Unofficial FAQ: Bolt Sizes

jblaine · 07-14-2005, 04:55 PM

I think this would be a great resource to have and is long overdue. Everyone share your information with as much accurate detail as possible. I will gather it all in this top post.

Common to WRX or STI regardless of year

Front O2 sensor plug = M18 x 1.5

Up-pipe EGT plug = M12 x 1.25

ECU cover plate = M6 x 1.0

Intake manifold to TGV risers = M6 x 1.00 x 40

Sway bar bolts (bushings and endlinks), strut tops, ram intake duct, the spare tire hold-down, plastic splash shield, and jacking plate = M8 x 1.25

Exhaust bolts and a bunch of other stuff under the hood (green brackets for fuel rail, radiator mount) = M10 x 1.25

EGT bung, lug nuts, and shift knob = M12 x 1.25

Gallery threading on the block for oil pressure/temp sensors = M18 x 1.5

Oil drain bolt = M20 x 1.5

Uppipe stud: automotive stud, M10 x 1.25 by 41mm

The female fitting on the clutch line is M10x1.00

The banjos on the brake calipers are also M10x1.00

The banjo on the turbo for the oil feed line is M10X1.5

Top-mount intercooler mounting bolts are 8X1.25

Rear seat upper part (3 of them) are 10x1.25

Rear seat lower part (2 of them) are 8x1.25

Front fender attachment inside the engine bay is M6 x 1.0 x 10

Breather lines attaching to TMIC (3) are M6 x 1.0 x 10

Model Year or Make-Specific

2002-2005 WRX: Caliper bracket to HUB bolts are M12 x 1.25 x 30 (Property class 6.6)

NOTES

If you can find it, grade 8 hardware is the way to go, especially high torque spec ones.

Bigger bolts/plugs such as M18 x 1.5 can be found at many automotive parts stores as oil drain bolts either with the oil change supplies or behind the counter.

THANKS:

tdxflex
Unabomber
checque
specialev
...and everyone else who has replied in this thread with info!

* Registered users of the site do not see these ads.

tdxflex · 07-14-2005, 06:34 PM

02 WRX

m6 x 1.0 ECU cover plate
m8 x 1.25 for the sway bar bolts (bushings and endlinks), strut tops, ram intake duct, the spare tire hold-down, plastic splash shield, and jacking plate
m10 x 1.25 for the exhaust bolts and a bunch of other stuff under the hood (green brackets for fuel rail, intake manifold, radiator mount)
m12 x 1.25 for EGT bung, lug nuts, and shift knob
m18 x 1.5 for o2 bung, the gallery threading on the block for oil pressure/temp sensors
m20 x 1.5 oil drain bolt

unsure of:

bov, intercooler mounts - I think are m8 x 1.25, either that or m10 x 1.25

brake caliper bleeder and clutch bleeder - not sure if it's m7 x 1.0, but they're both the same threading

rear seat mounting bolts look like they're m10 x 1.25

Unabomber · 07-14-2005, 07:54 PM

Good idea, I started this awhile back and lost interest.

Uppipe stud: automotive stud, m10 x 1.25 by 41mm

You may also mention that grade 8 or better is the way to go with bolts. No sense in having someone buy some cheapo Home Depot stuff to just have it break during the tightening sequence.

You may also mention that bigger bolts/plugs such as M18 x 1.5 can be found at many automotive parts stores as oil drain bolts either with the oil change supplies or behind the counter.

Ohannon7 · 07-14-2005, 09:11 PM

joined........................

checque · 12-02-2005, 12:48 PM

There's no way the 8 bolts holding the intake manifold down are M10, I haven't found the right size yet, but when I do I'll edit this post with what they really are.

jblaine · 12-02-2005, 12:52 PM

I think you're right, checque. In my case (JDM version 8 intake manifold), it bolts right to the heads and has no TGV housings.

Please do let me know what you find for a typical setup (bolts for manifold to TGV housings).

subieworx · 12-02-2005, 01:39 PM

Quote:

Originally Posted by checque

There's no way the 8 bolts holding the intake manifold down are M10, I haven't found the right size yet, but when I do I'll edit this post with what they really are.

