UNC or UNF or Whitworth

 

[Frank Acampora]

Re: broken Bolts

1/4 X 20 national coarse. 7/16 head. Most are an odd length, like 7/8 or 15/16 but when you use a million of them, a tenth of a cent savings becomes sizeable. I use 1 inch long stainless to replace them. You can tap deeper and use a slightly longer screw

Crankcase halve flanges are also 1/4 X 20, 3/4 inch length, 3/8 head (for clearance) Crankcase halves bearing bolts are 3/8 X 16 of two different lengths, I forget what. Manifold bolts--1/4 X 20 3/8 head----is a pattern beginning to emerge? I replace them with stainless allen head capscrews.

I also use #12 (or 14--again, I forget which) washers under them. These washers will just fit over the threads and are way smaller than regular 1/4 washers. Keeps from munging up the aluminum when they are torqued down.

 

[spool]

Re: broken Bolts

When i removed my water pump the thread came out along with it without using excessive force (soft alloy i guess)

I drilled out the holes, retapped and installed Helicoils, Good as new. When attempting to remove seized bolts its important to only use single hex sockets and i find giving the bolt a impact style turn to shock it loose rather than passive force.


Frank what do you use to heat the penetrating oil? some kind of torch?

 

[tpenfield]

Re: broken Bolts

Get a set of those Irwin bolt extractors (or something similar) and do the PB Blaster and heat the area around the bolt, but not the bolt.

 

[Frank Acampora]

Re: broken Bolts

I don't heat the oil per se. I soak the bolts for a couple of days--I have the time--then I heat the block with a propane torch. This way I am sure that I don't use enough heat to damage the aluminum. Then I try to remove the bolts. If they are still stubborn, I let the block cool to the point where it is still hot but not hot enough to flash the penetrating oil. Squirt more on and try again.