diff questions

[ehall]

Maybe the letters refer to a machine pattern?

 

[jeeperjohn]

You're kidding, right?

Care to elaborate on this 'tolerance' you're talking about?

'Cuz I've had carriers that don't even spin after torquing down an unmatched set of bearing caps.

All the bearing caps are machined to the same size, the tolerance doesn't likely vary more then a couple thousandths. I have never seen any that did not torque up properly when properly oriented, matched or not. It's certainly better to have the original caps if they are available but I think it is not a show stopper if you don't have the original caps.

 

[vetteboy]

I have never seen any that did not torque up properly when properly oriented, matched or not. It's certainly better to have the original caps if they are available but I think it is not a show stopper if you don't have the original caps.

I have, and it was.

Glad you got lucky.

 

[Begster]

Ya I'm going to agree with chris here on the original bearing caps. I've even seen someone buy an axle off someone that was a bare housing, then get his money back after he found out there were no caps and that he was basically SOL without them.

Unless I'm mistaken, I believe the bearing caps are machined to that specific axle, which is why they are marked for orientation and why you can't swap them.

 

[RCP Phx]

the bearing caps are machined to that specific axle, which is why they are marked for orientation and why you can't swap them.

X1000

 

[BryGuy]

I realize that this is an old thread... but I did the same thing as the OP and forgot to mark my bearing caps as well. Here's a couple pics of them:

Not sure if this is actually an "L" or a "F" or if it means anything at all.

Besides the "L" mark the only other difference is that there looks to be an "E" stamped in diamond symbol, and one is marked 23 while the other is marked 9.

Hopefully I can figure this out and haven't doomed my whole axle. BTW, it's a Dana 60 out of a 79 Ford Snow Fighter if that helps.

 

[VAhasnoWAVES]

O.K. I'm not sure of this but it seems to me that the factory is unlikely to machine the caps as a unit with the differential housing. It just seems like that would cost way too much. I'm not saying you're wrong, it just seems like they wouldn't put that kind of effort into a mass produced part. In the grand scheme of things the matching of the bearing caps is not that critical. The caps must be oriented a certain way because the inside surface of the cap is not machined to the right size the whole width, therefore you have to orient the cap so that the machined part of the cap is outboard to ensure maximum contact with the bearing race. If anybody has info that definitely proves that they are match machined from the factory I would really like to read up about it.

ive made thousands of bearing caps for ford and sterling...

our horizontal mills drill the bolt holes, deck the surface for the bolts, and deck the surfaces for the caps to mate to the housing. the caps then get sent to out, and the inner part that contacts the bearing race is bored after being mated and torqued to the housing.

 

[planewrench]

If you look closely at the inner surfaces of the caps which are DEFINITELY line bored with the housing, you can usually match up the machining marks of the caps to housing and figure out what goes where. As I and others have said, the caps are ALWAYS line bored with the housing. Any other response is wrong!

 

[jeeperjohn]

ive made thousands of bearing caps for ford and sterling...

our horizontal mills drill the bolt holes, deck the surface for the bolts, and deck the surfaces for the caps to mate to the housing. the caps then get sent to out, and the inner part that contacts the bearing race is bored after being mated and torqued to the housing.

Thank you for that, I had not seen any definitive info on the subject. Now the question is, do the tolerances vary enough that it is likely to prevent one from using bearing caps that came from another axle? I suppose I have just been lucky but it seems to me there would not likely be any dramatic variances. Obviously it is better to have the original bearing caps, I am just speaking hypothetically about if you had a couple of diffs in front of you and the bearing caps got mixed up.

 

[jeeperjohn]

I realize that this is an old thread... but I did the same thing as the OP and forgot to mark my bearing caps as well. Here's a couple pics of them:

Not sure if this is actually an "L" or a "F" or if it means anything at all.

Besides the "L" mark the only other difference is that there looks to be an "E" stamped in diamond symbol, and one is marked 23 while the other is marked 9.

Hopefully I can figure this out and haven't doomed my whole axle. BTW, it's a Dana 60 out of a 79 Ford Snow Fighter if that helps.

The mark on the top cap looks like an "E" that was not completely stamped into the cap. Note that the "E" on the other cap is rotated 90* from the one on the other cap, this corresponds with the marks on the housing ensuring you get the correct cap installed.

 

[planewrench]

You can't mix main bearing caps, connecting rod caps, or carrier caps! That's the way it is. They are all machined with what they are attached to to be a perfect circle. As I said before, you can swap your ORIGINAL caps around 'till the tooling marks (from the boring tool) on the caps and housing match. You may need a magnifying glass and/ or an inspection mirror. You just can't clamp down on a tapered roller bearing cup (outer race) and distort it and then expect it to function correctly!

 

[VAhasnoWAVES]

Thank you for that, I had not seen any definitive info on the subject. Now the question is, do the tolerances vary enough that it is likely to prevent one from using bearing caps that came from another axle? I suppose I have just been lucky but it seems to me there would not likely be any dramatic variances. Obviously it is better to have the original bearing caps, I am just speaking hypothetically about if you had a couple of diffs in front of you and the bearing caps got mixed up.

its hard to say...

our tollarances are pretty tight. id imagine that they are even tighter when the caps/housing are bored out. i think its just a matter of preventative practice. 99 people pull bearing caps from a different housing, and dont have a problem. then 1 guy gets a lemon, and it results in premature wear (or something more catastrophic)...