I agree. The nuts and bolts have 10mm heads and the size and pitch look similar to what holds the ECU in place. m6x1 or 1.25 looks better.

checque · 12-02-2005, 04:13 PM

Alright, I was going to just edit my other post, but I'll keep it less confusing and make this the most recent post on the subject.
The 8 bolts holding down the intake manifold are M6 x 1.00 x 40. Anywhere you can buy bolts you will easily find this size.
Edit: Note that I own an 05 WRX at this time.

jblaine · 12-02-2005, 04:16 PM

Updated top post.

Starkiller · 12-02-2005, 10:29 PM

What size are the bolts that attach the engine to transmission case?

D_Sagan · 12-03-2005, 12:39 AM

Yes what size are those bolts??? I need to get my new longblock onto the engine stand and I'm going to make a trip to Lowe's tomorrow to buy one of everything until I find it.

fogdor · 12-03-2005, 01:03 AM

I've learned by hard experience that SAE unit fasteners are "grade" and Metric fasteners are "class".

To get "grade 8" equivalent metric fasteners, make sure they are "class 10". To my dismay, "class 8" fasteners are about equivalent to "grade 5"...bleh

sixpack subaru · 12-03-2005, 05:05 AM

Bell housing bolts are M10X1.25.
There are really only a handful of sizes on a Subaru, (or any jap car really).
S/Plugs are std M14, EA82 head bolts are M11X1.0-trying buying that size at hardware!! I'm sure these are listed in a manual somewhere......

Sixpack

LyveWRX · 12-03-2005, 01:44 PM

fogdor- you're right, but the class is much more informative than grade.

http://www.marylandmetrics.com/tech/u19e2.htm

http://home.jtan.com/~joe/KIAT/kiat_2.htm

specialev · 12-03-2005, 08:46 PM

^^^^^^^^^^^
These articles on bolts that Lyve posted are a really good read. I would suggest them to one and all. I speak particularly in reference to the second link.

sixpack subaru · 12-03-2005, 08:59 PM

Very Good......note the part about Loctite being a good lube by design....great stuff that Loctite!!LOL.

specialev · 02-10-2006, 02:32 AM

M6X1.0 on the DP heat shield.

awdboxer · 03-06-2006, 09:44 AM

Are you sure the oil drain plug bolt is M18x1.5? I thought it was an M20...

LyveWRX · 03-06-2006, 10:09 AM

The Caliper bracket to front hub on the two pot WRX brakes is an M12x1.25x30...

i would figure this is an alloy steel bolt with a property class better than 8.8, likely its 10.9. However the marking on the head is a 6 with a dot under it.

If you brake this bolt off you are going to have a devil of a time finding something the right size and length with a small enough head. Instead you can temporarily use a hardened threaded rod and two nuts.

(I went to a midas and asked if they could help me. 15min later the broken bolt was out of the caliper bracket, I had two double nutted studs and only had spent $10.)

That will get you by until the dealer is open on monday. Use antisieze on these. The whole length too... (it also seizes to the knuckle, not just in the threads.)

jblaine · 03-06-2006, 01:04 PM

Quote:

Originally Posted by 2bar04

Are you sure the oil drain plug bolt is M18x1.5? I thought it was an M20...

Nope, not sure of anything. I can't recall where I got the M18 info in order to recheck. Did some searches just now and didn't turn up anything either.

So - reader beware. Updated top post.

specialev · 03-20-2006, 10:27 PM

Quote:

Originally Posted by 2bar04

Are you sure the oil drain plug bolt is M18x1.5? I thought it was an M20...

I just went and checked my bolt stash and in comparing the old drain pan bolt that I replaced with a Fumoto valve and the old galley plug that I replaced with a plug I bought for an O2 sensor I realize I furnished some bad info. The male hex drain pan plug is M20X1.5 and the female hex galley plug is M18X1.5, the same as the O2 sensor.

Sorry for causing any confusion.

LyveWRX · 03-21-2006, 11:18 AM

I also have provided bad information.....

