exercise bike repair question

I have an exercise bike, old one, has a fan thing for a front wheel for resistance. I moved it from NM to MO, it was in a non-airtight barn for less than a year, then brought to the rental we live in and put back together. It was working right when it left the desert, the humidity here has freaked out all my power tools, and I have been having to clean and grease them all, and I think I probably did the same to the bike (not sure what lubricant I may have used on it, I can narrow it down if it matters.)

When you pedal it, there is slippage, on either the back axle (pedal end) or the front axle (fan  end) I am more suspicious of the back one, but I haven't ruled out front. I thought I had it fixed last winter, we didn't use it, it seems it's not when I moved it last week to a winter use position.

This is all memories of what I did a year ago, and are faulty, sorry. At least one of the axles has splines that run down it, I tried putting a piece of wire in the splines to wedge them, but it's such a tight fit I couldn't get in the fine straight pins I was using. Not sure if I tried that on both axles. I assume I lubricated the bearings at least, not sure if I got it on the axles.

Any idea where I should look when I open it back up in the next few days?
I can post pics etc, and more info as required...
I appreciate any input! I'm good with bikes, and car and appliance repair, so I have skills and tools, but this is being silly. I thought it was fixed.

I was asked for pictures, so I took it apart, and remembered more about what I did last year. This must have been bought in or right around 1992 or 1993, from Sears. It had a digital display that I removed long ago. It has a fan type front wheel for resistance. No brand on it anymore, but, yay OCD, I still have the booklet that came with it. Totally useless for this, tells things like how to change the battery in the digital display, not what to look for if after 20+ years of living in the desert and being used, it gets moved to a wet climate and stored in a barn for a while. Don't know WHY they didn't cover that, but hey, it's a fact of life  :D

When it's together:  



When I have the main covers off:



The front wheel covers are a bitch to remove, and I recall now what happened last year when I pulled them. Besides they were bad to get back on, I had had to slide a bearing off the shaft, and it DID NOT want to go back on. It took me probably 3 or 4 hours and an amazing amount of mess to get it back on. I'm not inclined to do so again unless I absolutely have to. I think I'd live with the axle slipping rather than deal with that. It wasn't pretty at all.  
I took a picture of the axle, but it doesn't show much useful, was hard to get anything even sort of visible, and I tweaked this in photoshop to get it this clear.
The axle:



Recalling now what I did last year: cleaned and oiled everything. The oil tastes like I used light machine oil, like 3 in 1 or sewing machine oil. The slippage is definitely in the front axle. I possibly got oil in it, i did not actually TRY to get oil on it, if it has any it came off the bearings. The machine oils I have are drops, not sprays. The bearings run well, I'm sure they were oiled.
The axle shaft is splined, NOT a picture of my axle, something off the net, in case I'm using the wrong word:


What I can see of it looks a LOT like that. Metal shaft with plastic fan on it, that was working correctly in New Mexico. There's a problem with plastics changing their... dryness... I don't know the word, when they move from one area to another, they tend to shrink just a hair. My cars and trucks are unhappy about the move due to this, everything's just a hair looser than it was. So last year I tried hammering a super fine quilting straight pin into the crack between the splines and fan to tighten it up. I couldn't get it to even go in 1/16 of an inch. When that didn't work I tried pushing glue into it, that didn't have any effect either, I don't think any got in there.  

So, with as much data as I can come up with, any guesses how to make this fan quit slipping on it's splined axle?
Anything I am missing that would help figure it out?
At the moment, I am considering brake parts cleaner (nasty toxic ick!!) to spray in there and dry out any oil that might be in there. If it's the plastic shrinkage bit, that won't help and will just make a toxic mess.

Assistance would be GREATLY appreciated!!

And reading this as if it were someone else's post, I wonder if I could drill into the plastic fan shaft until I hit the axle, and insert glue there with a syringe. I know I can't drill the axle, not without totally gutting it and putting it in the bench vise.
hmmm.....

That is a splined shaft. Very good chance the plastic piece of the fan that attaches to the shaft is worn. When it's plastic vs metal the metal usually wins. Or perhaps a connected plastic piece that attaches to that plastic piece lost it's griptivity.

If all the moving bits are in plain sight hold any given part steady & try to observe exactly where the slippage is. Most likely you've tried that already though. Epoxy or superglue might tighten it up but it helps to know exactly where to put it. Duh.

Are you sure it's not the drive belt slipping?

