[tayto]

many years ago (like last 7 or 8 years ago) when I was down in Washington state, I picked up some "concrete prep” solution from Home Depot. came in gallon containers and the main ingredient was phosphoric acid. stuff worked great. I submerged a battery tray from my caprice and forgot about it for a week and half. when i fished it out it was paper thin. when used correctly it is great stuff. it also leaves a coating which helps steel from flash rusting.

 

[sherlock9c1]

So I used some of that Krud Kutter "the Must for Rust' - worked pretty good. Don't play around with phosphoric acid on your skin - be super careful.

This is the old Eaton clutch-type posi diff out of my 9C1; I think I bought this used back in 2005? Man, been 17 years in the family. It was getting tired so I re-shimmed it (I think it needed around 0.030" on each side) and the clutches still had 0.120" left of usable material on them. [edited:] Min spec is 0.008" of clearance between the axle shaft end and the center pin for thermal expansion of the posi clutches, as measured with the C clips and center pin installed using a feeler gauge. Tom's Differentials sells a shim kit down to 0.0025" if I recall correctly. I setup the diff sometime in the last four years so I'm just going off memory. He also sells thinner C clips if you really want to get creative on your clutch and shim stacks.

Back on track - after I rebuilt it, it got some surface rust on the gear mounting surface. Krud Kutter took care of that, and then I took a file across everything to make sure there were no burrs.

The existing pinion bearings looked good (clean, no pitting, spalling or deep scratches), but the races had these pits on them that wouldn't polish out with steel wool so I put new pinion races in.

New race about to get pressed in using the old race.

New outer race pressed in. The mess on it is WD40 (a great temporary lubricant to help them press in with less fuss).

 

[sherlock9c1]

New outer pinion bearing. There's the Timken part number - M88048. The old bearing was usable but whatever, why not. You can always spin these by hand and with some pre-load on it and make sure there's no grit or debris in the rollers.

New seal installed.

Time for the yoke. I had the Dorman one with a modified seal.... woops. Modified seal. Darn.

So we pulled that red seal out and installed the one that came in this kit.

This silver lip cover is part of the yoke. Apologies for not taking more pictures; I had a few guys helping me and we got on a roll.

BTW this pinion/yoke holding tool from Ratech (P/N 18001) is super handy and well worth the price.

 

[Caddylack]

I’ve had good luck with white vinegar, at least better than this video shows. I didn’t see him scrub any parts, which is when the vinegars results show up. After 24 hrs soak, I give it a brief scrub with a metal brush and then rinse, most parts except the worst offenders usually look pretty decent. Hard to beat considering the price.

I do about 72 hours and it all just falls off. Vinegar rocks.

 

[sherlock9c1]

Original 3.23 gears with ABS reluctor. These gears came out of this housing and the inner pinion bearing looked good (the camera isn't doing these rollers any favors) so I just reused it all.

I use the Ratech Smart Sleeve P/N 11002. Much lower crush torque and easier to get to the drag you need. We cleaned the pinion threads and splines, installed it into the carrier, installed the Dorman yoke, added the washer, and used the socket and a hammer to drive the yoke onto the pinion. Then we tightened down the pinion nut. It was around 125ftlb of torque that we started to get a drag reading on the dial indicator torque wrench. New pinion bearing drag spec is 18-36 inch-pounds, 10-15 on used pinion bearings. We ended up with 24 and called it good.

We transferred the 3.23 ring gear off the old carrier onto the Eaton Posi with the new carrier bolts. They have loctite pre-applied, and are left-hand thread. Torque spec is 89 ftlbs on those bolts.

I transferred the carrier shims from the old carrier to the new carrier. We installed the passenger side first, then gently drove the driver's side shim in. My calipers were on loan to a different buddy so I didn't get a measurement. It was pretty snug, but everything fit.

Don't mix the caps left to right; they're machined to their appropriate side. Torque spec on these is 55 ftlbs.

Backlash measured 0.009" - on the high end of spec (0.005-0.009) but I'll leave it.

After painting the gears and spinning them once with my hand on the ring gear to give a little drag, I got this pattern. Carrier location looks right but depth looks a little deep. If I were to reduce the pinion shim, the backlash would go out of spec. Maybe the pinion shims can be swapped from side to side to tighten it up a little?

