Oil Seals.

[John47]

Anyone know how oil seals are measured??? I am changing the seals and bearings out on a trailer, bearing numbers I've managed to get. Seal OD is 52mm but I don't know how the ID is measured, shaft size where seal seats is 31 mm.

 

[Hooked_on_HP]

The measurements you need are the diameter of the hole the seal fits in and the diameter of the shaft it is going over. Take you measurements with a good set of calipers.

 

[John47]

The measurements you need are the diameter of the hole the seal fits in and the diameter of the shaft it is going over. Take you measurements with a good set of calipers.

The old seal is "shot" so no chance of a reliable measurement of the Inner Diam.
Shaft size is 31mm as already stated.
Would a 25mm ID be too small?? 28 be too big? I'm ashamed to admit this, but I have fitted many thousands of oil seals years ago and damned if I can recall how we measured them!

 

[larso1]

John, sounds like you're trying to second guess the method of sizing the interference fit between radial seals and the shaft. The fluid seal industry has already done this for you, so the shaft O.D. size is all you need. Just make sure you get a radial lip seal with a garter spring cuz they last twice as long as seals without. Also, don't forget to call out the width of the seal too.

Bill

 

[John47]

John, sounds like you're trying to second guess the method of sizing the interference fit between radial seals and the shaft. The fluid seal industry has already done this for you, so the shaft O.D. size is all you need. Just make sure you get a radial lip seal with a garter spring cuz they last twice as long as seals without. Also, don't forget to call out the width of the seal too.

Bill

Thanks Bill, thats what I'm after, looks like the seal size I need to order is a 30mm X 52mm X 7mm wide

One thing I always do, is log the part numbers down in a file after I've done my repairs!!

 

[markct]

well close, if your shaft is 31 mm then ya need a 31 mm id not a 30 mm id

 

[cp1969]

Many times, metric seals with have those three numbers on the face of the seal. If you don't have any luck finding metric seals, I've gotten metric seals from a place called Harwal in New Hampshire. I usually buy the Viton lip seals (expensive, but very good) but they probably have others.