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Discussion Starter #21
Step 3: Press the bearing off

Now press the bearing off using the hand brake backing plate as your leverage and you’re done.

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Discussion Starter #22

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Discussion Starter #24
Removing the axle seals

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So now I need to get the axle seal out of the tube. While one of them just popped out with some prying all around it, one of them was a real pain.

Something I realized is that it likely would've been easier to get that tough one out if the axle tube was still on the pumpkin. If I was doing this again, I would remove the axle seal BEFORE pulling the tubes off the diff pumpkin. But for this go round, I ended up bolting the diff tube to a 2x6 piece of lumber to keep it from moving around as I tried to remove the seal. That helped a lot.

But there is a whole thread on how I got the problematic stuck axle seal out of the tube: https://www.alfabb.com/bb/forums/sp...ear-axle-seal-removal-i-must-doing-wrong.html. The net of it was use a punch to beat it out. Just be careful not to scar the tube. If you do (like I did a little bit) use RTV when putting in the new seal.
 

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Discussion Starter #25 (Edited)
So now that everything is disassembled and the hand brakes are rebuilt, time to start re-assembly.

Step 1: Press the bearings onto the axle shafts


Fairly straight forward. Put the assembled handbrake backing plates on, then the bearing. Put the axle hub side up and press the bearing on. A little lithium grease eases the bearing on. Press against the inner race of the bearing (about 4 inches of 1 1/2" pipe fit mine well), of course, to avoid putting undue stress on the bearing. Sorry, no pics of the press setup...forgot to take any. But @gprocket has a great thread here: https://www.alfabb.com/bb/forums/ge...rear-axle-bearing-replacement-pictures-2.html
 

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Discussion Starter #26
Step 2: Installing the new axle shrink rings

So I messed this up the first time. I decided to go the "oven" heating method for these that folks seemed to have success with elsewhere on the BB. I heated mine at 500F for an hour, then tried to hammer it into place with my short stub of pipe. Perhaps if I had had a longer piece of pipe that I could've hammered on with a 5lb sledge, it would've gone on. Dunno. What I do know is that I managed to get mine stuck halfway on. But since I have gotten so great at removing shrink rings per above (this was my 4th one), wasn't a big deal except for the waste of a new shrink ring.

Here @gprocket has a great video of this process:

I followed it and it made life easy. I am a believer in MAP gas now. Way better than propane for heating these shrink rings and they dropped right on...no drama, no stress. I didn't even need to seat them with a pipe (though I did just to be sure). Just cool them down immediately after seating them so that you don't cook the grease out of your bearing.
 

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Discussion Starter #27 (Edited)
Step 3: Install the new axle seals

This is fairly straightforward. Pack the back side of the seal with a little bearing grease...just enough to keep the seal spring from popping out when you are hammering the seal into the tube. Get a socket or pipe that matches the circumference of the axle seal, something flat over the top of that to keep it level as you drive it, and hammer it into place with a larger hammer (3lb sledge or so). Some people use gasket sealant around the outer metal edge of the seals (the part mated to the tube), some don't. 89 Spider manual actually calls for it. I used some grey RTV.


Step 4: Prep the axle tube and diff pumpkin surfaces

Mating surfaces should always be really clean, but especially true for metal-to-metal mating surfaces. And since the pumpkin is aluminum, you have to be careful to not gouge it with something sharp (e.g. screwdriver) when cleaning it. For this I use plastic razor blades, scotch brite pads (600 grit, if memory serves), mineral spirits and steel razor blade (carefully). Finish it all off with a final cleaning of the surfaces with acetone.

IMG_5473.JPG

And the results:

IMG_5475.JPG

IMG_5494.JPG

IMG_5495.JPG
 

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Discussion Starter #28 (Edited)
Step 5: Put the axle tubes on the diff pumpkin

So this seems pretty straightforward, but I found a number of possible ways to screw this up. Luckily they didn't screw things up for me, but figured they are worth listing for anyone else doing this the first time.

