Hello,

Picked up a old Schwinn Frontier GS mountain bike at a yard sale last weekend and was working to get it all lubed up. The bottom bracket is pretty stiff and feel like the bearings need some help... google seems to show there are multiple types of the square style bottom bracket and before I mess something up I figure I would ask what the proper method is to disassemble.

Can the bearings be greased in these or do I need a whole new unit? Thanks!

PARK HCW-4 for the DS & HCW-5 for the NDS.
Use lots of penetrating oil for a day or 2 before.
Fixed cup is Left Hand thread.

Once I get the adjustable cup & spindle removed, I'll lay the bike on its right side and dribble more PO along the BB shell threads so it can run down and reach the fixed cup from the opposite side .

One thing... If you discover the axle is pitted, a loose ball BB is not easy to find now..

Old choice; have bike shop use their tools that once, or buy them , used rarely thereafter..

Cartridge BB is what took over, separate tool set for those..


....

Get the right wrench as mentioned above. You may need a heat gun on the shell and mallet on the wrench handle for the drive side.

I wouldn't mess with the fixed cup unless I had to.

After removing the adjustable cup (non drive side), the spindle and the bearings, clean the drive side cup (with solvent and rag) in place through the shell and look and feel if there is pitting in that cup. study the bearing surfaces and balls and replace if there is pitting or discoloration then slap it all back together with fresh grease and adjust to make those bearings happy (no play, no drag). The adjustment works best if you finger tighten the adjustable cup til it stops then finger tighten the locknut til it stops and then use tools to back the adjustable cup into the locknut.

If you are totally unfamiliar with this type of bottom bracket I'd suggest finding a video on YouTube to familiarize yourself. In answer to your question, they can be serviced/greased. As long as the bearing surfaces on the cups and spindle races look good they will last a long time. Many came with caged bearing balls and going to loose bearing balls will often make them last longer. Especially those with slight pitting. It's great to have the right tools but I have used a big adjustable jaw wrench for the fixed cup with good results. Perhaps there is a bike coop close by with the right tools? The lock ring/nut on the adjustable side looks like it has a gash in it. As if someone used a chisel to tighten? Back in the 80's when I was poor and ignorant (not so poor now, lol) I would loosen and tighten the lock ring with an old flat blade screwdriver placed in one of the cut slots and a good sized hammer. Of course, getting the right adjustment was then pretty much a two person job. Having the correct tools is much better.

...+1. About the only reason to remove the fixed side cup is to repaint the frame, or to replace with something else, like a cartridge BB.

I would avoid using an adjustable wrench on the fixed cup. It's too easy to have it slip. Use the correct wrench (a Park HCW-4 or similar) to remove it.

Agree, and that also has pin spanner end for the adjustable cup, which comes in handy when eliminating spindle play. Alternatively..
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Even the fixed cup wrench has little to grip, but the edge, and so there have been tools made to hold down that tool..

and sheldon's BB bolt hack; a big bolt, nut + stack of split washers..

Bench vise works too .. just unscrew the frame from the BB cup then.. gripped in the vise ..

Yup. If your bench vice has sharp enough edges, you can put the cup in the vice and turn the frame. Easy peasy.

I would remove the fixed cup just so you can immediately put it in the garbage.

A Shimano UN55 cartridge BB is $15. I don't understand why anyone screws around with cup and cone BBs.

...in general, I do it because they often last longer than a cartridge unit in service. YMMV