Stubborn bolts

[Topcat47]

Pushing this out to the ether as I"m currently stumped.

Last season my trusty 1GM10 developed a hose leak at the cylinder head. Accessibility on my boat is not good, and the leak wasn’t immediately apparent as it occurred just before the coolant entered the exhaust mixer. I managed to replace the hose and carried on. When I hauled out and removed the cockpit sole, the engine looked a complete mess, so I now have it on my workbench at home. So far so good.

It is only to be expected that some nuts and/or bolts have been a bit reluctant to shift but so far, touch wood, only one has proven a complete Barsteward and has resisted all attempts to move it. As luck(?) would have it, it’s one of the 10mm bolts holding the water pump in place. I have a10mm hex socket and that proved good enough for two of the bolts, but the last has rounded too badly to give it up. Even my “never slip” wrench doesn’t touch it. It’s not a good place for soaking in Diesel or release oil and warming the casing hasn’t helped. Any ideas? I’ve plenty to do over the next week so I have time to wait until a new tool is delivered, if there is one I’m unfamiliar with that might help. I don’t think my mole grips are going to be man enough.

I just hope there’s something I can try before drilling off the head , which is all I can think of at the moment. I’ve never had any success with “easy-outs”.

 

[rogerthebodger]

Pushing this out to the ether as I"m currently stumped.

Last season my trusty 1GM10 developed a hose leak at the cylinder head. Accessibility on my boat is not good, and the leak wasn’t immediately apparent as it occurred just before the coolant entered the exhaust mixer. I managed to replace the hose and carried on. When I hauled out and removed the cockpit sole, the engine looked a complete mess, so I now have it on my workbench at home. So far so good.

It is only to be expected that some nuts and/or bolts have been a bit reluctant to shift but so far, touch wood, only one has proven a complete Barsteward and has resisted all attempts to move it. As luck(?) would have it, it’s one of the 10mm bolts holding the water pump in place. I have a10mm hex socket and that proved good enough for two of the bolts, but the last has rounded too badly to give it up. Even my “never slip” wrench doesn’t touch it. It’s not a good place for soaking in Diesel or release oil and warming the casing hasn’t helped. Any ideas? I’ve plenty to do over the next week so I have time to wait until a new tool is delivered, if there is one I’m unfamiliar with that might help. I don’t think my mole grips are going to be man enough.

I just hope there’s something I can try before drilling off the head , which is all I can think of at the moment. I’ve never had any success with “easy-outs”.

If the head has rounded there are several types of stud removal tools that may do the job. If the stud will not cone undone some of these may shear the bolt off. If that happens it would never come out any way.

https://www.google.co.za/search?q=s...AKHRwbDmIQsAQIJQ#tbm=isch&q=stud+remover+tool

 

[earlybird]

You could try drilling it out with a l/h drill of suitable diameter. The heat generated by the drilling can loosen a stubborn thread and the drill torque unscrews it. Essential to start off accurately centred. Centre pop of course, followed by a centre drill if you have one.

 

[ghostlymoron]

I've had success with small stillsons (or big ones if they'll fit). The advantage over Mole grips is that they tighten up under pressure.
Failing that there are stud extractors from Axminster tools which were successful according to a recent thread.
But expensive.

 

[Topcat47]

I've had success with small stillsons (or big ones if they'll fit). The advantage over Mole grips is that they tighten up under pressure.
Failing that there are stud extractors from Axminster tools which were successful according to a recent thread.
But expensive.

I've got stilsons but they're way too big for a little 10mm bolt head (it's 10mm across the flats) The same goes for "stud extractors", there isn't really enough clearance around the bolt on a water pump.

 

[Tranona]

If I remember rightly that is one that goes through the bronze, then the aluminium timing case cover and threaded into the iron block. Masterpiece in lousy design! The bolts are as you discovered very soft so round easily. Suggest you cut the head off, bearing in mind it has an integral washer, remove the pump and get a purchase on the remaining part of the bolt.

On my 1gm the bolts and the cover were all corroded in that area because of a drip from the hose, so I removed the whole timing case cover. Not a trivial job as the injector pump and governor have to be removed, but the instructions in the official Yanmar manual cover the process well. If you do go that route, make sure you retain the spacers under the pump as they set the timing. Tend to stick to either the pump or housing and may get damaged if you are not aware of them.

