-   YJ Wrangler Technical Forum (
-   -   Explorer 8.8 Axle Teardown/Rebuild/Install (

Feetwet 09-02-2013 04:14 PM

Explorer 8.8 Axle Teardown/Rebuild/Install
I have no issues with my stock D35. I run it hard hunting and fishing and it doesn't complain ( I must have one of the "good" ones :laugh:), but when I came across this 8.8, I couldn't pass it up. From a 98 Explorer.

These are rare around these parts . Even harder to find Axle Code 42 which is 4:10 gears and Open Diff. I've been on the lookout for months and when my local Auto Salvage notified me they had found one, I snatched it up. 300 bucks out the door.

Ominous shape in my garage door...

Knocked together a set of rolling cradles and dropped it in.

Toby, my Supervisor, approves...

The plan will be to clean this thing up, strip off all the brackets and brake hardware, pull the carrier and pinion, install all new bearings and seals and run a new brake system. In other words, a complete rebuild.

Feetwet 09-02-2013 04:14 PM

Now let's see what we got.

Passenger brake system

Differential section

Driver brake section

Brake line routing over diff

Pass Parking Brake connection

Driver Parking brake connection

After a degreasing and power wash it's looking a little better.
Partial teardown. Swaybar and brake lines gone. Rusty cover removed.

The Goods. After 2 cans of Brake Cleaner,surprisingly good shape. Teeth show no appreciable wear, old gear oil was black but no shavings or silver particles. I'm encouraged...

I ran an initial pattern check to see what ballpark I was in...

Drive side, favoring the heel but well centered and well within spec.

Pinion flange had some in and out play and ZERO preload. Pinion bearings are failing but that's okay...they're outta here anyway.

Feetwet 09-02-2013 04:15 PM

A couple taps with a BFH popped the rotors loose.

Parking Brakes are shot, as expected.

At this point I had pulled the axles, carrier and pinion. No need to go into great detail, it's the same basic procedure. Pull the center pin bolt and center pin, slide axles in a bit and pull the C clips and slide the axles out. Just take care to mark orientation on your bearing caps and shims for carrier bearings, they are side specfic, of course.

Some quick notes, though. Carrier Bearing Cap Bolts are 3/4" Hex. No Case Spreader needed. Center Pin Bolt is 5/16" Hex.
Pinion nut is 1 1/16", breaker bar probably needed to get it loose. I put a Drift Pin through a Flange Bolt hole and against the housing to keep the flange from turning during removal.
I used a 3 jaw puller to remove the Pinion Flange, hold onto the pinion when this comes loose, the pinion will want to drop out.
Pull Pinion Seal, then the outer bearing and Oil Shield will be loose in the housing.

Now to get after those axle bearings and seals.

A $5 seal puller is the tool for this. A couple whacks with the BFH and out they come.

Now you want one of these. $30 at Harbor Freight.

This one will do nicely...

Back off the nut, insert "T" toggle end in behind bearing and lock down the nut and washer.

Attach slide hammer, couple of firm jolts and...

thar she blows...

Repeat for other side. Now it's time to take a wire wheel on an angle grinder and get after all that rust. I also pulled a rag soaked in Brake cleaner through the tubes a couple times. Felt like I was swabbin out a Howitzer :laugh:.

I decided to go with a High Temp Epoxy Paint on this job, along with some serious Adhesion Promoter. Should hold up okay.

Wire wheel, Brake cleaner, Prime and Paint.

Now you want one of these. Seal Driver Kit. Also $30 at Harbor Freight. These drivers make this job a breeze.

Here are the new Bearings and Seals with matching Drivers.

Prelube bearings with your goop of choice.

Ready to install.

Cleaned up the tube ends.

Bearing started then tapped in.

Bearing seated.

A little High Temp RTV and new seal.

A little dab'll do ya...The RTV I used is the same color as the Bearing grease. Don't get em wrong...

