Seat bolts: need helping identifying head type

[MyBlueYar]

Well, after buying my 2009 Yaris a couple months ago for a song, I'm in the process of swapping out the existing driver's side seat, and putting a new used one in its place.

The previous owner apparently had a dog (or child) that liked to chew on the side bolster, and so I started to take out the bolts that secure the seat, or so I thought.

My ratchet set didn't fit this weird looking bolt head, so I was hoping someone might be able to identify what type these are. I'll attach a picture for your viewing pleasure.

[WeeYari]

Reverse Torx. Size E-10

[MyBlueYar]

Reverse Torx. Size E-10


You the man, WeeYari! Thank you for the timely help -

[MyBlueYar]

Well . . . just when I thought I had this thing licked. As you suggested, WeeYari, I went out and bought an E10 sized torx socket. I successfully removed 3 of the 4 seat bolts, but the last remaining one had been partially stripped previously.

After a few attempts, I could clearly see it wasn't going to work, and if anything, it served to round off the remaining nubs a bit more. I bought a set of bolt extractors at Harbor Freight this afternoon, but alas, even those did not work.

Any stripped bolt experts out there? Any suggestions would be appreciated!

[CrimsonEclipse]

Well . . . just when I thought I had this thing licked. As you suggested, WeeYari, I went out and bought an E10 sized torx socket. I successfully removed 3 of the 4 seat bolts, but the last remaining one had been partially stripped previously.

After a few attempts, I could clearly see it wasn't going to work, and if anything, it served to round off the remaining nubs a bit more. I bought a set of bolt extractors at Harbor Freight this afternoon, but alas, even those did not work.

Any stripped bolt experts out there? Any suggestions would be appreciated!

You're at the point where the job becomes a large problem.

First there is an "easy out" or bolt extractor.
You have to drill a hole in the middle of the bolt then drill in a reverse bit to help unscrew the messed up bolt

I would modify this technique and start with drilling a hole for the extractor, then using a larger bit to remove most or all of the bolt head.

With the bolt head gone, you can remove the seat and have more room to work.

Also with the bolt head off, you'll have room to inject deep penetrating oil before the extraction to improve your chances of success.

Down side: If the extractor breaks, you have a really big problem.

Also see if the bolt holes go all the way through the frame (like the rear seat ones do)
If so, you can hit the bolt from both sides with penetration oil.
Also, if it's exposed, it might give you a second direction for extraction.

Good luck!

[MyBlueYar]

You're at the point where the job becomes a large problem.

First there is an "ease out" or bolt extractor.
You have to drill a hole in the middle of the bolt then drill in a reverse bit to help unscrew the messed up bolt

I would modify this technique and start with drilling a hole for the extractor, then using a larger bit to remove most or all of the bolt head.

With the bolt head gone, you can remove the seat and have more room to work.

Also with the bolt head off, you'll have room to inject deep penetrating oil before the extraction to improve your chances of success.

Down side: If the extractor breaks, you have a really big problem.

Also see if the bolt holes go all the way through the frame (like the rear seat ones do)
If so, you can hit the bolt from both sides with penetration oil.
Also, if it's exposed, it might give you a second direction for extraction.

Good luck!



Crimson, I'm on it. Thanks for the timely advice on how best to remove this stubborn bolt. I'll let you know how it turns out -

[sh0rtlife]

id actualy reccomend filing the edges down and see if you can find a 6point metric or SAE socket that you can hammer onto it after filing it down a bit

now i say this as it has been a old fall back trick of mine for decades...but also....if the bolt is semi frozen in the threads drilling it and going the extractor route can actualy be HELL....and should only be used on broken bolts..as its kinda a last resort ...i had a frozen thread one on the rear seat top driver wheel well end, i personaly stripped it with the torx, then filed and beat a socket onto it and could feel the bolt trying to give up and snap..so i started working it back n forth a little at a time IE 1/8th turn..and eventuraly thought id free-d it ..got it half way out only to have the head snap....vise grips on the remaining threads again working it back n forth with kroil(pb blaster works almost as good) before finaly getting it out....

