[NEp8ntballer]

I'm in the middle of replacing the water pump on my 94 4.0 and I can't seem to find the water pump stud size anywhere. What I'm looking for are the four studs that hold the clutch and pulley onto the water pump. Thanks for the help!

[JasonStebbins]

I had the same problem. Isn't it stupid that the new pump doesn't come with new studs?

I ended up using the old studs from the original pump. Take a pair of vise grips and a cloth (to protect the threads) and unscrew them off the old pump.

[hdrocknroll]

I used double nut method to remove the old ones and reuse

[NEp8ntballer]

I got pissed and used a lisle stud remover to take one to Ace since they have a legit hardware section and came up empty. I might have to buy them online and just burn some V-power in the SHO until they arrive.

[JasonStebbins]

If you got one stud out, why not just take the other 3 out and put them in the new pump?

[hdrocknroll]

Originally Posted by JasonStebbins

If you got one stud out, why not just take the other 3 out and put them in the new pump?

Ah, ya
Did you some how ruin the one U took out ?

[dusterdude]

If its not metric,its 5/16 ths

[NEp8ntballer]

Originally Posted by JasonStebbins

If you got one stud out, why not just take the other 3 out and put them in the new pump?

shiny new pump needs shiny new hardware...

and a lisle stud remover does its job by getting smacked onto the stud with a hammer and then you use a wrench to remove the stud. It dorks up the threads to put it kindly. NAPA had what I needed but I need some nuts since the ones in the kit are threaded for the wrong side of the stud

[Obie95Sahara]

If you go to Advanced Auto they have them in the section with the radiator caps, and hose clamps. That's where I got mine, they were like $5.00 for a package. They're a 5/16".

[JasonStebbins]

Originally Posted by NEp8ntballer

shiny new pump needs shiny new hardware...

Next time try mine or HD's method of stud removal.

[hdrocknroll]

Originally Posted by NEp8ntballer

shiny new pump needs shiny new hardware...

My old parts work as good as new.
Maybe you should post it in this thread
What DUMB things have you done to your ZJ?

[AVR2]

FWIW, the water pump studs are different sizes at each end. I just reused the existing ones, although it was a minor PITA getting them off, since a PO had used metric nuts (they are SAE threads) and so they didn't quite fit the threads properly. This meant that with two of the nuts, trying to loosen them meant that they stayed gripping the stud and I ended up unscrewing the stud with the nut attached.

Useful in one way, annoying in another, as the stud was then held into the clutch fan pulley by the nut, and since the stud was now loose rather than rigidly secured, it made double-nutting it a bit more difficult with only two hands.

[5-90]

If they're SAE, they should be 5/16"-18x1" or so (would have taken a 1/2" wrench.)

If they're ISO, then M8-1.25x30m/m (13m/m wrench.)

Other sizes I've known to be used on vehicles: 1/4"-20x1" and M6-1.0x25m/m

The 1" length could also be 1.25" long, the 25m/m ISO could be 30m/m, but measuring the length of an exposed stud doesn't (damned well should not - or you shouldn't be changing a water pump) require instructions to do.

[AVR2]

The Mopar catalog lists them as .312-18/.312-24x1.250.

Mine had 13mm nuts on them; presumably the PO, or whoever last changed the water pump, didn't know that they were supposed to be 5/16, and 13mm nuts will certainly work, although they don't thread smoothly. I now have the proper 5/16 Mopar locknuts on them, but I use a 13mm wrench to get them off and on. Works fine.

[KoreaZJ]

I'm on my 3rd water pump using the original studs. Use double nuts to remove/install them... when you find them!