The cliper bracket to HUB bolts are M12x1.25x30.... However they are Property Class 6.6 (so they will bend a lot before they break) not 10.9 in my above post...

And also on the larger bolts there are head markings of a number with a dot under it... Those are the property class...

subaruzero · 03-23-2006, 03:18 PM

Bolt size for the rear exhaust hanger?

jblaine · 03-23-2006, 03:26 PM

Okay, so I have the following now:

Oil pan: M20
Oil galley on top of block near crankcase vent: M18

Correct?

awdboxer · 03-23-2006, 03:32 PM

Thats correct for the oil drain plug...I bought a new one and it has M20 imprinted on the top of it.

07-14-2005, 04:55 PM	#1
jblaine Scooby Guru Member#: 8512 Join Date: Jul 2001 Chapter/Region: South East Location: St. Pete, FL Vehicle: 2002 WRX chassis... stage-infinity.com	Unofficial FAQ: Bolt Sizes I think this would be a great resource to have and is long overdue. Everyone share your information with as much accurate detail as possible. I will gather it all in this top post. Common to WRX or STI regardless of year Front O2 sensor plug = M18 x 1.5 Up-pipe EGT plug = M12 x 1.25 ECU cover plate = M6 x 1.0 Intake manifold to TGV risers = M6 x 1.00 x 40 Sway bar bolts (bushings and endlinks), strut tops, ram intake duct, the spare tire hold-down, plastic splash shield, and jacking plate = M8 x 1.25 Exhaust bolts and a bunch of other stuff under the hood (green brackets for fuel rail, radiator mount) = M10 x 1.25 EGT bung, lug nuts, and shift knob = M12 x 1.25 Gallery threading on the block for oil pressure/temp sensors = M18 x 1.5 Oil drain bolt = M20 x 1.5 Uppipe stud: automotive stud, M10 x 1.25 by 41mm The female fitting on the clutch line is M10x1.00 The banjos on the brake calipers are also M10x1.00 The banjo on the turbo for the oil feed line is M10X1.5 Top-mount intercooler mounting bolts are 8X1.25 Rear seat upper part (3 of them) are 10x1.25 Rear seat lower part (2 of them) are 8x1.25 Front fender attachment inside the engine bay is M6 x 1.0 x 10 Breather lines attaching to TMIC (3) are M6 x 1.0 x 10 Model Year or Make-Specific 2002-2005 WRX: Caliper bracket to HUB bolts are M12 x 1.25 x 30 (Property class 6.6) NOTES If you can find it, grade 8 hardware is the way to go, especially high torque spec ones. Bigger bolts/plugs such as M18 x 1.5 can be found at many automotive parts stores as oil drain bolts either with the oil change supplies or behind the counter. THANKS: tdxflex Unabomber checque specialev ...and everyone else who has replied in this thread with info! * Registered users of the site do not see these ads. Last edited by jblaine; 11-13-2008 at 12:02 PM.

07-14-2005, 06:34 PM	#2
tdxflex Scooby Specialist Member#: 13634 Join Date: Dec 2001 Chapter/Region: NESIC Location: Boston Vehicle: 2002 WRX WRB	02 WRX m6 x 1.0 ECU cover plate m8 x 1.25 for the sway bar bolts (bushings and endlinks), strut tops, ram intake duct, the spare tire hold-down, plastic splash shield, and jacking plate m10 x 1.25 for the exhaust bolts and a bunch of other stuff under the hood (green brackets for fuel rail, intake manifold, radiator mount) m12 x 1.25 for EGT bung, lug nuts, and shift knob m18 x 1.5 for o2 bung, the gallery threading on the block for oil pressure/temp sensors m20 x 1.5 oil drain bolt unsure of: bov, intercooler mounts - I think are m8 x 1.25, either that or m10 x 1.25 brake caliper bleeder and clutch bleeder - not sure if it's m7 x 1.0, but they're both the same threading rear seat mounting bolts look like they're m10 x 1.25 Last edited by tdxflex; 07-14-2005 at 06:49 PM.

