Boxerworks.com

I have a /7 5-speed that needs rebearinging. I had thought I'd ship it off to GSPD one day when I had some extra cash, but after following Jeff's adventures, I'm seriously considering dong it myself. (Insert laugh track.)

It is one of the last airhead frontiers for me, always considered a no go zone for mortals. But now the internet has shown that an ordinary Jeff Joe can do the job with just a few special tools.

I have a couple of questions:

It seems that the front input shaft bearing is not always changed.

Does it stand up better than the ball bearings, or is it that it's just too freakin expensive?


Rather than useing a shimming plate to measure bearing clearance,

has anyone used plasti-gauge or solder?

It requires installing and removeing the cover a couple of extra times, but seems like a simpler way to make the measurement.



The box shifts well so I don't think there is any big isues other than a lot of whinning in the lower gears. What else should I expect to do while I'm in there?

Is whining bearings or gears.......I'm thinking more like gears?

Solder, hmmm. Compress 1mm solder down to perhaps .1mm?
The cover plate can flex .05mm reasonably easy by hand pressure. My question re solder is, how much does the solder distort the cover when it gets screwed down? If you give the cover a whack to help squash the solder, all bets are off.
The clearances called for are minute. There are a few things that can throw a taken measurement out the window.

Plastigauge will not withstand the heat necessary to install the cover plate. There is another option mentioned by Cycle Works, some sort of setting putty. But it requires the whole tranny to be heated to quite a high temp. Me no likey.

The front input shaft bearing is easy to replace. Well, the outer race is. The input shaft has to be dismantled (maybe not a big deal) to remove the inner race.
I replaced the outer with new, and left the inner original. Should be ok I think.
Re bearings being manufactured as matched inner and outer, I don't believe such is the case in mass produced stuff.
Example, new f truck disc rotors come with new outers only.....

If your cover plate is slightly warped, measuring pocket depth at the pocket will give a false reading.
Measure across the whole plate for real world accuracy.

Joerg's motorcycle pages offer good info.
http://jhau.maliwi.de/mot/gearbox.html

There are a few precautions but so far for me, it has been fairly easy.

Have a crack Garnet.

Matt Parkhouse gave a pretty good seminar at the national rally in Sedalia on shimming gear boxes. He didn't have a plate to measure from but used a couple of straight bars and a caliper, then did a bunch of math on the board.

Kurt in S.A.

Garnet
I recently used the solder squish method to measure mine. It worked out fine. For the heating source I used one of those disposable can butane torches and got it just spit sizzle hot.
After reassembly I made sure I could turn the input shaft by hand, well I used a pipe wrench with a rag wrapped round the spline, and it turned with some resistance. On the first ride I stopped frequently to feel the gearbox to see if it was getting too hot. All was ok. I have about 1000ks on it since and all is fine.
My biggest battle was getting the drive plate off......
I also did not replace the input bearing, it looked fine, I did all the others and seals as well.
Thread with pictures here:
http://www.wilddog.za.net/forum/index.p ... c=107078.0

I did one like Hobo Matt Parkinghause and raN INTO ISSUES with the then boxerworks board fav of .002 inches

when I did it again with a other well known other .004 inches

my setting at .004 tightened the orginal as delivered at .010

Why are so many people going to the trouble of rebuilding their transmissions and not replacing the input shaft bearing?

Jeff wrote:

Is whining bearings or gears.......I'm thinking more like gears?

The noise seems more RPM specific than gear specific. In other words it doesn't come or go with any certain gear, but continues till drown out bt the wind.

Solder, hmmm. Compress 1mm solder down to perhaps .1mm?
The cover plate can flex .05mm reasonably easy by hand pressure. My question re solder is, how much does the solder distort the cover when it gets screwed down? If you give the cover a whack to help squash the solder, all bets are off.
The clearances called for are minute. There are a few things that can throw a taken measurement out the window.

Plastigauge will not withstand the heat necessary to install the cover plate. There is another option mentioned by Cycle Works, some sort of setting putty. But it requires the whole tranny to be heated to quite a high temp. Me no likey.

The stuff from CycleWorks http://www.cycleworks.net/index.php?mai ... cts_id=344 calls for heat at 130C for 20 min. The box gets that hot on a warm day....... no?

If your cover plate is slightly warped, measuring pocket depth at the pocket will give a false reading.
Measure across the whole plate for real world accuracy.

Another reason for internal measurement.

The front input shaft bearing is easy to replace. Well, the outer race is. The input shaft has to be dismantled (maybe not a big deal) to remove the inner race.

Well.......your in there already.....

Have a crack Garnet.

Major Softie wrote:Why are so many people going to the trouble of rebuilding their transmissions and not replacing the input shaft bearing?

It was NLA, everything else was available at my local bearing supplier for prices well within my budget.
It looked as good as a newly minted coin.
I did not want to mess with removing the internal race from the shaft.
So I guess that you could say the pro's outweighed the con's when it came to the decision.

Mogas:

When you measured for end play, did you do it once, or did you try a couple of times to see if you got differing results?

Nice tools you made.

I did it twice, got very similar results the second time around with new solder wire.
I can't remember the measurements off the top of my head but I aimed for tighter rather than looser.