Water Pump Stud

R2.0 · **Posted:** Tue May 21, 2013 1:16 pm

Been a while since I've posted; still in the middle of my teardown, but have hit a snag. I was changing the water pump and when installing the new one I mis-read the torque values. Apparently M6 studs are NOT capable of 40 ft-lbs of torque. Fortunately I notices something was wrong and pulled everything back apart. The stud had necked down from 6mm to 4mm (Pics to follow). Fortunately I was able to get the stud out by double-nutting it.

Per the parts list the stud part number is 04797764. Google comes "STUD. Water Pump To Block. M6x14. 04720550AB, 04720550, 04797764" And not a lot of sources for it. So here's the dilemma:

1) Get it from the local Chrysler dealer and pay accordingly
2) Try the one online source that I found
3) It's a 6x14 stud. Just find one anywhere.

Anyone deal with this part before? It doesn't look like unobtanium, but this is the engine with the $100 thermostat, so I'm always hesitant.

geordi · **Posted:** Tue May 21, 2013 8:14 pm

Option 3. Its a stud, match one with the threads, size, and length... Drive on. Not like the engine is producing 10k degrees there, this isn't a grade-8 exhaust stud.

(FYI: Those exhaust manifold studs ARE NOT GRADED and are more than likely just grade 2 or 3 mild crap steel. If you replace them when swapping the turbo, you most likely WILL need to use a stud biter removal tool. I strongly suggest grade 8 replacements for that application) For this spot however, non-graded should be OK... Grade 5 would be better and under the heading of overkill.

Hexus · **Posted:** Tue May 21, 2013 9:32 pm

Gonna have to agree with Geordi as usual, just replace it in kind from the local hardware store. Grade 5 if you want to have something a bit heavier grade, pay attention to your torque values this time, lol.

TJ2 · **Posted:** Wed May 22, 2013 1:39 am

Geordi, I don't doubt what you say, but not using tempered hardware on an exhaust manifold is not something I can get my head around.

Is this industrial espionage?

geordi · **Posted:** Wed May 22, 2013 2:06 am

TJ2 wrote:

Geordi, I don't doubt what you say, but not using tempered hardware on an exhaust manifold is not something I can get my head around.

Is this industrial espionage?

How was the build quality of the Italian Navy? :roll:

What about the joke of owning a Ferrari, that for every 1500 miles you put on it, you need $1500 in maintenance? :roll:

I'm sensing a pattern....

I can't wrap my head around it either, and neither could Papaindigo when we were upgrading his CRD to Keith's incredible turbo. I don't remember if one of the studs snapped as the reason we started arguing with them - but we ended up having to use a stud biter, LOTS of penetrating oil, hammer strikes, a fair amount of heat... And even more swearing to get three of the dang things out. We elected not to pursue #4 after the 7 circles of hell getting the first 3 out.

I think what was happening was that the insane amount of torque and heat cycling in the manifold caused the studs to partly cross-thread themselves in the holes. As if they were being forcibly yanked OUT while in use. This is only a guess, but those things were way beyond stuck, and sheared off as if they were made of balsawood under the slightest torque. CLEARLY the engineering spec was to use grade 3 or below for those exhaust studs. It boggles the mind, I wouldn't ever use less than grade 8 for such a high stress application.

papaindigo · **Posted:** Wed May 22, 2013 9:15 am

The initial problem was caused by the distorted thread lock nuts factory installed on the weak OEM turbo studs which caused one of the studs to sheer off when simply removing the nut hence the need to remove that stud. As I recall one other stud sheered off during nut removal and we had to remove the 3rd stud as it was too short to clear and allow for a nut to be installed on the base of the new turbo. The stud removal tool combined with heat/lube did ok except for the stud that broke off too close to the manifold for the tool to grip. For that one we had to use vice grips, lots of heat, lube, and rocking the vice grips back and forth to break things loose.

Obviously we were not about to touch stud #4 but we did chase the threads on the other 3 holes before installing new studs and did not use distorted thread lock nuts on the Stage II turbo install.

To anyone messing with those studs I'd highly recommend several days of regular application of penetrating lube before attempting removal to avoid the "fun" we had.

R2.0 · **Posted:** Wed May 22, 2013 12:36 pm

Thanks. That's the way I was leaning; Dorman makes a "Water Pump Stud Kit" that might do the trick for $4. Cheaper than what they want for Grade 8 - $17. :shock:

geordi · **Posted:** Wed May 22, 2013 3:47 pm

Just be aware that the $4 kit isn't going to have a graded stud in it. Don't expect to apply 400 lbs of torque to it and have it survive.

I would apply the appropriate German torque spec to this application: Gudntite. Call it 15-20 lb-ft or so. With an M6 size shaft, it won't hold up to much more than that.

R2.0 · **Posted:** Wed May 22, 2013 3:52 pm

geordi wrote:

Just be aware that the $4 kit isn't going to have a graded stud in it. Don't expect to apply 400 lbs of torque to it and have it survive.

I would apply the appropriate German torque spec to this application: Gudntite. Call it 15-20 lb-ft or so. With an M6 size shaft, it won't hold up to much more than that.

No worry about that. I misread the torque chart in the FSM, so I used the "3/8 ratchet, one handed, and add 2-3 degrees for luck" method. It's not going anywhere.

R2.0 · **Posted:** Wed May 29, 2013 11:03 am

Quick update: went to local hardware store, bought Grade 8.8 M6 bolt, cut off head with Dremel. Voila - instant stud.

Water Pump Stud

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