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Brake Booster Losing Pressure with Engine Running

ntsqd

heratic car camper
Joined
Jan 30, 2005
Messages
3,815
Loc.
Upper SoKA
Some points that may or may not still apply.

Banjo bolt sealing washers; you can re-use old ones if they're not too grooved or damaged by heating them with a propane torch until they glow just a little. I hang them on a piece of wire and once they're almost glowing drop them into a Red* Solo Cup that is ~1/2 full of water. Unlike if you did this to steel it makes either aluminum or copper washers dead soft and they will seal properly.
*Cup color is crucially important to Country fans, not so much to others.

If you're questioning the pressure at the calipers then buy or build something like this: https://www.summitracing.com/parts/wil-260-0966 to get a pressure reading at the bleed nipple.

The day that I started using a hydraulic flaring tool (MasterCool brand in my case) was the day that my random leaking inverted flares stopped occurring. I have yet to have it make an off-center flare. Not cheap, but worth it if you periodically are going to be doing this sort of work.

Annealing of the SS flares might have got them to seal, but since the easy availability of the Cupro-Nickel tubing I don't bother with SS tube for brakes.
 
OP
OP
JeepGuy

JeepGuy

Contributor
Bronco Guru
Joined
Aug 24, 2006
Messages
1,268
Update:

Well, it's not perfect but the brakes definitely work.

I went back through and double checked all the joints. No leaks.

Jacked up the front and spun the tires, press the brakes, they stop.

Double checked the gap on the calipers after the install... Looks correct as there is probably 3/16" to 1/4" clearance, hard to tell from pictures.
Bronco Caliper Clearance 1.jpg
Bronco Caliper Clearance 2.jpg


Went on the Jungle website and ordered up a Vacuum Tester. Advertised to work on Engine vac as well as fuel pressure... Either way, I definitely have vacuum pressure at the booster. Only measured it at idle.
Bronco Intake Vacum.jpg


Road tested the Bronco and it does stop. I think I'm to the point of tuning in the pedal height. Still haven't really jammed on them as this was the first road test for the Bronco in a very long time and I'm checking for all kinds of things, not just brakes.

Thank you to all of the input in here.
 

ksagis

Contributor
Aspiring Bronco Guru
Joined
Jun 15, 2020
Messages
355
I get my conical crush washers from Crown Performance in Vista, CA, and keep some on hand for emergencies.

Looked them up today and realized they are close to my dads house in Escondido. May swing their shop the next time visiting him.

This is the website, correct? Unless I am blind, not seeing them on the website. Thanks again for the tip on the vendor

https://www.crownperformance.com/
 
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