[Biba69]

I've never rebuilt a differential - not planning on doing so now - but I'm in the process of removing a diff from a Spider.

The initial plan is to at least stop it from leaking. I gather the front seal is often the problem but this one looks as if it is also leaking from both sides of the housing and the 'oil pan'.

Obviously I can pop the oil pan off and replace the gasket - even if I have to make one. Is it safe to assume I can remove both sides and the axles will slip out AND will slid back in again without any major traumas?

My thought is to put some sealant on both sides after thoroughly cleaning the surfaces - though I suspect they're meant to be installed dry.

I believe there is a special wrench floating around to remove the front nut so the seal can be changed. If so, anyone know who the keeper of the wrench is?

The bearings sound/feel okay, but this car has sat for 20 years. Am I foolish to not take it completely down and check everything? If so, who do you recommend in the So. Cal. area to do this?

Any answers, thoughts, or opinions are most welcome,

Biba

 

[genericwood]

Biba, to my knowledge, your assumptions are all correct. You can easily make the pan gasket. I put a little bit of silicone sealant on the axles tubes whenever I reassemble. Unfortunately, I only have the pinion socket for the later 2L style diffs, but surely someone will loan the old style to you. If not, I'd bet you could make it easily enough with your skills. Unless there is reason to believe the diff was the reason the car sat for 20 years. I'd just seal it up, fill it with oil and drive it. That's what I did with my '56 after it sat for more than 20 years and it is fine. The diffs in these cars are much stronger than they have to be!

Erik

 

[Alfajay]

Biba:

I second genericwood's comments.

If the bearings are bad, you will feel it when you rotate the axles by hand. As genericwood wrote, they tend to last forever, so you can probably bet that they are OK if they past the feel test.

I disagree that the axle tubes-to-centersection joint was supposed to be assembled dry. When I have disassembled these, I saw evidence of some sealant that I believe came from the factory. I don't use silicone - I use grey, non-hardening gasket goop.

It is easy to thread the axles back into the splines in the differential upon reassembly. Really, nothing is that tricky as long as you don't go changing the ring & pinion in a given housing (the alignment is set using NLA shims, and precise measuring equipment).

 

[Gordon Raymond]

Aside from dried out seals, the only failure I've seen on these old axle assemblies is a tendency for the bolts that hold the ring gear to the differential proper to work loose. If you pull the axle tubes for inspection, you would easily notice this. Though the bolts are hardened, when I found one that has loosened up, (usually all the bolts loosen some, when they do) I used to drill and safety wire them all. I guess Loctite red would work as well. The bearings seem to last forever. Gordon Raymond

 

[101 Alfa Mike]

I will second the above comment that the bolts that hold the ring gear in place sometimes work loose.

 

[Biba69]

Which direction to unscrew the outer end bearing retainers? I gather it is clockwise viewing it from the splined end looking down.

Thanks for all of the good information. Bolts, which were held on by bent tabs were all tight. Yes, it does apear as if there originally was a light smear of sealant.

To show my ignorance about diffs, didn't realize the ring gear just falls out after removing the left axle housing.

Unfortunately both of the very expensive outer bearings need replacing, so do need to get the retainers off. There's a large bearing, etc, place not far so will see if they can get me the bearings for (hopeully considerably) less than the $113 ea. going rate.

Biba

 

[Gordon Raymond]

Ok, viewed from the splined end all I've reroved came off ccw (righty tighty, lefty loosy) like everything else. Even with the special wrench, these are tight! I tap them off with a punch and small hammer, working around the roots of the teeth. You will still have to press the bearings off unless you have the Alfa bearing removal tool, and then press the new ones on. Unless you have the proper tools and knowledge, this R&R is a job for a machine shop, particularly with the cost of the 750 bearings! Shop around, try Alfa Stop in GB, and Ok parts in Germany. Unfortunately these are not as common as the 101 and later bearings, but good ones will last.
Nice the way the canter section falls out isn't it? Find any loose bolts? Look carefully at the edges of the tapered carrier bearings. They will probably be ok, but ANY chipping at the edges of the rollers, or scoring of the races, indicate time for replacement. I seldom replace these as routine, as they hold up well. Best, Gordon Raymond

 

[Biba69]

Small hammer???? I'm using a five pound hammer and large screwdriver and neither axle is budging. True, I've been confusing the 'poor' retainer by trying to undo it in either direction, but having put a blob of White-Out on the edge to see if I've budged it at least a tiny bit - there is no indication this miracle has taken place. Did put some heat on it and was amazed to see some oil come out. Where did it find the room? Yes, all tabs are bent back (out of the way).

I'm pretty aware of the (righty tighty, lefty loosy) slogan, but know on later Alfas one side is cw undo.

Is it safe to assume the proper Alfa tool has really long 'legs'?

I have a small press but can't imagine how to go about pressing them off.

So glad it isn't my car. I couldn't afford to be doing this.

Thanks much for this quick info.

Biba

 

[Gordon Raymond]

Axle whacking

Hi again Biba,
Oh yes, they do that. One of the reasons I suggested a machine shop. By holding the axle in a padded vice, one can use a impact air hammer, (like a cutter, but with a punch) and ... ahem... tap it off. Hopefully without tapping off the little ears. The factory tool slipped over the shaft, and had a handle to... tap ... on. Probably by now all the tools have the handle whacked to a pulp. BTW, it takes a B I G press. Keep me informed. I'm very interested that you are having the identical results I have always had.
(P.S. in the day when available, we would split the special nut with an air chisel. No more, as the special nuts are no longer available!)

Best, Gordon Raymond

 

[Biba69]

Gordon, you are a prince among princes (or however the expression goes). As of now I have both bearing retainers off and a date with my machinest tomorrow to (fingers crossed) remove the bearings. Sure helps to know which way is 'undo'. I switched from very sturdy plastic handled screwdriver to hunky (fairly dull) chisel to get the retainer off. The force needed was such that the hammer blow needed something which would in turn amplify the blow. Make sense? The plastic on the screwdriver softened the blow.

I actually took the time to square off the rounded edges of the retainers that previous mechanic inflicted with a large punch. I slightly undercut an edge on each retainer using the large chisel.

I'll keep you informed as to how everything goes.

Hey it's only time...and money.

Biba

 

[Gordon Raymond]

Biba,
You've got it! Anything worth while is worth EFFORT! (and persistance!)

Best, Gordon Raymond