DIY: How to easily remove your Subaru factory Cam bolts. Enjoying the day instead of cursing it.

Subaru cam bolts…. These words strike fear in many Subaru owners. When Subaru was putting their engines together they decided to use 10mm hex or allen bolts. After many miles of driving these can became almost adhered to the cam shaft and using a 10mm allen and your ratchet doesn’t always cut it. You will find the amount of force you need to break these things free often rounds them out. Thus causing you even further problems.

Home sweet home…. This is where the cam bolt resides and would never leave if it was up to it.

Home sweet home…. This is where the cam bolt resides and would never leave if it was up to it.

There are tricks to take these off and I have used two different techniques prior. The standard way for most will be drilling the bolt through with the proper drill bit. This will break the torque on the head of the bolt when you make it through, thus the bolt will spin out by hand. It is very time consuming and I don’t recommend it. Even with top quality drill bits I spent an excessive amount of time to complete this.

A little magic with vise grips to hold the cam in place. Using your old belt and the cogged crank sprocket. If you look at the exhaust side cam bolt you will see a notch cut out of it to grab it with a adjustable end wrench or pipe wrench.

A little magic with vise grips to hold the cam in place. Using your old belt and the cogged crank sprocket. If you look at the exhaust side cam bolt you will see a notch cut out of it to grab it with a adjustable end wrench or pipe wrench.

The real ended to these bolts is a drill bit. With the appropriate sized drill bit, 7/16th, the stronger the better. As these bolts can take some punishment, but once you make it through the head of the bolt it will pop off with just your hand.

The real ended to these bolts is a drill bit. With the appropriate sized drill bit, 7/16th, the stronger the better. As these bolts can take some punishment, but once you make it through the head of the bolt it will pop off with just your hand.



Another technique was taking a cutoff wheel and making the outside of the bolt a hex. Allowing a socket to be hammered onto it. This can be a little dangerous as sliding off the bolt can easily cut right through a cam gear. The ACVS cams make this nigh impossible due to their tight fitment around the head of the bolt.

A few cuts on this show how you can square off the sides for gripping.

A few cuts on this show how you can square off the sides for gripping.

Lastly is taking an old axle nut and welding it onto the head of the bolt. This allows you to use a large 6 point socket and impact gun to spin it right off. If the trick below didn’t work this would have been our next step.

With the pain of these from three years ago still fresh in my mind I scoured the internet and thought to myself… What is another way than these to pop these things off. I stumbled upon a YouTube video showing a simple twist lock socket being hammered on and spun right off. Now I had tried this before with a Harbor Frieght damaged bolt remover kit and had absolutely no luck. But the design of these is very different and couldn’t get a good bite on the bolt head leaving it where it sat.

After looking through Amazon for awhile I found a Twist lock set with a decent overall review and hope that it could take care of business. I have used these at work when removing locking lugnuts and they seem to come through every time. So let us see how these turn out… ( <-that part was a joke, get it?)

Twist lock set from Amazon . Featuring a lifetime warranty.. Haven’t had to use yet. Also helps remove those rusted and rounded off nuts.

Twist lock set from Amazon. Featuring a lifetime warranty.. Haven’t had to use yet. Also helps remove those rusted and rounded off nuts.

Taking your favorite hammer in hand take the twist lock socket of your choice and rest it against the cam bolt. I choose the 11/16ths, it fit right over and with a few strikes with the hammer it was on. You can now either use your 3/8ths impact gun or ratchet or on the outside of the twist lock it will accept a 27mm socket. The 27 mm socket and 1/2” impact was my choice.

Hammer time! A few good hits and it is ready for the impact.

Hammer time! A few good hits and it is ready for the impact.

With everything setup I used my Company 23 Cam tool holders to keep the cam still. Otherwise you may just spin the cam sprocket and cam around. These Cam tool holder aid with this and can help hold the sprockets when installing the timing belt.

Company 23 acvs sprocket tool  keeping the cam sprocket from running away.

Company 23 acvs sprocket tool keeping the cam sprocket from running away.

Now it is time to pull the trigger! As long as the twist lock socket has enough bite it will take this cam bolt out like it was left loose from the factory. After spending a day drilling and removing my prior engines cam bolts I was more than overjoyed when each of these came out in less than 10 mins.

Proof is in the pudding! It is out! One of the top ACVS intake bolts.

Proof is in the pudding! It is out! One of the top ACVS intake bolts.

With the cam bolt wedged into the twist lock you can take it over to your vise and using a punch or small bolt you can knock them loose. Now you can start on the next three to go. My twist lock set easily removed them all with easy and looks like it could do a few more.

Using a punch or smaller bolt you don’t care about. You can knock these things right.

Using a punch or smaller bolt you don’t care about. You can knock these things right.

If you would even like to reuse these bolts the 10mm allen has been untouched and could easily installed again. I will be using Turn in Concepts FU cam bolts as they have been designed with a 17mm bolt head to allow for super simple installation and removal for the next time. Find my review here for the TiC FU cam bolts.

10mm allen head still intact and ready for another use. You can also see the bite marks from the twist lock socket and just how it works.

10mm allen head still intact and ready for another use. You can also see the bite marks from the twist lock socket and just how it works.

A second view of the bite and bolt.

A second view of the bite and bolt.

Congrats! You have succeeded over some of the most stubborn bolts known to many Subaru owners. You can now remove your cam sprockets and continue on with your engine build, head gaskets, cam seals or other engine wizardry you have up your sleeve.

Amazon Links:

Maximum Impact twist lock set

Company 23 Acvs cam holder

Company 23 NonAcvs exhaust cam holder














































Dan EngstromComment