no modify power brakes?

[jerrybromley]

Can a vacuum assist be added to an early Bronco with manual brakes without changing anything else ?

 

[Broncobowsher]

Yes, but with limitations...
The stock power brake bracket won't clear the master to the inner fender.
Most of the aftermarket bracket sets the master a little higher to clear the inner fender. But limits the booster diameter. The power from a power booster come from the diameter of the booster. Air pressure on one side, vacuum on the other. The pressure difference and the number of square inches of diaphragm is the force. Since you can't increase atmospheric pressure in a brake booster, and engine vacuum is pretty much fixed as well, the thing that can have a lot of change is the diameter. There are dual diaphragm boosters that have more power than the singles, but when you have to go small on the booster it is still small. What you will typically find is under light braking the booster has enough boost to feel good. But get onto the brakes hard and you run out of booster boosting and it feels like you ran out of brakes. There is still more to be had but the effort rise is so severe you don't know it. for a small tire rig, you can get away with vacuum brakes and have enough power even with the limited booster size. But as the tires get larger the vacuum booster doesn't cut it anymore. And the reason we just go to hydroboost these days. It works, don't run out of booster power.

 

[RPM289]

What is the most economical Hydroboost mod to go with? Stock power steering setup.

 

[73azbronco]

You want brakes, or cheap? Don't go cheap on brakes.

 

[Timmy390]

Power 4 wheel drum brakes...yup ran them for 10 years not my DD. I can't count the number of oh $hit moments I had. I drove knowing to stay away from everyone and took it easy. They did ok overall but I had to adjust the front all the time. Even rebuilt everything up front but lots of adjusting was needed.

I don't recommend doing it but it can be done.

Tim

 

[.94 OR]

I built my own with a mustang booster can. Has worked fine for me and I didn't have to dent the fender and can still remove the valve cover pretty easily.

 

[SteveL]

Cheapest hydroboost is most likely the astro van set up from the junk yard. You also need power steering to run it.

 

[RPM289]

I built my own with a mustang booster can. Has worked fine for me and I didn't have to dent the fender and can still remove the valve cover pretty easily.

Can we get some pics and details on your setup?

 

[Mike D]

booster brake

i also have a bronco with booster off 1992 mustang but i also have disc brakes. works great with 35 tires i am running.I have a buddy who built a half cab and installed the booster setup tom sells with manual brakes.. i drove it and it works great. he runs stock tires. i bought a toms booster this today off classic and i am going to try it on one of mine

 

[jerrybromley]

Great info Guys. I was looking at Toms and was not sure if I would have to put in an adjustable valve in to make it work.

 

[Skinnyr1]

I just ordered a vacuum assist unit for mine. For $160 shipped to my door, I figure it is worth a try. My rig has 31" tires, and stops ok, I'd just like more of a feel of a modern vehicle.

 

[.94 OR]

I'm sure I'll hear from the nay-sayers, but it has been on there since about 1990 and has worked well stopping 31's on 4 drums. The guy at the parts store told me there was a restrictor on the front port that could be removed for when I went front disc. Haven't needed to yet.

 

[jerrybromley]

Well I ordered my power assist from Toms .( They say no-modify). Not there yet but when I get everything installed and set-up I will post what I find....

 

[scotte6]

Well I ordered my power assist from Toms .( They say no-modify). Not there yet but when I get everything installed and set-up I will post what I find....

Did you get this installed yet? Looking to install a power set up on my '68.

 

[jerrybromley]

Yes I have all the pieces in place but haven't got the motor running so I don't have the brakes bled yet. The install was easy in that I had the motor out when I installed them. I will post again when I have them working

 

[Rustytruck]

in order to reuse the master cylinder you have to pull the peddle rod to go to the short one. I have never been able to pull the rod without destroying something so add a new master cylinder to the list.

 

[jerrybromley]

I had my bronco on the road for the first time this week and the Tom's no modify power drum brake set-up seems to work great. I have never had power brakes( or power steering) on a bronco before. I think this works extremely well on my bronco but, I've only driven it about 5 miles

 

[Skinnyr1]

Agreed. I've had my vacuum booster on mine for two years now. Works and feels great on the road.

 

[jerrybromley]

I now have a different opinion on the power boosted drum brakes. I had to do a panic stop the other day. It scared the ever lovin crap otta me !!! I'm sure the drums were probably not adjusted properly but I played hell getting her under control. I have ordered a disc brake conversion for her. I should have it on sometime next week.

 

[Timmy390]

I now have a different opinion on the power boosted drum brakes. I had to do a panic stop the other day. It scared the ever lovin crap otta me !!! I'm sure the drums were probably not adjusted properly but I played hell getting her under control. I have ordered a disc brake conversion for her. I should have it on sometime next week.

YUP....I had power drums for 10 years. It worked great till a panic stop was needed and you never knew where the rig was going to dart. If you keep them adjusted correctly it's not as bad. I just drove in a bubble. Made sure everything stayed outside my bubble and drove much slower than I do now......

Tim