Given the metal on metal assembly with no gasket, especially mating 2 dissimilar metals (steel & aluminum), that calls for anaerobic sealant. Whenever using a sealant, I like to put everything loosely together first without the sealant to make sure everything will go together well...threads mate well and are clean, etc. When doing this I found:


  • That my new locktabs from did not fit well and the bolt holes needed filed a bit
  • It is good to pre-bend the ends of the locktabs a little so that you can easily bend them into place once you torque the nuts down...and also to bend them in the right place so that they don't just flatten back out when torqued down
  • Some of the nuts are hard to reach with my torque wrench
  • Make sure you have the nuts going the right direction (built-in "washer" side down)

I also found you can mess up the following if you're not paying attention:
  • You can actually get the axle tubes on in the wrong position
  • You can put the brake fluid union in the wrong place
  • You can put the oddball single locktab on the large tube side in the wrong place. Will this matter much? Dunno.
  • Don't forget to install and torque the large bolt that goes into the "large" side diff tube.

Picture of "pre-bent" lock tab:

IMG_5497.JPG

So once done with the test run assembly, put anaerobic sealant in a continuous flow in the middle of the tube mating surface and around the bolt holes and seat it. Torque specs are different on the pumpkin and hub sides. Specs are below. Torque in a star pattern. Once torqued, clean up the excess sealant with a rag and acetone, then bend your locktabs in place. Done.
 

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Discussion Starter #29 (Edited)
Step 6: Axle shafts into the diff
This was straightforward, but some prep that should be done:


  • If you haven't already done so, be sure to put your brake dust shields on. And make sure to match them up to where they need to be oriented relative to the axle tubes (i.e. make sure the caliper cutout is in the right place).
  • Put a little diff oil on the splines going into the diff itself. Makes it easier to slide in.
  • Put some lithium grease on the axle seals
  • Don't drag the weight of the axle shafts across the axle seals...can damage the seals

You may need to tap the axle shafts into the diff with a block of wood on the hub end and a few taps of a hammer. From there just torque down to spec (spec attached to the post above). No gasket sealant needed here since all the oil should be kept behind your new axle seals!

And with that - a re-assembled diff:

IMG_5508.JPG
 

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1969 Giulia GT Junior, with 2 litre conversion
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Very informative write up. Thanks.

Do you have a shopping list of the bearings and seals required? Whilst I note that this is for a car fitted with an LSD, does anyone have the equivalent shopping list for a rear axle from a GT Junior 1300? Part numbers and bearing manufacturer would be ideal. Thanks in advance.
 

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Discussion Starter #31 (Edited)
This was my list...all from Classic Alfa. If you're doing your hand brakes, you may need some additional parts depending on their condition.

pan gasket https://classicalfa.com/gb052-differential-oil-pan-gasket-2000-cars/
oil filler plug https://classicalfa.com/gb062-oil-filler-plug-gearbox-and-differential/
2 bearings (kit includes seals, and shrink rings) https://classicalfa.com/su023hd-***-rear-wheel-bearing-kit/
3 Long tab washers https://classicalfa.com/gb073-differential-tab-washer-left-side/
4 Short tab washers https://classicalfa.com/gb074-differential-tab-washer-right-side/
2 - copper oil plug rings https://classicalfa.com/en091-sump-plug-washer/
2 - e-brake cable rubber gaiter (not needed if you are replacing the cables) https://classicalfa.com/br078-handbrake-side-cable-rubber-gaiter/
e-brakes shoes https://classicalfa.com/br051-handbrake-shoes-set-of-4/
e-brake cable end - left https://classicalfa.com/br055-handbrake-side-cable-left-side/
e-brake cable end - right https://classicalfa.com/br056-handbrake-side-cable-right/
 

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Discussion Starter #33
@gprocket - thanks for your video. Was super helpful to me.
 

