Broke head off bolt.....need advice

[model 10]

[QUOTE=Wotname;2939224]Or use freeze spray in lieu of ice,


We once once tried to take back an airplane by freezing the lock on the wheel chock and cracking it with a 6lb hammer. Didn't work.

[Charlie]

Originally Posted by HopCar

This video has some great ideas for removing broken bolts.

Thanks for sharing. Fabulous video.

[Bycrick]

On my 4JH2TE the heat exchanger is an aluminum casting and the end caps appear to be bronze. I replaced the bolts with studs and a nut. It’s easy to get the nuts off to service the heat exchanger and I’ll never care if the studs will come out: the heat exchanger will be junk before then.

[Boatyarddog]

Originally Posted by lovinlifebda

Another simple job gone off the rails. This morning I replaced my raw water impeller, the old impeller had lost some bits so I needed to retrieve them. I have always found those bits on the hose side of the cooler, so proceeded to remove the end cap from the cooler assembly. By the way this is a 50 HP Yanmar, 1995, 4JH2E. The end cap is held on by 2 bolts, from the parts manual they are M 8X 25. First bolt I put the wrench on the head comes right off the bolt. I have given the second bolt a tug but am pretty shy now and it seems like it may meet the same fate as the first bolt.
My dilemma, to give perspective we are in Grenada and parts are not quickly accessible.

I am looking for advice on my options

1) I have bought some Liquid Wrench penetrating oil and will attempt to remove second bolt. Should it come out I can remove the end cap exposing the bolt and with vice grips is the bolt likely to come out?

2) The second bolt breaks off, I remove the end cap and remove both bolts with vice grips.

3) I am getting hauled on August the 20th for a bottom job, it is about an hours motoring to get there and they have an on-site diesel mechanic. Does it seem foolish to motor with only one bolt holding the end plate on. If not I could wait until then. I have tested just at anchor and it does not leak at this point.

Bolt question, the manual says the bolts are M 8X 25 plated. Is there anything special about Yanmar bolts? The local Yanmar parts supplier does not have any bolts in stock.

Thanks for any advice Jim

I believe you have some room to work around that cooler.
I'd try some heat to the cooler body focused around the bolt.
You don't need to get it red hot, just so the paint starts to smoke abit.
Strike the stud or bolt end sharply.
Use a punch if needed.
The cooler body is aluminum, so avoid striking the cooler body,especially around the cap end edges, striking here may deform the sealing surface.
Reheat and strike a couple times liquid wrench works ok.
Kroil, or PB blaster works well.
Heat and tapping will loosen it.
Then an easy out.
You could try a left hand drill bit as well they are made to cut using a counter revolution LH turning and can remove the stud if you have to drill.
This bit may save you having to re tap the hole.
Good luck take your time.
Cheers
SV Cloud Duster

[drcat]

I agree with left hand drill bits as they may loosen the bolt.
I have a gas Volvo Penta on a powerboat. A screw on the distributor snapped as did one on the waterpump, both screws were pretty small. The distributor was steel, the pump bronze. The holes the screws went in, went thru to the other side of the flange of distributor and pump. I ended up drilling out both screws and replacing with a small diameter bolt with a nut and washer on other side of flange. Don't know if this is possible or desirable on your waterpump, but it eliminates it being frozen in the flange threads.
As an alternative or temp fix there are 12v variable speed magnetic drive water pumps on ebay for around $100 that could pump proper amount of water flow from idle to full throttle on your engine.

