I wold love to replace all the o-rings on the various black vacuum hoses on the engine. I think most are the same size. Anyone know what they are?

 

I wish I knew. I have an o-ring sizer cone, reference books, o-ring assortment kits and many hours involved in determining proper o-ring sizes. With all of this, I still end up buying a size or 2 above and below what I think I measured. Finding them in small quantity and the proper material is another chore.

The number one thing I have concluded with o-rings is that no matter how many hundreds of different sizes you have, you NEVER have the correct one! I don't think I have ever found a single useful o-ring out of an assortment kit.

 

https://www.allorings.com/ is a good place for o-ring research and purchase. They have a $50 minimum order last I checked. Their USA and Metric sizing tools are helpful if you manually measure the cross section, ID and OD you can get pretty close if not dead on to size. I still might order a up and down the range.

 

I would really prefer to know the correct sizing too! I think these same ones are used in the EVAP connections. They all, at first glance, appear to be the same size. I hate guessing. Especially since the originals are so old and deformed.