[jayoldschool]

lol, I came out after work yesterday to a garage door that was 2' open on the left, and 1' on the right. Snapped cable, not spring... thankfully. Finished fixing it around 8pm.

 

[sherlock9c1]

Well, the garage door is fixed. I got no call from the office ahead of time. Guy #1 said they'd call me when they had a new date/time. Literally as I'm walking into an afternoon work meeting, my phone rings. My wife says "Guy #2 is here to replace the springs (I asked for both doors to be done). He's skinnier than Guy #1 was (this was good as there was only 6" between the Impala and the door due to the QuickJack moving forward as it lifts). Oh, and it's $75 more than Guy #1 quoted." So I talk to Guy #2 and tell him to get started, Guy #1 quoted $X, we'll get it figured out after my meeting.
I come out of my meeting and find multiple missed calls and voicemails from the company stating "Good afternoon, our guy cannot leave until he gets paid. Please call us as soon as you can." I'm here thinking 'not my problem, you didn't even tell me he'd show up today.' I call them. "Sir it'll be $Y." Guy #1 quoted me $X. "OK let me talk with the manager." At this point if they had just said "sir, we're so sorry, Guy #1 only quoted you parts for the second door, not labor' I would have been OK with that, based on spring prices I saw online. But they didn't; just an "OK sir, we'll honor that price." Well, there ya go. Communication, folks. It's important.

Anyway, I started to dig into the valvebody on circuit 205D. Turns out there's only one end plug in that compartment, and the 3-4 relay valve (inside bore 205) beats against that plug. I pulled the retainer clip and the plug wouldn't even pop out; it's likely mushroomed against the retainer clip. But the bore of the plug that's against the relay valve was severely worn. My Sonnax O-ringed end plugs are hiding, so I'll have to wait for the new set to get here next week before I swap one in and retest. I should note that I don't expect this particular one to fix the line pressure issue; it was just a very low number so I want to see if a Sonnax end plug will improve it.

 

[sherlock9c1]

Here’s the end plug right as I pulled the clip out. My finger was unnecessary; it wasn’t coming out.

See the rough part of the plug? That’s where it’s been beaten against the bore a bunch. Lots of leaks there for sure.

 

[sherlock9c1]

Update - @Navy Lifer helped me out with replacement rear disc brake hardware, specifically the rubber parking brake boots, one bracket, and new bolts (which will be going in with high-temp never-seize). Parts are showing up tonight, paint is well cured on the rear axle assembly so we should be able to move forward on that.

I still need to coax the center rear brake hose loose from the body's line. Plan is to use @95wagon 's trick pull the retainer clip, slide the connection rearward, cut the hose completely off and gently persuade the fitting to come apart, perhaps with some heat.

 

[sherlock9c1]

Parts have arrived from @Navy Lifer . Enough boots and bolts to do what I need, and for the price, it was worth buying the Centric 118.66003 parking brake hardware kit from him.

I’ll get cracking on this soon.

 

[sherlock9c1]

Nice weather today so might as well paint the backsides of the axles while they’re out. GM never coated them so they get rusty if left as is.

grandpa’s wire brush makes quick work.

Halfway there.

Degreased, masked and ready to paint. I did the wagon axles too.

Primer laid down.

Top coated and curing. No more yucky rust here.

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]

The axle had sat for nearly a year with the shafts hanging on the seals. Since they were original, I replaced them with Timken 8660S seals to ensure no leaks. Step 1 is to use my seal puller to yank the old ones out.

Checking the rollers; usual wear, no cracks or pitting.

New seal hand pressed into the opening.

Driven flush with a sledge on a 2x4 block. Normally I cover the block with a plastic bag so it doesn’t throw splinters into the axle, just showing it bare here for clarity.

Make sure it’s flush when you’re done. If the axles have grooves in them from the original seals, leave them slightly proud to give them a new surface to ride on.

 

[sherlock9c1]

Driver’s side shown for posterity. Rollers look serviceable.

Clean it and Send it.

 

[sherlock9c1]

There was a lot of posi dust in the axle tubes. Passenger side:

Drivers side was cleaner but still dirty.

a lot of crap in the passenger side where the axle tube was pressed in. Hopefully this was not sealer?

I also noticed burrs on both sides of the cap surfaces. I filed and sanded the burrs down.

 

[sherlock9c1]

This was really hard to photograph but this was just before the final pass with a shop rag soaked in brake cleaner run through the pipe with a long pry bar. Tubes are now clean.

End cap surfaces are now deburred.

 

[sherlock9c1]

Time to swap the ring gear. 3/4” socket, LEFT hand thread.

Rear axle torque specs.

Ring gear is a tight fit. Some gentle tapping required to remove it.

Good used factory posi cleaned and ready. I always deburr the outer edge before installing, especially if you're installing a new differential.

 

[sherlock9c1]

Torquing the ring gear bolts to 89 ftlbs got a little tricky without a big vice. So I stuck a 1/2” pry bar through the middle that one son held while I held the 1/2” extensions that went through the cross shaft hole, and other son heaved on the torque wrench.

Bearing races cleaned and inspected. Not mint, but they rolled freely and silently on their respective bearings so good to go.

When you remove a differential, make sure not to swap shims and caps. This was the passenger side.

The driver’s side was 0.025” thicker. I will check the backlash to make sure nothing funny happened. 

 

[sherlock9c1]

Differential snugly in place with bushing chamfers facing out. It freely rocked ever so slightly, so we should be good. We’ll still check though.

