Lint in Bearings

[flagman1776]

Lint in bearings. My first project... once I had the wife's emergency repair off my work table... I noticed the belt drive on my older model TravelScoot was suddenly noisy. I'd gotten it into a snowy parking lot & had to get help freeing myself & "Scoot". The belt suddenly seemed snugger than before. It seemed like there might be some increased drag "somewhere".

I started an exploring... I've not had the drive appart in at least a couple of years. I found long fibers of stringy "lint'... for lack of a better term... wound into the bearings on the drive side wheel & the belt idler. I was able to get it out with a toothbrush & fingers. The "sealed roller bearings" on the wheel both sides and the idler seemed dry so I allowed some light oil to soak in & spun them. Seems much better now. I haven't looked at the non-driven wheel yet.

I guess some of this should be considered routine service but... I'm anxious to avoid breakdowns. The drive gear on the wheel is an inch or so less diameter than the tire. I'm just wondering how the tint gets sucked in there... and what I can do about it.

[Burgerman]

The drive gear on the wheel is an inch or so less diameter than the tire. I'm just wondering how the tint gets sucked in there... and what I can do about it.

Buy the wife a new vacuum cleaner! Shoot the dog.

[flagman1776]

I use a walker in the house... between seats... No dog, 1 cat. Scooter stays in car between outtings. I'm suspicious of long velcro straps, used to secure the battery... right next to the main wheels. I found some lint in the deep sockets where the seat arch mounts... right next to the drive gears. The battery must be removed for each use & sits in a bracket on each side. I think much of the velcro is unneeded... I'm planning to remove the excess.
What a bugger. It took another hour to get the wheel, belt & idler reinstalled. It would be much easier with a correct dimensioned dummy axle with a tapered end. I took measurements.

[flagman1776]

The battery bag I'm using does not rely on these velcros at all... it has straps around the seat legs. There's 1/8" of wear on both edges of the removed velcro... about 32" of velcro... all fibers to get sucked into the wheel bearings. Not useful to me, so it'll remain gone.
I'm glad I was paying attention... these drive belts can be fragile & this might explain why. I'm still on the original belt... Shhh!

[ex-Gooserider]

Bearing lint is almost impossible to avoid or prevent - though it helps to avoid places where the hair and such that makes up most of it comes from...

Cleaning it out periodically will make your bearings last longer, as it works its way under the seals which allows water to enter, and the lube to wash out, leading to corrosion and so on...

But eventually you WILL need to replace the bearings. Fortunately they are almost always 'commodity' items that any bearing house can give you for a price. They are very much cheaper on fleabay I have purchased lots of 10 bearings on e-bay for LESS than what the local bearing house charged me for ONE of the same brand, with free shipping....

BM is a big fan of replacing the usual steel bearings with the same number in stainless steel, as he says they last longer because they don't rust when the lint lets the water get past the seals. Downside is the stainless versions are usually more expensive.

Look at the sides of the bearing, usually there will be numbers etched either on the shields or the bearing metal itself - these will specify the size, the bearing house will know how to translate the codes, or you can look them up on-line. If you can't find numbers on the bearing, use a caliper or micrometer to measure the Outside Diameter, the Inside Diameter (May be easier to measure the OD of the shaft that the bearing rides on) and the Thickness of the bearing - you should get values that are either common inch fractions, or whole milllimeters - these can then be used to look up the bearing numbers... (I often like to find the values each way as a check to make sure I read the codes right...)

ex-Gooserider

[flagman1776]

Thanks ex-G!
I think I'm a long way from needing to replace the bearings but I did take a good look while I had it apart. I measured the shaft .38"D because I'm going to turn up a dummy shaft (with a tapered nose) to improve reassembly. The bearings were all bright, so they may be stainless already but they are small. I didn't see any numbers but that doesn't mean they are not there somewhere.
I have removed the excess velcro where I think the fibers came from but lint & dust is everywhere... unavoidable.

