This article is one in a series that have been released in conjunction with Wayne's book, 101 Projects for Your Porsche 911. The book contains 240 pages of full color projects detailing everything from performance mods to changing your brake pads. With more than 650+ full-color glossy photos accompanying extensive step-by-step procedures, this book is required reading in any Porsche 911 owner's collection. See The Official Book Website for more details.
If you are planning on restoring a car that is even slightly old, then you will undoubtedly come across the old nut, bolt, or stud that is rusted solid and won't come off. There are many ways to tackle this issue, and just about everyone who has worked on a car has a different opinion on the best and most reliable methods. This project will expose you to some of the methods used by several of the 'experts' in the field.
The first step in getting rusty or stuck fasteners off is to perform a pre-emptive strike. It is often the case where you will find that a nut or stud will not come off after you have already stripped or damaged it. If you think that the nut will give you problems, it's far better to tackle the removal process carefully, rather than end up destroying one of your precious parts.
If you are planning on removing an old rusty bolt in a day or two, it's a wise idea to soak the area with a good lubricant like WD-40. The lubricant will eventually soak down and penetrate into the joint, making it easier to remove and break apart. This seeping process takes time, however, and the bolt should be soaked the night before you attempt to remove it at the very least. This will place you a step ahead in the battle to remove it.
When removing these old bolts, it's very important to have the right tools for the job. A properly fitting wrench is essential. Many people often use the wrong tool for the wrong bolt. The twelve-point star bolts on the CV joints of some Porsches is an excellent example. A simple hex Allen key tool will fit into the bolts, and will probably be able to remove most of them, but the chances are likely that one of the bolts will become stripped. Using the right sized tool to remove a fastener means that you increase the odds that it will come off easily.
For pulling studs, Snap-On offers an excellent collet-based stud removal tool that does the job very well without damaging the stud. This tool latches onto and compresses around the threads of the stud, and then squeezes them tight. Then the tool and the stud can be removed. If you are removing head studs out of an engine case, an extra Vise-grips or two might be useful as well to get an extra bit of torque on the studs.
Exhaust studs are notoriously difficult to remove from the heads, and they also have a tendency to snap when removing heat exchangers. Make sure that the area is lubricated heavily before even attempting to remove a rusty heat exchanger. Unfortunately, if the stud snaps off, there really isn't too much that you can do. Since the studs are heated by the heads, they become very brittle over time. Basically the only way to remove a broken head stud is to have it drilled out or removed using an EDM process (see Pelican Technical Article: EDM Broken Bolt and Stud Removal).
A tool that may help you out when you need to remove bolts is a common propane torch or even better, an oxy-acetylene torch. Propane torches are available at most hardware stores, and are useful beyond belief. Particularly on bolts and studs that have had Loctite used on them, the torch can give you an extra advantage in removal.
Take the torch, and heat up the surrounding metal that the stud is embedded into. This will help to melt any Loctite on the threads, and also help to expand the metal that is surrounding the stud. Do not apply heat directly to the stud, as this will make the stud heat up and become even more stuck in the hole. If you are removing a head stud from an engine case, you will find that it will take a surprisingly long time to heat up the case. Aluminum and magnesium conduct heat very well, so make sure that you focus the torch on the case for a while before you try to remove any studs. Also make sure to use the torch only in a well-ventilated area.
On the opposite side of the equation, you can sometimes use coolant to help remove a stuck bolt. One of the best kept secrets is the 'compressed air in a can' that your local office supply store sells specifically for blowing dust out of old computer equipment. If you hold the can upside down, then the gas inside (which is not really ordinary air) will drip out as a very cold liquid. You can drip this liquid onto bolts and into areas that you might be having trouble with. Be careful though, as the cold will have a tendency to make the metal increasingly brittle and prone to breaking. Use eye and skin protection when using coolants: they can be deceptively dangerous.
The application of heat and cold together can be a powerful combination. As the joint heats up, and then is cooled again, rust and Loctite may break free from the rapid expansion and contraction. There is no real exact science for this, so trial and error is the rule of thumb.
