Changing oil seals

I've got a colchester chipmaster and I'm attempting to change the 2 oil seals on the clutch shaft. They are two different sizes. The smaller of the two popped out with just a little effort. The second larger seal does not want to come out at all and i ended up really giving it a bit of a pounding (any more and i am definately going to damage the flange). My replacement seals are made of what looks like a hard outer plastic casing with a more pliable seal face with a garter spring. The original smaller seal has a metal casing with the seal with garter spring bonded to it. The smaller seal was fitted so the bottom of the metal casing was facing out of the flange but on the larger it seems to be fitted the other way round so I think the metal casing has been pressed into the flange. How can I get it out? The two things I've been thinking about are heat or getting someone to try and turn the casing so thin I can get it out?

Got an old 1/4" wood chisel? Round off the square tip and tap it in behind the seal at the shallowest angle you can manage. Do this in several places and the seal should slowly come out. As the gap gets bigger, something blunter will be needed.

Thanks mart. Is it unusual for seals to get stuck like this?

Hi,when I’ve changed that type of seal on engines and gearboxes ,they are always fitted the other way round.

Then they are easy to get out with screwdriver or puller.

I would check the manual to see if that seal is in correctly ,before fitting new one.

Hope this helps

Maurice

Simple answer yes, they can be difficult even when you have done it many times. Most lip seals are formed around a metal ring. When the seal face is fitted against a full diameter shoulder you need to get something between the faces like a screwdriver. Of course you can do as much damage as you like to the old seal so brute force is the order of the day, just be careful when replacing it with the new one, one nick into the lip and it is toast.

What I have done to remove metal outer oil seals is to carefully drill a small hole about 1mm or 1.5mm diameter through the flange part, then screw in a very small self tapper or perhaps a wood screw. Then use a tack lifter etc to pull it out. If awkward, it may need two screws diametrically opposite.

I believe that the picture is showing the inside face of the end cap, so the seal is the right way round. The rubber surface type can usually be fitted with just thumb pressure working round bit by bit.

When I modified the Tom Senior spindle from MT2 to R8, I factored in an oil seal at the bottom and had no end of trouble. The lower end got rapidly hot and I removed the quill several times to re adjust the bearing preloads until I twigged that the heat was caused by the seal. It was a double lip with garter spring and removing the spring only helped slightly. Cutting away the entire lip and relying only on the outer lip, which works fairly well on its own as it is not to retain the grease but to keep swarf out. Even now with moly grease on the lip, the bottom of the spindle gets to about 50C after ten minutes at 3000rpm.

Hi Old Mart,

I was wrong ,looking at photo again ,I can see that is a cap which covers the bearing .The seal is in right way round.

Maurice

^^^^^ This is a common way of removing seals in industry and works well. Once you have a screw or two in place in the metal ring that forms the seal outer body, it will usually pop out easily with a pry bar, claw hammer, or slide hammer pulling on the screw.

Or you can use a proper seal puller tool available from most car parts stores, designed to pop out similar sized seals on engine mainshafts and camshafts etc. It is a kind of hooked end on the end of a long lever at right angles. Works well too. LINK

Thanks for this but not sure how it would work in this situation. My seal is fitted with the metal face in the recess. I don't think I could drill the seal without damaging the part it's mounted in

That makes it difficult. Try heating the housing to make it expand. Then get in there with a seal puller as linked to above, or carefully with a small screwdriver to pry the seal out. Or a seal pick, which is a tool like a small thin screwdriver but with a sharp point on the end. You buy them in a set and they have various angles bent over on the end to get in behind seals and pick them out. LINK

Or some heavy duty ones with a T handle you can really yank on LINK

Edited By Hopper on 29/08/2022 04:42:37

Possibly try using a Dremel, if you have one, to CAREFULLY cut a small groove in the metal ring to relieve some of the pressure before trying to lever it out.

Mart - thank you for the wood chisel tip. That and a bigger hammer sorted it!!

The good old hammer rules OK !

Getting the new seal needs care with larger diameter, thin sectio seals - they can buckle at the vital moment. Don't ask......

Cut a disk of at least 3mm plate, or a hog end of bar if you have one slightly smaller thaan seal OD. Preferably press in, or pull in with scre and stongback.

Martin

A socket of the right size makes a great seal driver ! Noel.

That's exactly how I sorted it - thanks

Colin, when fitting the new seals, do apply some lubrication to the shaft (Don't touch the seal lip! )

Running dry will shorten life considerably.

If the shaft is worn by the original seal, try to locate the new seal so that the lip does not run non the worn area.

(Ideally, the shaft and lipseal need to run in against each other, and a worn / polished track makes this process more difficult. )

Howard

Thanks for this. I fitted them on Monday. I did oil the shafts before assembling. I was back down there tonight and the oil was still in the lathe so I'm hoping it all went well!

Good!

Looks like you have succeeded.

I fear that the same task awaits me, since oil is starting to seep very slowly, at the moment, down the front of mu Headstock.

Not looking forward to the job!

Howard