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Brake Booster, 1973 Ranchero... |
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svENzoN 
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Joined: 08-May-2025 Location: Bavaria/Germany Status: Offline Points: 69 |
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 Topic: Brake Booster, 1973 Ranchero...Posted: 20-June-2025 at 10:20PM |
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Hi folks...
 Since yesterday, the brake pedal is returning very slowly after being depressed. 1973 Ranchero, 302cui, front disk brakes. The brakes themselves work normally, though. New master cylinder installed a few weeks ago. It now seems likely that the brake booster is defective. But before I look for and order a part, I checked the check valve today and discovered that it can be blown through in both directions. Am I right in assuming that this might be the only problem and I only need to replace this valve? It should only allow air to flow in one direction. Am I right?
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Greetz,
svENzoN '73 Ranchero 500, 302cui, AOD-Conversion, etc.! |
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Inkara1
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Joined: 17-November-2021 Location: Ridgecrest, CA Status: Offline Points: 515 |
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Posted: 20-June-2025 at 10:40PM |
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Try it. Way cheaper and easier than having to pull the booster and send it out to be rebuilt.
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1972 Gran Torino station wagon, light blue, 351C 2V, prior owner upgraded to 4V (2V heads), originally had a C4 but prior owner changed to C6 for some reason.
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svENzoN
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Joined: 08-May-2025 Location: Bavaria/Germany Status: Offline Points: 69 |
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Posted: 22-June-2025 at 6:38PM |
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Yes, I ordered that valve and try, sure.
But I think that in addition to rebuilding, there are also aftermarket parts that can be installed if it was not only the valve. The Cardone 54-73515 for example should work?
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Greetz,
svENzoN '73 Ranchero 500, 302cui, AOD-Conversion, etc.! |
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Inkara1
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Posted: 22-June-2025 at 9:51PM |
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If the photos online for that part number are accurate, then no. You'd need the bolt pattern to look like this:
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1972 Gran Torino station wagon, light blue, 351C 2V, prior owner upgraded to 4V (2V heads), originally had a C4 but prior owner changed to C6 for some reason.
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svENzoN
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Joined: 08-May-2025 Location: Bavaria/Germany Status: Offline Points: 69 |
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Posted: 24-June-2025 at 9:36PM |
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Really?
I found that...square pattern which should fit... ...every source says that it is a square pattern with 3 3/8" and that's also what it looks like when I look inside behind the brake pedal?  Edited by svENzoN - 24-June-2025 at 9:41PM |
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Greetz,
svENzoN '73 Ranchero 500, 302cui, AOD-Conversion, etc.! |
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Inkara1
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Posted: 25-June-2025 at 12:11AM |
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In this photo from a project on a 1973 car, the bolt holes for the booster can be seen next to the man working on the car. The holes aren't in a square pattern in this photo.
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1972 Gran Torino station wagon, light blue, 351C 2V, prior owner upgraded to 4V (2V heads), originally had a C4 but prior owner changed to C6 for some reason.
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svENzoN
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Joined: 08-May-2025 Location: Bavaria/Germany Status: Offline Points: 69 |
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Posted: 25-June-2025 at 12:40AM |
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Ur right. Thank you.
Hmmm...somewhere must be a mistake here...??? Someone else got an opinion? |
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Greetz,
svENzoN '73 Ranchero 500, 302cui, AOD-Conversion, etc.! |
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svENzoN
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Posted: 25-June-2025 at 1:25AM |
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I have to apologize.
The stupid AI was leading me on, and you were obviously right about the asymmetrical pattern. So the next question would be: Suppose it wasn't just the valve and I need a booster. Which one would fit? Or does anyone know something about working with an adapter? Any experience? Thank you very much!
Edited by svENzoN - 25-June-2025 at 2:52AM |
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Greetz,
svENzoN '73 Ranchero 500, 302cui, AOD-Conversion, etc.! |
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Inkara1
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Posted: 25-June-2025 at 4:46AM |
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Mine is a 1972, which uses a one-year-only booster. I tried to buy a new one, but one place let me buy it only to cancel my order and refund me, and the second place, I asked their customer service if "in stock" was true and they said it wasn't. I ended up having to send my old one off for a rebuild. I think 1973 is another one-year-only booster, but I'm not sure if that one is more available. If it's like 1972, sending it to get rebuilt might be the only option.
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1972 Gran Torino station wagon, light blue, 351C 2V, prior owner upgraded to 4V (2V heads), originally had a C4 but prior owner changed to C6 for some reason.
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svENzoN
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Posted: 25-June-2025 at 5:15AM |
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Thank you very much for your feedback.
