Best rust solvent

[Onemoreproject]

MY boat has a sprocket frozen onto the shaft. I am replacing the shaft, so I cut the shaft and now have the sprocket with a short section of shaft sitting on my workbench. I have been pouring PB blaster on it and into the bolt holes, but it has not released from the shaft, so I am thinking to buy 2 qts of the best rust dissolver know to man to try to submerge the sprocket in hopes of being able to release it from the shaft. After getting it off the shaft, I plan to use Ospho to kill the rust so this doesnt happen when I clamp it onto the new shaft.

I don't know if the sprocket is fused onto the shaft with rust, or if it is frozen internally and cant open when I tighten the bolts that force it to expand and slide off the shaft.
If anyone has suggestions for a rust solvent or dissolver and a way to kill the rust so the sprocket doesn't get frozen onto the shaft, I would appreciate it.

Thank you for your suggestions.

[MicHughV]

At this point, I'd suggest some heat to get the sprocket off.
If you have a propane torch or something similar, I'd heat the sprocket up and try to drive the shaft out with a hammer.

I notice that there is a keyway in the second picture, would try to tap that out first, before trying to tap the shaft out.

I think heat will be your friend here.

[Onemoreproject]

Thank you for your suggestion. The sprocket weighs about 12 pounds and it would take a massive amount of hear to expand it. I am concerned with softening the metal and of cours, all the paint would burn off as well. So I would like to try everything else.

I tried to remove the key, but there isnt enough sticking out to grip with plyers or tap.

[BenBowSirocco]

Might try a shop with a press as well. Sometimes the hammer causes the shaft to mushroom, which causes more issues.



When you reassembly: coat liberally with "TefGel".



As for a solvent, I have had good luck with 50/50 acetone and ATF.

[senormechanico]

Phosphoric acid.

[wholybee]

For sure, a press. I wouldn't even attempt any other way. There are many other rebuilding tasks that would need one, from rebuilding a water pump">raw water pump, a gearbox, etc. So, if you have the space, they aren't very expensive.

If you don't have the space or don't want one, pressing something like that is probably only $20 at a typical machine shop, and would take 30 seconds.

https://www.harborfreight.com/12-ton...ess-70604.html

[Onemoreproject]

So, I was able to pound on the shaft and drive it out about 4". The key is now no longefin the shaft. So the problem was not that the sprocket is fused to the shaft, but the internal mechanism that causes the sprocket to clamp onto the shaft is frozen. So, if anyone has a solvent suggestion, please do.

[Calaban-Alleria]

In my experience patience is required here. Patience and Weasel Piss - the best thing for freeing stuck parts.

Weasel Piss = 50/50 ATF & Acetone.

Heat and cold will likely help - dont worry about the paint you can always make it pretty later. I expect you will ultimately require access to a press or some sort of puller. Since you have the "item in hand" you could soak it for a few days then take it to a machine shop to press it out. That will likely be much less frustrating.

If the part is steel and rusty - any commercial "rust stop" containing phosphoric acid will work to pacify the surface (if that is the right word).

[Onemoreproject]

Thanks. Pounding did mushroom the end and its not able to pass through the spocket to remove. I will soak it in weasel piss and see if I can get the clamp to expand. If not, I'll; take it to a machine shop to press it out and then soak it some more. If I can't get it to expand, then I am not going to be able to put it on the new shaft.

[Onemoreproject]

In case of replacement, any idea where to get one? I think it might be an HTD sprocket or pulley. It is intended to be used with a ribbed, 3 ½" Gates belt. i looked, but havent found one, but I bet it expensive.

[Bowdrie]

Originally Posted by Onemoreproject

Thanks. Pounding did mushroom the end and its not able to pass through the spocket to remove.

You were warned about that in a previous post.

Originally Posted by Onemoreproject

In case of replacement, any idea where to get one? I think it might be an HTD sprocket or pulley. It is intended to be used with a ribbed, 3 ½" Gates belt. i looked, but havent found one, but I bet it expensive.

Contact a good source of "Browning" power transmission products.
Yes, quite expensive.

[Onemoreproject]

"You were warned about that in a previous post".
I am not sure what your intent was by posting the above. Was stating the obvious meant to be helpful or spiteful,? The post came after I had pounded on the shaft. However, thank you for the useful aspects of your posts.
And thankyou everyone else for your helpful suggestions.

[Tupaia]

Mushroomed end. Last resort since it is moveable (the assembly that is) you could drill out the shaft using a pillar drill, multiple holes, until sufficient material is removed that the shaft collapses.

[Iron E]

I don't know what this is from, and I don't see where you mentioned it.

However, this gear appears to have 3 holes in it meant for a puller. As others have said, you will need a puller or a press to remove it. I've worked on engines for 30+ years and haven't had much success removing "pressed" parts with a hammer.

[lifeofreilly57]

Theres a YouTube channel called Project Farm. He recently did a video on rust solvents that was pretty informative. He takes no sponsorship for the products he tests.
But my first go to would be heat. You can always paint it again. I use a MAP gas torch since I no longer have an acetelene setup.
I was once a skilled tradesman prior to going to college, I've taken apart and rebuilt 100 year old machines, which was good preparation for working on boats.
A pulley that size will be very difficult to remove with penetrant alone.