KDSS is evil..

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Just broke one off up in there :)

I thought this video was interesting
 
So now the broken bit won't come out of the head ..any ideas on that?

The old Hammer has not affected it
 
So now the broken bit won't come out of the head ..any ideas on that?

The old Hammer has not affected it
drill out the hex bit? Or use a screw extractor? (with the latter you wouldn't really need to "extract" it but a tiny bit

weld a nut onto the end?
 
Be careful trying to drill that bit out. The steel is MUCH harder than the surrounding screw so if your drill slips with much force on it you’ll tear up the screw.
 
Chisel clockwise? Brass drift? I wouldn’t try to drill it, probably try welding on it?
 
Interestingly, my 2019 has 8mm flanged hex head bolts for the KDSS valves in lieu of allen head screws. I checked the FSM and sure enough, it says to use either a 5mm allen or 8mm socket when adjusting the valves.

D2E3CA4E-52C0-4856-9460-90C7F4A2377E.jpeg
 
So now the broken bit won't come out of the head ..any ideas on that?

The old Hammer has not affected it

If you haven't gotten it out yet try a screw extractor. You will have to drill a hole first for the extractor. Use a hard awl to make a dimple in the broken bit. That's your starting point for the bit. Make sure you are using a fresh bit for metal. Also make sure the bit size corresponds to the extractor. You may have to start small and work your way up to final size. Wear safety glasses! The hex bit got stuck because it is softer than the hex screw and just twisted a bit into the screw. All you need to do is crack it back 1/128" or so and it should fall right out. Welding should be a last resort. That's surgery for me. Not sure where the bit broke but if its inside the threads... you dont want to weld the threads. Good luck!
 
I’m curious because I’ve seen lots of posts about these seized bolts but I haven’t seen any mention of impact wrenches. Can I assume that a significant number of attempts were with impacts?
 
Breaker bar is good for leverage, but only if your hex bit is strong enough to withstand that torque. (See posts above.) I know none of my hex bits are up to that task.

IMO, the combo of patience, penetrating fluids (ATF & acetone), tapping the hex head with a hammer, and more patience will eventually win the day.
 
I’m curious because I’ve seen lots of posts about these seized bolts but I haven’t seen any mention of impact wrenches. Can I assume that a significant number of attempts were with impacts?
It is a 5mm internal hex, many impact wrenches will probably do more harm than good.

That said it does tend to "crack" loose when it goes.. a 1/4" hex impact gun might do a good job of shocking it loose without overwhelming things. A big risk would be it turning more than 3 rotations when it does let go though.. and if it goes too far it is -BAD-
 
When I got our '08 in 2019, I didn't know about this issue. After being on the forum from that time, I learned it would be something I would eventually need to confront. A month ago I put PB Blaster on the valves and the nuts on the metal cover. I have no way to test how effective was the PB Blaster, but I realized I needed something with more grit and punch because the valves would not budge and one bolt was not letting go of the body frame.

I began to use Kroil. I put it on the bolt 2-3 times over a few days. That bolt finally came off. I then had access to scrap off all the rust - especially between the edge of the valve and the housing. Put on Kroil a few more times over the course of a week.

Yesterday I used a new 5mm 3/8 socket with a 3/8 normal-sized drive. Didn't use a breaker bar because I wanted to have a very good feel of the tension.

The valves came free!!!!!!!!!!! Oh my gosh... I was incredibly relieved!

After 1/4 of a turn, I put more Kroil and let them sit for over 30 mins. I was able to do 3 turns without issue. Today/tomorrow I'll put CRC anti-seize on the threads and then slather the housing with grease when I'm finished replacing the front left lca.

As @bloc said, the valves will crack when they are freed.

Use Kroil and a high-quality 5mm socket.

Patience, focus, persistence (and prayer)
 
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Glad to hear you got them to finally spin!!

Now without saying, keep them smeared up with Fluid Film, marine grease, etc.

One less thing to worry about...

Peace.
 
If you don't already have one, an "old school" impact driver can be quite helpful with stubborn screw heads. These are hit with a hammer/small sledge, and both are driven into the head of the screw/bolt, and twist CCW simultaneously. It is nearly impossible to strip the screw head using one of these, unless you're using the wrong sized bit. I almost always break this out when I see phillips or JIS screws. The one linked can accept 3/8" sockets, and is what I have.


It is, however, quite possible to break your 3/8" drive hex... Don't ask me how I know. This is where picking up some impact hex/allen drives is helpful:

Amazon product ASIN B000JOR0J6
When I loosened the valve screws on my '08, the impact driver was able to get one of them loose, however I did end up using an electric impact driver on the other one. By doing "bursts" and only allowing 3-4 impacts at a time while keeping eyes on the socket lettering to watch for rotation, I was able to just get the screw broken loose and then do the rest by hand.
 
If you don't already have one, an "old school" impact driver can be quite helpful with stubborn screw heads. These are hit with a hammer/small sledge, and both are driven into the head of the screw/bolt, and twist CCW simultaneously. It is nearly impossible to strip the screw head using one of these, unless you're using the wrong sized bit. I almost always break this out when I see phillips or JIS screws. The one linked can accept 3/8" sockets, and is what I have.


It is, however, quite possible to break your 3/8" drive hex... Don't ask me how I know. This is where picking up some impact hex/allen drives is helpful:

Amazon product ASIN B000JOR0J6
When I loosened the valve screws on my '08, the impact driver was able to get one of them loose, however I did end up using an electric impact driver on the other one. By doing "bursts" and only allowing 3-4 impacts at a time while keeping eyes on the socket lettering to watch for rotation, I was able to just get the screw broken loose and then do the rest by hand.
There is another trick that works well with electric/air impact guns, and that is to hold the socket by hand while trying to loosen it with the trigger.

Sometimes if the bolt/nut to be loosened is near the limit of the gun the slack in the square drive and bit in/on the bolt allows some amount of “bounce” back and forth, or more precisely rotating then rotating back. This effectively eats up some of the impact force, defeating the purpose of the small but high energy “hits”. Grabbing the socket dampens this tendency and subsequent “hits” of the socket apply more of the intended force to the fastener and do the job more effectively.

The 3/8” electric impact gun I use will just rattle the socket and extension back and forth on lug nuts, not doing any good. Put a gloved hand around the socket, while trying to loosen, it will zip the lug nut right off.
 
That is a good tip; I haven’t heard of doing that. I have cursed mother makita for making a crappy impact driver that can’t even loosen lug nuts on more than on occasion.
 

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