FS5W71B Rebuild Thread - Tips tricks and discoveries!

[zKars]

And now that Christmas is over, the real fun begins.

First up is something for the "tips" section I guess. Part orientation. The FSM mentions in several sections to ensure part orientation/direction is maintained. They however spend zero time showing you the correct orientation of the parts. So.

Let's begin with the 5/reverse synco hub and it's nasty little springs and shifting inserts as they are called.

First the syncro hub. It has an offset circumferential groove in the outer teeth, not shown in the FSM pic above. Put the groove more to the front to orient it properly. Front is at the top of the picture, obviously the intermediate plate is there are were are taking pictures of the 5th/reverse parts that are in the rear of that plate.

Second, the three little shifting inserts. They have an offset bump on the outer face. Put the bump toward the front. Oh, and bump OUTWARD. The spring touches the flat bottom

The FSM shows the three shifting inserts, but the one lower right incorrectly shows the bump to be offset to the REAR. The other two are sort of ambiguous. The bump on each insert is definitely toward the FRONT (left side of the screen grab picture).

This picture was taken as I was disassembling the hub. Shows the LONG end of the insert facing toward the camera (rear). Front of the trans is into the picture, so the short end is facing FRONT (can't see it, it's in its groove in the hub)

I've confirmed this insert orientation on all the other trans I've taken apart.

The other hubs have the same type of inserts but they are symmetrical. Their bump is just like the 5th gear ones, but it's in the center. 

You can't confuse them with the 5th gear inserts, these have little legs on the back side as well. Here in the picture they are shown with their mating springs in the correct orientation, with the bottom of the picture being outward.

Edited December 28, 2019 by zKars

[Zed Head]

EuroDat and Dave WM had a discussion going about the insert orientation and how the FSM was wrong, quite a while ago.  For the record.  It's out there somewhere.  Found it - 

 

Edited December 28, 2019 by Zed Head

[zKars]

Also worked on the  bell housing C conversion bearing 62 mm drilling / centering problem. Progress! It will be possible and likely easy.

The idea of using an old 56mm bearing as a pilot is working perfectly. The mill can easily push it through and align the bell housing in 15 seconds. You get the most satisfying woosh/scrapping sound as it gets pushed through and back. Very smooth.

I’ll be able to put a 62mm bearing on the bottom of this thing once it’s drilled to 62ish, to test the fit of the bearing. No measuring error, just “Does it press through with the right amount of effort and smoothness” Pretty slick I think.

 The bell housing is bolted to a piece of 3/4 plywood with four recessed 8mm bolts. The plywood is then anchored to the mill table once it’s centered over the hole. 

The custom milling head you see is my first attempt. This one is not quite concentric. Practice makes perfect. It is welded to a MT3 mandrel. Fun to align and center. Seems the trick is don’t bother getting it final OD until AFTER the welding is done.  Duh...

It lacks the horizontal 1/2” hole that will hold the cutter bar. It does have the 56mm bearing nicely sitting on a 22mm boss with am M14 bolt locking it in.

The mill head itself has enough clearance to the bell housing sides and plenty of travel.

Bit a question about whether it’s worth making one of these or just taking it to a machine shop.

Guess it depends on how many I’m going to do. For me in the near future, it makes sense. 

There is still the issue of needing to machine off a few mm from the OTHER side and make the 1/2 shift rod 16mm.  Access from the other side is much tighter obviously. How long a mandrel can I make with a surfacing cutter that won’t wobble....

 

 

Edited December 29, 2019 by zKars

[Captain Obvious]

Nice. You sure do have a long chang!

Do you have any fly cutters. Seems your diameter adjustment could be made a littler easier, and no welding required.

Usually used for facing a flat surface (like a head mating surface), but with the right cutter grind and geometry, I don't see any reason you couldn't use one to bore your hole:

[Zed Head]

13 hours ago, zKars said:

The idea of using an old 56mm bearing as a pilot is working perfectly. The mill can easily push it through and align the bell housing in 15 seconds.

Did you measure "slop" in the bearing?  Just curious.  I'm not a machinist but I took a GDT calls years ago.  You could end up with a hole bigger than your cutter edges or one offset to one side.  From slop in your alignment tool/bearing.

[240260280]

Perhaps an alignment "pseudo-bearing": A 56mm machined disc with precision alignment hole drilled in centre (or a alignment machined pin)  would remove bearing-slop-impairment.

This could be turned on a lathe..... for all you lathe envy folks!

 

                  

Edited December 29, 2019 by 240260280

[zKars]

1 hour ago, 240260280 said:

Perhaps an alignment "pseudo-bearing": A 56mm machined disc with precision alignment hole drilled in centre (or a alignment machined pin)  would remove bearing-slop-impairment.

This could be turned on a lathe..... for all you lathe envy folks!

 

                  

I had considered this, but a real bearing is the ideal pilot. Nice rounded edges,  no guessing about “is it tight or loose enough” and the endless trial and error that incurs. 

Zed Head I did measure one of the worn dry bearings I have here, and I swear the side to side play is less than 0.001. I’d even consider welding the inside to the outside to remove any play at all. 

[Zed Head]

Convenient and easy.  Maybe not ideal though.  Can't really say without numbers.

Grab an input shaft of an assembled transmission and wiggle it.  That will give you an idea of how much play there is in the bearings.  Probably doesn't matter much though, people have taken apart working transmissions and found that the adapter plate bearings were shot.

[zKars]

Progress!

Finally got a good tolerance tool done. Now just have to bore the 1/2” hole through the body for the boring bar and start making practice 62mm holes.

[240260280]

Nice. Did you weld up the bearing to kill the play?

Edited December 30, 2019 by 240260280

[zKars]

Not yet, I got as far as what you see, then had to leave it. I have to do a proper job of determining the real play, then decide if the bearing inner/outer need to be connected. I’d rather they didn’t,  as I don’t want to use drilling torque to overcome friction of spinning that outer bearing race in that tight bore. Even if I have to blow $20 bucks on a new fresh bearing to get minimal play. Adding some grease, ie pretending its a wheel bearing, would also take up some clearance.

[Captain Obvious]

About a thousandth total runout? Kinda hard to tell because the indicator is buzzing around at such a high spindle speed. Usually when I'm doing something like that I disconnect the spindle drive completely and just rotate it by hand to find the high and low spots.

Might be nice to know where the high and low are. Would help you determine if the runout is in the tool, the spindle, or just random mounting variation. You work with what you got, but MT3 aren't known to be the most accurate tool in the drawer.