Whats the difference between light and heavy duty?
 

I need to buy a master cylinder and maybe booster for my '74 f-250 but when I talk to the counter guys, I'm asked if truck is light or heavy duty. Is this stated on title or registration? Is it determined by gvw? Thanx for any help.

Should be determined by GVW.

Is your truck 4wd or 2wd? My '74 F250 4wd has a 7700lb GVW and the 3550 lb "HD" front axle. Hubs, brake drums, etc. are different than on the light-duty axle & maybe this makes a difference w/the booster & master cylinder?

Everybody is telling me the parts are different for the light and heavy duty trucks. I can look at the registration and find my gvw but still won't know which category it falls in. By the way, it's a 2wd Custom, not a Camper or trailer Special. Thanx for the input.

Look to see if it has front dual piston calipers. They are HD. Ted

'74 stock has front drum brakes, I believe. Maybe that only the F250 4X4. '76 was first F250 4X4 with dual piston front calipers, I think.

Sorry I haven't replied earlier. I was in the wrong screen and didn't see the other messages. I was told to look and see if it has dual piston calipers but I'm not sure if I can tell without removing the wheel. Ford dealer just told me that if it has the big axle hub coming through the rear wheel it's a heavy duty (1-ton) chassis, which my truck has. That may have answered my question. I'm leaving work now so I'll check back tomorrow to see if there are any additional ideas. Thanx for the help.

The 2wd had front discs in 74. The 4x4 didn't come with discs until 76. All the trucks had the hub sticking thru the rear wheel. As far as seeing the dual piston calipers, if you crawl to where you can see the back side of the wheel, then you can see if there is 2 bulges for 2 pistons on the calipers. That is if you have a 2wd. As far as 4x4 HD brakes, I don't know. Anyone else?

Thanx for the info. I'll turn the front wheels as far as I can and look for the bulges. My back keeps me from climbing underneath and looking.

over 8600 lbs GVW is a HD PU

are you sure it's not 8400 GVW. or 8500GVW. mine is a 8400GVW and when they ask i always say heavy duty and it's the right part everytime. i have a 4500# front axle.

I need to look at the registration to see what the GVW is but I did manage to look at the back of the caliper and saw two bumps so I'm guessing these are the dual piston ( heavy-duty ) brakes.

I have an 8600 GVW Suburban 3/4 ton 4x4 and it is still considered a light duty truck. I thought HD were the bigger dogs. 1, 1.5, 2, etc. ton trucks.

All the trucks had the hub sticking thru the rear wheel. Not if you have a 9" rear!!! :-X06

:-X22

Yeah, but he asked about a 250. Hopefully, nobody has a 9" under their F250.

are you sure it's not 8400 GVW. or 8500GVW. mine is a 8400GVW and when they ask i always say heavy duty and it's the right part everytime. i have a 4500# front axle.
-Aaron
1978 F-250 Ranger Explorer Trailer Special 4x4
351M, C6, Np205, D44HD, D60 4.10LS

On the older trucks I suppose it's possible, I am only going by dealers say so and all of the trucks I was buying parts for were 83 and newer, up to 96. My owners manual also says this but it's an 89 so...? There are also sometimes HD parts used for the camper special and trailer special but then they give them the lower weight rating because the truck did not have to be certified as HD Emissions that way.

Mike