Gear Oil dipstick broken (Yanmar 3GM30). How to get it out?

jfkal

jfkal

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I need some ideas. I overtightened the dipstick cap of my gearbox. So sure enough it broke. Handle and dipstick came out in one piece but the threaded part is still fast in the gearbox.
I tried to get it out using a circlip tool but it would not move and I hate to use force causing broken off plastic pieces going into the gearbox.
Any good ideas?
 
Before you do anything, pack the top of the gearbox with a long piece of cloth so that, if any bits do come adrift as part of the removal process,they won't drop into the workings.
 
Gear stick removal

This has also happened on my Yanmar (same model ) so thanks for the info

Pretty obvious to stick a cloth to catch the bits but I had not thought of it !!

Cheers again Gary
 
Pour boiling water over the remains of the cap?

You could use an angle grinder pin wrench and drill a couple of holes (or make one if that won't fit).
 
Broken dipstick

Assumed there is a central hole, you could make a tool from a square steel bar a little larger than the hole, tapered by file, and force it in the hole, then unscrew, same as with the mentioned wooden tool.
If the culprit was metal, some good tapping on top the tool would seat the 4 corners in it.
Given the danger of breaking the plastic, you could heat the tool in the first place so the 4 corners can seat themselves deeply in the molten plastic and, once cooled down, they could apply the torque needed to unscrew the culprit.
I hope this can help.

Sandro
 
I used a dremel to make a slot down the side of the plastic, carefull not to damage the thread in the gearbox. I then used a large blade of a knife to wind out the broken piece.
 
Use a HOT screwdriver to make a slot .. Remove and cool driver .. Reinsert and unscrew .. ( Same as Davidej ) No bits to worry about .. Empty oil when done just in case and be very careful with the next one .. Why do you need to tighten it that much ..
 
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Just did it

Last friday I used on a 4JH4E a sharp cisel, without any warming.
Worked at first try.

IMHO problem originates from lousy plastic processing procedures in some far east plant: the broken surface looked very "grainy", so probably the moulds were not heated enough or there was a bad mixing of pigments, plastics etc.

Price for the spare part: 38,99 € + VAT. Anyone complayning about VP prices (by the way, never happened in the 16 years of VP2002 use on previous boat)?

Now planning to manufacture one myself, usinf a S/S bolt, drilled to host the stick and closed by a screw.
 
why not glue it using super glue gel, have removed some before this way even when they are in bits. even if its only to remove the bits

steve
 
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the problem is the dipstick is also the vent to prevent overpressure when the box warms up. I paid about £25 inc Vat for the genuine yanmar. Bit steep but mine was almost 30 years old
 
replacement yan gearbox dipstick..

be careful on the replacement dipstick length, as i recall that gearbox oil level on that yan is measured to the line on the dipstick when the cap is loosened and set in place, not measured with the cap tightened all the way down. so your new s s bolt head should have the same length for the dipstick assembly as the original when your new bolt is set loosely on the threads.

be interesting to see the cost of what design you come up with, it's bound to be cheaper than yanmar's replacement cap..
 
gianenrico said:
Last friday I used on a 4JH4E a sharp cisel, without any warming.
Worked at first try.

IMHO problem originates from lousy plastic processing procedures in some far east plant: the broken surface looked very "grainy", so probably the moulds were not heated enough or there was a bad mixing of pigments, plastics etc.

Price for the spare part: 38,99 € + VAT. Anyone complayning about VP prices (by the way, never happened in the 16 years of VP2002 use on previous boat)?

Now planning to manufacture one myself, usinf a S/S bolt, drilled to host the stick and closed by a screw.
Click to expand...

hi gianenrico, i had the same problem and gear box as you, but as in turkey got the local industrial estate to make me a new screwpart in tefnal and fit the old dip pipe peice. cost me 6 quid. my problrm is am not sure on the length of the dip stick now. would you be good enough if you have the time to measure it for me.
thanks in advance... stuart.
 
pathfinderstu said:
hi gianenrico, i had the same problem and gear box as you, but as in turkey got the local industrial estate to make me a new screwpart in tefnal and fit the old dip pipe peice. cost me 6 quid. my problrm is am not sure on the length of the dip stick now. would you be good enough if you have the time to measure it for me.
thanks in advance... stuart.
Click to expand...

His post is now 15 months old. Lubrication is by splash, so the level is not very critical. So long as some of the gears are in the oil all should be well.

This seems to be a not uncommon problem, mine has also broken. There seems to be some degradation of the plastic, which is very sticky to handle. I see that replacement ones are £25 each, so I shall continue to take mine out with a screwdriver for now.
 
vyv_cox said:
His post is now 15 months old. Lubrication is by splash, so the level is not very critical. So long as some of the gears are in the oil all should be well.

This seems to be a not uncommon problem, mine has also broken. There seems to be some degradation of the plastic, which is very sticky to handle. I see that replacement ones are £25 each, so I shall continue to take mine out with a screwdriver for now.
Click to expand...

Cobblers children :D
 
If you can drill a hole into the centre of the broken bit, get a stud extractor, which has a tapered reversed thread which as you wind it in is supposed to grip the broken off bit and unscrew it. Available from local Halfrauds, not expensive. Not much good in proper engineering as they are not hard enough and can snap off before a well stuck stud releases.
 
vyv_cox said:
His post is now 15 months old. Lubrication is by splash, so the level is not very critical. So long as some of the gears are in the oil all should be well.

This seems to be a not uncommon problem, mine has also broken. There seems to be some degradation of the plastic, which is very sticky to handle. I see that replacement ones are £25 each, so I shall continue to take mine out with a screwdriver for now.
Click to expand...

thanks for that mr cox, sounds good advice.!
 
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