Tapped in and done.

Next up, the new Parking brakes.

Feetwet 09-02-2013 04:16 PM

Backing plates look a little better now. Went with shoes and hardware from NAPA. No need to get crazy, they're just E Brakes.
Shoes Napa P/N UP-10701-PB
Hardware Kit NAPA P/N 2979

Some White Lithium Grease on the raised bosses where the shoes ride...

All 4 shoes are identical. Pick 2. Attach large inner top spring. Hold thusly.

Insert tops of shoes into actuator lever and spread bottoms apart.

Insert newly lubed and assembled adjuster wheel.

Use a clamp or your third hand and hold shoe back against backing plate. Insert pin from rear and through hold-down clip. twist pin to secure.

Attach large top outer spring and small lower spring. I'll adjust them later.

Over to the grinding table.

One done.

Plenty of meat left on these rotors. they"ll go back on.

All cleaned up.

Some paint on the hats.

Also did the axles and diff housing while I had it all going on...

Next up...bearings and seals in the differential housing.:thumbsup:

Feetwet 09-02-2013 04:16 PM

The Carrier Bearings are in perfect shape. After a thorough degreasing and inspection I elected to leave them alone. The Pinion Bearings are another story.
With all the play in the Pinion Flange, and no Pinion Bearing Preload, these need to be swapped out.

Pinion Bearing Inner Napa P/N M802048
Pinion Bearing Cup Inner Napa P/N M802011
Pinion Bearing/Cup Outer NAPA P/N BR52
Pinion Seal NAPA P/N 18136

Using a Drift pin, tap out the Pinion Cups (Races). Access to the edges can be had through the oil galleys.

This is what you're after.

Clean surfaces, lightly oil cup seat and edges of new cup and drive to seat using 81mm Drive on Inner and 65mm for outer.

Races (cups) completed, ready for Pinion install.

I used a friend's Shop Press to swap inner bearings. No mystery off, press on. There was a factory shim between the pinion gear head and the bearing. This was cleaned up and reused. Prelubed and ready to go in.

From the top down...Oil Shield, Outer Bearing (both loose and slid on for visuals), small gap where Crush Sleeve will live, Inner Bearing, Shim and Pinion Gear Head.

Crush Sleeve was Dealer Item P/N B7A-4662-A Spacer-Pinion

Pinion Nut was Dealer Item P/N 389546-S100 Nut-Flanged

Here's the part that is really easy. The only problem was both hands full of grease so I wasn't touching the camera...:nono:
I rotated the axle to pinion up in the cradle. Placed the Outer Pinion Bearing in the race with the oil shield on top. Next a bead of RTV and tap in the Pinion Seal. Also run a light bead of RTV around the splines in the Pinion Flange, about halfway up the shaft.
Slide the Crush Sleeve onto the Pinion Shaft and slide the assembly up into the housing from below. It'll pick up the Outer Bearing and Shield as it comes through the back of the housing.

Tap the Flange Yolk into place while holding the Pinion up and start the nut. Now it's hangin there lookin nifty. :thumbsup:

It should be noted at this point that I used the old nut with a little oil under the cap to reduce friction. I will crush the sleeve most of the way with this one, then remove it, clean the area and replace with the new one for final setup. The new nut comes preloaded with Threadlocker.

Cranking down on the Crush Sleeve can be a chore with the axle out of the vehicle. It wants to flip all over the place. I set it on the ground and had a beefy neighbor hold down one end. You can see a drift pin through the flange bolt hole at the 3 o'clock position to keep the flange from rotating.
1 1/16" Hex socket, 3ft Breaker Bar and a 5ft section of Big Rusty Pipe (henceforth known as the BRP). Worked just fine.
Began cranking the Pinion Nut tight using a regular 1/2" ratchet. Jumped to the Breaker Bar, then added the BRP.