[flagman1776]

What do you think of my oiling the roller bearings? My thought was "nothng to lose"... but oil attracts & retains dirt... After I go the fibers out of the bearing... it turned much better and turning the bearing was part of freeing the threads. I wonder how the bearing seals wear & how much thread fibers damage the seal?
What I did was laid the wheel on it's side... puddled a bit of light machine oil on the seal... wiped off what didn't soak in... stuck the axle in an inch & spun the wheel. It spun much better after oiling... though the question is how much oil will stay. Flipped the wheel & repeated on the other side.

[Williamclark77]

What do you think of my oiling the roller bearings?

A drop of oil inside is good. Mainly for rust/corrosion purposes moreso than a lube. Those bearings are run at such low speeds and light loads that they'll last virtually forever from normal wear. It's the dirt, hair, etc that get in and ruin them. No way to really avoid it but do as you're doing occasionally.

Don't ever use any of the modern super slick moly or teflon type oils in ball bearings unless it specifically calls for it. They're too slick. The balls will literally slide in the guides instead of roll and get flat spots.

[flagman1776]

I didn't think anything of it at the time but there's nothing to keep the axle from turning in the fork except the tiniest end pressure... but there was a bit of scoring on the axle. I bet the axle had spun at least a little, accounting for the extra drag I barely noticed.
Spinning the wheel as I did, should have distributed the oil through the bearings. That was the idea anyway. TravelScoot USA claims you don't need to read just the idler once set, that you can wind the belt on & off without. I might try that next time. You can't inspect the bearings without removing the wheel. I'm thinking the dummy axle with a tapered end will be a boon to re-assembly.

[ex-Gooserider]

How good is your measuring tool? 0.38" sounds awful close to 3/8" or 0.375" It's equal to about 9.65mm which is on the loose side to be 10mm, but could be...

My first tool to ID a bearing material is a magnet - if it sticks hard you have regular bearing steel, if it only sticks a little, or not at all, it's stainless... Try it with known bits of steel to get a comparison...

A dummy shaft can help, but I often just use a drift or alignment pin for reassembly. If something is really stubborn I might file or grind a very small radius on the end of the shaft...

Bearing numbers are often very faint if they are etched into the actual bearing steel, usually it's a bit easier if they are on the shield... A good magnifier can help, along with bright light and tilting the bearing in different directions...

If all else fails, go to any of the big bearing house / manufacturer websites (SK bearings is a good example) and they will have tables that list all the dimensions, and you can ID the bearing by process of elimination. Most charts, look at the ID first, then OD and Thickness in that order... Standard industrial bearings are enough different in size that it usually isn't a big problem to be sure which one matches on all three numbers.

Lubricating is probably not going to hurt as long as you don't over do it, and make sure the outside of the bearing is as clean / dry as you can get it. Use a good oil, not crap like WD-40, as Will suggested.

ex-Gooserider

Thanks ex-G!
I think I'm a long way from needing to replace the bearings but I did take a good look while I had it apart. I measured the shaft .38"D because I'm going to turn up a dummy shaft (with a tapered nose) to improve reassembly. The bearings were all bright, so they may be stainless already but they are small. I didn't see any numbers but that doesn't mean they are not there somewhere.
I have removed the excess velcro where I think the fibers came from but lint & dust is everywhere... unavoidable.

[flagman1776]

I just used a digital caliper, not a micrometer. I used a piece of 3/8" aluminum stock to make an alignment tool... an extended pin with a taper on one end & a step on the other to closely fit inside the threads on the axle. So what I made is not a "dummy" axle... I used the wrong word.
I did look at bearing charts briefly & agree it's likely 3/8" or 0.375" ID.
Yes, I used a good light machine oil... I avoid WD40...
Scoot is back together again... in use daily... so I am noting everything to be prepared for "next time". Yes, there will surely be a next time. It would make sense to have bearing in hand before the next service.

