XtraSpecialK

Shimano Deore XT PD-M735 Pedals

So, not knowing when to leave well enough alone and suffering from a touch of OCD I couldn't help but take apart my pedals too, even though they were spinning like a Swiss watch. In my defense they are 23 years old and have never been serviced.

So I took apart the first pedal very carefully, making notes as to which way everything came out. I counted the ball bearings as I cleaned them, 24.
I cleaned up everything and applied fresh grease.
It took a bit of monkey business to get the pedal back together with all the bearings that were in my container back into the pedal.
I don't have the proper tool to lock the end nut and cone together without cinching the cone down a tad...but that's another story / question.... (anyone know the part # for the proper tool?)

I have the first pedal put back together and it binds up a bit.....not too happy with the outcome.....so I move onto the second pedal which I had already taken apart to do a comparative analysis with the first pedal I had taken apart and had mental note fade....getting old sucks!

OK, so second pedal is apart, I'm cleaning the ball bearings and counting as I go, 25....??? How could there be 25? So, I recount, and yup, there's 25 ball bearings. Ah! That must be why the first pedal is binding up, I missed a bearing. Some how I must have cross contaminated my pedals...or my wife is playing a cruel trick on me!....That's got to be it, she's mean like that!

OK, take apart the first pedal and sure enough the outer bearing race only has 11 bearings. Problem solved!....

Not so fast! I've now taken apart the first pedal at least a dozen times and tried inserting all 24 bearings (12 on each side) with no luck. The most I can get on the outside race is 10 without them stacking on top of each other. I went ahead and put it back together with 10 bearings on the outside race and it turns smooth. I think the binding problem I had before was that the 11th bearing was bunching up on top of the others.

So the head scratcher here is how in the world were there originally 12 ball bearings on that outer race?

I have spent hours searching on the net for an exploded view that is large enough to let you count the bearings, with no success. I did come across a few threads that were in Swedish...with few pictures.
And the search engine on this forum wasn't much help either.

Suggestions? Ideas?

Thanks in advance!
XtraSpecialK

Bill Kapaun

I'm not sure the tech docs would help-
I downloaded one for the M-785.

https://www.paul-lange.de/support/sh...-M785-3195.pdf

Picture shows 2 rows of 12 per pedal.
Parts list states 62 pieces.

XtraSpecialK

Thanks Bill, completely different animal.

bikeman715

sometime the cups (pedal ' s body ) is different in size from front to back . so maybe 10 bearings in one cup (side) and 14 in the other .

XtraSpecialK

Thanks bikeman, I thought that too.....but tried and its impossible.

bikeman715

ok , it was just a thought . have you try the 12 -1 bearings and see how that work out ?
meaning you put 11 balls in each cup instead of 12 .

XtraSpecialK

I did try that and it worked....but it goes against my grain to have parts left over.

After taking the kid and the dog for a walk around the neighborhood in his red Radio Flyer wagon I gave it another try.

I think the gods just needed me to humble myself on this forum and display for all to see that I'm an idiot.
Everything went together smooth as butter. The correct number of bearings on each side is 12.

Now I just need the correct tool to lock down the nut against the outer race so they don't come loose while I'm pedaling down the street.

Thanks for all the input, I think it was your collective good karma that was the key to these pedals being reassembled.

Thanks again, you guys rock!

Special K

davidad

Shimano SPD Pedal Adjustment Tool TL PD73 Very Hard to Find M535 M505 | eBay

FBinNY 

This is very common. Take a look at the cone and compare it's diameter to the "cone" on the spindle. If the diameters of the inner races is different, and the balls are the same size, then the outer races CANNOT be the same. They may look similar but the ball track will be smaller.

This is obvious if you stop to think about it. Assuming the bearing is radial (it's not, but easier to imagine that way), then the diameter of the inner ball track + twice the ball diameters = the diameter of the outer track. Therefore, if the inner track is smaller, either the balls are bigger, or the outer track is smaller (or both). Then if the tracks are smaller, then they take fewer balls.

BTW - the exact ball count isn't critical, as long is it's not too many. Too few would only be an issue if there was a total gap spanning more than 60° of arc. (minimum number of balls in a bearing is 6, more typically 7 or more are used).

XtraSpecialK

Thanks for the link Davidad, I sent him a message, want to make sure it is for the correct nut sizes. If so I will buy it.

FBinNY, are you a rocket scientist in your spare time...? If not I think you could be!
Thanks for the info. I'll have a lot to ponder tonight when I should be sleeping.

FBinNY 

No, but I can draw pencil sketch on a napkin. (I don't use toilet paper because it tears as you draw)

Sometimes solutions only require that you step back and think about a problem for a minute or two. Once you realize that "that can't be right" it opens up your mind to look for what may be.

Jeff Wills

If I had been sipping coffee, it would have been sprayed across my monitor by now.

FBinNY 

Jeff,

Since I have you, do you have any idea if there's anything I can do to help my cat with his head cold?

fb

Jeff Wills

Are you sure he's not allergic to cat hair?

Otherwise, rest, fluids and chicken broth.

spdracr39

So basically in the future keep your inner balls and your outer balls separate? I have heard before it is bad to mix opposing balls

FBinNY 

Balls are cheap enough that that you can replace with new each time you rebuild. Even Grade 25, which is better than you need is too cheap to pass on.

Going new means not having to worry about a dropped and lot ball, or segregating balls when you take things apart.

The thing to remember it that the balls in each bearing is a matched set, and like paint, no two lots are identical.

spdracr39

Umm that was meant to be humor

FBinNY 

Yes, but it was close enough to a commonly asked question about reusing and/or mixing balls, that I figured an answer couldn't hurt.

XtraSpecialK

Thanks for the laughs and the advice.
I did buy the tool the Davidad recommended and it worked like a charm.
The pedals have been reassembled and installed on my cranks. The bike is almost back together and ready for a shake down ride.

Thanks again, much appreciated!

davidad

The thing to remember it that the balls in each bearing is a matched set, and like paint, no two lots are identical.

You do realize exactly how close the tolerances are on grade 25 bearings. I doubt that there is a lot number on the bag unless you buy a few thousand. And even then....

davidad

When you adjusted them did you have a small amount of drag that indicates bearing preload? That is very important for the life of the bearings.

fietsbob

I put a pinhole in the plastic dust cover , and use a Greaser pump , needle type tip, to push fresh grease in from the Outside end
forcing the other contaminated grease out around the inside, then seal it up with a tiny sheet metal screw.

XtraSpecialK

davidad, I tightened the cones to the point where there was no play at all in any direction but the bearings were still able to spin freely.
Should I tighten them up a smidge more so there is slight drag when the pedal spins?

fietsbob, Thanks for the tip!

davidad

Yes.
This is for BB's, but it holds for all bearings. Bottom Bracket Bearing adjustment by Jobst Brandt

XtraSpecialK

Thanks for the advice and the link. I will tighten them up a smidge.