You have a lock-ring, at least on the front wheel pictured.(Easier to see on front wheels, inside duals). ring is about 1/4-inch thick,between the outer rim,and the inner wheel). I had my "New" 9:00X20:00's installed at a truck-tire shop,and these rims are safe. It's the Firestone rims that are called "Widow-Makers".The easiest way to identify the 2-piece Firestones,is the lack of a lock-ring. Grigg was so kind,as to post a warning about these rims in his "Wheels and Tires" thread. Good read! Buddy of mine bought a '51 6700 bus,and 2,(out of 6),were 3-piece,the other 2 he replaced,since they were "Widow-Makers". As far as the Hydro-vac,mine is located on the outer frame rail,directly under the passenger-side door,across from the master-cylinder. Yours may be located in a different position,since you have an older truck. Should still be located under the floor of the cab,or maybe,directly behind the cab. For the size of your truck,I would think that you would surely have a hydrovac unit installed. Maybe I'm wrong. Check the "Tech Tips",under "Brakes",to see a good description. Bob Burgoyne's thread is full of information. Hope this helps.
Last edited by wetwilly5757; 06/06/2013 12:05 AM.