[Aethelwulffe]

1. Easy outs don't break easily. People easily break them. Takes skill, a learned one. Learning isn't hard, it is mostly accepting the level of preparation it takes, and not trying to go for the kill early.
2. As someone else stated, an easy-out is mostly used for removing the thin shell and threads of an almost hollowed bolt.
3. An easy-out should appear as a tapered left-hand screw looking thing. square cross-section easy-outs are crap, though they can work if everything is totally prepared.
4. If you decide to attack it head on, don't use vice grips. Use a pre-made jig by drilling a hole in the edge of a 1/4" plate or wood guide with an 8mm bit. If you have a plane or surface planer, you can drill into a thicker piece of stock and plane it down on both sides until you have cut away the edges. slip the guide onto the bolt, then use a small grinder or a file to make nice *square* edges to fit a very good quality 1/4" wrench. This option exists if you can't lock two nuts (don't use a nylock for the inner!) onto it.
5. Jigs and a drill press are your friend. So is a nice slow rpm high quality 1/2 chuck drill.
6. Drill skills are important even when using the jig to drill out the bolt. Your hand does NOT grab the drill like a pistol. Your index finger is NOT for pulling the trigger. Your drill should NOT be battery operated, as there are NONE on the market that allow for proper hand placement. Your hand goes BEHIND the motor. Your little finger and maybe second finger go on the trigger. Your palm should be balanced/centered behind the bit. You will find that many corded drills (certainly older porter cable and even the bulkier Dewalts and Makitas) have a behind-motor grip you may have never noticed. Your hand will fit nicely. It is good if you have large hands. Practice using the drill this way. You can feel the balance and twist of the drill and be able to tell if you are off-center or not aligned. You will also almost never snap a bit again. Practice low-speed cutting of steel with small bits before attacking the bolt(s).


What gives assurance of success, and provided more options if not (after getting most comfortable access as possible, which can be a lot of work too):


1. Make a block that fits over one or all exposed bolts. You can use the removed plate as a template, and there are other methods as well.
2. Drill out the templated block of wood with an 8mm bit ONLY AS DEEP as the exposed bolts. The bolts should be ground FLAT before you template your jib block. Another option is to cut and file the bolts FLUSH (easier drilling), and use something else as an alignment lock.

3. Also using a drill press ($89 Ryobi will last decades) drill a 1/8" hole penetration from the bottom of each 8mm hole. This will guide your punch and initial drill hole.
4. Fit the jig block/drill guide you have created into place. Clamp it, glue it on with pookie, something. Bolt it into place if you have any good bolt holes.
5. Use a sharpened 1/8 nail punch as a center punch (won't work great) to dimple your starting point.

6. Using your awesomely dexterous drill skills, start drilling into those bolts with a LEFT HAND 1/8" bit. You will need to buy this special. You should have a full set of these, matched with the easy-out set. If the easy-outs do not have left hand bits with them, then they are junk. Drill speed should be something like 200rpm or less. Use your variable speed, with that trained pinkie finger on the trigger.

7. Do not drill more than 1/4" to 3/8" into the bolt with the 1/8" bit, unless you have awesome skills for real. As the hole gets deeper, you change up sizes and drill through the wood to enlargen the drill guide hole, clean out the wood and metal shavings, and keep going.
8. About 80% of the time, the bolt may just decide to start turning itself out. If not, keep going until there is little left of the 8mm bolt for at least 20mm of depth. Use tape on the drill bit as a depth guide, and frequently check your work.
9. If you should get mis-aligned, don't worry too much. Just stop before you actually grind out the threads. You can always helicoil it otherwise restore the threads if you mess up a little. I don't mess up, but that is what I tell everyone anyway...
10. Last step...the easy-out. It should be EASY. If it is not EASY, you use little pumping motions with light-weight tweaks, use your little mini-torch or whatever... but generally speaking, that bolt should just come out. Torque on the easy out in a drilled out bolt will EXPAND the bolt. This will not make you happy.
11. With the bolt out...now run a tap (preferably a nut-tap) into the hole, and blow it out good. Your new bolt need not be the Yanmar coated crap, just use Anti-sieze -the good old metal-laced looking kind, and run the bolt in several times coated with the stuff...then clean off any excess. You don't want to have a hydrostatic lock at the bottom of the hole because you have put a bunch of goop in there. That will keep you from tightening the bolt.


