DoubleThunder

I installed a new oil seal on a u joint and pinion gear assembly and not sure about the rolling resistance for the nut when putting it back together. Watched a video and I have the manual but Im getting different info on the torque spec. Manual says 6 to 10 #s and the youtube video says 4 to 5. Anyone know which to go with? I tested the resistance on the other u joint and maybe Im doing it wrong but it doesn't read anything. I have the 2nd drive apart to replace the clutch but never took apart the u joint. Also is there any shimming involved in this if Im not replacing anything else?
Thanks for any help

kaama82

iTrader: (1)

I think 6 to 10 inch pounds. I'm not 100% sure. If your just changing the clutch, no shimming.

1 MAIDEN AMERICA

Used bearings require less preload than new.
Install steel shims between the bearings to stop the nut from tightening up the preload too much when tightened. This allows the nut to be tightened against a stop, tight. Start with too thick a shim and work down.
Tighten pinion nut with the assembly tightened in the case beforehand. This keeps everything aligned and the outer races compressed. Use 2-4-C on the spanner nut. DO NOT use it in the U joints and gimbal bearing. I use Kendall SHP in the joints and bearing, and 101 on the shift linkage.
After you've assembled and disassembled several times and have everything correct, toss the nut in the trash. Clean the threads with brake clean, put lots of Red Loctite on a new nut and put it back together.

Now that you have it figured out, do the same to the other drive. You always want some preload on the bearings. When you tighten the spanner nut, preload will go down and the gear may "slop" around.

That's the easy part.

Now check backlash.
Install the lower gear by itself, then tighten the pinion in. Check backlash in several spots, average, and adjust if needed(probably not). Make sure the driven gear is staying flat on the bottom. Take the lower gear out and install only the top gear and pinion. Turn drive upside down and check backlash keeping driven gear flat.
If they are looser than shims will allow to adjust, guess what, take the pinion all apart and put a thicker shim under the gear, and start all over.

On final assembly make sure the + and - on the cones are opposite. + - one side - + the other.

If the top cap doesn't fall straight down you may have a tweaked tower. Driven gear bearing races may show an offset wear pattern.
Caged needle bearings are available for the driven gears, free up rolling resistance and are rated for more RPM.

Fill drive from the bottom until it vents (slow down at this point) without bubbles, plug the vent and continue filling until it starts showing in the reservoir. Install plug and top reservoir off. Don't swap bottles when filling. This will pump an air bubble in. Use a container to pump from that has more than enough to fill the drive.

Run the drive through a few heat cycles before hammering it, checking reservoir in between. Everything has been moved around, it will run warmer than normal for the first bit.

DoubleThunder

Thanks for the info. This is something I really wanna learn and thatll help

Mr Gadgets

6-10 new, 3-7 used bearings. Merc states that bearings are used after being spun once under load. Using supplement #28 procedure with the proper tools you can check lash on both fwd and rev gears with gear stack fully assembled which gives you more life like results.
I don't care for caged bearings, they have a lower load rating than the non caged.
Hope that helps.
Dick

Cobra100+

iTrader: (3)

Any good place to get a copy of supplement #28 reasonable? Thanks

1 MAIDEN AMERICA

A random 2" ID caged needle bearing has 140% more RPM (6000) rating than a non-caged (2500)
The same bearing, non-caged, has 35% more dynamic load carrying capability than a caged.
At 5000 engine RPM with a 16/19 upper, the driven gears are spinning 4237 RPM=way past the limit.
Getting into load ratings, I couldn't begin to tell you what the bearing see's, only that the one has a 12390NM/9138ft lbs and the other 16726NM/12336ft lbs rating.
At 500 ft lbs of engine torque, what is the load on the bearing? I'm guessing lower than either of these numbers.

For comparison:
Wrist pin bearings are caged
Cam bearings are caged
I see more non-caged bearing failures in everyday transmissions although neither fail that often, it's usually the balls(which are caged, lol).

Opinion:
The caged bearing allows more room for oil which helps cooling and lubrication.
The needles aren't forced to run against each other which helps cooling by reducing a friction element.

Bottom line-
I'm just bored!
It shouldn't even matter now that I have SCX's. Thanks Dick!

How's your boat going?
Have you purchased SCX tools yet?

Mr Gadgets

I have the lower tools, waiting on funds for the upper tools. 70hrs on my SCX. So far so good. Still haven't gone WOT yet. Looking forward to upgrading my Megsquirt this season to get a better handle on the combustion event.
I find very few failures of the non caged bearings inside the gears. And I remove them on the clutch shaft. I put a longer, non caged bearing in the lower tower.

Cobra
Look on ebay for the #28 supplement. I have seen it there. Otherwise you need to purchase a large set these days to get the same info..

1 MAIDEN AMERICA

[QUOTE=Mr Gadgets;4122634]I have the lower tools, waiting on funds for the upper tools.

You shouldn't have sold me SCX's. lol

kidturbo

Hey Double, do ya know anyone around Columbus who is experienced with Bravo XR's? Mine has 300hrs on it now and would like to do a full inspection. I've had the top off twice, but wanta tear it down and check the lower gears.

Thinking about heading to Buckeye on Sunday so thinking maybe someone around there to speak with.

Tks