Pinion seal for 53-55 rearend

[Joe L.]

Re: Is this a Pinion seal for 53-55 rearend?

John et al,

I've been studying this issue for the last few days. I'm now of the opinion that the published dimensions for the 3707355 are wrong and misleading.

The misleading part is that 3.4375 dimension. I believe that is the OD of a flange which limits the plunge depth of the seal. The actual OD of the seal, or more accurately the ID of the bore into which it is to be inserted, is about 3.250".

The inaccurate part is that 1.875 shaft diameter. In "Good Times" Vol 4, No 2 there are two different mentions of dimensions slightly less than 1.75" and this makes sense to me.

Think about it this way: On the later differentials ('56 - '62) the pinion shaft diameter was about 1.75", and all of these cars had engines which produced waaaaay more torque than the 6 bangers could ever have hoped to make. A 1.875 shaft would have been approximately 32% stronger and there was just no need for that extra strength. Near as I can determine, 1.875" pinion shafts were used on heavy, more powerful cars of the era such as Cadillacs.

Rolling all this up, it appears that a proper pinion shaft seal for the '53 - '55 differentials would have an OD of 3.25" (maybe a couple of thou less) and fit a 1.75" shaft.

So maybe the seal I have is the right one afterall. Or at least right enough.

Anyone disagree? Go ahead, tell me I'm full of it. But tell me why also.

Jim

Jim-------

Some of the information as to the dimensions of the seal originate from the "description" column in the P&A catalogs. As I've mentioned previously, the information in this column can often be inaccurate or misleading. Also, there seems to be no "standard" for the dimensional information found in this column----sometimes dimensions are figured one way, other times another.

As far as whether the seal you have is correct, it may very well be correct. However, it's OLD. For something like a seal, especially one made from material technology 50 years old, this can be a problem. If there was no other piece available, then I guess using what you have might be the way to go but finding out AFTER you install it that it fails or leaks is a "hard pill to swallow". I'd contact Grossmeuller's as has been suggested and see if they have fresh replacement seals for the application.

[Joe L.]

Re: Is this a Pinion seal for 53-55 rearend?

He said they would make us any seal we wanted for the Fi's but the quantity was more than I could afford.

John------


A VERY common problem for obtaining parts for obsolete and low-demand applications.

The major manufacturers will make just about anything you want BUT ONLY IF you're willing to pay a "set-up" charge and order a minimum quantity. In a lot of cases, the "minimum quantity" would be enough to supply the entire world's demand for the part for 50-100 years.

[Jim L.]

More on the dreaded '53 - '55 pinion seal

From those who have 1st hand experience with the '53 - '55 cars, I'd like to know:

1. What is the precise diameter of the pinion shaft?
2. What is the precise ID of the opening in the carrier into which the seal fits?

What I am attempting to do is to apply a machete to the thicket of incorrect and misleading information about these seals.

It's my belief, so far unconfirmed, that a proper seal for the early diffs will have an OD of 3.241 and fit a 1.739 shaft. But is that right?

Any help from those who know for sure?

Thanks,
Jim

[Gary C.]

Re: More on the dreaded '53 - '55 pinion seal

Tom,

Corvette Central advertises their part #581240 for 53-55 rear pinion seal http://www.parts123.com/parts123/yb....~~~~~~0000050e

Found this website by googling http://corvetteparts.com/item/seal-d...ion-1953-1955/

My friend Steve Newsom said when he needs one he usually gets it from ebay

Gary
....

[John D.]

Re: Is this a Pinion seal for 53-55 rearend?

John------


A VERY common problem for obtaining parts for obsolete and low-demand applications.

The major manufacturers will make just about anything you want BUT ONLY IF you're willing to pay a "set-up" charge and order a minimum quantity. In a lot of cases, the "minimum quantity" would be enough to supply the entire world's demand for the part for 50-100 years.

More than a 100 years Joe. They wanted me to commite to 10,000 seals. Whew!!!!!