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Discussion Starter #34
Powder coated.

It won't be on the car for quite awhile, but I actually asked the same question before removing the "big" axle tube and got advice that removing it (and even pulling out the LSD mechanism) would not disturb anything.

Someone smarter than me can answer the question definitively.
 

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Caution about powder coating. The reason is that the bearing shell for crown wheel is embedded in the axle tube— as is the sealing surface for the diff assembly. So if you decide to powder coat then make sure the sealing surface and the inside is masked. How how do they bake it these days on powder coat?

Personally I think powder coat is a colossal waste of time and money on this. It should be painted. That way it can be easily touched up. Plus it’s way cheaper and the axle tubes came from factory painted. NO ONE following you on the road will even see these, much less know if you powder coated. Save your money and hassle and paint with satin black rattle can rustoeum. That way you will be able to use the welded tabs to secure the brake lines
 

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PS you did a BEAUTIFUL job! Now that it’s done and powder coated it is fantastic!!
 

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There are shims in the big side tube but they are behind the bearing race so nothing will fall out. If you do remove it make sure you re torque the 14mm nuts to spec. I use Permatex 51813 Anaerobic Gasket Maker, 50 ml Tube on the flanges.
I've been told(and respect the guy who told me)to not remove a left side axle tube because by simply removing and replacing that tube(even when re-using the original carrier bearing and shims) will affect ring and pinion settings,gear mesh/backlash/total pre-load,possibly causing unwanted whine or noise.I'm just guessing that using "any" amount of sealant would have additional affect on the R/P relationship.Can someone whose actually done this with a good,used rear end and had success please chime in,it's very important.
 

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I've made my own tool to measure from center of ring gear to pinion face. Then incorporate the value stamped on the face of the pinion by the factory to determine the shims needed to go behind the race of the inner pinion bearing to attain that distance. I guess the point I'm trying to make is I've rebuilt several rear ends with Timken bearings to factory specs for pinion and crown lash, pinion preload, and inner bearing preload. The anaerobic permatex is great for the big tube and if it goes back together clean with the same bearings the preloads shouldn't be affected. They get taken apart and put back together enough just to get the shim thickness correct that r&r_ing the left tube is no big deal.
Here is a link that might be helpful...
https://www.alfabb.com/bb/forums/ge...-propshaft/544521-pinion-bearing-preload.html
 

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the anaerobic sealant works just fine. There is a DANA diff shim kit that I posted a year or so ago that fits the crown bearing shim size. Its about 13 bucks.

If you measure well, take your time, and do it right, the diff will be fine.

bob
 

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Discussion Starter #40 (Edited)
Re: powder coat vs. rattle can...

Expecting that a non-baked rattle can paint on suspension parts will hold up to rocks, etc. is probably wishful thinking. I drive my cars a lot, so optimize for durability where it makes sense. Rattle can paint certainly won't hold up as well as powder coating, but it will be easier to fix if a chip does happen. As usual, everything has tradeoffs. If I hadn't powder coated I would've used POR, which is more durable in this application than rattle can and can also be repaired in the event of chips. Not to mention POR is easy to make look nice, which is important since I am a crappy painter.

As for cost, yes, doing the tubes by themselves would've been a waste of $$. But I was doing pretty much everything you'd want to powder coat on a car and got it all done for ~$200. So made the cost of doing these tubes about $20...about the same as a can of top shelf rattle can paint.

As @goats pointed out, it is absolutely a must for any part getting powder coated that the mating surfaces and threads get masked off. Also since parts get baked, all rubber (bushing, etc.) will be ruined in the process.

Re: the pinion measurements, guess I'll see in a couple years when I install it. There's a lot of voodoo around messing with pinions and backlash. I was told by a couple experienced folks that the way I went about it, since I was changing nothing, would be fine. They could be wrong. I'll report back in a couple years. ;-)
 
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