As the nut tightens, periodically check the Flange for resistance to rotation. You did beg, borrow or steal an inch/pound Beam-style Torque Wrench, Right? :cool:
Now it's an 1/8th of a turn and check preload. 1/8th of a turn and check preload.
You're looking for 8-14 in/lbs of resistance on used gears and 16-29 in/lbs for new gears. It may take a little more pressure to start the rotation but read your Beam Torque Wrench while rotation is underway...

When I got close I backed off the old nut, cleaned up the area and installed the new one, then tightened to my final values. If you overdo it here you're getting a new Crush Sleeve and starting all over, so be patient.
I settled for 22 in/lbs of Pinion Bearing Preload. Used gears but new bearings. Should be good to go.

Time to drop the Carrier back in. Fully degreased and Bearings prelubed. I lightly painted the pinion and carrier Gear Teeth with 75-90w Gear Oil to get a smooth mesh. Races held in place with shims on their proper sides, drop that puppy into place. Place Bearing caps in their proper orientation and lightly tap em to seat. Clean Cap Bolts, add Threadlocker and Torque to 75ft/lbs.

Time to see how I did.
Harbor Freight once again for a Dial Indicator and Magnetic Base. ($14 & $12 resp.)
Set up 90* to a Ring Gear Tooth and Set Dial to Zero. Hold Pinion and rotate Ring Gear til it engages the Pinion. You're looking for a value of .010, the amount of "play" in the Ring gear before it wants to move the Pinion.

Zeroed out

.010 Backlash on the money!

Now to check the Pattern. White Lithium Grease for Marking Compound.

Fingers crossed...



New Pinion Bearings and correct Pinion Bearing Preload has brought the drive side down to the center of the tooth with diffuse edges. Nice contact. Most excellent.
Coast is a tad high but well within spec.

Moving on....!:cheers2:

Feetwet 09-02-2013 04:17 PM

Time to put the axles back in. Simple. First, check the inboard ends for a rubber O ring. Both mine were split.

Replacements from the hardware store. A roll in some gear oil and pop em on.

I'm guessing they add a little pressure to the C clip and keep them tight in there.

If you reassembled the carrier after you got the axles out, like I did, it's time to remove the Center Pin Bolt. 5/16" socket will do.

Slide Center Pin out.( yeah, it's an earlier picture...)

Oil up the rubber on your axle seals and carefully slide the axles in, supporting the weight as you go. Almost in, give a gentle twist to engage the splines and slide them home.

Now the ends poke into the area vacated by the Center Pin. Slide the C clips into the channels over the O rings.

C clips loaded.

Now pull the axles outboard and insert the Center Pin. Locktite on the Center Pin Bolt and snug er up tight. 8ft/lbs or something, just get it tight.

Adjust the Parking Brakes now, piece of cake. Throw a rotor on and see how much slop there is between shoe and rotor. Mine had a lot. Pull the rotor off, slide a pin under the spring to release the adjuster wheel and start cranking.
The spring lays in the curve of the adjuster wheel and keeps it from spinning.
There is an access port on the backside of the backing plate but the adjuster is hard to reach from there.
Fine tune the adjustment from there later if you have to. Doable, just awkward.

On and off with the rotor and keep adjusting out til it just barely contacts the shoe.

Pop the rotors back on and call it good.

Time to weld those tubes.
There are 3 plug welds at the diff on each tube. While okay for every day use, if you're gonna beat on your rig you want to add some insurance. Wheel hop coupled with high RPMs has been known to shear the welds and spin a tube now and again. Not that my little 4 banger will be putting out massive torque :p, but a little insurance won't hurt.

I chose to do three stitch welds on each tube, located between the factory plug welds, as opposed to a full perimeter weld. I was a bit concerned about the high heat possibly warping the tubes. Maybe overly cautious but I'm comfortable with this approach.

The Supervisor is looking forward to this...

Hurry up and wait for the Auto Darken Batt to Solar charge...