basicly what you have to realize is if its something like stuck threads that caused the head strip you need to be prepared to do the long work instead of just going extractor..as you may break off the extractor in the hole you drilled making a whole new problem for yourself

if you do go the extractor route...do yourself a favor and drill it out as close to the thread size as you can..this way the chances of snapping the extracor is minimized

[MyBlueYar]

id actualy reccomend filing the edges down and see if you can find a 6point metric or SAE socket that you can hammer onto it after filing it down a bit

now i say this as it has been a old fall back trick of mine for decades...but also....if the bolt is semi frozen in the threads drilling it and going the extractor route can actualy be HELL....and should only be used on broken bolts..as its kinda a last resort ...i had a frozen thread one on the rear seat top driver wheel well end, i personaly stripped it with the torx, then filed and beat a socket onto it and could feel the bolt trying to give up and snap..so i started working it back n forth a little at a time IE 1/8th turn..and eventuraly thought id free-d it ..got it half way out only to have the head snap....vise grips on the remaining threads again working it back n forth with kroil(pb blaster works almost as good) before finaly getting it out....

basicly what you have to realize is if its something like stuck threads that caused the head strip you need to be prepared to do the long work instead of just going extractor..as you may break off the extractor in the hole you drilled making a whole new problem for yourself

if you do go the extractor route...do yourself a favor and drill it out as close to the thread size as you can..this way the chances of snapping the extracor is minimized


Good to see you again sh0rtlife - I appreciate the input for how best to remove a stubborn bolt. I tried filing down the edges of the one remaining bolt on my Yaris seat, only to find out that there are no metric or SAE sockets which fit the tiny head size once filed down.

My next move was to order an Irwin screw extractor set on Amazon. The #3 sized bit worked, once I used a 5/32 metal drill bit to drill a hole inside the head bolt.

My only problem now is that the bit holder keeps slipping, on the side of the drill. I'm guessing I need a more solid drill bit holder, but maybe someone can chime in as to what might work best from here on. Here's a picture to give you an idea of how far I've made it.

[WeeYari]

I tried filing down the edges of the one remaining bolt on my Yaris seat, only to find out that there are no metric or SAE sockets which fit the tiny head size once filed down.
Of course there are. My kit has 4mm as the smallest.

[MyBlueYar]

Of course there are. My kit has 4mm as the smallest.

Perhaps I misworded my previous comment WeeYari. With the nubs intact, the seat bolt accepts an 8mm socket. My problem, however, was once I filed off the nubs as per sh0rtlife's suggestion, I was in no man's land between a 7mm and 8mm as far as fitting.

My socket set also goes down to a 4mm like yours - however - to reiterate, the conventional socket sizes do not align with what I need.

[WeeYari]

You need a size which is close but slightly to small. Then smack it down onto head of bolt with a hammer.
Between SAE and metric, you will have a socket that almost wants to fit.

[sh0rtlife]

as mentioned you file it then BASH a socket on there and never expect to get the socket off again..tho i have tricks for that...


what you need to hold the extractor is not a drill..NOOOOooooo not a drill

theres 2 tools made for that, tho in this situation i reccomend neither...and to use a very tight fitting cresent wrench

anyway the 2 tools ment for holding that are the same 2 tools used in a tap n die set

[MyBlueYar]

as mentioned you file it then BASH a socket on there and never expect to get the socket off again..tho i have tricks for that...


what you need to hold the extractor is not a drill..NOOOOooooo not a drill

theres 2 tools made for that, tho in this situation i reccomend neither...and to use a very tight fitting cresent wrench

anyway the 2 tools ment for holding that are the same 2 tools used in a tap n die set



With the extractor embedded deeply into the head of the bolt, nothing is even coming close to being able to grasp the tiny body to exert any twisting force.

I tried an open ended crescent wrench, it was woefully inadequate. A conventional socket doesn't fit over the extractor, so my only choice now is to find a deep socket that might reach. My existing deep socket is only 2" long, which is too short unfortunately.

