How to prevent broken bolts?(long thread)
 

Hello everyone. I am trying to learn certain techniques when fixing automobiles. I have had problems trying to remove old bolts. I know that the two metals, the bolt itself and the other part that fastens to the bolt become one. This happens after aging and corrosion(also other reasons but I forgot). I have read and heard to put lubricants like wd-40, liquid wrench, etc. But when I spray these lubricants, which is usually right away(not a week in advance, and also dont have the time), I feel that it is not penetrating towards the threads, it just coats the head of the bolt. I have on many occasions, have had problems with bolts snapping. Once I overtighted it and it snapped(my mistake). I also snapped a bolt on a ground bolt on the frame of a 92 legend(removing). But most of the time its when removing that it snaps. I have also thought of driving the car towards its normal operating temperature, so everything can be warm and be more easily removed. But then scientfically the bonds in the material expand as due anything else in nature, so wouldnt the thread be different when removed? Wouldn't it shrink back when reinstalling the bolt? Sorry to make this thread long, but I'm so curious, and I also want to take care of my baby's valve cover seals and other seals. :D Thanks everyone, I hope this thread helps more automotive enthusiasts like myself:)

Pb Blaster is a thread penatrant that works well.

Hey professor, long time, how are you? Thanks again for all the great advice on helping me fix my svx. I tried pming you a couple of times, but I dont think it went through.

Thanks for the reply. How long does it take to work? is that the name of the company or brand? where can I find it? You always have a great answer to technical questions!!! Hope to talk to you soon, take care. bye

Having restored old cars (most with at least minor rust problems) all my life, I've busted a few bolts off. Here's a few tricks I've picked up over the years.

1) 1st, if you expect trouble, use penetrating oil early and often - WD40 will work too, but not as well. Use liberally. Soak from every angle you can get to. Soak over a couple days if you can - reapplying if necessary. Even if it doesn't look like it can get in the threads, it will. Rust is highly absorbent and draws it in like a sponge.

2) Heat is your best friend. Get a map gas torch. Heat the area so the two metals (the bolt and the metal surrounding the bolt) can expand. Usually they will expand at different rates such that you can break it loose.

3) Heat and cold. (never tried this one but heard about it) Heat the area as noted above, but shoot the bolt with compressed air from a keyboard cleaner held upside down (shoots ice cold air out). This will contract the bolt. The flip side of this- if the part is off the car and you can put it in a freezer - freeze the part then put heat to the surrounding part. This method is often used for getting old bearings out of hubs.

4) Last option: If you break the bolt off, don't worry. Now you have better access to the threads. Douse with penetrant and let it soak. Get a set of EZ outs (weird drill bit looking things). If you still cant get them out, drill out the old bolt and re-tap.

Remember preventive maintenance too. Whenever you replace bolts, except those that you want to use thread lock on, put a little oil on the thread to avoid these good times in the future.

PB Blaster is like a cat - it'll get into anything. It got into my sock drawer and made a total mess.

Your Cat? :rolleyes:

Bad joke I guess... :rolleyes:

In addition to using a penetrating oil, tapping on a bolt can work wonders. After applying the penetrant, use a hammer (and a drift punch if necessary,) and beat on the head of the screw as hard as you dare. If you expect that you may break the head off the bolt anyway, try using an impact wrench. (Start with low pressure and massage it for a while.) Vibration will help a lot.

Also, extreme heat does work. A map gas torch may do the job. Sometimes acetylene will be necessary. Alternating a few times from heating the bolt only, to heating the bolt's seat only can help loosen things. If it's a hardened bolt, don't get it too hot.

One thing I cannot overstate is how important vibration and shock is for loosening screws. I've used enormous impact wrenches to remove hub nuts without success. I've massaged the same part for twenty minutes with a smaller impact wrench until it finally just unscrewed easily. I feel like a dumb monkey beating quarter-inch screws for several minutes with a three-pound sledge, but it just freakin' works!

Thank you everyone for the great advice. I was in auto zone, and I looked to my right and there it was Pb Blaster, I said oh S*** I found out the penetrating oil everyone is talking about. Next step valve cover gaskets.:D

Yeah the label on the can looks like it escaped from MAD magazine. :D

If you fold it in the right way it spells out the lyrics for three Fleetwod Mac songs...