[flagman1776]

I'm noticing a greyish marking on the back of the drive belt. I'm suspiction of drag. The idler is just a small ball bearing which rides on the back of the belt. I am wondering if the idler bearing needs further attention. The deflection is within spec (1/2" under finger pressure). The bearing rides on a small bolt, through a simple bracket.
I suppose I need to do another inspection...
_check the bolt is not over tightened creating drag.
_check the bearing turns freely

[flagman1776]

When I came home today... 20*F with a wind chill into the single numbers... I brought Scoot in the house & got it up on the table for exploritory surgery. Oh, F***. I made several mistakes the other day. As I was disassembling I noted:

_scuff marks inside the little sheet aluminum belt guard. It appears there's some clearance in the mounting holes... enough free play that the belt can brush the guard. That can't be good! On reassembly, I can position the guard for maximum clearance.

_The Idler was tight. I had to remove the idler bracket to get the idler axle bolt out. I found a bit more lint to remove. I also noted the bearing was tight in the bracket, I had to lever it out. The bearing had been scuffing the sides of the bracket. It must be easy to over tighten, bending the bracket ever so slightly... enough to cause a problem. I put the bracket in a vise near the bottom & used wooden carpenter's wedges (used to shim windows & doors) & a hammer (gently) to spring the bracket enough to get my clearance back. I reassembled it without over tightening. I still have to re-install the idler bracket.

_I removed the wheel again. Found no problems this time & it spins free. I added a step to my re-assembly tool. The tapered end starts the tool through the wheel... the step on the other end is a slip fit inside the threaded axle end keeping the guide tool & the axle aligned. The axle then is used to push the tool out, leaving the axle properly installed. One bump & it was done. It was slick.

While it was open again, I measured the bearings as best I could.

SOoo... my instinct was right that the drive was not as it should be. The new marking on the back of the belt was my clue.
I'll clean up & save all these notes in my file on Scoot...

[flagman1776]

The wheel bearings are marked TTN 6000RS & measure 3/8"ID x 1"OD.
The idler is a double bearing set one side is marked TIAWAN NTN 608L8 while the other half is marked NBN 608FS .86"OD, .20"ID

[Burgerman]

https://www.amazon.com/6000RS-Bearing-1 ... B004YL45AC

https://www.amazon.com/S608-2RS-Sealed- ... +stainless

[ex-Gooserider]

Sounds like good progress and I see that BM has you covered on the bearings... Not terribly surprised to hear about non-robust construction, sort of fits with the general concept of the scooter, namely keeping weight down, not to mention costs.... Glad you have it rolling again.

ex-Gooserider

[flagman1776]

You are right, it's not rugged construction. But it seems to be stong enough. It's all aircraft aluminum, reputed to be the lightest scooter made. That IS the point, that it's light enough to actually have it with you. I don't go out every day, but if I do, it gets used. It takes about 2 minutes to assemble each time.
I have had 'Scoot' out, used it & back in the house adjusting the drive belt idler. Amazing how a little play will cause the belt to slap the guard. Test drive again tomorrow.

[flagman1776]

The belt tension still isn't right. I am really frustated with the "hit or miss" tension on the drive belt idler. There isn't a way to control the slide adjuster. I've been thinking about a temporary screw tensioner to position the slide. It's an easy concept but very tight quarters. I piece of stock with a threaded hole under the part... a screw through the thread... just need an anchor point.

[flagman1776]

The belt was much quieter in todays test. While I'm happy with this, I noticed with the battery removed (as it is for transport) that the mounting bracket would be a good anchor point. I have dug out some aluminum stock & will proceed to make the temporary screw adjusting tool. With the means to tension the belt... and hold it while securing the lock down... there will be no reluctance to loosen the adjustment for service. It shouldn't be this difficult.

[ex-Gooserider]

Actually thinking further on the oiling subject, I have seen some stuff suggesting that it is not a really great idea to try lubing sealed bearings other than as a temporary fix to make them last until you can get replacements...

The basic argument is that the bearings are supposed to be SEALED - and it does no good to oil the outside of the bearing, as that doesn't accomplish much other than possibly attracting dirt... In order to do any good, you need to get whatever lubricant is being used INSIDE the bearing seals, and if the seals are bad enough to allow you to get oil into them, then they have been compromised enough to let dirt in as well....

