Classic & Vintage - Sand in front fork bottom ball bearings

I recently purchased a late 80s Miatat 310. I have been riding the Lake Shore trail here in chicago and occasionally come accross small patches of sand.
After about five rides or so the headset started to sease and became hard to turn.
I took the fork off and noticed that the bottom ball bearings are packed with sand. I cleaned them off and placed in the wd-40 bath. Also cleaned out the inside of the fork.
I am ready to pack them with grease and reinstall the fork back on the bike, but would like to take some kind of measure to prevent this from happening again.
Have anyone else ran into a similare issue and/or has any tested ways of sealing the ball bearings?

Thank you,

Cut a section of inner tube about .625 to .75" long, install that around the lower head set cup on the frame, fold back, pack headset, add a thin film of grease to the lower crown race sides, install, adjust and fold over tube section.
Protection.

Decent headsets often have a gasket on the bottom and top to prevent/reduce intrusion.

Some headsets also have sealed cartridge bearings that will mostly be impervious to any intrusion of sand or moisture.
Stronglight makes them in the form of their newest version of their A9 headset.

Chombi

Another option is to install a set of vintage alloy shorty fenders:

http://www.bikingindallas.com/wp-content/uploads/orange-012-400x300.jpg (http://www.bikingindallas.com/1973-schwinn-world-voyageur-revisited)

Some headsets also have sealed cartridge bearings that will mostly be impervious to any intrusion of sand or moisture.
Stronglight makes them in the form of their newest version of their A9 headset.

Chombi

I considered using sealed cartridges, but not sure if any will work with an older bike like mine. The cups and race sides are part of the frame and fork, respectively.
Am I missing something?

You would have to replace your old headset with a new cartridge-bearing headset. But a front fender as Metacortex suggests will solve the problem and keep the bike cleaner.

wrk101: any links, examples?
repechange: do you have pics of the final product? Sounds like a good idea. I was considering going to Home depot and browsing in a plumbing section.

You would have to replace your old headset with a new cartridge-bearing headset. But a front fender as Metacortex suggests will solve the problem and keep the bike cleaner.

That's what I was thinking too. I would like to keep the bike as original as possible and also avoid spending a lot of money on upgrades. Will have to go with either Metacortex's fender or repechage's inner tube seal.

Thank you everyone for the help.

wrk101: any links, examples?
repechange: do you have pics of the final product? Sounds like a good idea. I was considering going to Home depot and browsing in a plumbing section.

No, I don't do images. Any old mtb. mechanic will know the solution I describe, the early days of mountain biking required using adapted road equipment. Home Depot will not have suitable material, a local bike shop should have a dead 27 x 1 1/4" tube around though, and may not even charge you for it if you say please, and even more so if you show up with a beer.

wrk101: any links, examples?
repechange: do you have pics of the final product? Sounds like a good idea. I was considering going to Home depot and browsing in a plumbing section.

I'm away from my workshop right now, but I was thinking both the Ritchey Logic and the Tange Levin both have gaskets. These are the two headset models I use. Not perfect, but may be a lot better than what you have right now.

+1 fender would help a lot.

Cut a section of inner tube about .625 to .75" long, install that around the lower head set cup on the frame, fold back, pack headset, add a thin film of grease to the lower crown race sides, install, adjust and fold over tube section.
Protection.

+1. I think they still make Velcro/neoprene bearing condoms...

http://www.ebay.com/itm/HEADSEAL-LIZARD-SKIN-Black-/200806754493?pt=LH_DefaultDomain_0&hash=item2ec103e8bd#ht_2330wt_980

+1. I think they still make Velcro/neoprene bearing condoms...

http://www.ebay.com/itm/HEADSEAL-LIZARD-SKIN-Black-/200806754493?pt=LH_DefaultDomain_0&hash=item2ec103e8bd#ht_2330wt_980

Ordered two of those from Amazon for $11 total including shipping.

Thank a lot for all the help. Can't wait to get back on the trail.