How to Measure Imperial Oil Seals?
Imperial Oil seals will sometimes have the sizes written on it, for example175 075 025 written on the seal tells us it will be a 0.75" Inside Diameter (ID, 1.75" Outside Diameter (OD)& 0.25" ide/Thick.
Imperial Oil seals will be listed by OD/ID/Width. Eg. 175075025 If nothing is printed on the seal you would just need to take Vernier etc and measure the ID,OD and Width.
You may also see letters on the seal, if it has TC this means it is a Double Lip (R23) seal or if SC is written on it this means a Single Lip (R21)