Stud part number

[CA_LEO]

So, I’ve tried searching this forum and countless others. I’m looking for the 5/16 shouldered studs that mount onto the nose of the water pump and keep the fan pulley centered and attached to the water pump. I found a part number in the 289-34P TM, which was 14061661. Problem is this is listed as a metric bolt thread, and the TM says I need two, whereas mine has four. I’m super confused about this.

I’ve searched everywhere I can think of and can’t find any studs that are the same size. Does anyone know if my studs are just odd, or if there is another part number or source to get these?

I should also note, the ones from LMC do not have the flanged shoulder like mine have. Below is a picture of the only one of these studs I was able to get out of the original water pump semi undamaged.

Thanks for any help you can give

 

[Curtisje]

So, I’ve tried searching this forum and countless others. I’m looking for the 5/16 shouldered studs that mount onto the nose of the water pump and keep the fan pulley centered and attached to the water pump. I found a part number in the 289-34P TM, which was 14061661. Problem is this is listed as a metric bolt thread, and the TM says I need two, whereas mine has four. I’m super confused about this.

I’ve searched everywhere I can think of and can’t find any studs that are the same size. Does anyone know if my studs are just odd, or if there is another part number or source to get these?

I should also note, the ones from LMC do not have the flanged shoulder like mine have. Below is a picture of the only one of these studs I was able to get out of the original water pump semi undamaged.

Thanks for any help you can give

I'm seeing you need 4 in the TM. I pulled all the accessories of a 6.2 that I got rid of last weekend and I can only find 2 of the bolts.



I think I have read on here that they aren't made anymore.

I think I can find the other 2. Let me know if you need them.

 

[CA_LEO]

I forgot to ask if I was wrong in the assumption that these appear to help center and prevent the pulley from slipping around on the water pump. If there is another type of stud or bolt that will work just as well I will gladly take those recommendations.

I'm seeing you need 4 in the TM. I pulled all the accessories of a 6.2 that I got rid of last weekend and I can only find 2 of the bolts.

View attachment 825971

I think I have read on here that they aren't made anymore.

I think I can find the other 2. Let me know if you need them.

Thanks, I can find those ones that you posted, but the ones I pulled out are perfectly cylindrical and do not have the hex head on them. That’s why I was wondering if they are designed that way to minimize the pulley slipping.

 

[Curtisje]

Huh. I see that now. Maybe mine are still on the pump... which went with the engine. Good luck.

What about these from Autozone?

Dorman - HELP M6 X 1.0 Water Pump Stud Kit 12 Piece
Part #23743
SKU #102826

 

[CA_LEO]

Thank you. The ones from Autozone will not work either unfortunately. The shorter part of the stud is 5/16 20 thread and the longer part of the stud is 5/16 18 thread. Leave it to GM to use a part as messed up as this...

 

[cucvrus]

Just bolt the fan on with a bolt that fits the threads in the water pump flange. Use lock tight and a lock washer if it worries you that much. A bolt that fits and gets tight is all you need. No special rocket science needed for this application. It was an assembly design that made quick assembly when the engine and fan were mated during total vehicle assembly. It wasn't meant as a way to make things difficult. Get a short grade 5 bolt that fits the pump flange and install the fan. Done. Drive On.

 

[royalflush55]

Just bolt the fan on with a bolt that fits the treads in the water pump flange. Use lock tight and a lock washer if it worries you that much. A bolt that fits and gets tight is all you need. No special rocket science needed for this application. It was an assembly design that made quick assembly when the engine and fan were mated during total vehicle assembly. It wasn't meant as a way to make thing difficult. Get a short grade 5 bolt that fits the pump flange and install the fan. Done. Drive On.

It really is this simple!

 

[CA_LEO]

Just bolt the fan on with a bolt that fits the threads in the water pump flange. Use lock tight and a lock washer if it worries you that much. A bolt that fits and gets tight is all you need. No special rocket science needed for this application. It was an assembly design that made quick assembly when the engine and fan were mated during total vehicle assembly. It wasn't meant as a way to make things difficult. Get a short grade 5 bolt that fits the pump flange and install the fan. Done. Drive On.

