What size are the 4 screws that hold the IAC to the throttle body
- Thread starter Pyral
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GhostRing
Member
On Toyota's, Always use JIS Philips.
This.
Treat yourself to a Vessel set of drivers or similar
Ball Grip: 220W-3
I wish I could ditch the PoziDrive for a 4/5mm bit, but otherwise indispensable
Pyral
Member
I was using a vessel JIS driver, still didn't work. From my experience with a 1984 XR100, once galvanic corrosion sets in it is next to impossible to remove JIS screws without the exact right tools. I didn't have an impact driver (initially), or a bench vice, or an induction heater. But I still had a JIS screw driver and fairly decent tools.
I tried everything at my disposal:
-applying penetrant over night
-shocking the screw head with a hammer blow
-heating it with a mapp torch (limited by it being too imprecise to apply heat)
-turning a JIS screw driver with pliers as I put my weight on it
-trying an impact screw driver (I could only get one with Philips heads)
-turning the screw with vice grips
-turning the screw with knipex pliers
I successfully removed one screw by drilling it and using a screw extractor, but I broke off extractors in 2 other screws. And I've given up and will pay someone to deal with the mess.
I'm sure someone with better tools and workshop could do it, but I don't and wont because of the temporary living situation that doesn't allow me to have such an arrangement.
brillo_76
Elite Member
So you didn't use a induction heater? Mostly if you can heat them with induction then use wax crayon. The heat and cooling cycles should break that galvanic corrosion. So you cant completely remove the throttle body out of the vehicle ?? That way you have excellent access to those 4 screws.
Sometimes, this is few cycles to get that corrosion to shear. Especially if you can get the wax to wick into the threads
The MAP gas is going to heat the screw as well as the metal around it.. That's not going to be as efficient nor as quick. Induction heat would be on that screw threads only, not the surrounding metal. I was amazed on how much quicker I could get frozen bolts, screws with induction heat.
However, with a wax if you can get that in there. MAP gas will work. Drilling off the the head is absolute last resort because sometimes. This makes this 100X worse. If the heads strip out. Try to dremel the sides of the screws so you can get plyers to grip on them. Now dremel off some of the head will help you get the wax closer to the threads.
The only drawback I have seen is locations at times. Sometimes, we just cant get into the location with a induction heater.
When this happens, now that makes it a nightmare.
Sometimes, this is few cycles to get that corrosion to shear.
Especially if you can get the wax to wick into the threadsThe MAP gas is going to heat the screw as well as the metal around it.. That's not going to be as efficient nor as quick. Induction heat would be on that screw threads only, not the surrounding metal. I was amazed on how much quicker I could get frozen bolts, screws with induction heat.
However, with a wax if you can get that in there. MAP gas will work. Drilling off the the head is absolute last resort because sometimes. This makes this 100X worse. If the heads strip out. Try to dremel the sides of the screws so you can get plyers to grip on them. Now dremel off some of the head will help you get the wax closer to the threads.
The only drawback I have seen is locations at times. Sometimes, we just cant get into the location with a induction heater.
When this happens, now that makes it a nightmare.
GhostRing
Member
This is what your first post should have looked like.
Save a few of what you knew would be the initial responses.
brillo_76
Elite Member
Well in fairness he is asking what the thread and screw lengths were. I can only guess at at would be a 4mm X 1mm unknown length.. I would just order new screws from the dealer then use that as your template for your replacement screws.
I just hope he can get these. Or he be souring another throttle body with screws that will come out. :-( I know they can be a nightmare if they will not come loose. Taking days or a week or 2 to get removed. Been there done that on many occasions. Not a good time but learn tricks along the way to make it faster the next time.
I just hope he can get these. Or he be souring another throttle body with screws that will come out. :-( I know they can be a nightmare if they will not come loose. Taking days or a week or 2 to get removed. Been there done that on many occasions. Not a good time but learn tricks along the way to make it faster the next time.
Pyral
Member
As brillo_76 said, that was not the initial purpose. Someone always asks if you used a JIS driver, so I should have put that matter to bed in the initial post. :shrug:
I think I'll put anti-seize on the new screws.
Also I found a screw was missing for the throttle position sensor, would that affect anything?
phattyduck
Elite Member
That was the only thing I was going to say. I just had my IAC apart a few months ago without much issue. Always still a bit of anxiety until it cracks loose...
-Charlie
brillo_76
Elite Member
+1 on antiseize. The screw missing would only be an issue if the sensor was not staying stationary. Was the sensor moving? I would replace that as well since you are there.
I like the copper antisieze instead of the aluminum. Hopefully, your not like me and end up with it everywhere...:O
Pyral
Member
I think I did one better, I found that the IAC is held in with M5x.8 threads (or something close enough). I bought some 8mm M5x.8 bolts and put a tap through it for good measure. This is a huge upgrade, and I'd highly recommend it regardless of if you remove the screw or not.
I still have to grind off the other 2 screw heads that have broken extractors in them, and drill out the 3rd screw.
The tps wasn't moving a whole lot, but it was leaning out a bit.
I still have to grind off the other 2 screw heads that have broken extractors in them, and drill out the 3rd screw.
The tps wasn't moving a whole lot, but it was leaning out a bit.
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