Thank you for replying Mike!
It's a chain drive, solid welded gears on both ends, tensioned correctly (I dinked extensively with the tension last year, just in case, no effect,) definitely not slipping there. Slip is between the axle and that fan. That much I'm sure of.

I tried putting glue in it last time, by laying it down so gravity helped and pressing glue into that little crack between the axle and fan. Odds are high, knowing me,that I used Duco cement, since it is a nitro-cellulose adhesive, that is thin enough to possibly go into that joint. Epoxy would be way too thick, and my water based glues don't adhere to metal well. The crack won't take a fine quilting pin (even hammered,) it looks very tight, but that's the only place it could be slipping.

Maybe I'll try drilling it and putting glue down the hole. I'm thinking 90 degrees off the shaft, coming straight down on it, so the glue is hitting the axle. Would be a fairly small spot though, unless I drilled a lot of holes... Hm... Not today, tomorrow maybe. Still up for better ideas than mine  :)

Assuming the fan & the plastic sleeve that fits over the metal spline is all one solid piece ....

Maybe a hose clamp tightened around the plastic sleeve would do the trick. A heat gun might help squeeze it together. That method could also break it. It's doubtful that glue will last long even if it does work. But you never know until you try.

My preference would be to disassemble that beast into a zillion pieces carefully arranged all over the living room until I found the culprit. (think Pink Floyd the Wall movie)

Mike Barkley wrote:Assuming the fan & the plastic sleeve that fits over the metal spline is all one solid piece .... Maybe a hose clamp tightened around the plastic sleeve would do the trick. A heat gun might help squeeze it together. That method could also break it. It's doubtful that glue will last long even if it does work. But you never know until you try.

 Yeah, looked at it closely, one piece, and looking at it from the edge, the shaft is even with the width of the blades, like this  | |   so no place to put a hose clamp. Good call, made me look :)

My preference would be to disassemble that beast into a zillion pieces carefully arranged all over the living room until I found the culprit. (think Pink Floyd the Wall movie)

Tear down the bike! Tear down the bike! :D
That's how I keep track of parts I take off machines, I line them up, if they are small I use bead design boards to keep track of pieces in order.

If you don't get OCD on a project, you never figure out where that washer went. Until it fails because it was short an important washer...

But getting the wheel off and forcing out the axle, which could be done, I guess, seems fairly useless. I'd still have to get it back in, and then I'd be right back where I am... And I'd get annoyed with it, then there would be shredded bike all over the exercise room for months. (She says, looking at the standing fan that has become a clothes rack by the desk since it's pieces are in a ziplock and there it stands, since May or so, still with no new switch.)

Hmm...
I will contemplate it. Drilling and gluing might be the best option still.

Its good to know I'm not the only OCD dismantler out there. I think what you are describing sounds like the fan collet? that goes over the axle shaft is worn and slipping under load; Probably due to the torque of starting and stopping. If it was me I would try to drill straight through and put a pin of some sort. All the way through so the load is split between two points. Its plastic so there is a good chance it breaks in the process.
Have fun,  David

David Baillie wrote:Its good to know I'm not the only OCD dismantler out there.

Far from it!! Most of  the guys who see me do stuff, though, don't know about bead design trays, having never made jewelry. They really work well, and are inexpensive.  

I think what you are describing sounds like the fan collet? that goes over the axle shaft is worn and slipping under load; Probably due to the torque of starting and stopping. If it was me I would try to drill straight through and put a pin of some sort. All the way through so the load is split between two points. Its plastic so there is a good chance it breaks in the process.
Have fun,  David

hmm. looked up "collet" I think that's higher tech than this might be. Quite possible that it's just a splined shaft forced into a plastic fan with a female splined hole (don't know the words there.) if it does have a collet, it's inside the fan hole, as I can't see it.
Drilling through has it's issues, mostly bad angles, no way to clamp it, and the axle is very hard. Last year  when I got that bearing off, to get it back on I had to taper the tip of the axle down a bit with a dremel to get it started. It was not easy. That's a tough axle. The plastic would be easy to drill.

I will think on this more...
Thank you!

So. I drilled holes in the plastic fan part up against the axle, some from this way, some from that way. About 8 holes total I think. Filled them with duco cement, being sure to let it dry before turning the wheel for the next set. Packed it in nice and tight. Let it dry well. Put it back together.... And... It's WORSE!

Actually now I think the chain tension is loose, feels like chain slip, haven't had time to adjust it. So whether it worked or not is in limbo still. Tell y'all more when I get it adjusted right.