cyberkill

Seems like a simple question, but everyone has their own methods, and I can't really tell if any one is better than the other.

I'm STILL doing my gear install...the flu didn't help.
So, long story short, I put everything back together with a new pinion crush sleeve, then found an oil leak, which was caused by a groove in the yoke. I took everything apart, fixed the groove, and this time I'm doing a solid spacer instead of another crush sleeve (damn that was hard!).

So, I used a caliper to measure the crush sleeve and the solid spacer + shims, and it turns out that the entire set of solid spacer + shims matched the width of the crush sleeve. I put that in, and then I torqued down the pinion nut (with washer) on pinion through yoke down to 125 ft lbs. Using an in/lb beam type tq wrench, there was almost no rotational resistance. I then upped the pinion nut torque to 135 ft lbs, and still no rotational resistance. I went to 145 and still none.

So my question is...should I be purchasing another set of solid spacer shims so that I keep adding shims until I get my desired rotational resistance at 125 lb ft on the pinion nut -OR- do I just keep torquing down the pinion nut further and further until I get to my desired rotational resistance? If I'm supposed to keep torquing the nut, is there a point where you'd stop and say something's wrong?

01ssreda4

iTrader: (96)

I've done these in 10 and 12 bolts. Here's what I know. You can't match heights to a crush sleeve, it just doesn't work. The pressure forces do different things to each one and the results won't be the same even when they appear exactly the same length. So throw your crush sleeve away. Another big thing, follow the instructions for torque. More or less will change your reading even when you haven't changed shims. Meaning if you tighten to 75 and get no resistance, then go to 125 you may get too much resistance. Do not treat this like a crush sleeve, picture it like a lug nut, same torque every time and never more or less. If you aren't getting spinning drag, reduce by a shim, if it hangs too much, add one. Keep changing till you get it perfect, I prefer 25 inch/lbs with just the pinion gear installed. Lube the bearings, it will make your measurement more accurate.

handyandy496

iTrader: (9)

Ya if there's just a little play in the set up take out a .005 shim/shims till u get some resistance while spinning the yoke. Then go to smaller shims to get the desired resistance. After that I would race it and check it again just to be on the safe side........... Jmo pinion.

cyberkill

Thanks for the info. Is it normal to use more than 1 spacer kit to achieve the desired rotational resistance at 125 lb ft? Obviously I'm not going to use 2 of the big spacers, but I think I need more shims.

At 125 lb ft (and even at 145) I have almost 0 rotational resistance, so that means more shims, right?

cyberkill

So, I'm a little confused...My thought was that if I'm getting 0 resistance at 125 lb/ft, then I need MORE shims. Both of your replies say I need LESS shims.

I'm trying to visualize this, and is the reason because having too many shims will keep the front pinion bearing from pressing into the the front pinion bearing race?

guppymech

iTrader: (7)

If you have no resistance to spinning the pinion then the solid spacer is too long and it's keeping the pinion bearings from seating. While you're homing in on the correct length for the spacer stack use a old pinion nut with the self locking feature ground off because it's going to take alot of trial and error assembly. I think you'll have a hard time getting the small bearing off the pinion with the posi unit installed. A solid spacer should be set up before the carrier is installed in the rear.

cyberkill

Awesome! Thanks for the confirmation. Can't wait to try it again!

01ssreda4

iTrader: (96)

Right, you were going the opposite. Reduce spacers and your resistance will come in real fast. You'll see.

S10xGN

iTrader: (11)

And the torque on the nut is relatively meaningless with a solid spacer - while checking. You only need around 100 ft-lbs to tighten things up and get a good check. After you have the preload right, go for the final value...

cyberkill

Ugh! Well, my Ratech RAT4111 kit only came with the spacer, 3x 0.010" shims, 1x 0.015" shim, and 1x 0.020" shim.

The spacer + all 5 shims = 0.610", and that's what I had the first time, where no matter how much I torqued the pinion nut, there was no rotational resistance. I took a single 0.010" shim off (the smallest shim), and at something like 90ish ft/lb, the resistance was at like 35-45 in/lb!

So, somewhere between 0.600" and 0.610" is my sweet spot. Guess I have to order another RAT4111 set for an extra 0.015" to swap out, so I can get to 0.595".

Honestly...is it actually possible to have this many F-ups in a single install?!?!

cyberkill

I'll keep that in mind. In my case, by the time I got to 90ish lb/ft, I was already way past my mark, so I think once I get this new pack of shims and get to 0.605", I think once I hit 100 lb/ft I'll just adjust the rest. After all, I'm not seeing anywhere where I can get 0.001" solid spacer shims to get to 125 lb/ft.

guppymech

iTrader: (7)

Did you get the little instruction sheet with your Ratech solid spacer set? If not it's at the bottom of this page. http://www.ratechmfg.com/gmsolidspacers.htm
You should have:
1ea .010, 2ea .012, 1ea .016 and 1ea .020 which when combined give you from .020 to .050 in .002 increments.
Also I have to disagree with S10xGN. You want to torque the pinion nut to the final setting you will be using (125 ftlb) when setting up the solid spacer. Any variation in the pinion nut torque will effect the pinion rolling torque for a given solid spacer stack length.

cyberkill

Mine only came with the 5 shims I mentioned. I googled the same part number, but every picture I see only shows 5 shims, granted, most are stock photos. In any case, I just ordered another RAT 4111 from Summit, so guess I just have to sit tight until then.

S10xGN

iTrader: (11)

Take the time to carefully separate all the shims - believe me - you'll *think* they are all separated only to find out later some were stuck together. Soak them in solvent, then rub with something grippy like an old timey eraser. On my Ford 9", the difference between 2 in-lbs and 30 in-lbs preload was 0.002" in shims...

cyberkill

So...I'm an idiot...blinded by frustration.
I completely glossed over shim sizes you posted (or didn't believe that's what I had), but that was exactly correct, and was exactly what I needed. I didn't even need to order the 2nd shim pack.

I think what screwed me up was my Harbor Freight caliper that gave me different readings. Anyway, thanks Guppymech and everyone for all your input and suggestions...and patience with my noobness!

01ssreda4

iTrader: (96)

Digital caliper? Those things suck in my experience. Needle pointer is the only way to go.

S10xGN

iTrader: (11)

Hmmm, since when did a solid stack of metal become compressible at room temperature? I must have slept through that lecture in school... As long as the bearings are fully seated, it won't matter what torque you "check" with. Just remember to use the final torque value for final assembly. BTW, anyone building a rear with a solid spacer can check this "theory" on their own easy enough.

01ssreda4

iTrader: (96)

^^^ive done it, final torque does effect pinion preload, to a degree. First time I tried a pinion spacer I chased my tail for a while till I figured this out.

guppymech

iTrader: (7)

Cyberkill, I'm glad you figured it out.

The Ratech solid spacer assy is indeed compressible, especially the stack of .010-.020 shim washers. You could probably crush them if you wanted to.

You can see this same effect with the front wheel on your bicycle (if it uses skewers). Properly set up axle bearings will have a slight end play with the skewer loose or just pinching the wheel in the forks, you will be able to wiggle the front wheel alittle. After the skewer is closed the bearing endplay will be gone, the wheel will not wiggle as the axle is compressed by the skewer.

hrcslam

Metal is compressible and malleable. At 125 ft/lbs on a 7/8-14 bolt the clamping force is over 8500 pounds. This will both stretch the pinion and compress what ever is between the pinion gear and nut.