At this point we were tired, and my buddy who's a tech at a local dealership suggested I leave it until the car is assembled, and if we want to reduce the pinion shim, we do it at his place on a lift with the axle in the car. Sounds good to me.

EDIT - Chevy DIY says for used gears, ignore the drive pattern and focus on the coast pattern (due to gear wear). I will take more pictures tomorrow.

 

[sherlock9c1]

Coast pattern. I'm guessing these gears have well over 100k miles on them together.

 

[sherlock9c1]

I'll get pics up soon, but some buddies and I installed most of Navy Lifer's "Wagon Rear Disc Conversion" (WRDC) onto the axle last night. I got this kit with the car from the previous owner, and didn't find any directions so we made it up as we went.

Lessons learned / tips (starting from a bare axle with no brake equipment or axle shafts installed, only ring/carrier and pinion):

1. Nothing from the old drum brakes needs to be reused.
2. Every component was included, and all were top quality.
3. Install the new backing plates with center anodized insert WITHOUT the shims, then tighten one of the 5/8" bolts to keep everything in place. Put that bolt in a hole opposite the caliper mounting bracket and close to the eye for the parking brake cable. The parking brake shoe needs to stay attached.
4. Install the axle shaft and C clip.
5. Reinstall the center pin (retainer bolt can be loose).
6. Measure the axle shaft end play with a dial indicator (or better yet, a feeler gauge between the axle and center pin). You may need to add a second bolt to the backing plate to provide a solid base for it if you're using a magnetic base like I was.
7. Minimum end play must be 0.008" (check this). End play contributors are the end of the axle shaft, C-clip thickness and the differential spider gear stackup; if you use a clutch-type posi (Eaton or Yukon Dura-Grip), this clearance will open up as the clutches wear).
8. Stock C-Clips are 0.150" thick. I had additional C-clips that were 0.165" and 0.170" thick. On my passenger side I measured 0.027" clearance, so I decided to add the 0.170" C-clip. Driver's side measured 0.010" so I left it.
9. Magnet tools are really useful at getting C-clips in and out.
10. I reinstalled the center pin (loosely), then loosened the 5/8" backing plate bolt a quarter inch and moved the backing plate out so I could install one of the two half-shell shims.
11. Install the shim next to the caliper mounting bracket. Pay attention to orientation, it is asymmetrical. Add loctite to the backing plate bolts and screw them in loosely.
12. Remove the original backing plate bolt and add the other shim. Loctite those two bolts and screw them in. Tighten all four.
13. Recheck axle end play with a dial indicator (or better yet, a feeler gauge between the axle shaft and center pin). At this point I had zero on the passenger side and 0.004" on the driver's side. So I made a measurement error somewhere.

Pics to come.

 

[sherlock9c1]

Time to get going on this. I ended up working on a lot of other cars last year. This one is going to the 2023 ISSCA nationals in Kansas so I need to get cracking.

Next step on brakes is installing longer wheel studs. @Navy Lifer says it is optional but there’s very little threads available if you use aluminum rims with this kit. Pound the old ones out with a sledge. Put a little WD40 on the splines, high pressure grease on the threads, a lug stud installer tool, fresh lug nut and my trusty Milwaukee impact got this job done in ten minutes.

I specifically used a lug nut that had threads on 100% of the inner diameter (ID). Once I was done, the tapered end was pretty smashed, so I’ll save it only for use with the tool.

 

[sherlock9c1]

All the studs are in. That lug has a pretty good step in it now.

time for primer. I did the Impala axles at the same time.

Top coated and curing. I very carefully masked off the areas where the bearing and seal ride so I don’t get paint flakes wearing off inside the axle.

It is very important NOT to get paint on the axle face where the brake rotor goes. That surface must be completely clean and flat to avoid runout on the rotors, which eventually causes shimmy.

 

[sherlock9c1]

Similar to @nsaness , my job and family keep me busy. Finally got back to the axle. ALWAYS inspect parts before assembly, especially anything that has sat for awhile. Cover openings where possible. I need to scrape the loose rust out of here first.