Recently my PC 333 ROS started making a grinding noise while slowing down (after turning it off). Opened it up last night and it looks like the lower ball bearing is about to seize...the upper one turns nice but once you grip the lower one the shaft doesnt turn so nice anymore.
I wasnt sure if it just slides right off, but I gave it a tug and it didnt budge. Is the bearing pressed onto the shaft? If so, any tips on how to remove and reinstall it? (going further, anyone have measurements on the bearing? Im pretty sure I could find an equivalent replacement locally if I knew the size)
I like the sander, considering the part is only 5 bux I figured it would be worth it to fix over buying a new sander. Am I wasting my time?
Bearing puller is safe way. You may be able to make a cradle and use a brass drift and drive the shaft but is risky. I've replaced bearings on them multiple times but I have a puller so haven't really tried the other on these.
Don't know what the PC parts pricing is these days and don't know actual size offhand but any decent bearing house will have replacements. W/ the price of steel these days, expect more than $5 though is my guess. It's been about two years now since the last time I worked one over--I'm thinking they were about $7.50 then???
Thanks for the info, I take it its pressed on then.
According to PCs "Servicenet" website, the part is 5.83+shipping. I know the +shipping will kill me (friend of mine just ordered some 8.00 parts and they charged him like 10.00 shipping). If I can pull the bearing off Ill just try to get a size on it and find it locally.
Any advice for pressing it back onto the shaft? Standard "use a socket the same size as the inner race" installation procedure?
They're tight enough to need persuasion, yes...a little penetrating fluid can help if there's dust gotten onto the shaft to help if slide a little, but I doubt you'll be able to get one off w/o some mechanical advantage.
Just take it to the bearing supply and they'll cross-reference it from the manufacturer's mark or mic it if they have to...
Reassembly is simpler than pulling and no additional advice other "be careful".
BTW, if I had it apart and were replacing one bearing, I'd likely go ahead and do both just on general principles--but that's me...others like to wait 'til something is definitely on it's last legs--your choice/call.
Thanks for the info. Ill probably pull the second bearing anyway (then I can slide the shaft out to get better leverage on the lower bearing I need to replace). At that point Ill just buy both.
The shipping isnt the only thing stopping me from getting the parts from PC......when I opened the case I was greeted with "Made in China" on the bearing. Wonder if thats part of the reason why they fail so early. I figure Ill order a good set of bearings from a bearing place online (or to go Napa to see if they have the right sizes). As far as the brushes, Im hoping maybe I can find those locally considering they are a "wear" item.
BTW, I noticed there was a small hole in the bottom of the casing (in the area that is supposed to be sealed off from dust). Im wondering if that hole allowed dust to get into the armature area that shouldnt have been able to get there. Going to epoxy it over to prevent more dust from getting to the new bearings.
-Chris
Le> > BTW, if I had it apart and were replacing one bearing, I'd likely go
More than likely the bearings you'll find from an online outfit will be Chinese as well...virtually no bearings of such small size are made in the US any longer...
As for NAPA (or any auto parts supply), I can virtually guarantee they won't have them--go to a local bearing distributor and save the extra (wasted) trip (and shipping and help keep some local supplier in business if even minutely, as well).
As for brushes, I've run the legs off these for years and brush wear has not been a problem yet--unless your wear experience is far different than mine, the armature and/or rotor windings will develop a break before a set of brushes wears out to the point of needing replacement.
If that bearing is pressed against a shoulder, it's possible it may never come off. When a bearing is pressed on or pulled off, you're supposed to use the inner race as the surface to be pushed or pulled on. My own personal experience is that sometimes removing the bearing works but most times it doesn't. When the bearing is against a shoulder, you have to pull on the outer race and that means it's highly likely to simply tear off the lower. The only connection between the two races are the balls themselves. Now with only the inner race remaining on the shaft, how's that coming off?
Of course, if it comes off, installing the new one is a piece of cake. Be sure to press it on by the inner race and push it on straight otherwise damage to the bearing can result.
As to another posters advise about replacing *both* bearings, IMO the upper bearing doesn't see the business end of the actual work. It doesn't see the dust or oscillating side loading that'll cause the heavy wear. Personally, I wouldn't bother. Of couse I understand the others feel differently. YMMV.
Generally bearings last for many 100s of millions of revolutions or more. That's a long long time.
Of course, severe service conditions can and will shorten bearing life as you've witnessed with the lower.
More to the point, with all the parts you're planning on buying and the effort required to replace them, don't you think it would make as much sense to simply buy a new sander?
I was thinking about a new sander, but if I can remove the existing bearing, and a replacement comes in at 10 bux or less, why spend 60.00+ on a new sander?
I went as far as checking around for sander opinions, and the Porter Cable that I already have seems to be one of the most popular and recommended (oddly enough, lots of the complaints on Amazon are about bearings that failed prematurely). On the other hand, one of the pros about the sander is that it *comes* with full ball bearing construction.
