Question about adding a brake booster

[Potshot]

Okay, I revived the sport enough to drive it around the yard and down the street. As with the previous Bronco I owned, I am now interested in adding a power booster.

I'm not feeling super compelled to do discs up front, but has anyone added the power booster option with drums all the way around? I'd be curious about the experience and would appreciate any advice.

 

[BGBronco]

I researched this years ago and decided to go disc up front. Easier to press but doesnt fix the weakness of drum brakes ... fading when hot, pull to one side when wet, requiring frequent adjustments, etc. Makes it easier to lock up the wheels but it doesn't change how fast the truck stops and my understanding is that drums are highly sensitive to pressure so there may be a few things there to check into.

If you go that route and you don't like it, you can reuse the booster but the Master Cylinders would be different.

My amateur opinion.

---

 

[Broncobowsher]

Brake booster is just an amplifier.
It amplifies the input effort into brake effort.
It amplifies any issues with the brakes as well. A little bit of pull will turn into a lot of pull. A little bit of brake fade will turn into a lot of brake fade. A little bit of wet brake loss of performance will turn into a lot of lost performance.
Brake booster do not add capacity, that limitation is with the brakes themselves. It only makes it easier to apply.

With all that said, hydroboost has been the brake booster of choice for several decades now. A lot of people have gone from vacuum boosters to hydroboost, never heard of anyone going from hydroboost to a vacuum booster.

Vacuum boosters in a Bronco is a challenger to get right. Ford ended up with the angle bracket. And that took a different inner fender to clear it. Vacuum boosters come in different sizes. The small ones package better, but at a bad performance aspect. The feel just fine under light use, but under hard braking you run out of booster and are suddenly pushing through the booster back into manual brakes.

The booster doesn't care what kind of brakes they are applying.

 

[73azbronco]

Biggest drawback on brake booster, make sure you have good vacuum.

I have good vacuum, 19 last I checked.

I tested my booster system disk front drum rear with another EB on 4 wheel disk with hydro boost, I noticed no real difference except the all disk would lock a rear easier. My booster system feels pretty close to my 2024 Rubicons brake pedal.

 

[Potshot]

Thanks guys. I'm reasonably familiar with both hydro boost and vacuum boost. I put a hydro boost system and 4 wheel discs on my '67 charger and it stops like a modern car. Putting vacuum boost (and front discs) was one of the first upgrades I did on my last Bronco and even with the large wheel setup it did okay. It's interesting to see how common hydro boost has become.

Somewhat related, I had a 69 Chrysler 300 with drums all around for a bit and I was amazed at how well it stopped, so with this little Bronco sport I thought I might just leave things relatively untouched and just enjoy the thing for a while. Until I drove it lol.

After I first posted I started thinking about going with discs in front, but now with hydroboost in mind it means I'd be adding power steering too.

The wife is interested in driving it so I'm guessing I'll be going down the power steering route anyhow, I'll just need to consider whether the extra money for the hydroboost makes sense.

 

[Broncobowsher]

Often a hydroboost setup is less expensive than a vacuum booster setup by the time you are done.

 

[ntsqd]

I've converted an SJ (Wagoneer) and a FSB to hydro-boost, but not an EB. After driving those and the Bronc-up (which came to me with H-B installed) I highly doubt that I'll ever consider a vacuum booster. The SJ's conversion was fairly inexpensive. I used an H-B unit from a late 80's full size GM van, all AN hoses and and a Rock Auto sourced m/c. It cost less to do that than the vendor sourced H-B conversion kit that I used on the FSB, and that kit re-used the existing m/c.

 

[Potshot]

Respectfully, how so if I also have to add power steering? Even if I add it, hydroboost seems more expensive than vacuum.

Granted, I'm also looking at kits so I might be skewed in my view. If you have a way (or have seen a way) to make this less financially painful, I'm all ears!

 

[ntsqd]

There's a fair number of threads here about how each has done an H-B conversion. The input push-rod seems to be the biggest hang-up for most. If you have fabrication skills that's easily solved by making it adjustable or at least two piece. The Astro van H-B seems to be a quite popular JY donor. About the only other issue that I see is the return plumbing. BEst if you have a reservoir with two separate returns, but it can be done with only one return.

Something that I didn't know until I started the first of these conversions is that Ford has a different m/c mounting stud spacing than GM uses. If you go the JY donor route keep that in mind. If the donor is a GM, then you'll need GM application m/c's. If the donor is a Ford, then you'll need Ford application donors.