I know I'm going to win a Gomer award for this question, but here it is anyway!

[math1960]

What is the size and thread type of the nuts that are on the positive battery junction on the firewall ? I bought a box of 5/16 coarse hex nuts and was told this is the same as 12mm. I tried both fine and coarse 5/16 but they don't screw down right. What am I missing here? The bolt is not stripped, that I can see. I used a 13mm crescent wrench on this and the other nuts.

It seems my blazer is in good shape, but most of my electric problems is loose connections.

Thanks for any help.

Wally

 

[doghead]

[h=2]5310-00-252-8748 ( MS20341-516C, MS33650-3314, MS35650-3314, FF-N-836 ) Characteristics Data[/h]
MRC	Criteria	Characteristic
BZRR	THREAD SERIES	UNF
CQJX	NOMINAL THREAD SIZE	0.312 INCHES
CMLP	THREAD QUANTITY PER INCH	24
AAJD	THREAD CLASS	2B
AAJF	THREAD DIRECTION	RIGHT-HAND
MATT	MATERIAL	STEEL COMP 302 OR STEEL COMP 304 OR STEEL COMP 304L OR STEEL COMP 305 OR STEEL COMP 309 OR STEEL COMP 310 OR STEEL COMP 316 OR STEEL COMP 316L OR STEEL COMP 317 OR STEEL COMP 321 OR STEEL COMP 347 OVERALL
MDCL	MATERIAL DOCUMENT AND CLASSIFICATION	QQ-S-763 FED SPEC ALL MATERIAL RESPONSES OVERALL
SFTT	SURFACE TREATMENT	PASSIVATE OVERALL
STDC	SURFACE TREATMENT DOCUMENT AND CLASSIFICATION	QQ-P-35 FED SPEC SINGLE TREATMENT RESPONSE OVERALL
CQFM	HARDNESS RATING	NOT RATED
ACTA	NUT STYLE	A12 HEXAGON
ADEA	NUT HEIGHT	0.208 INCHES MINIMUM AND 0.225 INCHES MAXIMUM
ASDB	WIDTH ACROSS FLATS	0.545 INCHES MINIMUM AND 0.562 INCHES MAXIMUM
CRTM	BEARING SURFACE TYPE	CHAMFERED
AZKQ	TEMP RATING	NOT RATED
ZZZT	NONDEFINITIVE SPEC/STD DATA	2 TYPE AND 13 STYLE
SR-1	MANUFACTURERS CODE	81348
SR-1	NON-DEFINITIVE GOVERNMENT SPEC/STD REFERENCE	FF-N-836

 

[doghead]

I'll give you one guess how I found that info.

I'll also give you one hint. Technical Manual

 

[MarcusOReallyus]

I bought a box of 5/16 coarse hex nuts and was told this is the same as 12mm. I tried both fine and coarse 5/16 but they don't screw down right. What am I missing here?

Nut size is one thing. Thread pitch is a very different animal.

For example, 1/2" and 13 mm are close enough that you can use 13mm wrenches on 1/2" nuts & bolts. But try a 1/2" nut on a 13mm bolt and it won't work at all.

Same deal on 3/8" and 10 mm.

Best advice?

Don't try to mix them.

 

[math1960]

Thanks for the info. I see your point Marcus, I'll try metric. Doghead don't think the guy at auto zone can use this TM data for a hex nut. Nice try tho.

 

[forest522]

I love the technical manuals! Best advice I ever received from this forum long ago when I too received my Gomer award. Read the TMs, print out some and put them in the bathroom.

Some find them complicated, hard to read and difficult to understand. Why don't they make TMs for women?

 

[Warthog]

Let's see. From DHs technical info:

UNF=fine thread
.312 = 5/16
24 thread/in = fine

I would say a 5/16 fine thread is what you are looking for.

I suppose you "could" make a course thread fit.

 

[DieselBob]

Also GM decided sometime around 1980 that it was time to start mixing in metric fasteners in totally random location just to make them more “universal” to the rest of the world so it could be anyone of 3 or 4 thread pitches.

 

[KsM715]

Thanks for the info. I see your point Marcus, I'll try metric. Doghead don't think the guy at auto zone can use this TM data for a hex nut. Nice try tho.

He didn't post that for the guy behind the counter at Autozone.

 

[hndrsonj]

I am also guessing that someone "tried" the coarse and that is why the fine isn't working correctly.

 

[Cookie]

Liquid solder works better

 

[rickf]

Yew speled "duck tape" rong.

Depends on whether he was wrapping a duct or a duck.

WOW, Not only jumped the track with this one but drove off down the road!

 

[doghead]

What is the size and thread type of the nuts that are on the positive battery junction on the firewall ?

So, I give you the exact information you asked for, then I tell you how I found it, and you reply with this?

Thanks for the info. I see your point Marcus, I'll try metric. Doghead don't think the guy at auto zone can use this TM data for a hex nut. Nice try tho.

I think I understand the problem.

 

[porkysplace]

Find a real parts store .

 

[swbradley1]

• Do not post in all CAPS or in giant run-on sentences without punctuation. Do not post as if texting and do avoid the use of texting abbreviations. We are not the grammar police but we want everyone to easily read your post in at least 8th grade English. It is extra work to post proper sentences from a smartphone but the result will be greatly appreciated. Please do your best to use capitalization, proper spelling and punctuation. It makes it easier for everyone to read!

 

[doghead]

He didn't post that for the guy behind the counter at Autozone.

Nor did he ask for an Auto Zone part number. I guess I was supposed to guess that part.

Either way, here is what you need. http://www.autozone.com/autozone/ac...-5-hex-nut/_/N-26qp?itemIdentifier=966058_0_0_

 

[doghead]

Oh, could you post a picture of your 13mm crescent wrench?

I'd like to add one to my toolbox.

 

[bkwudzhom]

I intended to spell it incorrectly...I think.