 

[Topcat47]

Thanks for the tip. These wee cheesy bolts are a pain.

 

[steve66]

I encounter this problem every day with corroded 10 mm bolts on Hondas. The easiest way i have found to do it is drill a 3 mm hole in the top of the bolt. Then hammer in a good quality torx bit socket into the hole. The torx will grip it and the hammering should shock the bolt so you can remove it.

 

[garvellachs]

I encounter this problem every day with corroded 10 mm bolts on Hondas. The easiest way i have found to do it is drill a 3 mm hole in the top of the bolt. Then hammer in a good quality torx bit socket into the hole. The torx will grip it and the hammering should shock the bolt so you can remove it.

That sounds brilliant - what size torx do you use?

 

[steve66]

That sounds brilliant - what size torx do you use?

I have a few in various sizes. Find one that doesnt slip when you hammer it in

 

[BabaYaga]

I've got stilsons but they're way too big for a little 10mm bolt head (it's 10mm across the flats) The same goes for "stud extractors", there isn't really enough clearance around the bolt on a water pump.

10mm across flats sounds like a M6 bolt. In similar situations (stainless into aluminium) I have sometimes had success by using a file to create two new opposing flats suitable for an open spanner. In this case I guess 7 or 6mm would suit.

 

[essexboy]

Have you tried tightening it a bit first ? This often works, and the Torx socket is a good idea I have used that several times.

 

[NormanB]

If it is a steel bolt then one good way if you have access to arc/mig/tig welding equipment is to weld a short length of studding to the head of the recalcitrant bolt and then wind on a couple of nuts and lock them together - then with a six point socket and a breaker bar - Heave ho.

 

[Binman]

Saw this tip and it worked I think it is on U Tube, heat the exposed thread with a lighter at the same time hold a wax candle above the flame the runny wax will run around the thread where it enters the nut and bobs your uncle it works.

 

[philwebb]

Have you tried an impact driver? You will have to file some new flats on the bolt head and take it down to the next available size. If the head comes off you have the rest of the bolt to grip, and also you can also get penetrating oil on the seized thread.

 

[RichardS]

Saw this tip and it worked I think it is on U Tube, heat the exposed thread with a lighter at the same time hold a wax candle above the flame the runny wax will run around the thread where it enters the nut and bobs your uncle it works.

I've not heard of that before and do wonder what the molten candle wax is supposed to do as I can't imagine that it will penetrate as well as penetrating oil? However, in the OP's situation, I'm puzzling where the "exposed thread" is?

Richard

 

[PaulRainbow]

[pedant mode]

Bolts are not measured by their spanner sizes, but by their thread diameter. Referring to this as a 10mm bolt suggests it is bigger than it is and will result in some unsuitable suggestions. Typically (with metric bolts) :

10mm spanner = M6 bolt
13mm spanner = M8 bolt
17mm spanner = M10 bolt

The other pedants will be along soon to tell me some M8 bolts are shouldered and take a 10mm spanner, some M10 bolts take a 15mm spanner etc. But it is helpful to refer to a bolt by it's thread diameter, irrespective of spanner size.

[/pedant mode]

Using the torx tool is a good idea. You can often hammer a torx socket on, with the need for drilling. Torx or spline tools are also good for hammering into hex socket head screws that have rounded internally.

Taking the comments by Tranona into account, would it be useful/possible to replace the bolts with studs and nuts ?

 

[No Regrets]

Hacksaw a slot in the top and try a screwdriver bit on a bar?

 

[BabaYaga]

Using the torx tool is a good idea. You can often hammer a torx socket on, with the need for drilling. Torx or spline tools are also good for hammering into hex socket head screws that have rounded internally.

Yes, a torx SOCKET might be worth a try, as drilling a hole into the bolt head, as suggested in post #8, sounds very risky, if this is an M6 bolt.

 

[earlybird]

A note of caution about hammering anything into the bolt head sufficiently hard to deform and grip the steel. This bolt goes into the fairly thin, aluminium, (I think), timing cover casting. Cracking that will cause considerable further damage; to the wallet!