The Setup.

I didn't want to overthink this stage too much. I've heard so many differing opinions about welding to cast, high nickle rod, low hydrogen, etc. I'm just gonna dive in and see how it goes.

The Prep. Preheated area with propane torch for a few minutes.

The stitch w/6013 rod.

Slag cleaned up.

Ground smooth. ( mostly)

Painted up.

Carried that around both tubes, alternating and allowing for cool down. I think it will be fine.

Chased the Flange Yolk threads with a 12mm x 1.75 tap to clean em out.

So that's where it stands for the moment. New Diff cover, Lubelocker gasket, Flange Yolk Adapter, Perches, U bolt Kit all enroute from various suppliers and due any time now.

Meanwhile, I'll pick up the Disc Brake lines, hoses, Calipers and Pads and get the Brake job underway.

I'll post up my progress as I make some...:laugh:

czjeeper 09-02-2013 07:17 PM

Looking good!
I just did a passenger axle, bearing and seal on a customers Exploder at work. Some sort of collision bent the axle flange.
225,000 miles on the diff and it looked great! These are such good differentials!

Sparrows 09-03-2013 12:05 AM

Sub'd! :thumbsup:
Another killer 8.8 write up! :cheers:


Gage56 09-03-2013 05:50 AM

Very nice :thumbsup:

Ill be coming back to this when i have to put my 8.8 back together

mywhyjay 09-03-2013 09:25 AM

Congrats on the find! Great attention to detail, love the pics!

I'll be starting this soon...

Feetwet 09-03-2013 09:50 AM

Thanks for the kind words guys.

There were a couple of posts lately from guys asking about what to do now that they found their 8.8.
I figured I'd take the pics as I went along and post em up.
Lotsa fun to do, hope this helps people down the road.


StanF 09-04-2013 11:50 AM


Prelube bearings with your goop of choice.

A little High Temp RTV and new seal.

Very nice writeup and pictures! :cheers2:

I'm curious about the RTV on the outside of the seal. Did you see some instructions that it was necessary or was it just preventative?

Also, why was it necessary to prelube the bearings? Shouldn't the oil flow from the pumpkin to the tube/bearing after you fill it up with gear oil?


Feetwet 09-04-2013 04:30 PM

Hey Stan.
Thanks for reading. I know you have an 8.8 Axle as well.

I prelube bearings as a general rule. The more grease the better.

In this case it may be a little while til I'm ready to fill the Diff with gear oil. Loading up the bearings will keep em happy as I spin the axles or pinion for various reasons as the build progresses. Still have to mock up my perches and set the Pinion angle, yank it back out and weld and so on.
After the gear oil is added then yes, all those components will be swimming.

As to the RTV, I always want sealant on metal to metal contact where seals are mounted. The press-in fit is probably good enough, but now I'm sure...:thumbsup:

RockWoRM 09-04-2013 05:19 PM

Nice write up, nice work.:thumbsup:

It appears at some point you've already cut off the old perch's. Did you take measurements prior? It could be helpful/easier for the new perch location.


jeepster93 09-04-2013 05:36 PM

Good writeup.

I welded the whole tubes. I needed to rent a 220v welder, all I have is a 110 wire welder(not good enough for tubes), and it was $$ to rent($60 for the morning), so I welded the whole thing. With nickel rods. Bought more rods than needed so I used them up...)Preheated it with a torch too. Used my wire welder for the rest of the welding.

The time now is 08:15 PM.

Powered by vBulletin Version 3.8.8
Copyright ©2000 - 2017, Jelsoft Enterprises Ltd.

User Alert System provided by Advanced User Tagging (Pro) - vBulletin Mods & Addons Copyright © 2017 DragonByte Technologies Ltd.
vBulletin Security provided by vBSecurity v2.2.2 (Pro) - vBulletin Mods & Addons Copyright © 2017 DragonByte Technologies Ltd.