Will a 78-89 brake vacuum assist work on 77?

[84toy]

Will a 78-89 brake booster retrofit on a 74-77. I notice that the later unit is larger but the master cylinder and mounting bracket are the same. Anyone tried to swap and are there any issues?

Also, I need one for the daughter project if you have one laying around.

[Bill Verburg]

It can be done, but not easily. There are some structural changes that are needed in the front firewall area.

You can look here for a summary of how to do it

[javadog]

I've never done this on an a 911 but I have swapped boosters on a 930 with no issues.

JR

[Bill Verburg]

Originally Posted by javadog

I've never done this on an a 911 but I have swapped boosters on a 930 wirt no issues.

JR

The issue is converting a non boosted system to a boosted system.

converting from one boosted to another is just swapping parts

[javadog]

Well,

It's hard to tell from his original question. In the title, he asks about swapping the booster on a '77, which had the boosted brakes. Then, he mentions the '74-'77 year cars. And lastly, he has a sentence there that sound like he just wants a larger booster, presumably for his daughter, as it would require less force on the pedal.

So, I just threw out the answer about the boosters, in case that was his actual question. If he is talking about adding a booster to a car that doesn't have one, then you are right, it's a pain.

JR

[84toy]

Thanks for the responses....I'll try to be a little more clear. The 77 already has a brake booster but it's NFG. It is significantly smaller in diameter than the 78-89 booster units. What I want to do is find a 78-89 booster and use it on this project if it will work.

According to PET, the MC is the same and the bracket is the same that holds the booster so I can't see any issues with using the 78-89 unit but I want to make sure it will work before buying one. So, the big question is: Can a 78-89 booster unit be bolted on a 77 car?

[javadog]

Paul,

As I mentioned before, I've done it on a 930, so I can't think of any reason it wouldn't work on a 911, although I've never specifically looked at the details for your exact example. Maybe somebody else can reply.

JR

[84toy]

Thanks JR, I'll post a WTB for the 78-89 unit. I'm 90% confident it will work perfectly.