Assenmacher Specialty Tools 201 Metric Stud Remover/Installer Set - 4 Piece

Hands down only stud extractor I’ve used that actually works

Do recall the accurate statement made by the initial reviewer of this product. With that in mind, keep the appropriate die on hand. In my situation, a conventional, circular, puck-like thread die was not able to re-thread compressed areas of the exhaust studs, as a result of my misuse, due to clearance.Ideally, the appropriate amount of torque necessary to install an exhaust stud is wherein the shank or non-threaded area of the exhaust stud just mates snugly, in my application, to the cylinder head. Then the exhaust nut will perform the remaining torquing of the exhaust stud, as most exhaust nuts I encounter are somewhat compressed to out-of-round. Additional torque may deform areas of the threads by the internal "rollers" of this product - as in my case. The deformed areas of the threads will directly, of course, correspond to the "rollers" that have made contact with the threads during torquing.The simplicity of the mechanism is ingenious: housing interior wall has elongated lobes (such as camshafts), long rollers of equal length and diameter, and a "cage" for the rollers (similar to a c.v. joint design). As the housing revolves around a bolt, the internal lobes allows the "rollers" to reduce the air gap between the bolt threads or shank, by guiding the rollers toward the center of the cavity or towards the bolt threads or shank. The amount of inward travel of the rollers is predetermined by the peak height of the internal lobes.The moment the "rollers" seize the inserted object or occupies the air gap between the rollers and the bolt and rotational force is applied, inward pressure from the internal cams to the "rollers" and the "rollers" to the "rollers'" cage is ultimately generated on to the bolt along with outward pressure towards the housing. Ultimately, the durability of this product can be determined by how well the housing can withstand outward pressure as a result of rotational force induced by a ratchet's anvil or wrench.Do note that the mechanism has the potential to radially compress the threads of a bolt, throughout its circumference, if tool is misused by applying the tool to an incorrect sized or too soft, in material, of a bolt. Or the tool may not work at all if a larger bolt than what the tool is designed for is used.

Excellent tool. Works perfectly. The Assenmacher 10mm stud remover/installer made repair of my Chevy K1500 exhaust system straight-forward. I easily pulled the six studs from the exhaust manifold. No drama. I was concerned about the tool damaging the new stud threads (Dorman 675-216) when inserting. After installing the first stud, I ran a thread-chaser (M10 x 1.5) over the threads – tool rotated easily with no binding. I completed the remaining five studs with no problems. The cap nuts started and threaded on (compressing the helical springs) as designed.Some notes: The 5.7L Chevy exhaust manifold stud shanks are 11mm; the threaded portions are 10mm. I wanted to grab the shank and not threads, but did not have an 11mm (7/16”) tool. As it turned out, this was not necessary. These studs are case hardened and very strong – not certain if the treads of softer metals would hold up to being compressed by the tool’s three cams. Also, when removing, I started by tightening (yes, counter-intuitive) each stud a small amount. This helped break the “weld seal”. In other words, I rotated the studs both ways. I have broken these before and had to pull the manifold (and even worse – the head off engine!). The studs cannot be drilled out of an installed manifold. There is not enough room to get a straight shot with any type bit. Also, I soaked the studs with penetrating oil the day before doing the repair. This was worthless because none of the oil got into the threaded area. The treads on each stud were dry after being removed. The instructions say to not use an impact wrench. I used an 18” breaker bar and slowly rotated the socket. Took some muscle but easy enough with that much leverage. If you don’t have the Assenmacher, could possibly double-nut the studs, but the treads on mine were too corroded to allow this procedure. Save yourself a lot of grief – get the remover/installer.

Used this thing to remove exhaust studs when the portion for inverted torx sockets are rounded off. Works great. Pulled some threads because of rust on the other end but it came off! I wouldn’t suggest installing studs with this because once you clean the threads or retap the the place where the stud goes it should easily screw in with a torx socket. I haven’t used it for installing studs because I figured and heard that it flattens the new thread. Other than that, tool works great when you don’t want to remove the exhaust manifold to get locking pliers to fit and pull the studs out. Did everything inside the car👍. No complaints

These are supposedly the best stud pullers that damage threads the least, if they fit these sizes - too small or too large, and you are out of luck.They tend to slip a few times initially, but once it locks on, it will remove the stud unless it's seized badly.The tool is slimmer than most other stud removers, so that's a big plus in tight spots.This set is worth the cost!

I bought these after seeing them used in a YouTube video to remove the motor mount bracket studs on the front of the engine. These worked very well when I used them to remove and install the studs and unlike in the video they did no damage to the stud shaft, no scoring at all.

I bought the same set but SAE off the snap on truck. Great tool and this one was 1/3 the price!

These work really well. I had never removed studs or used any type of tool like this before. I had 6 studs out of a 42 year old engine block in less than 10 minutes without damaging either. They aren't meant to grip on the threaded portion without damaging the stud. The design was ideal for my application. There is a hole at the top so the you can bring the grip as close as possible to the block which reduces the risk of you applying too much lateral force to the stud and snapping it off. It grips so well, more time was spent releasing the studs from the remover than removing them from the block.