[How-To] Modified Colchester lathe headstock "clutch housing" - fixing headstock oil leak on Colchester Chipmaster/Harrison 10-AA

[paul s]

Bought a nut splitter, but the body of it interfered with the 1232 washer, so I had to resort to a carefully manipulated hacksaw, here's what's left of it:


I still don't understand why it wouldn't unthread, but the male threads on the rod are OK, gave them a clean up with a threading die. The two orings are indeed hard and brittle, the rod slid through them with no resistance. I opted to leave the other nylock in place at the brake end, no need to remove it, really. I suspect that the spinning nylock has something to do with the relief at the end of the threads on the rod.

Here's where I'm at:




I see one lip seal - is there another larger one hidden in the above assembly? Now I understand regarding the "modified circlip pliers" - I had to go one size down to open that circlip inside the bore. And regarding the oring that seals the brake end of the rod - do I need to remove that assembly to get at it? It's a bit deep in there.

 

[FliesLikeABrick]

I see one lip seal - is there another larger one hidden in the above assembly? Now I understand regarding the "modified circlip pliers" - I had to go one size down to open that circlip inside the bore. And regarding the oring that seals the brake end of the rod - do I need to remove that assembly to get at it? It's a bit deep in there.

Great progress!

Indeed I suspect you found the smaller seal ("1133 Plate Oilseal") in the plate ("1149 plate c/w brgs") that you took off the face of the large timing pulley ("1171 pulley")

If the bearings inside the pulley look like they have had oil leaking into them (the grease is all thin/oily or washed out) then indeed the bigger seal in the back is probably leaking. You'll need to slide that timing belt off (after taking some of the other parts off the jackshaft where the smaller timing belt goes down to the leadscrew gearbox), then remove the big snapring and slide the pulley off.

Then you'll be left with something looking like this:


The seal that is responsible for the common worst oil leaks is behind that last casting. After you remove the socket cap screws, carefully work that housing out and you'll find the seal pressed into the back



That's the sucker that this is probably all for.


As for the o-rings - you don't need to remove that input shaft, it stays the whole time. If you look inside the end of that shaft where the rod was, you'll see a groove (or feel it with a pick), which is where the o-ring will live. Here's mine before I replaced the o-ring:



And after:




and there is an equivalent on the brake side of the input shaft:

 

[paul s]

I've already removed the oring on the back side, still need to remove the one on the brake side.

I'm curious - in the third picture down in your last post; what are the three "o's" worn/stamped on the end of the hub? Are they some kind of match mark, or something presses against there, or nothing?

 

[FliesLikeABrick]

I've already removed the oring on the back side, still need to remove the one on the brake side.

I'm curious - in the third picture down in your last post; what are the three "o's" worn/stamped on the end of the hub? Are they some kind of match mark, or something presses against there, or nothing?

I think it's just a greasey witness mark from the ends of screws or holes in the part that bears against that surface - looks like maybe the hole pattern in the "1275 Operating Collar", probably just oily smudges matching where those 3 tapped holes are touching the end of the part you see in the picture you referenced

 

[paul s]

I think I may have found a source for the unobtainable seal - can someone give me a sanity check on this?

 

[FliesLikeABrick]

I think I may have found a source for the unobtainable seal - can someone give me a sanity check on this?

Can you provide the link to the parts here so I can take a closer look at them?

 

[FliesLikeABrick]

I think I may have found a source for the unobtainable seal - can someone give me a sanity check on this?

So that is similar to one that I've gotten, I may have even mentioned it in my original post in the thread -- it's worth a shot. However the original seal has a metal housing for a press fit. I bought a rubber-bodied one (prior to considering modifying the part), and ended up having a hard time getting it pressed into the housing. It ended up distorting and not going in straight. Ultimately it ended up just becoming a mess of RTV, getting damaged and I aborted.

That said, if you have easy access to those seals it's 100% worth a shot... just perhaps temper your expectations. Or if you can find one that is slightly undersized (So that it is less of a press fit), perhaps you would have more luck with that. I thought I had a picture of my poor outcome on this path but unsurprisingly it looks like I opted not to photograph the failure

edit: I stand corrected, I think maybe the one you found does have an integral metal ring. Go for it!

 

[paul s]

Here's those links:
https://www.123bearing.com/seals/seal/rotary-shaft-seal/oa-41.27x55.56x9.52-nbr
https://www.123bearing.com/seals/seal/rotary-shaft-seal/oas-25.40x44.45x6.35-nbr

The previous owner of my lathe was a good record keeper - I found a receipt for the larger of the two seals dated May 2013 with a Timken PN 24600-0758. Here's what I found:
https://www.motion.com/products/sku/01296195;orderDetail=true
https://www.motion.com/products/sku/02672801

 

[FliesLikeABrick]

Here's those links:
https://www.123bearing.com/seals/seal/rotary-shaft-seal/oa-41.27x55.56x9.52-nbr
https://www.123bearing.com/seals/seal/rotary-shaft-seal/oas-25.40x44.45x6.35-nbr

The previous owner of my lathe was a good record keeper - I found a receipt for the larger of the two seals dated May 2013 with a Timken PN 24600-0758. Here's what I found:
https://www.motion.com/products/sku/01296195;orderDetail=true
https://www.motion.com/products/sku/02672801

hah, your previous owner sounds like he could have been me
ehttps://www.motion.com/products/sku/02672801 this is the exact one that I bought, and it was too flexible to install in the press fit required, leading to damage. The one you found on 123beaerings is more likely to succeed because it has the metal ring inside it

 

[paul s]

Ah, I see that now - and for some reason, the previous owner ordered two of those seals. I may go ahead and try 123bearing.com, there's not much to lose, but the prices do seem rather low, which makes me suspicious.

At any rate, I'm all the way in now - all I need are seals and orings. Truthfully, once the "spinning" nylock was conquered, the rest was easy.