So the argument is basically that if the bearing is worn enough to lube, it really needs to be replaced instead....

ex-Gooserider

What do you think of my oiling the roller bearings?

A drop of oil inside is good. Mainly for rust/corrosion purposes moreso than a lube. Those bearings are run at such low speeds and light loads that they'll last virtually forever from normal wear. It's the dirt, hair, etc that get in and ruin them. No way to really avoid it but do as you're doing occasionally.

Don't ever use any of the modern super slick moly or teflon type oils in ball bearings unless it specifically calls for it. They're too slick. The balls will literally slide in the guides instead of roll and get flat spots.

[flagman1776]

I can't argue with that. Clearly the seals are compromized by the strands of thread that were would into them. Were it a high speed application, like automotive or motorcycle, it would be considerably more stressed & would need replacing immediately. For now it is working.
I intend to replace the bearings the next time I take it appart. I'm assuming the wheel halves must be split & the nearing pressed out from the inside. I should probably get the bearings in hand.

[ex-Gooserider]

That sounds reasonable, I'd just keep an eye / ear on the bearings in the mean time...

I liked the description that a mechanic put in a book I read at one point - he described many parts as 'flotation test' items - that if you get one in your hand, it should be flotation tested... I.e. toss it in a bucket of water, if it sinks it needs replacing...

The argument was that if the part cost is fairly low, and the pain factor in getting to it is high, then replacing it any time you actually do get to it is worth while as an attempt at putting off the next time as long as possible... Seems like a lot of bearings meet that description.

ex-Gooserider

[flagman1776]

I have Scoot on the bench to troubleshoot the power issue.
I immediately noticed lint & threads sticking out from the front wheel bearings. When I got the drive opened up, ditto. I had noticed the drive belt seemingly getting tighter which I recognize now as a symptom of debris in the bearings. I had previously removed as much of the velcro as possible from Scoot so maybe it's coming from floors / rugs when out & about. Given a choice or hard floors or rugs, I choose floors because it takes less power & Scoot is obiviously faster. It's been about a year since last wheel off service.
Except for cleaning the bearings periodically... I don't know what to do.

[Burgerman]

Go get a

[flagman1776]

My impression is that Scoot (now 6 years old) didn't collect lint at first, at least not like this. It's probably due for bearings. I don'tthink the bearings are "bad" but my thought is the worn seals ARE! At any rrate... I'm sure they'll fail the float test.
I will, of course, buy stainless. What type of seals? rubber? I'm looking at e bay bearings... huge price differences. But the bearings themselves will never fail in this light service... but the seals will wear out & collect crapola.

I'm not finding the double bearing on the idler.

[Burgerman]

Just search for sealed stainless bearings. Avoid unbranded ones and buy from a bearing dealer for good quality.

[flagman1776]

I had noticed the back of the drive belt looking greyish... I think that's an indicator of the idler bearing binding... needing debris cleaned. A good marker!

[flagman1776]

I have querries out about the stainless sealed bearings I need. I found an error in the bearing number for the idler. I think is is a 608LB 8*22*7

I found a YouTube video about freezing the bearings & heating the wheel to aid installation... Advise from those more experienced? It wouldn't do to melt the plastic wheels.

[Burgerman]

608 is the bearing size you need. RS so 608RS or 608 2RS or 608 RS search ebay for these plus stainless. They just push out. Or tap out. No need for heat.

https://www.ebay.co.uk/sch/i.html?_from ... s&_sacat=0 Take your pick! Skate ones tend to be low quality unless stupid money. You dont want ceramic. Just buy branded from a bearing supplier, quality ones.

The ones with blue rubber seals are not usually bad, they are for the food industry. Often pretty cheap. Conveyers etc in a factory. The blue is so you see it in food if anything fails.

[flagman1776]

I need 6 for each scooter of the 10*26*8 wheel bearings & only 2 of the 8*22*7 idler bearings. EBay in the US has little selection right now, but I have a single source for each.
Since I'm on my backup scooter, it's not critical... yet.