My master cylinder is leaking between it and the booster which looks old and has surface rust. It is my guess that now is the time to replace them since I don't know the history of the parts and I want to make it safe. I haven't driven the truck yet as it is a new purchase and project. I've spent hours trying to find a booster for disc brakes to no avail. I would rebuild if I were more experienced and paint it, but my to do list is already too long. Any suggestions?

 

Does your truck have a single or dual diaphragm booster? My truck is a 1972 F250 with factory disc brakes and it has the dual diaphragm booster. My truck is a 7500 GVW truck so it is close to being a F350 in regard to GVW. To get a replacement booster for my truck from NAPA I need to put in F350 to get the correct booster.
When you replace the master cylinder, I suggest you get a new MC not a rebuilt one.

Here is a good thread that covers the dual diaphragm with pictures: Brake Booster donor - Ford Truck Enthusiasts Forums

 

Not sure how to tell if dual or single. It is still on the truck. Mine is a camper special if it matters. My Marti report says 8100lb. GVW. The internet said F250's were around 4700Lbs. I need to learn how to put it safely on jack stands as it sounds heavy and I need to get under it a lot. I will look on Napa again or maybe go into my store as I have one close but many times they can't help me. Yes, I'm hoping for all new parts, but it seems boosters for my application might only be rebuilt. Update, Mine has to be a dual diaphragm. Napa has this "www.napaonline.com/en/shop/replacement-parts/brakes/brake-boosters/325626278" For a 72 F350. Doesn't say anything about discs which maybe they all were. Is this F350 booster an exact bolt in part with no mods to replace my F250 booster with discs? That "brake booster donor Ford Enthusiasts Forum" link is a wealth of info on this topic as you can also read related posts. Some of it above my head as I need to learn more. Thanks

 

When I go to replace my brake booster, this is the one I am going to get, it matches up with the information in that thread I sent you. Measure your booster and make sure it matches up with the one you have. The dimensions are listed in the NAPA description.

Power Brake Booster without Master Cylinder NBB 5473112 | Buy Online - NAPA Auto Parts

 

Also note that the NAPA brake booster replacement does not come with the mounting hardware, or the brake pedal rod extension, so don't turn them in with your core. There is also a plastic boot that goes next to the firewall that you want to keep, as there is no source for them except a junk yard. Here is a good picture that shows the brackets, plastic boot, and the pedal rod extension (still attached to the booster).

 

Take a quick pic of yours and post it up here. I'm sure someone can tell you from just looking.
That said, I always thought it was a simple matter of it being double the thickness of a regular single diaphragm version. But with all the variations to booster/master/bracket/pedal setups on these trucks, I'm just not sure.

It probably does, but who knows what was changed out by perhaps multiple PO's (previous owners) over the last few decades.

There is often a misinterpretation of GVWR and Curb Weight. A base 2-wheel drive 250 might just be in the 4700lb weight range. Probably a bit more, but it's not too far off.
The 8100 GVWR likely indicates a nice heavy duty suspension and brakes.

And even when you find someone that knows there old vehicles (rare anymore!) you just can't trust the parts in the box are going to be correct and match the old numbers. It's just a crapshoot sometimes.

The parts crapshoot extends to parts that don't work as well as the originals did. If you have any reason to believe that yours is original, I would have it rebuilt by a shop that specializes in that.

Great suggestion to ask for parts for an F350 just in case. You might find the right part that way. It's not that the other listings are wrong necessarily, but they're STILL trying to keep computers up to date with old parts applications. And that's subject to the info-inputter inputting the correct info interpreted from whatever they're interpreting it from. Assuming they even know how to do it!
Sometimes 'ya just gotta get creative.

Good luck!

Paul

 

Here are some photos. Not sure how to tell if it is original. I think my first choice might be to send it to be rebuilt as suggested. I figured out the GVW is the maximum truck and cargo/human weight combined. It seems camper specials have different brake parts which are harder to come by, and you have to figure out what models and years might have compatible parts.




is original

 

Do you know if yours is original? I posted pictures of mine and am thinking just having it rebuilt.

 

Are you asking me? If so, yes, mine is the original booster from 1979.
It’s the one that is shallower than yours, but of a notably larger diameter.

 

Sorry, I asked the wrong person

 

GreenF250, Do you know if yours is original? It looks different than mine. Maybe if yours isn't a camper special is why as I think non camper specials might be different. I posted pictures of mine and am thinking of just having it rebuilt for a sure fit. Just wondering if mine is factory

 

The picture I provided with the booster, mounting brackets, and plastic boot is not a picture of my booster, I think this booster is for a Dentside truck (1973-79) as it does not have the adjustable rod. I don't know for sure if my booster installed in my truck is the original one for sure, but I believe it is. Here is another good thread that talks about a 1971 F250 with disc brakes and is a Camper Special. If you look in the thread it has the same part number listed as the one in the NAPA add. The thing about the bumpside boosters is it has an adjustable brake pedal rod vs the dentside not being adjustable. The one thing about getting one from NAPA or O'Reilly's is that the core that was turned in may be from a dentside truck, so you never know. To make sure you get the right one, it might be best to send yours out to get rebuilt. There isn't much difference in my truck vs your truck, as you should have a little more beefed-up spring as it is 8100 GVW. I have the same problems with finding parts for mine. I would change out your soft brake lines if they are original to your truck, as they may look ok on the outside, but they get bad from the inside. I also recently found that Inline brakes make the hard lines for our trucks as well. They make them in stainless steel and OE metal.
Brake booster for 1971 F250 CS - front disk brakes - Ford Truck Enthusiasts Forums
1972 Ford F-250 2wd Complete Power Disc Brake Line Kit 3/4 Ton, Longbe – Inline Tube

 

I was wondering if I should replace all the lines while I'm at it and I needed that encouragement and reference where to get them. I will be looking for a place tomorrow to rebuild the booster. Hopefully the correct master cylinder won't be hard to find as I'm seeing a few variations. I'm thinking I need to consider my truck a F350 finding a correct MC as I'm not seeing specifics listed. So much to learn. Thanks

 

This discussion is serving to remind me that I need to get my Booster over to my local rebuilder before they close their doors!
I don’t actually know that they’re going to, or that they haven’t already. Just know that a lot of places like that have disappeared over the years, and the one Local to me has been there forever!
No more time for me to waste I guess.