Water Pump Studs

[mxfrank]

Just when I thought it would be easy, I snapped a stud. There's an inch protruding, so I can either double nut it or use a pipe wrench. Anyone have a preferred method? Do I need to apply heat first? Trying not to make a small disaster grow.

[smokin_944]

Make sure to spray the stud with WD40 or some other stuff and let it soak for a while. Makes it easier to remove the stud.

[HondaDustR]

50/50 acetone/ATF mix, or PBlaster. Depending on your timeframe and how bad it is, let soak overnight, or apply multiple times over the course of a couple days. My preferred method is a large pair of vise grips clamped on as hard as possible.

[mxfrank]

Double nutting stripped the thread. No room for pipe wrench. So.......I went down to the friendly tool store and bought a cam-type stud puller. Nice tool. Even with this, it was a struggle, but finally...out. 8-)) Is there any reason Porsche chose to use four studs? Seems to me that I could easily replace them with bolts, and maybe have less hassle next time.

[Slam]

Positive location of the WP on install would be the only reason I can think of. It's not like there's a lot of torque on those fasteners anyway.

[mxfrank]

Now that I think about it, I may replace the bolts and studs with 316 stainless bolts. The manual calls out 6ftlbs, which is low enough for good quality stainless fasteners (but no where near the potential clamping strength of 8.8 steel). Stainless will require a little more torque, but 8 ftlbs should be safe.

[HondaDustR]

Really, your weak point is the threads in the aluminum. They may be able to hold higher torques when freshly cut, but after years of corrosion, you're lucky if you can put 6 ftlb on them without pulling the threads. One or two of mine are barely hanging on. I'll probably need to timesert them next WP job. Stainless bolts would be a good idea, though.

[wild man]

Stud snappage is more prevalent than thread strippage. I believe it is possible to buy the replacement studs as a kit. But to prevent such scenarios as stripped aluminum threads, and flush-snapped studs (that will be very hard to remove), I would strongly suggest using anti-seize compound on them.

[joejoe1]

944online carries stud kit. The studs are for hanging the gasket for w/p.

[fmartenies]

If you replace the studs with bolts, the wear and tear you had on your studs will now be on......the engine block.

I'm not a mechanical engineer so I can't give you a precise figure, but the torque is spread between the nut/stud surface and the stud/block surface. Replacing with a bolt would transfer all the torque to the threads in the block. So it would fare even worse than the stud has.

[HondaDustR]

Not really, since the tensile stress in the fastenner has to be held equally by both ends of the fastenner. A bolt head simply holds the force by its contact with the pump, whereas a stud will send the same force through threads, to the nut, and to the pump behaving in the same manner as the bolt head. I believe one of the advantage of studs is that you are not initiating heavy metal to metal sliding load in the soft aluminum block threads as you torque the nut. I am not sure of other reasons, but I'm sure there are more reasons to use studs versus long bolts.

[looneybin]

i think the main reason for using studs is it aids in the alignment of the pump & you don't have to hold it in position while you install the other bolts

[mxfrank]

Went half and half. Kept the Porsche steel studs. Swapped the bolts for stainless. Will take another look in 40,000 miles.