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The MJ screw/bolt size thread. Help gather the info...


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This thread will be to list any and every bolt/screw size for any part on our MJ's. Hopefully we can get a good size list and then Pete will move it to the DIY section. So please list any screw/bolt sizes you know.

 

If anyone can explain measurements of how bolt/screw sizes are measured that would be good too.

 

Great pics of screw head types and threads with other info.

 

http://www.pro-twist.com/generalinforma ... p?Action=3

 

http://www.gizmology.net/nutsbolts.htm

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Reporting as ordered, Sir!

 

American: We use two series of threads, "coarse" and "fine". From a shank diameter of 1/4" and larger, the first number is the shank diameter and the second number is the number of threads per inch. As in:

 

1/4-24 is a 1/4" bolt with 24 threads per inch. That's a coarse thread.

 

1/4-32 is a 1/4" bolt with 32 threads per inch (closer together). That's a fine thread.

 

Below 1/4" they go by numbered sizes, but they still also go by thread pitch. As in:

 

12-24 (Coarse)

12-32 (Fine)

 

Metric threads are also listed by shank diameter, but the second part of their listing is NOT the number of threads per (ahem) millimeter, but rather the "pitch -- the distance between two threads.

 

So a nut I was just looking for, as an example, was an M6x1.0. That means the shank diameter is 6 mm and the distance between threads is 1.0 mm.

 

-----------------------------------

Then we have grades. In American (SAE - Society of Automotive Engineers) parlance, we normally encounter Grade 2 bolts, which have no marking on the hex head; Grade 5, which have three hash marks on the head; and Grade 8, which have six hash marks on the head. Grade 5 is stronger than Grade 2, and Grade 8 is stronger than Grade 5.

 

In metric, there are also grades: 8.8, 10.9, and 12.9. Metric bolts will usually have the grade written on the head as a number.

 

I strongly suggest that y'all bookmark the following link. The Nutty Company has a lot of good technical data on fasteners on their web site, and they also sell to individuals in small quantities (unlike some industrial supply places, that can get that odd-ball bolt you need three of -- but only if you buy a case of 5,000.)

 

http://www.nutty.com/index.shtml

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I hope this helps someone.

 

---Drill bit size for Tap size---

 

 

---------------------<....APPROXIMATE....DRILL....SIZE....>-------

--------------------------------------|___75%___|___70%___|___60%___| ----

---------------------------------------------------------------------------------------------------

 

0-80--------------------------------|.......56.......|......56.......|......3/16.....|

 

1-64--------------------------------|.......54.......|......54.......|.......53.......|

 

1-72--------------------------------|.......54.......|......54.......|.......53.......|

 

2-56--------------------------------|.......51.......|......51.......|.......50.......|

 

2-64--------------------------------|.......50.......|......50.......|.......49.......|

 

3-48--------------------------------|.......48.......|......50.......|.......46.......|

 

3-56--------------------------------|.......47.......|......46.......|.......45.......|

 

4-40--------------------------------|.......44.......|......44.......|.......43.......|

 

4-48--------------------------------|.......43.......|......43.......|......3/32.....|

 

5-40--------------------------------|.......39.......|......38.......|.......37.......|

 

5-44--------------------------------|.......38.......|......38.......|.......37.......|

 

6-32--------------------------------|.......36.......|......35.......|.......33.......|

 

6-40--------------------------------|.......34.......|......33.......|.......32.......|

 

8-32--------------------------------|.......30.......|......29.......|.......28.......|

 

8-36--------------------------------|.......29.......|......29.......|.......28.......|

 

10-24------------------------------|.......25.......|......24.......|.......22.......|

 

10-32------------------------------|.......21.......|......20.......|.......19.......|

 

12-24------------------------------|.......17.......|......16.......|.......14.......|

 

12-28------------------------------|.......15.......|......14.......|.......12.......|

 

1/4-20-----------------------------|........ 7 ......|.......6........|.......4........|

 

1/4-28-----------------------------|.........3.......|.......3........|.......2........|

 

5/16-20---------------------------|.........F.......|.......G........|.......H........|

 

5/16-24---------------------------|..... .272.....|.... .275......|.....9/32......|

 

3/8-16-----------------------------|.......5/16....|........O......|........P........|

 

3/8-24-----------------------------|........Q.......|.......R........|.....11/32....|

 

7/16-14---------------------------|........U.......|......3/8......|...... .382.....|

 

7/16-20---------------------------|........W......|.....25/64....|.........X.......|

 

1/2-13-----------------------------|.... .425......|..... .430.....|.....7/16......|

 

1/2-20-----------------------------|.....29/64....|....29/64.....|.... .461......|

 

9/16-12---------------------------|.....31/64....|....31/64.....|......1/2.......|

 

9/16-18---------------------------|.....33/64....|....33/64.....|.... .519......|

 

5/8-11-----------------------------|.....35/64....|....35/64.....|.... .554......|

 

5/8-18-----------------------------|..... .575.....|.... .575......|....37/64.....|

 

11/16-16-------------------------|...... .631....|.... .631......|.....41/64....|

 

3/4-10----------------------------|.....21/32....|....21/32.....|.....43/64....|

 

3/4-16----------------------------|.....11/16....|.... .693......|.....45/64....|

 

7/8-9------------------------------|.....49/64....|.... .774......|..... .788.....|

 

7/8-14----------------------------|..... .805.....|....13/64.....|..... .819.....|

 

1-8---------------------------------|.....7/8.......|.... .886......|.....29/32....|

 

1-12-------------------------------|....29/32.....|....59/64.....|......15/16...|

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So I have all the bolts out for the water pump and power steering pump.