And sorry if some of my statements sound naive. I disassemble a pan or shovel down to the last screw and back again and it works, but with four wheels, I'm really still like a toddler and have to ask. As far as I know, several booster-models would technically work. Isn't the main issue here the mounting pattern? Pushrods can be adapted, or threaded ones used? Regarding the pattern, I wonder why someone don't just drill a corresponding hole in the firewall for this one asymmetrical screw? Isn't there enough space inside to mount this one screw slightly offset? Btw., what does your 72 pattern look like? And why do you think that the 72-booster was 8nly this year? What's the difference? And unfortunately, I don't know about this one-year thing. You'd have to look it up using the part number. I actually thought 72 and 73 were compatible... but maybe I'm wrong again?
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Greetz,
svENzoN '73 Ranchero 500, 302cui, AOD-Conversion, etc.! |
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72 RS 351
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Posted: 25-June-2025 at 6:48AM |
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Ford very often changes parts during model runs, and the 1972 year had a ton of changes that happened before or early in 1973.
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Don
73 Ranchero "Sport 72 front end", floor shift/console, planning EFI 7000 rpm 351 stroker 73 Ranchero GT 351C-4V &4R70W for sale later. 92 Lincoln Mark VII SE GTC, OBDII 347/4R70W |
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Inkara1
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Posted: 25-June-2025 at 7:09AM |
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I'm pretty sure the 1972 and 1973 boosters have the same bolt pattern and it changed for 1974, but I'm not 100% sure. You could drill the holes for any pattern you want, but you'd have to make sure the firewall is strengthened around the new holes so it doesn't flex when you hit the brakes. The stock mounting has more than one layer of steel.
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1972 Gran Torino station wagon, light blue, 351C 2V, prior owner upgraded to 4V (2V heads), originally had a C4 but prior owner changed to C6 for some reason.
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svENzoN
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Joined: 08-May-2025 Location: Bavaria/Germany Status: Offline Points: 69 |
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Posted: 25-June-2025 at 7:33AM |
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Thanks, guys.
Yes, I understand the stability issue, but since only the one asymmetrical stud bolt would change anyway, I assume it would still be more than sufficient and secure. It would still have to be checked whether the connection to the brake pedal is approximately the same length and whether the bolt fits the mounting.
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Greetz,
svENzoN '73 Ranchero 500, 302cui, AOD-Conversion, etc.! |
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pyntre
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Posted: 25-June-2025 at 7:37AM |
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Get the correct part , rebuild yours or get another correct core for rebuild .
You’re dealing with most integral system on the vehicle !! If not for your safety , the safety of the other people on the road !!
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svENzoN
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Posted: 25-June-2025 at 7:55AM |
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Don't worry, ...
...I would never endanger the safety of others, nor my own. I'm simply trying to get closer to the topic and the solution and am doing research on it.
If certain parts are no longer available, you're practically forced to look for other solutions. By the way, an offset stud bolt for attaching a booster to the firewall doesn't endanger anyone if it's done correctly. There are even adapter plates for this purpose...they do nothing else.
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Greetz,
svENzoN '73 Ranchero 500, 302cui, AOD-Conversion, etc.! |
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pyntre
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Posted: 25-June-2025 at 9:11AM |
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I went through the same thing with the
Unavailable booster for my 75Mercury . I put a request in at Rock auto so that if one became available they would email me . I had no faith that would ever work but to my surprise I got an email in about 4 weeks saying they had one ! I had talked to Booster Dewey folks and was just about to ship mine out when I got the email . The new (rebuilt ) one from Rock Auto went back in perfectly . The studs on these 75 cars are not symmetrical . And the studs go through a sizable interior steel plate that’s designed to carry the pressure of braking ! The actual firewall in my car would never hold that load by itself !
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svENzoN
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Posted: 25-June-2025 at 8:00PM |
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You were incredibly lucky. Nice story.
For my model, RockAuto doesn't even have a "notify me" button for this part. They seem to have given up on that. Whatever. If I really need a new booster, there will be a solution, I'm sure of it.
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Greetz,
svENzoN '73 Ranchero 500, 302cui, AOD-Conversion, etc.! |
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svENzoN
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Posted: 26-June-2025 at 5:31AM |
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Hej there...
There's good news for today. I just installed the new check valve this morning (german time zone wayyy earlier than yours) and, lo and behold, it seems to be working. Vacuum is being built up, and the pedal becomes hard again after the engine is turned off, which wasn't the case before. With the engine running, I can brake multiple times in a row again, and the pedal always behaves the same. It's not like it immediately returns like an arrow after I release it, but it didn't do that before either. The miserable whistling also seems to be gone; at least, it didn't occur again during the test run that lasted several minutes. So, the original condition, as we know it, has been restored, and we can drive. Nevertheless, I'll stick with the booster story and discuss the membrane replacement issue with our parts specialist. Thanks for all that input, people, I liked it!
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Greetz,
svENzoN '73 Ranchero 500, 302cui, AOD-Conversion, etc.! |
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Inkara1
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Posted: 26-June-2025 at 6:12AM |
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That is good news!
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1972 Gran Torino station wagon, light blue, 351C 2V, prior owner upgraded to 4V (2V heads), originally had a C4 but prior owner changed to C6 for some reason.
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