How to remove broken radiator drain plug

Cathy Liebchen

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KUBOTA L3901, MX5800, MULE PRO FX, MULE PRO FXT
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In trying to change the coolant, the plastic drain plug at the bottom of the radiator broke off almost flush. What’s the easiest way to extract the broken off threaded plastic male part without messing up the threads on the female part attached to the radiator? Thanks!
 

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MOOTS

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Left hand drill bit? If that don’t work, tap it. Toss a bolt in with a nut against broken piece and back out?
 

Henro

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Left hand drill bit? If that don’t work, tap it. Toss a bolt in with a nut against broken piece and back out?
You could also drill it and use an easy out. But whatever you decide to do, do it when you do not need the tractor for a while.

If you are like me, easy things soon turn to poop...using a less offensive term...:)
 

Jim L.

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You're right to be careful.

Small flat blade screwdriver, chisel (very small), something to gently tap into lodged piece. Then turn it out. Just make sure that it is not getting into threaded area.
 

Tughill Tom

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whitetiger

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You're right to be careful.

Small flat blade screwdriver, chisel (very small), something to gently tap into lodged piece. Then turn it out. Just make sure that it is not getting into threaded area.
A straight fluted extractor works very well in plastic. A spiral extractor just screws in further as you turn it expanding the broken sleeve tighter.
1599946819004.png
 

Russell King

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Why do you want to remove it? You can drain the fluid by removing the lower hose probably.

If it does not leak consider leaving it alone and not making more work??
 
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Cathy Liebchen

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A straight fluted extractor works very well in plastic. A spiral extractor just screws in further as you turn it expanding the broken sleeve tighter. View attachment 48315
This looks like the answer thanks!
Why do you want to remove it? You can drain the fluid by removing the lower hose probably.

If it does not leak consider leaving it alone and not making more work??
im guessing it may eventually leak without the head and gasket on it but that’s a good thought. I looked at the lower hose and the connection is behind a guard so it looked easier to just get the new plug
 

BruceP

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I 'second' the notion to LEAVE IT ALONE and simply drain by pulling lower hose.

In other words.... Why risk messing up the radiator when there is a simple alternative to drain it?

I view attempting to 'fix' the radiator-drain plug as a big waste of time when there are better things you could be doing improve your tractor.

As a reminder - I find it useful to pull the lower hose and use leaf-blower directred into the radiator-cap to help get all the fluid out of the radiator/engine. I drain/fill/drain/fill several times with DISTILLED water until it comes out clear. (never EVER use anything except DISTILLED water to mix with antifreeze. )
 
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Cathy Liebchen

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KUBOTA L3901, MX5800, MULE PRO FX, MULE PRO FXT
I 'second' the notion to LEAVE IT ALONE and simply drain by pulling lower hose.

In other words.... Why risk messing up the radiator when there is a simple alternative to drain it?

I view attempting to 'fix' the radiator-drain plug as a big waste of time when there are better things you could be doing improve your tractor.

As a reminder - I find it useful to pull the lower hose and use leaf-blower directred into the radiator-cap to help get all the fluid out of the radiator/engine. I drain/fill/drain/fill several times with DISTILLED water until it comes out clear. (never EVER use anything except DISTILLED water to mix with antifreeze. )
The prospect of the broken drain bolt failing miles from the house and then not being able to move the tractor without ruining the water pump is just not acceptable when it looks to be a pretty easy fix. SIL says he can drill it out and pick out the remaining threads with a dental pick if the tapered extractor and screw extractors don’t work,.
 

Russell King

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I think the tank is plastic and the threads will also be plastic.

Your reasoning for wanting it fixed is well thought out and sound.

Be careful and see if there is anything to coat the new plug with to keep it from getting stuck. I would use silicone grease but have no idea how it would work out long term.
 
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whitetiger

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Can anyone weigh in as to whether the threaded piece on the radiator is plastic as well? I can’t tell from the parts diagram and it looks like if I screw that up it will need a new radiator?
It is a plastic plug screwed into a plastic radiator tank. I have extracted several for customers that have broken or twisted of there plug. I always have used a tapered fluted extractor, never ran into one I could not remove.
I drill with a small bit, insert the extractor and turn using a 3/8" brake over bar and socket so I can push the extractor in with hand pressure. Use moderate steady pressure to slowly unscrew the plug. You may have to pull on the bar, hold pressure, slowly increase the pressure a couple of times but it will unscrew.
 
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Mark_BX25D

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I 'second' the notion to LEAVE IT ALONE and simply drain by pulling lower hose.

In other words.... Why risk messing up the radiator when there is a simple alternative to drain it?

I agree. I do this with any vehicle that has a plastic drain plug, which is pretty much all of them. I learned that lesson by having to replace a radiator.

I never use the drain plugs anymore.

  • It's very common for them to freeze in place.
  • It's nearly impossible to get them out without trashing the radiator.
  • If you do, well, you are okay for this time, but the next time you are back to the same old problem.
  • Pulling the hose is usually easier, and drains it better and faster.
 
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SidecarFlip

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Never take mine out. I use the lower rad hose method. It's a piss poor design at best. I kind of think the lower rad tank is plastic.
 
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RCW

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I vote for the remove/replace option also. Makes better sense than chancing a failure later.

I also pull the lower hose.

When I first looked at the drain on my little BX, my first thought was that’s just going to break.....

whitetiger knows much better than me, but that extractor looks like the ticket!

Good luck!
 
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SidecarFlip

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Don't know who makes the rads for Kubota but they need to change the design. The wimpy plastic bung don't cut it at all.
 

Mark_BX25D

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Yes we are going to replace it and never use it again!

Maybe I missed something. If it's in place, and not leaking, why not just leave it that way? Done!

If it's partially out and leaking, of course you need to replace it.
 
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