But it really depends on how hard or easy it is to get the bearing off. Its a small enough bearing that Im guessing it will be pretty inexpensive, even if I have to pay shipping.
The sander always worked well for me.......I really think what did it in was that I used it for some drywall sanding which probably isnt bad by itself, but once the dust made it thru the small hole I found in the case, that was the beginning of the end of the lower bearing.
All those "belts" are (besides being totally unecessary and and an undesirable heat generator that is imo the prime cause of the early bearing failures) is an o-ring. Go to your local gasket supplier and they can give you one out of the drawer for $0.75 or less. You might even find one at a good hardware store w/ a sizable stock in the o-ring kits, but they're pretty large for most ordinary h/w store selections...
Of course, the better thing is to take them off when you get the sander to begin with (imo, ymmv, $0.02, etc., etc., ....)
Possible, but _highly_ unlikely. In 40+ yrs of farm and other repair I've pulled a lot of bearings and never had a bearing come apart unless it was already completely failed. Even then, there's virtually always a way.
On the PC sanders, these are such small bearings there is no real heavy force needed, but it does take more than just pulling on it by hand...
A little heat will do wonders if one gets in such a bind. Virtually always the race diameter will be larger than the shoulder and you can still use the puller on the remnants. What one would have to resort to in any given situation, of course, depends on the particulars of the situation but I don't recall ever having to scrap a piece of gear for this particular problem.
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That would have been me... :)
It is also a lot smaller, lighter bearing and my experience has been if the bottom one is failing the top one is also dry and since you went to the trouble of taking the thing apart and it's pretty cheap, why not?
At say 2000 rpm, 100E6/2E3 = 50E3 / 60 < 1E3 hr --> 33 days of operation at 6hr/day, 5 days/wk. I (w/ hired help) put that on three of these easily while doing the repair and preparation for painting the barn where we were at it six days a week for nearly 3 months. OP undoubtedly doesn't abuse use his that way but I know of other painters that use them at least as hard as we did. The point being not to argue what the design life is but that there are folks out there who _use_ these things far beyond what I'm sure PC ever had in mind but they are simply the most comfortable, overall cost-effective way to do prep on areas of large size but not totally flat where larger pads are suitable. In my instance, the siding is 3-1/4" wide T&G with the coved top edge and it takes something like this to get into that cove.
Anyway, this is a sidetrack to OP's original question...
Precisely, and you definitely _can_ pull the bearing but it will take some effort--it's always good to have a set of tools, so here's your chance to justify a small gear/pulley puller if you don't have one already... :) As I recollect, I had to grind the head on the pawls to make them thin enough to get between the fan and the bearing, but that's just part of working on stuff--you often have to make or modify tools for the job.
As you note drywall dust is terrible for getting into stuff and probably did contribute to the drying out of the bearing. But, my personal opinion is that a lot of the cause of the early bearing failures is the heat generated by the stupid (MO, YMMV) "belt" they added for the automatic stopping "feature". All it is is an o-ring around a _fixed_ post so that it rubs continuously. For very short operating periods this is probably not too big a deal but when one is operating the sander nearly continuously for long periods of time it really gets hot.
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It's really not that difficult, but you will have to have (or rig up your own) a puller because there's no way to get bearing to apply force against the bearing w/o breaking the fan.
As noted before, there's no reason to pay shipping--any community of any size at all will have a bearing distributor who will have them in stock or will be able to get them from their supplier next day (or two at most) for no additional charge--they'll just add them to their normal daily order and they'll come in when the next shipment arrives. I'm in a place of only 20k population and there are two places here, even.
I actually used a battery terminal puller, the bearing came right off. Stock size (629-2RS), got 2 of em off Ebay for 3.50 shipped. I figure if any bearing I find is gonna be cheap, I might as well get 2 cheap ones and be ready to repair it again. I have learned my lesson, this sander will get nowhere near drywall.
The upper bearing is actually only double *shielded* and not sealed......they have the size on Ebay, but I didnt order it yet. Should I convert it to a double sealed or match the double shielded thats already there? I know the seals add a little friction, was wondering if Porter Cable used shielded for a reason.
Being a designer of devices with small motors, some which use ball bearings, I'll say that they used shields instead of seals because of cost and that they're good enough in most applications.
I'd go with the seals if I had the choice. Teflon seals are even better. Lower friction. But I'll bet they're not generally available so you'll probably get neoprene (black).
With the seals, you won't have to worry about drywall dust anymore.
I was looking at replacements, and the Bosch seems to get not-so-great reviews because of the dust collection (or lack thereof). The thing I like most about my PC is that I can use it with a Shop Vac without a fancy expensive adapter.....the Bosch sanders with the funky rectangular dust cannister look like they wont hook up that well with a shop vac.
Plus Im looking at 60.00 for a new sander vs 3.50 worth of parts to fix the one I have. No brainer.....for now.
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