Removal of rusty dynabolts from bricks

[Russ42]

I have quite a few places where dynabolts have been put into the bricks in the past and have since rusted up badly making them thus far impossible to get out. The rusting is expanding the bolts and breaking the bricks (see photo)

The bolt itself has broken off inside the surrounding metal cylinder. I have a plan A and a plan B.

A. try to drill out the metal cylinder until the drill hits the bolt. Then.......try to drill out the bolt and cylinder together. Perhaps, in the process, the drill bit will grip the cylinder and cause it to spin, thus making it possible to remove.

B. use a  "Vacuum Diamond Dry Drilling Tile Drill Bit" to drill it out. I foresee problem with this.

1. The hole produced will be large and must be filled.

2. if the drill tries to drill the metal of the bolt, it will lose the diamond chips on the end and be rendered useless.

Is there a tried and tested method of removing these pesky things

[MitchellMc]

Hi @Russ42,

Dynabolt sleeves can be notoriously hard to remove. I'd suggest option A to begin with. Choose a cobalt drill bit a millimetre smaller than the sleeve and drill at a slow speed. You should be able to drill through the bolt, and it will significantly weaken the wall of the sleeve. You can then crumple the sleeve into itself with a hammer and flat head screwdriver and allowing you to pull it out. To crumble the sleeve, work your way around the perimeter with the flathead screwdriver. Strike blows directed towards the centre of the sleeve, folding it in on itself.

Let me mention @redracer01 and @TedBear to see if they have some suggestions.

Mitchell

[Russ42]

Thanks Mitchell. I have gone off Dynabolts bit time! Plastic plugs seem to be a lot less of a problem.

[TedBear · Accepted solution]

I'd like to add another suggestion before resorting to the drilling,  since that could be a messy way to go.

I would first try:-

a) spraying the internals with CRC or similar, to start loosening the rust and its attachment to the (previously) movable parts.

then after an hour or so...

b) Use a strong bolt or any rod that will fit into the hole as a punch to hammer the broken bolt and nut back down into the hole.

If they will go back, this should allow the casing to close in again and release its grip on the brick work.

At this point, if you have any "Easy outs" screw the largest one in that fits, or use any other large screw or bolt that will grab the sides and give you something to lever the casing outward with.

Another way to pull it out, (if you have managed to drive the nuts back in & released the casing's grip) is to crush opposite sides of the cylinder inward using a large screwdriver to form a sort of tongue and then grab that with some narrow nosed snap-lock pliers - or any other pliers that will grab it.

https://www.bunnings.com.au/trojan-3-piece-locking-plier-set_p0126941

I love snap-lock pliers because you can usually get the edge of a lever between them and the surface, and then lever the pliers along with whatever their attached to, out. They will, hopefully also allow you to twist the casing to loosen its grip in the hole.

If you can't drive the internals back in, then drilling may be the next option.

Good luck with it.   It will be interesting to find out what method you end up using to get them out.

[redracer01]

Hello @Russ42 

I pretty much use the same method @TedBear uses. Spray it / soak it really with WD40 and once it has soaked in use a bolt that is slightly smaller than your dynabolt. Tap the center bolt back down in to the hole. Using a flat head screw driver gently tap the dynabolt sleeve to loosen it from the wall. Grab a pair of heavy duty long nose pliers and grab the dynabolt sleeve. Slowly turn the sleeve in clockwise then counterclockwise direction. Our objective is to tear and shear the sleeve. Once you have the majority of the sleeve out you can then attempt to pull the center bolt of the dynabolt out. Just to be clear you want all the of the dynabolt sleeve out of the wall before trying to get the  center bolt out. It is a long process so take your time. I understand your frustration as dynabolts tend to really anchor themselves and become a nuisance to take out. Take care and be safe.

Cheers,

Red

[Russ42]

Thanks Ted, a very good idea to try first. I suspect trying to drill it out will be an exercise in frustration. I can see the drill bit getting part way in and then the bolt spinning. In any case, there will probably be an issue getting the bolt out as one of them at least has broken off well into the sleeve. I will give it a go and let you know how it went. There are rusty dynabolts in many places in the walls of this house so I need a good, repeatable method. I do have easy outs as I used to live on an old boat.....

[Russ42]

Thanks Red. I have only ever been disappointed with the results from WD40. This is probably been because it is a Water Dispersant and I have not used it as such. The spray penetrating oil has not been much help either though but will give it another try if the CLR doesn't do the job. I have been trying to free up an an aluminium telescopic wishbone from a sailboard (who at Tyronsea thought a telescopic wishbone would be a good idea?). Will post this problem and see what suggestions I get. Perhaps Tyronsea will have a solution. 

[TedBear]

Hopefully the bolts will come out, still in the nuts when the sleeve comes out....  Sounds easy when written, but may require some twisting and pulling. 

(Another tip, plan for success by keeping your mouth closed, or off to the side. I broke a front tooth off once while pulling something out with pliers and it suddenly succeeded!)

[Russ42]

Thanks Guys, I have had limited success on my first bolt as the brick around the bolt was so broken up it just crumbled and so I have a sizable hole to fill. My drill didn't make any impression on the bolt as I suspect the bolt is hardened and the drill bit is not. I am thinking of putting something over it (a light sensor, perhaps).  I am going to try the drill out method with the ceramic hole saw. The hole will be 20mm as the bolt + rust is 18mm but at least the hole will be neat.....famous last words. Not quite...... Ted, I feel your pain. I once tried to pull something out with the claw of a hammer with a similar result. Thankfully the hammer just hit my head, so no harm done. 

[Russ42]

Well, the hole saw did the job of getting the things out. Was quick and easy. After I removed the remainder of the bolts, the deeper rusty dynabolt bits broke up with a sawn-off slotted screw driver. I will just fill the holes with a mortar mix. Not pretty, but at least the bricks wont get broken up any more.