The rear caps had lots of burrs. I gently dressed them with a file but not so much as to take down the total cap height.

We torqued the caps to 55 ftlbs in no particular order.

We checked backlash with a dial indicator touching in the middle of the tooth and 90 degrees to the direction of rotation. Rocking it back and forth showed we had 0.005” which is min spec (max is 0.009”) I’ve gotten in trouble in the past when I tried to get it slightly moved so this is good enough. Send it.

 

[sherlock9c1]

Time to assemble the emergency brakes. I got new hardware on a tip from @Navy Lifer : Centric 118.6003 Parking Brake Kit. The purple grease is CeramLub that he sourced and sold to a bunch of forum members probably in 2005-2010 timeframe? I still have a bunch of it. A little film is all you need.

The kit also includes new spring retainers so I pushed them on. They are side-specific so make sure you take pictures before removal.

Here, I have installed the parking brake actuator lever and am about to install the rear cap and the little push bar. They are shown dry but I put a dab of grease on each end before assembly.

@Navy Lifer was able to sell me some new 5/16” self-tappers to replace the busted ones. If you zoom in, you can see the blue loctite on them. I also did this for corrosion protection; otherwise with the dissimilar metals, you’re guaranteed to get galvanic corrosion over time.

 

[sherlock9c1]

Final shot before assembly of the remaining side.

Last step is new boots and boot retainers. @Navy Lifer has plenty of boots as of this post, and sold me an extra retainer after one of mine disappeared (apparently one bolt head is not good enough!). Blue loctite on all of these little bolts.

Once the backing plates were assembled, it was time to install them to the axle. They are 9/16” head and the factory spec is 35 ftlbs. I used never seize on there to keep the threads clean. The nuts are locknuts.

Driver’s side done, just about done the passenger side. Per original, we put the nuts inboard. For corrosion’s sake, I would have probably assembled them the other way but oh well.

 

[sherlock9c1]

Axle #1. Usual bearing and seal witness marks. The camera makes it look like there's pitting on the race, but there's really nothing of any significance. You can see the two light beams across the axle showing a pretty even surface.

Axle number two in good serviceable shape as well. Send it.

Here is the differential cross pin from the donor differential. The surface is in excellent shape, but notice the witness marks where the axle shaft ends rubbed it. This is normal.

Let's see if we can measure the wear. Overall thickness is 0.794".

 

[sherlock9c1]

Measuring the differential cross pin on the wear surfaces showed 0.792". So .001" off the radius. That's fine.

Just for giggles, let's see if the Impala's cross pin has less wear HOLY CRAP WHAT IS THAT??? Nasty wear on one of the spider gear surfaces! I did attempt to measure it but it was barely discernable. With all this damage, that pin is going in the scrap pile. I had planned to disassemble that differential and see if I could shim it to restore the limited slip but eh...

Passenger side C clip thickness. I think these are 0.150" when new so 0.0015" wear over 170k is pretty good. Send it.

Driver's side reads the same. Send it.

 

[sherlock9c1]

To install the C clips, shove the axles in all the way, then use a magnet to drop them in. Pull the axle outboard and it'll disconnect itself from the magnet. Boy this is so much easier than doing it in the car.

Other side in place and pushed outboard.

Time to install the cross pin. Make sure the retainer pin hole is lined up. The factory cross pins have a chamfer that helps with misalignment. I bought an aftermarket one for the wagon that showed up with no chamfer... that one was not fun to attempt to install. You may have to tap it a number of times to get it all the way in.

Tighten the bolt with a QUALITY 5/16" socket. I used a long 1/4" wobble extension to get clearance. Do not be sloppy on this bolt. If you round it off, it's going to be a bad day. Factory torque spec on this was a ridiculous 27 ft lbs if I was reading the FSM correctly. I just did it good and tight. Although this photo doesn't show it, I did put blue loctite on the threads before screwing it in.

 

[sherlock9c1]

Time for everybody's favorite job... getting the gasket surface clean and flat. Yay.

Years ago in the B-body community there was a rash of passenger side axle bearing failures that would trash the axle. It was most likely due to insufficient lubrication. There was a big stink made about the big round holes on either side being specifically for axle lubrication. As an engineer (albeit not an automotive one), I maintained that those holes were for spreading the case to make installation easier. This was not a popular opinion, so whilie I'm here, let's poke around. At the very top, there is a small, rough hole where oil can get in. You can see it between the upper cap bolt and the cover bolt hole just to the right.

On the driver's side, theer's a similar hole just to the left of the cap. It is very small, and would only get lube if the ring gear is rotating fairly fast. The passenger side one, being farther away, would really need high oil level AND high speed to get flow.

Here is the GM gasket, P/N 15807693. Notice it had no holes. This was a big deal back in the day. Apparently the Fel-Pro gasket had two slots, and that PROVED that the big holes were for oil flow. My retort was that GM engineers couldn't have been that dumb not to allow a lube path to the end bearings.

 

[sherlock9c1]

Well lookathat. The GM gasket does NOT cover the holes.

But 30 seconds with a pair of scissors fully opens those holes. It's just paper, people.

One other point - I seriously considered just buying new Dorman covers and not dealing with rusty factory ones. But the factory ones hug the ring gear much better, promoting oil pumping against the cover, AND the sides are shaped to channel oil to those big holes. OK, years later, case closed. We were all correct. The holes are for case spreading AND for lubrication. The GM gasket DOESN'T have holes but it DOES allow for lubrication even if you don't trim it.