[WeeYari]

Crescent wrench was recommended for use on square end of the extractor.
Socket requires extractor to be backed out first.

[sh0rtlife]

2 things i should probably add here as well, the "impact" of bashing a socket onto the head will help break the threads free

secondly the bolt should be TIGHTENED ever so slightly before attempting to loosen it..this will both "stretch" the threads as well as help break it free

as it starts to work its way out and starts tightening back up back off and tighten it again

ie dont just try and crank it out you need to go in out in out in out going a little more out every time but not over doing it


these are the tricks you learn working on stuff more than 50 years old


something else....a solid set of vice grips on the head as well as a cresent wrench on the extractor would be highly reccomended as well, so your not applying all of the force on the extractor

also once you do expose threads spray in some "kroil" if you can ..pb blaster is an ok second choice, once youve got the bolt a good 1/4inch or so out apply antisieze to the threads and work the bolt back in flush an back out a few times re-appplying anti size, the trick here is your working it into the "nut" threads on the body...after that you should be able to get it out without much issue

FWIW i had the EXACT same problem on the driver rear seat rear most bolt and paid hell getting it out due to a lack of working space..i actualy found it benificial to chissle the edges off the head so i could remove the seat bracket and get a better bite on the bolt

[MyBlueYar]

2 things i should probably add here as well, the "impact" of bashing a socket onto the head will help break the threads free


secondly the bolt should be TIGHTENED ever so slightly before attempting to loosen it..this will both "stretch" the threads as well as help break it free

as it starts to work its way out and starts tightening back up back off and tighten it again

ie dont just try and crank it out you need to go in out in out in out going a little more out every time but not over doing it


these are the tricks you learn working on stuff more than 50 years old


something else....a solid set of vice grips on the head as well as a cresent wrench on the extractor would be highly reccomended as well, so your not applying all of the force on the extractor

also once you do expose threads spray in some "kroil" if you can ..pb blaster is an ok second choice, once youve got the bolt a good 1/4inch or so out apply antisieze to the threads and work the bolt back in flush an back out a few times re-appplying anti size, the trick here is your working it into the "nut" threads on the body...after that you should be able to get it out without much issue

FWIW i had the EXACT same problem on the driver rear seat rear most bolt and paid hell getting it out due to a lack of working space..i actualy found it benificial to chissle the edges off the head so i could remove the seat bracket and get a better bite on the bolt


OK, quick update before I wrap it up for tonight. I managed to get a crescent wrench on the extractor to back it out, which it did, but snapped the extractor in half and probably irreparably damaged the bolt head at the same time.

I've worked on plenty of cars, and this is the first time I've had a seat bolt be this badly stuck. At any rate, I'm really in a mess now, with the integrity of the head bolt gone.

I appreciate all the input from you guys - I know on paper all your suggestions should have easily served to get this bolt out, but I guess it's a reminder that real life sometime serves us up a big can of surprise and frustration.

Here's a close up to give you an idea of the carnage -

[sh0rtlife]

sorry to say...but...thats EXACTLY what i expected to happen

now...grab a chissel and try and bite the edge of the base of the bolt and hit it in a direction of loosening it, it may or may not budge but keep doing it all the way around and youll either chew enough material off to get the seat off the bolt or youll loosen it up and it will slowly walk out

if you chew the ridge off the head so the rail can come off you can easily get a set of vise grips on the head and slwoly work it back n forth

[MyBlueYar]

sorry to say...but...thats EXACTLY what i expected to happen

now...grab a chissel and try and bite the edge of the base of the bolt and hit it in a direction of loosening it, it may or may not budge but keep doing it all the way around and youll either chew enough material off to get the seat off the bolt or youll loosen it up and it will slowly walk out

if you chew the ridge off the head so the rail can come off you can easily get a set of vise grips on the head and slwoly work it back n forth



sh0rtlife, much obliged. Your chisel suggestion did the trick. I picked up a cheap set of chisels at Harbor Freight, and it was literally a 2-3 operation from start to finish. Thank you for your insight and ingenuity.

[ern-diz]

Hope this turned out well.