WP is stuck on stud
 

I'm trying to get the water pump off, but it appears to hanginging on one stud:

http://forums.pelicanparts.com/uploa...1258523018.jpg

As long as all the nuts and bolts are removed, it should just pull off. Corrosion builds up around the bolts and studs really easily on the water pump. Soak it in penetrating oil like PB'laster and work it loose.

All the bolts and nuts are removed, and when I shake the pump, it wiggles a bit, but I noticed that the stud circled above also moves with it: I'm wiggling the stud in the block! The other studs have visible clearance around them; this one doesn't. I'm guessing that a threadlocker has been used, and it glued the stud to the pump body.

I've tried heat with a butane torch, gently prying with a pry bar from behind the pump, and penetrating oil (which is visible on there).

Any advice? Anyone dealt with something like this before?

http://forums.pelicanparts.com/uploa...1258523367.jpg

wiggling in the block isn't good. How about putting tension on it with a pry bar, spinning a nut flush with the the end of the stud to give a bigger target, and hitting it through with a hammer. It certainly looks packed up with rust.

Soak it down with KROIL. Put a nut on the stud and hit with a hammer a few times and apply more Kroil.

Cheers,
Larry

you can't use leverage against the little tab sticking out to yank it out?

I can get plenty of leverage... the problem is that at this stage what is likely to give first is the stud in the block.

I'm trying the soaking/whacking approach, but no joy so far. All I've managed to do is flatten the head of the stud a bit.

If the WP bolt is wiggling you will have to use a heli coil insert or a "Timesert".
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There is a WP bolt kit or here is an old link:
http://forums.pelicanparts.com/porsche-924-944-968-technical-forum/93995-part-water-pump-studs.html

If the bolt breaks off:
http://tech.rennlist.com/924_944/brokenwaterpumpBolts.PDF

Follow the Arnnworx method of replacing the WP and use gasket sealer.
Water Pump

Do not overtighten the cam belt or you may burnout the new WP bearing.

GL
John_AZ

Thanks for all those pointers, John -- I hope I don't need them. I think the wiggle in the stud is probably still minor enough at this stage that when it is torqued to 6ftlb it will be solid enough. Maybe not, perhaps wishful thinking. Anyway, I'm just trying to get the pump free without making it too much worse. One step at a time...

If the stud snaps then the pump will be off, I guess. Ugh.

I cant really see what whacking it with a hammer will do other than destroy the threads in the block even more.

Maybe the stud was so loose when the PO changed the WP that he simply threadlocked the stud to the pump instead of to the block to make sure it wouldn't come undone?

Can you get a very thin screwdriver or some sort of pick in between the pump and the stud to scrape the corrosion off?

Are you reusing the pump? if not you could get a small hollow drill bit and drill through the aluminium pump round the stud to effectively enlarge the hole itself and free it. I used one of these to free a broken extractor from the camshaft bolt. you may need more than one, as the cutting diamonds are meant for glass and will wear off.

http://www.cliftonlaboratories.com/u...s/Protot10.jpg

Regardless of method I would replace the stud when done.

NB! When you reassemble you MUST make sure the stud cannot work itself loose again. If in doubt get an insert! Any loose hardware in this area can eat your belts and wreck your engine. Use locktite and correct torque and you should be fine.

A couple more thoughts:

You might want to put a couple of washers on there and *carefully* tighten a nut down, whack it with a hammer and see if you can push the pump on a little more and break the seal.

Alternatively, it looks like you might be able to double-nut the stud and if you can get a box-end wrench on the inner nut, you might be able to unscrew the stud from the block through the pump, and again break it loose.

+1 emoore924

Double nut the stud and take it right out. Sounds like you will want to take the stud out anyway to get a good look at what the real problem is with the "wiggle." I think that would be the best solution.

Good luck!

This is a concern of mine as well. I can see how the impact could help break the seal, but I am worried about the additional wear and tear on the block threads...

I suspect that most of the wiggle that's there now is due to _me_ wiggling the pumps trying to get it loose after the nuts and bolts had been removed. I couldn't see what the problem was at first... it didn't shift at all initially, and I thought it was the gasket seal that was holding it on. So eventually after a certain amount of prying and wiggling it got to the point where I spotted the problem...

No. It's not even 100% sure that it is corrosion... it's not like there is a brown ring of rust obviously around the stud. It just looks like the hole in the pump is a smaller diameter than the other holes for the other studs, which is why I was thinking more of loctite than corrosion. But it might be deceptive...

I was going to return it for the core refund, but it's not critical... if I have to destroy the pump to get it off without damaging the block, it's no biggie.

I'm not sure how I can get a drill onto the stud that close to the radiator though... I think I've seen an angle drilling attachment for power drills. Would that work, do you think?

Can you get that hollow drill bit in the photo with a 6mm inner diameter?

Yeah, I'll have to see if I can a properly spec'ed replacement stud... I don't mind the idea of replacing it, the idea of breaking the old one off trying to get it out of the block is what gives me the willies...

Take the radiator out. It's super easy from that point of disassembly, and you'll have to drain the colling system anyway, so it's also a perfect chance to give it a good backflush.

I'm 99% sure it's bound up with various types of corrosion. It happens all the time with those bolts near water passageways, most notably the water pump and the various bolts and cap screws holding the heater and radiator hose manifolds to the cyl head. It fills up gaps and practically welds stuff together.

HondaDustR is right, remove the radiator. I wouldn't do that on a turbo however as more dissasembly is needed because of the lines to the external oil cooler.

I used a flexible extension for the camshaft bolt, but a 90 degree bend would be better. I believe they are quite expencive though?

I don't know if you get those bits in 8 or 9 mm but I would think so. I would think you have more stuff to choose from overe there than we get over here. If you can find a hardened hollow bit with proper teeth that would be an even better choice.

Good luck.

Hey Mark, any progress?

Not much progress, I'm afraid. I have determined that the problem does indeed seem to be corrosion rather than loctite, as most people have been suggesting.

I have been digging in the space between the pump and the stud (about a 1mm gap) with sharp objects trying to remove some of the corrosion that way, and reapplying penetrating oil. I've ordered some fine drill bits to try to get a drill in there to speed things up -- I may need to get a 90 degree attachment or a right angle drill to get in there. I really don't want to mess with removing the radiator unless I absolutely have to -- the plastic/aluminium components aren't well known for being the most solid design.

If digging at the corrosion doesn't work, I will probably have to drill out the pump around the stud, destroying it in the process, which would be a pity.

One step at a time. This isn't a job that likes to be hurried, it seems. Hope your WP is in better shape than mine... its hard to know untill all the nuts and bolts are removed, and you give it a tug.

Maybe the S2 might be different, but the radiator is very easy to remove on the regular 944's. Just don't slam/throw it around and it'll be fine. Sounds like a good excuse to buy a new tool. ;) jk... I'm sure we all can relate... A right angle drill is one of those really useful for more than you realized sort of things.

light firm continuous tapping with a punch or blunt chisel or bolt should break the corroision after some time, like 2 beers worth.

I'm sure the wiggle is just the stud bending. Not a problem with the threads in the block