Hex Bolts

[Forbsie]

I am currently stripping down my outdrive for a good service. A number of the hex bolts in the skeg casting refuse to budge. I have flooded them in WD40, heated them, smacked them but to no avail. In at least 2 of them, the hex has now rounded. Any ideas?

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[Gordonmc]

If they are rounded they must be a fairly soft metal so it will drill. Get hold of a set of easy-outs from a motor factor. The act of drilling a hole up the centre of the bolt will help.
If that doesn't work, grind off the heads and try mole-grips on the shaft when the casting is dropped. If that doesn't work, drill out and re-tap the threads.
The last one will alway be the worst.


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[summerwind]

I believe that this is a fairly common problem. The answer is heat, applied to the right place. You need a fine flame directed onto the end of the bolt. This will expand faster than the surrounding casting and crush the aluminium oxide that is causing your problem. Once you have given the bolt (Not the casting) a good blasting of heat, give the end several real hard whacks using a brass punch. Then, using a socket wherever possible, try turning the bolt. If you can't get a socket on the bolt head, use a ring spanner. Only use an open ended spanner as a last resort. Once it starts to move, work the bolt in and out a bit before unscrewing all the way out.

You can try heatring the bolt, then quickly cooling with a squirt of water. This might break the bond of the oxide.

If you can get them on, use stilsons on the rounded bolt head rather than mole grips. You get more leverage and a better grip. It is quite likely that you will break off the head of the bolt, but you will get your casting off. You will then have a better grip on the bolt with the stilsons. Applying heat as above, it will then be a lot easier to get the bolt out.

When you put it all back together again, run out the boltholes with a tap and use marine grade grease on the new bolts. This should save you loads of grief the next time you decide to take things apart.

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[Forbsie]

Thanks Summerwind and Gordon.

The problem with these bolts is that they are all flush with the casing. If I could just get the oil drain plug out, I would probably forget the others . If I drill it out, then I think I will have to take the skeg off to clean out the debris which will involve another 3 jammed bolts.

I did try using a heat gun, but maybe I'll try a blowtorch coz I couldn't seem to get it very hot.

Thanks again for your advice.

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[Gordonmc]

Certainly a heatgun won't give the amount of expansion Summerwind was suggesting and although a blowtorch will be better, it will spread the heat, but I don't suppose you have access to oxy-aceteline.
Is the oil-drain plug rounded? If not a combination of heat and an impact driver with a socket might budge it. Failing that an Abyssinian spanner... ie. a cold chisel into a flat, then angle to turn.
Easy-outs should not put swarfe into the housing.
Good luck. Don't forget the band aids for skint knuckles.

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[aztec]

hiya, if they're reccessed, you may have to drill the heads off. remove the casing and with the exposed studs, use a mig welder to weld on nuts, then use a socket to back out the remaining stud. works every time.

if you get stuck, bell me. you don't say whether the offending bit is off or on the boat. if it's off shouldn't be too bad to rectify.

all the best, steve.

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[Forbsie]

Hi Gordon

The drain plug has rounded to I'll try the Abyssinian spanner (Luv It).

Too late with the advice on the Band aids as all knuckles now skint, broken finger nails, chipped nail varnish, ermmmm.

Gordon

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[tr7v8]

Most importantly try to use flank drive sockets, they are 6 point not 12 an drive on the flats not on the points. This was the only way most of mine came out!

<hr width=100% size=1>Jim

Draco 2500

 

[oldsaltoz]

G'day Forbsie,

See if you can beg borrow or steal a set of Metrinch sockets, they are fantastic on rounded nuts and bolts.

And NO, I don't have any connection with them.......

Hope this helps

Avagoodweekend. Old Salt Oz /forums/images/icons/cool.gif

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[tr7v8]

Mine came from Screwfix and are the air set. Good quality and flank drive solved a lot of my problems!
They were about £ 30 + VAT.

<hr width=100% size=1>Jim

Draco 2500

 

[Forbsie]

Thanks Oldsaltoz and Jim,

I have a feeling that I may not have described this properly. The bolts I'm talking about would I suppose be called Allen Screws when I was a lad. The problem ones are embedded flush into the outdrive casing. The other problem is that they are imperial and not metric.

I have seen Metrinch spanners before but I don't know if they do something for these hex bolts. I also did a search on Screwfix site for 'flank drive' and came up with nothing. I also looked in the automotive and air tool pages. Is there another name for the one you were describing?

I tried the heat and chisel methods yesterday without luck and phoned Sillette Sonic who are going to send me their help sheet on taking out the drain plug. This sort of indicates to me that others have had the same problem. I'm also going to see if the local motor factors have 'Easy-Outs' this morning.

Sorry I'm such a clutz with this mechanical malarcy. At least I should be really knowledgable by the time I retire. )

Thanks for your perseverance.

Gordon

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[tr7v8]

God see what you mean! OK
Socket set is actually 37 PIECE IMPACT SOCKET SET, 13872 and is now £ 39.99 and worth it. They do screw extractors as well (18643, £ 4.29) but if you use them be very careful as they are very hard. And if you break them then you are totally stuffed.
As regards imperial hex drivers or allen keys, they are very difficult to find in 1/2" drive versions these day. Way I've done it in the past is to get a set of decent allen keys saw off the 90deg turn and using loctite push them into a socket. hence a set of drivers. By the way B & Q sell a good set of metric & imperial allen drivers for just over a tenner with handle and keeper/holder thingy.





<hr width=100% size=1>Jim

Draco 2500

 

[Forbsie]

Thanks for all your help, Gentlemen, problem solved.

I ended up drilling them out with a screw extractor and only had a problem at the end getting the remnants of the heads out but all done now.

Next problem..................

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[tico]

Watch it !!!
Some V*l*o allen screws are imperial and some are metric. You need to use the correct allen keys to do the job or the buggers will round off. I speak from bitter experience!!!!
The screw down the centre of the prop cone neds an imperial key!!!! a metric one, altho it seems close enuf will round off the hole and u are left with a stainless screw to drill out.... took me 4 hours!

best of luck

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[Forbsie]

Thanks Tico.

All the screws on a Sonic are imperial and luckily I noticed that first. They have now changed the oil filler plug from a grub screw to one with a proper nut on the end. I've still got 2 to remove in order to change the CV Bellows. A mate of mine said that he got fed up and drilled his out and replaced them with s/s split pins.

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