Note, they bolt is probably not corroded in. It is probably stretched. This is from over-torquing, probably with some sort of liquid or lube in the bottom of the hole (see hydrostatic lock above). You should also run your brand-new bolt through a thread die or thread cleaner before installing it. You may be shocked to find it isn't perfect.


On heating: Aluminum block is difficult to heat. Aluminum conducts very well. It also dissipates heat well. Steel is very much different. Heating tactics for this situation vary, but mostly it is about trying different things. Eventually the metals soften (allowing extraction) or you get the hole to expand, or less often you get the bolt to shrink, but mostly you are just putting the whole mess through variations of heat cycles until the bind on the threads just give up.

[sailorladd]

I'm assuming you are referring to the heat exchanger on your Yanmar? but either way I have always had the most success removing stubborn bolts and threaded object with a little propane plumbers torch, set on barely alight, carefully heat the head of the bolt and heat it well... a good 2 to 4 minutes and then slowly try to remove... using a wrench...but if it too breaks off, you may consider removing with vice grips, nothing wrong with that, but again, heat well...if using a propane torch is impractical perhaps get hold of a good soldering iron , but your best bet is a torch for the most effect...if this also breaks off then grinding both broken stubbs to surface level and if there is sufficient "meat" on the housing, drilling and tapping may be your next option if 'easy out' does not work...and yes good penetrating oil is advisable right away..diesel is a good penetrating oil too BTW...good luck and keep us informed.

[Normanskier]

Originally Posted by HopCar

This video has some great ideas for removing broken bolts.

Great stuff. Thanks for sharing.

[Seabear120]

Hi folks
I have a Lotus 9.2 sailboat powered by a 3ym30 Yanmar
It has always been a concern to me that if the raw water pump impeller decides to break up that pieces of the impeller may potentially be lodged within the tubes of the heat exchanger.
To prevent this from happening I have installed a small mesh filter with a clear bowl between the raw water pump and the heat exchanger
Being able to view the water flow to the heat exchanger you are then able to asses the Iintegrity of the sea strainer ,observe if there are any air leaks on the suction side of the raw water pump and just as importantly eliminate the need to dismantled and clean the heat exchanger due to breakup of the raw water impeller should this occur

[arcticmonkey]

I once watched a "great welder" pop a nut onto a broken bolt....it was a joy to watch... bolt came out.... starter replaced

[evm1024]

Originally Posted by s/v Jedi

Take end plate off, thread nuts on stubs, weld them on, wrench them out

Exactly - I've done this. The heat from the welding helps break it free (let it cool). You can spray PB blaster or some such (acetone/ATF mixture, etc) and then try rocking the nut back and forth to break it free.

[Phil Reddy]

Great tips on that clip and the thread many thanks for sharing. Hope the guy in Grenada with the issue gets it sorted ok and I never end up with that problem but firmly lodged in my brain if I do!! Off to buy more essential bits !!

[Buzzman]

"Keep your ship out of the surf and spray or you will plunge to destruction. -Homer"

"When in doubt, donuts are your friend. -Homer Simpson"

[lovinlifebda]

OP here, Since the 23rd when I opened this thread I have been spraying the bolt with Liquid Wrench and then PB Blaster. A few days back I bought a propane torch and have heated the bolt quite a few times since then. Put the vice grips on the bolt and gave it some torque. It did not move and I lost my nerve to really give it a go. Had a mechanic come over this morning, he heated it one last time, put on the vice grips and out it came. I was so relieved when he had it out, I have been worrying about this darn bolt.
I want to thank all those that posted, every post was valuable and some took the poster a great deal of time to write with an obvious wealth of experience. This thread is a keeper for myself and anyone with a stuck and/or broken bolt. Next time I have access to first world tools then there will be a few purchases made to prepare for a possible broken bolt scenario.

Thanks again to everyone. Jim

[Wotname]

Thanks for the update Jim, it is always good to hear the final result of these issues.