Seized bolt

[IsaakOker]

So, continuing with my rebuild, I have the alternator bracket bolt stuck inside the waterpumo housing and it won’t move.

Tried heat, bolt extractor (with CCW drill)& initially the bolt head but it won’t move. It’s a Yanmar 4jh2-the.

I’ve tried to drill it but the bolt seems to be either bent or a size smaller and glued in with some epoxy or something as it’s off-center.

Any ideas?

Could I just leave it in and attaché the alternator bracket to rhe bolt to the left?

https://ibb.co/drPTYrt

[Nekton73]

Does the bolt still have the head on it?


If yes is the head stripped or can you still gain purchase?


If still able to put a socket on it then liberally soak with penetrating oil of your choice (endless debate potential here but I find Seafoam Deep Creep to be pretty effective) for days, seriously days (be patient), then apply heat to surrounding area but not bolt, use impact wrench or gun to shock it out. If you don't have one, rent one or otherwise acquire. Can't say I've met many bolts that this didn't work on.


If head is stripped but still there, use a file to take it down to the next size socket that will fit. Then try above.


If head is twisted off, grind or file flat, centre punch, drill out the full depth of the bolt to whatever size lets you fit the largest bolt extractor you can without oversizing and drilling out the old threads, and repeat above with penetrating oil and heat. You'll have just a shell of bolt left at this point so it would truly have to be epoxied in or the worst possible corrosion welded for this not to work, in my experience anyway.


But if it doesn't,drill oversize and re-tap or helicoil, assuming you have enough material around the bolt hole to do so.



If someone has seriously epoxied a smaller bolt in there but not told you about it after they sold you the boat I would also spare a moment or three for some serious cursing of them, their future success in life, and possibly their family and progeny.

[Jammer]

Choice 1.



If you heat the housing with a torch until it's cherry red you should be able to back the bolt out with an extractor, regardless of how much epoxy or threadlocker is in there.


That much heat will likely damage the water pump bearings and seals so they should perhaps be replaced.



Choice 2.

Get a rebuilt waterpump and save yourself the trouble.





Choice 3.

Originally Posted by Nekton73

drill oversize and re-tap or helicoil, assuming you have enough material around the bolt hole to do so.

You probably will not get the hole exactly centered, but if it's just for the sliding alternator support that may not matter much.

[markxengineerin]

The photo looks very much like an undersized bolt glued in, or some other type of hack job. Remove waterpump, vice grip the bolt out now that you have inches of access to grab onto it, and then evaluate how to repair the probably damaged threads in the block.

[IsaakOker]

Thanks for all your replies.

I tried with a wrench when it had a head and it broke off, then I tried with vices and I broke the “sticking out bit” and now it’s flush.

For some reason it just won’t move. I had it in on blaster for a week before trying to turn it and it didn’t work, then did a mix of ATF and Acetone and had it another few days and then the bit broke off and now I’m out of ideas except for drilling it out.

The problem is that it is nearly an 8M so I think it’s the right bolt but it’s bent to one side which might explain why it doesn’t move at all.
As it’s bent I’m going to drill the thread in the pump housing and head for sure… so will have to redo that with a 10M which is rather large…

Maybe ai can just leave it in there as it’s very tight anyways and attach the alternator bracket to the bolt to the left… not sure if the bolt, housing and head can handle it as it’s not intended for that but suppose yes.
Also, it would beat the right angle possibly…

[markxengineerin]

Why don't you just remove the waterpump, and then work on the bolt with much more access?

[IsaakOker]

That would be great but the bolt is half threaded into the pump housing and half in the head so I can’t get the pump off…

[markxengineerin]

It should not be threaded in the pump housing- no threads in there. Maybe it's glue threads, but if it's glue, heat + careful prybar + hammer taps on non-critical areas.

[IsaakOker]

Ok, that’s strange because the bolt that’s to the left of it has a slight thread in both housing and head and I’ve tried hitting the housing from the other side with a hammer but it doesn’t move at all…

[markxengineerin]

If there were threads in both housing + head, it would be impossible to assemble- the threads would not line up. That and there would be no reason to have a bolt at all- the bolt is used to pull the waterpump against the head. And pull the alternator bracket too, on that particular bolt.

[markxengineerin]

Do make sure you checked thoroughly for every possible bolt- easy to miss hidden ones and have this problem releasing waterpumps.

[IsaakOker]

That makes sense but I’ll have a closer look at one of the other bolts and the housing when I get back to the engine in a bit.
I’m fairly certain the one next to it has a thread during maybe a 1/4 inch or so also because looking at the bolt when I pull it out, it has a rusty part from being in the block and a greyish part from threading in the housing but I’ll check as what you’re saying makes a lot of sense…

Still doesn’t explain why I can’t release the pump then by hitting it with a hammer from the head side as close as possible to the bolt…

[markxengineerin]

My guess is either a hidden bolt, or it's just corrosion (and glue?). You'll get it

[Jammer]

Fire is our friend.

[IsaakOker]

Yep, fire is our friend but even with it glowing red I had to hit it strong enough to dent the back plate of the pump, so I’m going to order a replacement asap.

And yes, I am cursing the previous owner for stuffing some sort of epoxy or adhesive in there… he just filled the void up with something 🤬