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07-14-2005, 07:54 PM	#3
Unabomber Big Ron Super Moderator Member#: 18062 Join Date: Apr 2002 Chapter/Region: MAIC Location: I can save you a ton of cash Vehicle: on car parts so PM me b4 j00 buy	Good idea, I started this awhile back and lost interest. Uppipe stud: automotive stud, m10 x 1.25 by 41mm You may also mention that grade 8 or better is the way to go with bolts. No sense in having someone buy some cheapo Home Depot stuff to just have it break during the tightening sequence. You may also mention that bigger bolts/plugs such as M18 x 1.5 can be found at many automotive parts stores as oil drain bolts either with the oil change supplies or behind the counter.

07-14-2005, 09:11 PM	#4
Ohannon7 Scooby Specialist Member#: 63824 Join Date: Jun 2004 Chapter/Region: South East Location: Da Butt Vehicle: 05 WRX WRB pearl Cobb II+	joined........................

12-02-2005, 12:48 PM	#5
checque Scooby Specialist Member#: 68562 Join Date: Aug 2004 Chapter/Region: MAIC Location: Pitt/VA Beach Vehicle: RIP Edwin	There's no way the 8 bolts holding the intake manifold down are M10, I haven't found the right size yet, but when I do I'll edit this post with what they really are.

12-02-2005, 12:52 PM	#6
jblaine Scooby Guru Member#: 8512 Join Date: Jul 2001 Chapter/Region: South East Location: St. Pete, FL Vehicle: 2002 WRX chassis... stage-infinity.com	I think you're right, checque. In my case (JDM version 8 intake manifold), it bolts right to the heads and has no TGV housings. Please do let me know what you find for a typical setup (bolts for manifold to TGV housings).

12-02-2005, 04:13 PM	#8
checque Scooby Specialist Member#: 68562 Join Date: Aug 2004 Chapter/Region: MAIC Location: Pitt/VA Beach Vehicle: RIP Edwin	Alright, I was going to just edit my other post, but I'll keep it less confusing and make this the most recent post on the subject. The 8 bolts holding down the intake manifold are M6 x 1.00 x 40. Anywhere you can buy bolts you will easily find this size. Edit: Note that I own an 05 WRX at this time.

12-02-2005, 04:16 PM	#9
jblaine Scooby Guru Member#: 8512 Join Date: Jul 2001 Chapter/Region: South East Location: St. Pete, FL Vehicle: 2002 WRX chassis... stage-infinity.com	Updated top post.

12-02-2005, 10:29 PM	#10
Starkiller Scooby Specialist Member#: 82741 Join Date: Mar 2005 Chapter/Region: NESIC Location: Bristol, CT Vehicle: 2007 350Z Silver	What size are the bolts that attach the engine to transmission case?

12-03-2005, 12:39 AM	#11
D_Sagan Scooby Newbie Member#: 22902 Join Date: Aug 2002 Chapter/Region: TXIC Location: Houston Vehicle: 2005 STI CGM	Yes what size are those bolts??? I need to get my new longblock onto the engine stand and I'm going to make a trip to Lowe's tomorrow to buy one of everything until I find it.

12-03-2005, 01:03 AM	#12
fogdor Scooby Specialist Member#: 45726 Join Date: Oct 2003 Vehicle: 2007 Mazdaspeed3 Cosmic Blue	I've learned by hard experience that SAE unit fasteners are "grade" and Metric fasteners are "class". To get "grade 8" equivalent metric fasteners, make sure they are "class 10". To my dismay, "class 8" fasteners are about equivalent to "grade 5"...bleh

12-03-2005, 05:05 AM	#13
sixpack subaru * Banned * Member#: 64974 Join Date: Jun 2004 Location: My Shed, Melbourne, Australia Vehicle: 1995 WRX,APEXi,HKS,$ Faded, Stonechipped Red	Bell housing bolts are M10X1.25. There are really only a handful of sizes on a Subaru, (or any jap car really). S/Plugs are std M14, EA82 head bolts are M11X1.0-trying buying that size at hardware!! I'm sure these are listed in a manual somewhere...... Sixpack

