maddogandnoriko

I have an older Miami Sun tricycle I am preparing to paint. I have gotten almost everything apart and am ready to start sanding, but......I cannot figure out how this bearing seat comes out, it is the silver colored piece in the picture. I tapped it with a hammer and screw driver and got it to loosen about three turns clock wise, I think, and the it seemed to tighten back up. I did this a few times to see if it would "give" but every time it just loosened up and tightened again. What is it called and how can I remove it?



Thank you,
Todd

Kimmo 

That looks like the diameter of the one-piece crank 'American' system you get on BMX and old cruisers, etc.

But that middle bit looks odd... if it wasn't for that, I'd say you should just be able to punch it out...

Are there threads on the other side of the frame?

maddogandnoriko

Yes, there are threads on the other side. The cranks are multiple pieces with wedge type fasteners. and a spindle that goes through the frame and a handful of nuts to secure the whole thing in place. the bearings are not sealed but individual ball bearings. This bike seems to be kind of a hybrid between a bmx type bike and a large mountain bike, cruiser or ten speed. Like I said earlier, that middle piece seemes to start unthreading like it is going to come out, them BAM...it tightens up. I can see a thred or two also I believe as it starts to come out.

Todd

maddogandnoriko

The ad up there reminded me... the frame folds in half, if that makes any difference. I tried to contact Miami Sun to get some info on this bike, but they were absolutely no help at all.

Todd

FBinNY 

This is fairly common when there's rust or galling in the thread. As you turn the thread small bits of metal roll in the thread, until they jam. The more you work it the worse it'll get. Soak the thread in a penetrating oil such as Liquid Wrench, PB Blaster or Kroil for 24 hours then try again. Work it gently back and forth within the range that's fairly free now, until that loosens up a bit more, then slowly try to extend the range by degrees working back and forth. Be sure to check the area for heat and rest it to cool any time it's hot to the touch.

This can go either way. If you're patient and keep it cool and well oiled you have a decent chance of getting it out with only a bit of damaged thread, but if you overwork it, or are just plain unlucky, you'll get it out but there'll be serious thread damage, which may not be repairable at low cost.

If after soaking and trying fresh you make headway go ahead and remove the cup, but if it still resists, consider re-tightening it and leaving bad enough alone. Mask the cup and paint the frame around it.

Kimmo 

Well I suppose if you loosened it three turns, that should be enough to confirm you were turning it in the right direction, yeah? Like, there should be a little thread showing after that, or something?

So, you need lubrication and leverage, by the sound of it. Lube's pretty straightforward; a bit of WD40 or whatever should see you right.

Obviously you don't have the correct pin spanner for the leverage, and the tapping with a hammer kinda sucks on that score. You might be able to find a pair of long-nose pliers sharp enough to fit securely in those holes. If so, you can get a shifting spanner onto the pliers' pivot area, and you can actually get a fair bit of torque into it if you're careful to ensure the pliers don't jump out and injure you horribly, perhaps even without doing much damage to the pliers.

But if it starts feeling nasty, I defer to FB's galled thread primer.

FBinNY 

In this application, all lubes aren't created equal. Products made for this job, have specific additives to prevent galling that general purpose products don't. This is important, because those small bits rolling around will rip up the good threads increasing the damage. Use the right product for the job, work carefully, and excercise discretion. It's entirely possible that you're better odd leaving it alone.

Kimmo 

Yeah, I typed that up before seeing your post, then just added the last line.

There's stuck and there's stuck, know what I mean? I'm not sure it's clear which this is.

maddogandnoriko

Thanks for the replies. It seems like it should come out but the threads are "clogged". I will briefly try to gently remove it, but if it resists too much I guess I will mask it off and paint around it. Kills me to leave it partially broken, but it works so I will leave well enough alone.

Thank you again,
Todd