Another important point to remember is to make sure that a nut or bolt that you are trying to remove can actually be removed. It is often the case where someone will try to remove an embedded stud or a nut that has been welded on, only to find that this is an impossible task. The long starter bolt on the 914 and the welded nut on the inner fender strut of the 911 are two examples of this type of fastener. Before you dig out the angle grinder, check and double-check to make sure that you aren't missing something that's not too obvious.
Sometimes it makes sense to take a nut and have it welded to a stud that is stuck. This will allow you to place a wrench on the nut and hopefully remove the stud. Make sure that you clean all of the rust, debris, oil, and anything else that might be on the stud before you attempt to weld to it. Sometimes the stud will be old and brittle, and may not take well to welding. This is usually the case with the exhaust studs. Also, most studs can only be effectively welded to if they are made of steel. The alloy Dilavar head studs of the later 911 engines cannot have nuts welded to them: the nuts just break right off as soon as you try to turn them.
Another useful tool is the impact wrench. This is most helpful when you are trying to remove a nut that turns on a bearing, or one that is attached with a great amount of force. The steering wheel nut is an example of one that turns. The impact wrench 'hits' the nut with repeated blows, knocking it loose. It's a very useful tool, and will save you plenty of time when you need to remove one of these specialty bolts.
The weapon of choice when all else fails is the Dremmel tool or it's big brother, the angle grinder. These two tools of destruction really don't stop at anything when it comes to cutting through metal. The Dremmel tool is my personal favorite because it is so small and can be positioned and placed in so many different positions. Adding to its versatility is the fact that you can add a flexible shaft to the tool that allows you to place the rotating blade just about anywhere you can reach.
The Dremmel, or rotary tool, spins at about 50,000 rpm and uses small ceramic-like discs to cut and grind through steel. There are small carbon-fiber reinforced discs available that are more expensive than the regular discs, but they last longer, and are more effective at cutting through steel quicker. I recommend using these discs: particularly if you can buy a large bag of them at a swapmeet or other venue. Make sure that you don't ever use the Dremmel tool without eye protection.
The angle grinder makes no apologies for being the most destructive off all tools. The grinding wheel can grind, wear, cut and melt away steel much faster than any other tool. It's especially useful for grinding off nuts and studs that have rusted so bad that there is no way to get a tool on them. Make sure that you use appropriate eye, ear, and nose/throat protection when using the grinder, as this tool kicks up a lot of small metal particles into the air.
When all else fails, you can sometimes use a hand drill to drill out an embedded or broken stud. Not the prettiest solution, the hand drill is still an effective method of removal. Make sure that you start drilling with a very small drill bit and gradually increase the diameter of the bit. Also make sure that you use plenty of lubricant. When the hole that you have drilled gets to be about the size of the stud, try to remove the remains of the stud using a pick. Be careful not to damage the threads of the hole by drilling too large of a hole. When you are finished, chase a tap down the hole to clear out the threads, or if it's damaged, thread the hole to a larger diameter.
The propane torch is one of my personal favorite tools. Make sure that you heat the case and not the stud. You will notice that it may take a long time for the case to warm up. Keep the torch focused on the area and don't let it stray onto the stud. The white inner portion of the flame is the hottest: the blue part indicates a cooler region. Make sure that you only use the torch in a well ventilated area, as the propane will create harmful carbon monoxide gases.
The tools of destruction and mayhem are shown here. The Dremmel rotary tool (upper right) with flexible attachment is best suited for cutting off small nuts, bolts or studs. These will account for about 95% of your problems. The angle grinder (left) is for more serious tasks were rusted nuts must be completely ground down. WD-40 is an excellent penetrant for removing rusted and stuck bolts. The Snap-On stud remover (lower-middle-left) is a hard-to-find tool, yet very useful for removing those troublesome studs. Finally, the electric impact wrench is a useful tool for removing nuts that are mounted with a lot of torque.