12-03-2005, 01:44 PM	#14
LyveWRX Scooby Specialist Member#: 19057 Join Date: May 2002 Chapter/Region: MWSOC Location: The Lost Valley, Detroit, MI Vehicle: 2002 WRX & Blue Ford & '72 CB350	fogdor- you're right, but the class is much more informative than grade. http://www.marylandmetrics.com/tech/u19e2.htm http://home.jtan.com/~joe/KIAT/kiat_2.htm

12-03-2005, 08:46 PM	#15
specialev Scooby Specialist Member#: 90156 Join Date: Jun 2005 Chapter/Region: NWIC Location: Auburn, Wa Vehicle: 1986 Syncro Vanaru 07 SV650	^^^^^^^^^^^ These articles on bolts that Lyve posted are a really good read. I would suggest them to one and all. I speak particularly in reference to the second link.

12-03-2005, 08:59 PM	#16
sixpack subaru * Banned * Member#: 64974 Join Date: Jun 2004 Location: My Shed, Melbourne, Australia Vehicle: 1995 WRX,APEXi,HKS,$ Faded, Stonechipped Red	Very Good......note the part about Loctite being a good lube by design....great stuff that Loctite!!LOL.

02-10-2006, 02:32 AM	#17
specialev Scooby Specialist Member#: 90156 Join Date: Jun 2005 Chapter/Region: NWIC Location: Auburn, Wa Vehicle: 1986 Syncro Vanaru 07 SV650	M6X1.0 on the DP heat shield.

03-06-2006, 09:44 AM	#18
awdboxer Scooby Specialist Member#: 38425 Join Date: Jun 2003 Chapter/Region: RMIC Location: Denver Vehicle: 2015 STI CWP	Are you sure the oil drain plug bolt is M18x1.5? I thought it was an M20...

03-06-2006, 10:09 AM	#19
LyveWRX Scooby Specialist Member#: 19057 Join Date: May 2002 Chapter/Region: MWSOC Location: The Lost Valley, Detroit, MI Vehicle: 2002 WRX & Blue Ford & '72 CB350	The Caliper bracket to front hub on the two pot WRX brakes is an M12x1.25x30... i would figure this is an alloy steel bolt with a property class better than 8.8, likely its 10.9. However the marking on the head is a 6 with a dot under it. If you brake this bolt off you are going to have a devil of a time finding something the right size and length with a small enough head. Instead you can temporarily use a hardened threaded rod and two nuts. (I went to a midas and asked if they could help me. 15min later the broken bolt was out of the caliper bracket, I had two double nutted studs and only had spent $10.) That will get you by until the dealer is open on monday. Use antisieze on these. The whole length too... (it also seizes to the knuckle, not just in the threads.)

03-21-2006, 11:18 AM	#22
LyveWRX Scooby Specialist Member#: 19057 Join Date: May 2002 Chapter/Region: MWSOC Location: The Lost Valley, Detroit, MI Vehicle: 2002 WRX & Blue Ford & '72 CB350	I also have provided bad information..... The cliper bracket to HUB bolts are M12x1.25x30.... However they are Property Class 6.6 (so they will bend a lot before they break) not 10.9 in my above post... And also on the larger bolts there are head markings of a number with a dot under it... Those are the property class...

03-23-2006, 03:18 PM	#23
subaruzero Scooby Newbie Member#: 92378 Join Date: Jul 2005 Chapter/Region: MWSOC Location: Michigan Vehicle: 2002 Impreza WRX Aspen White	Bolt size for the rear exhaust hanger?

03-23-2006, 03:26 PM	#24
jblaine Scooby Guru Member#: 8512 Join Date: Jul 2001 Chapter/Region: South East Location: St. Pete, FL Vehicle: 2002 WRX chassis... stage-infinity.com	Okay, so I have the following now: Oil pan: M20 Oil galley on top of block near crankcase vent: M18 Correct?

03-23-2006, 03:32 PM	#25
awdboxer Scooby Specialist Member#: 38425 Join Date: Jun 2003 Chapter/Region: RMIC Location: Denver Vehicle: 2015 STI CWP	Thats correct for the oil drain plug...I bought a new one and it has M20 imprinted on the top of it.