Removing old bushes

[guswa]

Ok guys have got the pins out of my h frame and z arm of my wheel loader,any sugestion on removing the old bushes, i have heard welding a bead on the inner face of the bush will shrink it enough to remove.

 

[Scrub Puller]

Yeah...guswa you heard right mate. I've not had alot to do with loader arm bushes but that technique is very common for bush and bearing removal.

It's best if you can weld them late and allow to cool over night. Put a good weave in there and you will probably bump them out with the hammer handle next morning.

Cheers.

 

[Nige]

+1 - That's the way we do it. Better instead of just making circular beads around the inside of the bush run the beads in a zig-zag fashion around the ID. You need to allow the welds to cool so that they shrink. Sometimes we just throw a bucket of water in there to shock them cool and shrink them. Generally only a light tap required to get the bush out after that.

 

[RayF]

Or you could do what most fitters here do and blast it out with an arc air torch.:tong That guarentee's that the local line borer always has plenty of work
But the way I do it is simple and we probably remove hundreds a year. Get your oxy torch and holding it up close and starting one end heat the surface of the bearing till you start to melt the surface.Run the melt line to the other end.Sometimes do that in two places (opposite) Cool it with water or let it cool by itself and the bearing will tap out.

 

[guswa]

Does anone know how much liquid nitrogen do i need to install the new bushes and where i can get it from ive heard boc gases sell it.
Iam thinking i will only need 10 to 20 litres.

cheers

 

[RayF]

It depends how many bearings you have to put in and how big they are. I can fit say 8 bearings 200mm dia X 150 long into a Hitachi 2500 bucket with 50 litres. You can buy it from BOC in Kewdale and you will need a flask to put it in. Otherwise they will deliver to you and you would need a large foam esky and be all set to go as it won't last long in the open.
Its not a job for the inexperianced although not hard once you have seen it done. The bores normally need to be heated especially on smaller bores and you need a quick and steady hand.The other way to do it is to pull them in with a porta power.

 

[tuney443]

And here I thought this was a thread on bushes,the kind that is for landscaping.Should have known better from the location.You Aussies really do have your own little English lingo going for sure.:drinkup

 

[Nige]

And here I thought this was a thread on bushes,the kind that is for landscaping.Should have known better from the location.You Aussies really do have your own little English lingo going for sure.:drinkup

For the record. We speak ENGLISH, you speak American ..........:tong:tong

 

[tuney443]

For the record. We speak ENGLISH, you speak American ..........:tong:tong

I'll see what my 11th grade English teacher of a wife has to say about that!!!! :stirthepot

 

[kshansen]

I'll see what my 11th grade English teacher of a wife has to say about that!!!! :stirthepot

You're going to take the word of a schoolmarm over Nige?

 

[guswa]

Thanks ray for the advice,the bushes are aprox 100mm in diameter by 80mm in length i have 7 of them, have rang boc gases and for 20 litres they want $90 + gst,the only problems is i need a flask to transport it in but they dont hire the flask you have to buy it which is not practical in my case, you dont know were i could hire a flask do you.

cheers

 

[RayF]

I have a 50 litre flask you can use.BOC will likely only put in 50 litres.Liquid Air will send a truck and put in what you want.
Send me a PM

 

[kshansen]

Another option is "Dry Ice". We have used it to install pins that are press fit in various machines. Although I'm sure a liquid will do a better job of cooling something as it has 100% contact.

 

[Nige]

Another option is "Dry Ice". We have used it to install pins that are press fit in various machines. Although I'm sure a liquid will do a better job of cooling something as it has 100% contact.

Dry Ice is always an alternative. However it only goes down to about -80 DegC temperature. Liquid nitrogen is at a temperature of around -200 DegC IIRC. You get much more "shrink" on your bushes using liquid nitrogen, if they are cooled for about 5 minutes they literally fall into place.

Be VERY CAREFUL how you handle liquid nitrogen. No exposed skin, safety glasses, welder's gloves, etc, are a must. Especially true if you have to lift the flask and pour the fluid. If it splashes on skin it will burn you badly instantly. The modern flasks have a valve and an outlet hose that you can direct straight into the container you're using to freeze the bushes. Much safer.
Wrap a bit of wire round each part so that you can haul it out of the liquid easily then cut off the wire before installing.

I've used an old esky as a container (the cold destroys it BTW), but anything will do so long as it's big enough to get the part into it. Whatever container you're going to use for the liquid, knock up or find a box about twice the size, and fill the bottom with dry sand 3-4" deep. Put your container in the box and then fill all around it with more sand to act as an insulator. That way the liquid does not evaporate so fast.

 

[guswa]

Dry Ice is always an alternative. However it only goes down to about -80 DegC temperature. Liquid nitrogen is at a temperature of around -200 DegC IIRC. You get much more "shrink" on your bushes using liquid nitrogen, if they are cooled for about 5 minutes they literally fall into place.

Be VERY CAREFUL how you handle liquid nitrogen. No exposed skin, safety glasses, welder's gloves, etc, are a must. Especially true if you have to lift the flask and pour the fluid. If it splashes on skin it will burn you badly instantly. The modern flasks have a valve and an outlet hose that you can direct straight into the container you're using to freeze the bushes. Much safer.
Wrap a bit of wire round each part so that you can haul it out of the liquid easily then cut off the wire before installing.

I've used an old esky as a container (the cold destroys it BTW), but anything will do so long as it's big enough to get the part into it. Whatever container you're going to use for the liquid, knock up or find a box about twice the size, and fill the bottom with dry sand 3-4" deep. Put your container in the box and then fill all around it with more sand to act as an insulator. That way the liquid does not evaporate so fast.

cheers nige will give that a go,it will give me an excuse to buy a new esky hehe..

 

[Nige]

If you want a good party trick to amaze your friends, try this - take 1 normal banana (can be green or ripe, makes no difference), a length of 6" x 4" timber, and a 6" nail. Freeze the banana in liquid nitrogen for 2 minutes, remove, and use as a hammer to knock the nail into the wood. Works every time - amazingly the banana will not shatter.

 

[TheOldMan]

I love this exchange, but not I'm confused. What's american for esky?

 

[Nige]

Esky = Eskimo aka cooler/cool box ........

 

[typ4]

Its what we keep the beer in, lol

 

[Greg]

If you asked the Brits what you speak down under I bet they would have a different opinion of what your language is called. LOL.

After all, they still refer to us as the colonies here.:usa