Picked up a 1970 GMC C3500 dump truck that needs some TLC

[Stimw]

The part you are calling a caliper is actually a wheel cylinder.
They will get stuck from sitting. Usually the dust cover doesn't seal and there is an aluminum piece up against the cup. The aluminum piece will corrode to the steel cylinder.
I have taken them apart and cleaned them up and they worked again. As long as the cylinder isn't pitted.
NAPA used to be able to match up the wheel cylinders just by the 3 digit casting number.
Check out your brake lines really well!!! I worked on a low 60's 1 ton that someone repaired the rear brake line with low pressure fittings with ferals. (brake line pressures can be about 2000 psi)
Brake lines must be flared and preferably double flared.
In case you didn't know, when putting the rear hubs back on put grease on the bearings which will protect them until the rearend oil reaches them.

 

[2458n]

The axle on a cab& chassy- no bed from factory is narrower. You needed the steel plates so the acorn lug nuts have someplace to locate the wheel. Newer trucks use the hub to center the wheel and use lugnuts with flat faces. If this does not make sense get a tire guy to explain it. The change over while simple can be dangerous if not done right.

 

[Gale Hawkins]

Look like you are making good progress and getting away from the two part rims will be a plus. We just went to one piece rims on our 1989 Ford F700 16' flat dump. We got lucky at a school bus company and got four mounted recaps with new like tread for the rear and two new like mounted Kumho's for the front for $600 and sold the six two part wheels and tires for $100 to a tire store and two tires where brand new. I just did not want to go home with them on the truck because I would have dumped them in the woods one day when I needed the truck and they would have rotted there.

I would like a truck your size around the place but at 23,000 gross and with farm tags no special driver license is required.

While there are repairs on old equipment they are one time events most likely for a truck that is going to be used around the place.

Concerning the rims around here it is getting harder to find shops that will handle the two part rims of years ago so should I need a tire years down the road I can now just grab a radial that was a fresh pull unlike the old bias tires that went on the old rims.

Keep us updated like you have been doing. Thanks for the tread.

 

[ultrarunner]

Bought two new OEM wheel cylinders for my 3/4 Chev truck (smaller size) for $6.18 each.

Always would buy the kits but, for $6 I just went new.

 

[FairfaxStu]

Forgive my ignorance here, but I am not sure I have ever heard of a split rim. Does that mean that there are front and back halves of the rim that require them to be bolted down before adding air? If so, I could see where that would be a problem.
-Stu

 

[Gale Hawkins]

Split Rims - YouTube

Some call this type split ring also. Basically they are make up of two parts. There have be other styles over the years. No machines are required but larger tires could require a large hammer.

They can be dangerous if the person does not pay attention. The inflation cage reduced deaths. Go to an old tire shop and look at the bowed out cages.

 

[hawkeye08]

Forgive my ignorance here, but I am not sure I have ever heard of a split rim. Does that mean that there are front and back halves of the rim that require them to be bolted down before adding air? If so, I could see where that would be a problem.
-Stu

Split rim is just that. the lip on one side is just like a normal one piece wheel. The other side, the lip that the bead of the tire goes against is a ring that is cut at one point. It goes in a groove on the wheel and when done properly, is a good design. Large trucks use this because the beads of the tires really won't go over the normal wheel. The bead of the tire keeps it from expanding and coming off normally. It is pretty straight forward to work on, let air out, break the bead down, pry split rim off, remove tire from wheel. To put tire on, put the tire on the wheel, put the split rim on, seat tire. The danger comes when the tire is being inflated to set the bead. If the split rim is not all the way on and everything in good shape, when the tire seats the bead, it can blow the split rim off. This projectile can kill easily. Truck shops have cages the wheels are put in that contain things when inflating in case something goes wrong..

 

[ultrarunner]

A old time retired mechanic told me the split-rim design allowed him to change a tire with only hand tools and the wheel could be left attached to the truck.

As far as I know, all split-rims use a tube so inflation with a small pump if necessary.

My Model T's have two piece rims and my Model AA truck has a split-rim...

 

[paulharvey]

Split rims are still the norm for front end loaders, rock trucks, traffic rollers ect. These often have 12-16 ply tires on any where from a 15"-30+" wheel. In the future look for an equipment tire service company to work on them

 

[FairfaxStu]

Thanks for all of the replies on this matter. I had no idea. I suppose it makes sense for heavy duty tires that have to be changed out while onsite in the field - no massive tire changing machine. I do see from the youtube video that it is a pita to change them even at the shop.
-Stu