That’s what I was hoping to hear, but wanted to tap the knowledge source here. Thanks so much! Sometimes my OCD gets the best of me.

 

[frank8003]

You never did get the OEM ......................
Stud part number

Are you done doing what you had to do or would your like the original stud part number and where to get them?

 

[CA_LEO]

You never did get the OEM ......................
Stud part number

Are you done doing what you had to do or would your like the original stud part number and where to get them?

I found part number 12337960, however from everything I have seen, this does not have the flanged shoulder. If you have a source for the one with the flanged shoulder, I would greatly appreciate it. Like I said, my OCD gets the best of me and I would prefer to put the OEM part on there.

 

[cucvrus]

The fan clutch hub will center itself on the water pump. Do as you wish but you are way over thinking these studs to attach the fan. If they were the sole centering shoulders I would be with you. But being that the hub center fits into the fan clutch center they are just there. Good Luck.

 

[frank8003]

Just thought" like that old ad"
was trying to keep His GM or toyota all GM

Keep it like it was built.

 

[CA_LEO]

Just thought" like that old ad"
was trying to keep His GM or toyota all GM

Keep it like it was built.

Ideally that’s what I would prefer to do. But I appreciate both sides of input. I’m very thankful for the information that I won’t be SOL if I have to use a standard stud or bolt.

 

[royalflush55]

All the small block chevy gas engines that I have worked on had smooth studs that screwed into water pump hub and then the pulley slipped on over them, then the fan clutch followed by a lock washer and nut. Real easy to assemble.

Some of the big blocks had a longer stud bolt with lock washer that went thru the pulley and fan with spacer into the pump hub. A little harder to assemble but worked fine.

The 6.2's I have are the smooth type also without the rounded flange.

 

[Guyfang]

This is what came up for the part # 12337960

	THREAD CLASS	2A NUT THREAD
	THREAD DIRECTION	RIGHT-HAND NUT THREAD
	THREAD DIRECTION	RIGHT-HAND STUD THREAD
	THREAD LENGTH	0 39/100 INCHES MINIMUM STUD THREAD AND 43/100 INCHES MAXIMUM STUD THREAD
	THREAD LENGTH	0 57/100 INCHES MINIMUM NUT THREAD AND 3/5 INCHES MAXIMUM NUT THREAD
	SHOULDER DIAMETER	0 41/100 INCHES MINIMUM AND 11/25 INCHES MAXIMUM
	SHOULDER LENGTH	0 9/100 INCHES MINIMUM AND 13/100 INCHES MAXIMUM
	OVERALL LENGTH	1 1/20 INCHES MINIMUM AND 1 4/25 INCHES MAXIMUM
	THREAD QUANTITY PER INCH	18 NUT THREAD
	HARDNESS RATING	33 ROCKWELL C MINIMUM AND 39 ROCKWELL C MAXIMUM
	NOMINAL THREAD SIZE	0 39/125 INCHES NUT THREAD
	NOMINAL THREAD SIZE	0 8/25 INCHES STUD THREAD
	THREAD PITCH IN MILLIMETERS	1 1/4 STUD THREAD
	THREAD TOLERANCE CLASS	6G EXTERNAL STUD THREAD
	MATERIAL	STEEL
	MATERIAL DOCUMENT AND CLASSIFICATION	GM 500-M 10 9/10 FSCM 11862 MFR REF SINGLE MATERIAL RESPONSE
	SURFACE TREATMENT	PHOSPHATE OVERALL
	SURFACE TREATMENT DOCUMENT AND CLASSIFICATION	GM 6047-M OR GM 6147-M FSCM 11862 MFR REF SINGLE TREATMENT RESPONSE OVERALL
	STYLE DESIGNATOR	SHOULDERED
	THREAD SERIES DESIGNATOR	M STUD THREAD
	THREAD SERIES DESIGNATOR	UNC NUT THREAD