Broken water pump stud

[zerokreap]

Why not? Once you get to the core diameter (if it didn’t work) you then use a pick to remove the tread remnants.

Can’t see that penetrating oil is going to get anywhere with a thread sealant in there, either.

Yeah, didn't know there was thread lock in there until after I tried...and removed one of the others.

My thoughts on this are colored by my conversations with others working on the same model vehicle. Some have had success with the left-handed drill route, but many not it's difficult to do without some sort of jig. My garage is not a metal shop. I may end up giving this a try, but wanted to try the welding strategy first.

 

[500e]

The Locktite is usually destroyed by the heat from welding the nut or end of stud

 

[zerokreap]

The Locktite is usually destroyed by the heat from welding the nut or end of stud

I doubt I'm dealing with the original water pump, but the shop manual says to assemble the fasteners with Loctite 270. So, 500° is supposedly needed to break it. I was thinking that was another good rain to use the weeks method here. That said, I didn't need to heat the other one I removed. So, it might not be the original water pump, and someone used something a bit less permanent. Though, there was definitely something in the threads of the other.

 

[Melvyn Best]

Yeah, didn't know there was thread lock in there until after I tried...and removed one of the others.

My thoughts on this are colored by my conversations with others working on the same model vehicle. Some have had success with the left-handed drill route, but many not it's difficult to do without some sort of jig. My garage is not a metal shop. I may end up giving this a try, but wanted to try the welding strategy first.

Can you temporarily refit the old pump to use as a drilling jig? At least use it to centralise a drill bit?

 

[not done it yet]

One question would by some idiot has used thread locking compound on a stud?

Far more likely it would be a thread sealant, not locker? Are these through-holes into the block interior? If so, into the coolant or lubrication system? If the coolant system the stud may well be corroded at its far end.

The usual sensible design was to use a coarse thread into the fixed end/weaker material with a finer thread for the nut, providing better clamping force at a lower torque requirement.

As an aside, what engine? Not so many with aluminium blocks. I can think of some peugeot petrol engines that were aluminium (I think).

 

[Morrisman]

You need a 6mm washer but an 8mm nut. The washer protects the surrounding material while the 8mm nut gives you room to get a good ball of welding in to the end of the stud. You have no chance trying to weld through a 6mm nut.

 

[Gareth J]

Are you working on this in/under the car? That will make it harder. Drilling centrally and not damaging threads in an aluminium housing on a 6mm bolt sounds beyond hard. Picking threads out afterwards similar.

It'll obviously be harder with the gassless mig and rely on you chipping all slag off between blobs but worth a shot.

Don't panic about damaging the aluminium you won't stick steel to it and it's so conductive you won't melt it other than maybe a very small amount very locally.

 

[Argonman]

This is very similar, though not air-cooled...Porsche 968. I tell ya, I'm wishing this was an air-cooled 911 right now!

I've been cleaning the end of the stud with the wire brush attachment on my Dremel. I feel like it has been working pretty well. What do you think, is something like that good enough? I added some pics above, in case that helps. Thanks for chiming in!

The wire brush may be brass coated and this can also contaminate the weld. Best to get back to shiny metal using one of the small dremel grinder attachments.

 

[zerokreap]

Can you temporarily refit the old pump to use as a drilling jig? At least use it to centralise a drill bit?

Yes, that's a good idea and what I will do if I go the drill route. If I go the drill route, I'm pretty much accepting that I'll have to helicoil that hole. I think it will be nearly impossible to drill that thing out without damaging those soft aluminum threads. Of course, the helicoil will be stronger. So, not a huge deal. Still, I would love to make the welding route work.

 

[zerokreap]

One question would by some idiot has used thread locking compound on a stud?

Far more likely it would be a thread sealant, not locker? Are these through-holes into the block interior? If so, into the coolant or lubrication system? If the coolant system the stud may well be corroded at its far end.

The usual sensible design was to use a coarse thread into the fixed end/weaker material with a finer thread for the nut, providing better clamping force at a lower torque requirement.

As an aside, what engine? Not so many with aluminium blocks. I can think of some peugeot petrol engines that were aluminium (I think).

Porsche 968 - 3.0L I4. The shop manual calls for Loctite 270 on those fasteners, due to the vibration. They are not through holes...I'm not even sure why that one stuff was getting hit with coolant. I'm assuming the paper gasket was failing, though the pump was in fabulous condition... probably didn't even need to be changed, but too late now. I was hearing a chirp that sounded like the bearings failing.

 

[Morrisman]

Porsche 968 - 3.0L I4. The shop manual calls for Loctite 270 on those fasteners, due to the vibration. They are not through holes...I'm not even sure why that one stuff was getting hit with coolant. I'm assuming the paper gasket was failing, though the pump was in fabulous condition... probably didn't even need to be changed, but too late now. I was hearing a chirp that sounded like the bearings failing.

Maybe like BMW motorbikes, they use thread lock on lots of parts, to seal the thread to water, and corrosion. It works very well, but heat is required to remove a lot of parts.

 

[zerokreap]

Are you working on this in/under the car? That will make it harder. Drilling centrally and not damaging threads in an aluminium housing on a 6mm bolt sounds beyond hard. Picking threads out afterwards similar.

It'll obviously be harder with the gassless mig and rely on you chipping all slag off between blobs but worth a shot.

Don't panic about damaging the aluminium you won't stick steel to it and it's so conductive you won't melt it other than maybe a very small amount very locally.

Luckily I'm in the front Bay if the car rather than under it. The water pump attached directly to the front of the block. With the radiator fans removed I have just enough room to work.

Good to know about damaging the block. I figured the aluminum would quickly disperse the heat. That was my main worry.

 

[Pigeon_Droppings2]

Theres no harm in cleaning the end of the bolt lightly with a drill to get it nice and clean and dish the top...more surface area for the weld too. You want the wire protruding from the torch and dead center. I usually do short blasts to get a nice blob going....then build from there.

It might be trickier with using gasless flux cored though.

 

[Keithmac]

I deal with this a lot working on motorcycles. A steel stud corroded into aluminium is a nightmare really.

Ideal tool would be a core drill that would take the 6mm stud out but leave enough meat for a tap and Wurth insert.

If.you do decide to drill it, make sure it's bang on centre..

 

[Ace Paul]

Bump!

Other thought to add to whoever said use old pump as a jig.

Use other bolts stuck out to make a jig to hold drill. Not a race to battery drill will do

 

[addjunkie]

Ive had success drilling in the past. If its a 6mm stud, start with a 2.5 drill, then 3 etc….then if your not quite on centre your not damaging threads straight away. Eventually you will be touching the ali threads, if noting else it lets penetrating oil around the threads for an easy out, or you can pick out threads if not too far off.

 

[eddie49]

I think that your AI bot has confused screw threads with sewing thread, which is why it talks about sleeves and seams and stitches.

 

[steveo3002]

ive struggled before to make the weld stick , cleaned the broken stump with a dremel and worked first time after that