Clutch hub differences

[39voorti]

I have two different clutch hubs. I believe that the bigger one came from 8RT with original 3-speed. Problem is that throwout bearing B7580T does not fit over it.

The smaller came from SBC/Corvette Borg&Beck clutch/early Ford trans
-combo. And it should be Ford-item because it fits over Ford transmission.

But how there can be SO different ones? Macs antique says that even the B7580 fits from 1932-1948 passenger and 1948-1964 trucks.

 

[rotorwrench]

The 3-speed light duty transmissions used the same basic throw out hub from 1935 till the top shift light duty transmission went out of production in 1952 or so. They all have the loop that the spring hooks on to. Ford eventually changed over to the heavy duty 3-speed which may have some difference but I can't find a photo of one.
https://www.dennis-carpenter.com/en/cars/transmission/clutch/48-7561-set-clutch-release-bearing-hub

The Hays heavy duty clutch throw out hub looks a lot like that big one except it has wire spring clips to keep it attached to the throw out arm.
https://www.holley.com/products/dri...MIwqHFgZWz5wIVCtvACh3jHwBjEAQYBCABEgLmOfD_BwE

 

[flatheadmurre]

That bearing might be from a -53 pickup.
Some odd bellhousings and stuff thoose years.
Does it have the same style returnspring holder as the other one ?

 

[DavidG]

As an aside, there are two different versions of the B-7580 hub. Failure of the loop for the return spring resulted in the release of a beefier loop which is the one to use if you are seeking a replacement. I've encountered many of the earlier version where the loop is cracked or has been welded in repair.

 

[39voorti]

That bearing might be from a -53 pickup.
Some odd bellhousings and stuff thoose years.
Does it have the same style returnspring holder as the other one ?

Yes, both have same kind of return spring holder. Difference is the dimensions, i don’t know where to get new bearing for that big one.

After measuring distances in the bellhousing and the clutch, I’m going to use the big one. It has to be the right one for my 8RT setup.

 

[flatheadmurre]

I might have a bearing here in sweden.
You have a number on it ?
Or what diameter is it ?

 

[39voorti]

I might have a bearing here in sweden.
You have a number on it ?
Or what diameter is it ?

New B7580T bearing which I have has 53mm inside diameter - the bigger one ha approx 55mm or something like that, if I remember right. Can't measure again, just put it back together, old bearing felt quite good. But intrested in new one, of course.