Bicycle Mechanics - Suntour Freewheel Removal - Help Needed

Can someone please give me some guidance/direction on how to remove the freewheel shown in these pics? It's a Suntour Powerflo 7-speed off a 1992 Trek 750 Multi-Track. I want to give it a good cleaning and service the hubs bearings.

Do I need to remove the rubber dust seal that's inside the smallest gear? If so, how? It doesn't appear that the smallest gear is threaded onto the freewheel body, but it's hard to tell. I have a Park FR-2 freewheel tool that I've used on another Suntour freewheel. In that case it was obvious what needed to be done.

Thanks in advance for any help that can be provided.

Ken

Taking a freewheel apart can be a real nightmare. The normal route is to just toss the whole works and get a new one so the methods used to put them together are often unique and involve making some of your own tools.

But all is not lost. You can do a really nice job of cleaning and lubing but you'll want to get the freewheel off the hub first. That's a topic all its own and a quick search will find you some threads about how to clamp the tool in place so it doesn't jump and ruin the freewheel.

Once off the hub you can dunk the whole assemby into a bucket of mineral spirits. This is often more commonly known as "low odor paint thinner" used for oil based house paints. Using some nitrile rubber gloves spin the freewheel while submerged and lift out to drain often so it flushes out the grunge. Once clean let drain and then sit on a pad of paper towels to drain overnight. To lube the freewheel I found a mix of 50-50 mineral spirits to a thick body oil like chain saw bar oil or some 50 weight straight grade motor oil works fine. Squirt a lot into the freewheel through the joints and spin well to distribute and then let drain for a few hours again.

It'll sound really noisy for the first day or two until the mineral spirits evaporate and leave just the right amount of oil behind. Then it'll be smooth as the cooing of a pigeon.

http://www.sheldonbrown.com/suntour.html

That's a Suntour freehub, not a freewheel. Hence the lack of anywhere to insert a freewheel remover :) Grab the driveside end of the axle in an axle vise. Unlock the cone and locknut on the non-driveside and remove them from the axle. Now release the axle vise, pick the wheel up by the axle, and slide the axle out of the hub (being careful not to lose the bearings in the process). Bingo, you're into the hub bearings to service them :)

Bigger picture: that stuff's obsolete. You'll have a tough time locating more AP-II cassettes. So keep your drivetrain clean and well-lubricated to prolong its life, and plan to eventually migrate to a different system that you can get parts for.

That's a Suntour freehub, not a freewheel. Hence the lack of anywhere to insert a freewheel remover :) Grab the driveside end of the axle in an axle vise. Unlock the cone and locknut on the non-driveside and remove them from the axle. Now release the axle vise, pick the wheel up by the axle, and slide the axle out of the hub (being careful not to lose the bearings in the process). Bingo, you're into the hub bearings to service them :)

Bigger picture: that stuff's obsolete. You'll have a tough time locating more AP-II cassettes. So keep your drivetrain clean and well-lubricated to prolong its life, and plan to eventually migrate to a different system that you can get parts for.

If it is indeed a freehub, there has to be some way to remove the cassette from the hub body. If I use the method you recommended, how do I deal with the rubber seal that shows in the photos? Will it pop out on its own when I pull the axle out?

Thanks,

Ken

I've not dealt with Sun Tour in a long time but the absence of a lock ring tells me the cassette is held in place by the threaded-on first position cog. You will need two chainwhips to unscrew it and the rest of the cogs should slide off. I don't know how the freehub body is fastened to the hub shell. Shimano uses a 10 mm hollow bolt but I think that design is patented so I don't know how Sun Tour did it.

The "rubber seal" is probably a dust seal and the axle will come off right through it when you remove the nds cone and locknut. It probably pries out to make access to the bearings easier and snaps back in when you are done.

This stuff is old enough and "out of print" long enough that posting the same question in the C&V forum may get more detailed info.

Yeah, you'll need a couple of chain whips if you want to remove the cassette. But why risk the breakage of that mission-critical outer-position cog, when you can't get any more of them? Let well enough alone, is my advice :) Overhaul it with the cassette in place.

2 chainwhips and a little muscle did the trick. The small gear came loose and the remainder of the cassette slipped right off. Before I attempted it, I did notice the splines on the freehub when looking through the dork disc. That would have given me a clue if I had noticed it earlier.

Thanks everyone for the help.

Ken

There are many wrong answers here.

I know this is an old thread, but I just found it, searching for an answer to solve a problem with used equipment.

The item here is a Suntour cassette-like threaded freewheel.


I think it was actually a cassette on a cassette body, analogous to Shimano's system. Example diagram of a '92 Suntour cassette hub:

http://farm6.staticflickr.com/5265/5661348533_d602655f4b_b.jpg

Trek's 1992 catalog says the MT 750 comes with a cassette, although knowing Trek, that could mean anything :D Next time one rolls through the shop, I'll verify what's on it. Could be a while :)