How to remove rusted forks

Minimichael

Minimichael

Well-Known Member
#1
#1
I think I invented this :p

Lots of penetrating oil, a big rubber mallet, patience, some light hammer taps here and there , ...oh, and a bottle jack!

I've found even badly rusted tubes still mostly rust around the opening where the tree meets the down tube, and then maybe up another inch or so. I say this to give you an idea of where to concentrate any rust-busting blows, heat, penetrant, or more heat.

Flickr fork 1
Flickr fork 2

I used heat as a last resort here because it wasn't budging and my axle bolt was losing its patience. Well, I had little hope of saving the sleeves anyway. About a minute with the torch at the sweet spot around the seam, ... a couple more blows with the mallet, and it started creeping upward.

Abrade the rust out of the tree as best you can before installing the new sleeves.
 

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minibikefever

Well-Known Member
#4
#4
Minimichael said:
I think I invented this :p

Lots of penetrating oil, a big rubber mallet, patience, some light hammer taps here and there , ...oh, and a bottle jack!

I've found even badly rusted tubes still mostly rust around the opening where the tree meets the down tube, and then maybe up another inch or so. I say this to give you an idea of where to concentrate any rust-busting blows, heat, penetrant, or more heat.

Flickr fork 1
Flickr fork 2

I used heat as a last resort here because it wasn't budging and my axle bolt was losing its patience. Well, I had little hope of saving the sleeves anyway. About a minute with the torch at the sweet spot around the seam, ... a couple more blows with the mallet, and it started creeping upward.

Abrade the rust out of the tree as best you can before installing the new sleeves.
Click to expand...
I used your advice and built a quick jig out of a couple 2x6s and a set of sawhorses to hold the forks and a hydraulic jack in the middle I bent a few axle bolts and pissed through a couple cans of penetrating oil and a heat gun and constant tapping, After 3 days under pressure one fork popped, then I had to run down to harbor freight and pick up another small hydraulic jack to get some even pressure on the single fork, I would of liked to break out the real heat but I had to preserve the bushings in the forks so it took almost 5 days to get the struts and bushings out, Thanks for the tip, Never had any idea these forks would be the hardest part of the build, The best tool you have to have is PATIENCE,
 
Minimichael

Minimichael

Well-Known Member
#6
#6
minibikefever said:
I used your advice and built a quick jig out of a couple 2x6s and a set of sawhorses to hold the forks and a hydraulic jack in the middle I bent a few axle bolts and pissed through a couple cans of penetrating oil and a heat gun and constant tapping, After 3 days under pressure one fork popped, then I had to run down to harbor freight and pick up another small hydraulic jack to get some even pressure on the single fork, I would of liked to break out the real heat but I had to preserve the bushings in the forks so it took almost 5 days to get the struts and bushings out, Thanks for the tip, Never had any idea these forks would be the hardest part of the build, The best tool you have to have is PATIENCE,
Click to expand...
It's worth the wait and saves energy AND your back! Cool story about it finally "popping". I think my old jack would have leaked down it's pressure overnight. But penetrant works overnight, and a jack might just get 'er done the next day.

It's just way more satisfying to remove them carefully and not cause any new damage in the process.
 
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Minimichael

Minimichael

Well-Known Member
#7
#7
sparkwizard said:
One tree, two chains and a tractor.
Kroil is much better than PB
Click to expand...
It's hard to know when your penetrant is really penetrating, ya know? I'd let the tube soak in a bucket except in a bucket of what? I'm too cheap to buy a gallon can of PB or kroil. So it also has to be something you can reuse. Like a bucket of old oil and gas. I had some kerosene around last summer and that came in handy for cleaning. Tho it seemed to get old and brown pretty quickly. Maybe oxidized?
 
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Minimichael

Minimichael

Well-Known Member
#8
#8
You guys think the ever-popular recipe of automatic transmission fluid, brake fluid and a thinner would do the trick? The mix is oft quoted by our members on here. Anybody know if it would keep for future uses or expire?
 
sparkwizard

sparkwizard

#9
#9
ATF by itself is good for penetrating rusty joints. You can buy a gallon for 25-30 bucks and pour it right back into the jug. It stinks, but it won't evaporate or oxidize. I think if you mix acetone with it, the acetone will evaporate out if it's not covered. If you add brake fluid to it, it will absorb humidity from the air, but that shouldn't bother you for your purposes. The brake fluid is added as a paint dissolver.
 
sparkwizard

sparkwizard

#16
#16
I have not tried this with a fork, but with old boat motors, there is a driveshaft that goes from the lower unit up into the bottom of the vertical crankshaft. They pump salt water up to cool the engine, and that driveshaft stays wet whenever it is running. If we couldn't get it apart after we unbolted the power head from the middle part, the exhaust housing, we would hang the whole thing upside down from a tree. Wrap a rope around the lower unit by the prop, hoist it up, dump some trans fluid down inside and walk away.
 
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