I know they all came out with 13,14, and 15mm sockets but how do you guys want me to measure them (meaning like with a tape measure from where to where.) And do you want me to count the threads?

 

calipers would be the best way, but why would you want to measure them for?

measure the diameter on the shaft not the head, the length, and yes how many threads per inch.

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So I have all the bolts out for the water pump and power steering pump.

I know they all came out with 13,14, and 15mm sockets but how do you guys want me to measure them (meaning like with a tape measure from where to where.) And do you want me to count the threads?

 

Chico, this is what eagle said when i asked him that exact question:

 

Bolts and screws that have a round or pan head measure just the length of the shank. Flathead (countersunk) screws measure the total length including the head.

 

Best way to figure out the thread is to use a thread gauge, or take one into Lowe's or Home Depot and try it in the sample thread gauges they have in the hardware aisle. A lot of metric sizes are so close to SAE that it can get very confusing.

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-Screws from inside molding along door jamb: #8 1.5" self-drilling modified truss head (similar to washer head) screw

 

-Grill- 3/4" phillips head hi-lo thread

 

Transfer case fill/drain plugs- 30mm 12point socket

 

-Valve Cover Bolts- 1/4" X 20 UNC

 

-2 bolts on top of bellhousing- E12 external torx

 

-steering box bolts- 7/16-14x4

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I realize we are trying to collate a thread of the MJ fastener sizes, but I came across several links that are on Pirate 4x4 site that link to Billa Vista's web page. I cannot find the metric equivlant lists, but the standard are:

 

http://www.pirate4x4.com/tech/billavist ... 0Sizes.pdf

 

and:

 

http://www.pirate4x4.com/tech/billavist ... nsions.pdf

 

If this is not appropriate please move elsewhere :D

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  • 1 month later...
looking for the bolt size to the lower front shock mounts

 

I know the heads to them are 13 MM... and a PITA to change

 

any idea on the diameter and pitch? thanks pong

 

Between 6mm and 8mm, are the most common size bolt sizes used. The lower shock bolts are 8mm X 1.25. They resemble a 5/16-18 but don't trash them out by forcing one on the other. A simple way to determine the difference between 8mm and 5/16 is measuring the hex head with calipers. An 8mm bolt head will be larger than 1/2 inch. Usually close to 13mm or about .512". A 5/16" hex head will measure close to 1/2" or .500".

 

The smaller torx head bolts holding the fenders on will be 6mm X 1.00.

 

All of the pipe fittings will be standard thread.

 

So far on the older models I have removed parts from , brake lines are still standard thread.

 

The 4.0 motor bolts are standard thread while any brackets and accessories that don't bolt directly to the head or block are all metric.

 

I am sure there are variations over the years.

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  • 4 weeks later...

I identify bolt threads by matching them up to something in my standard and metric tap-die sets first check the thread gage .Just don't force any thing or you'l cut the threads up.then measure length. I think also knowing the size of wrench or socket you need to remove them would save a few trips back and forth from tool chest to back under Jeep.

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I identify bolt threads by matching them up to something in my standard and metric tap-die sets first check the thread gage .Just don't force any thing or you'l cut the threads up.then measure length. I think also knowing the size of wrench or socket you need to remove them would save a few trips back and forth from tool chest to back under Jeep.

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  • 4 weeks later...

Hi everyone

 

I'm wondering if somebody knows the size and specs for the bolts that holds the manifold or where the exhaust begins, hope I'm explaining myself, i need to change the gasket(already bought) but theres 2 bolts missing, so i need the specs in order to buy them...

 

Truck Specs:

Comanche 1988, 4x4, 2.5 tbi engine, manual trans

 

sorry about the pic size!

 

hope you can help me guys

 

Thanks

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  • 2 weeks later...
This may have some bolts/screw sizes that will help someone. It all so lists torque for tightening.

 

http://www.geocities.com/JeepI6Power/1989XJMJ.html

 

Nice! Now that's a bookmark! :thumbsup:

 

Here's a nice tool I found and have been using for Tech Specs like this. Go to http://www.Docudesk.com and they have a free PDF writer. It loads as a printer, so when you click on the link above and it opens, you right click to "print" then select deskPDF as your printer and it converts it to PDF and lets you save it.

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