Brake Buddy type system question.

[Don4107]

Do these systems supply vacuum to the brake booster?  If not they would have to push a ton on the pedal to get much brake action. 

[Nick Badame Refrig/ACC]

Hi Don,

I did alot of reading today on 3 systems and all seem to be brute force with no vacuum.

Nick-

[Jerry Liebler]

Don,
    The instructions for my 'brakemaster'  from 'Roadmaster' advise depressing the pedal several times to bleed off the vacuum before connecting the cylinder to the pedal.  The 'brakemaster' uses a pneumatic cylinder 'teed' into the bus airbrake system. Evidently it provides plenty of pedal force and doesn't depend on the towed having 'power brakes'.
Regards
Jerry 4107 1120

[jjrbus]

Same on Brake buddy, pump brake to bleed vacuum. We would think this would be hard on the toad brake and body structure, but I could find no evidence of problems surfing the RV boards.

[ttomas]

I did not know about bleeding the booster pump, and have never had any trouble with the brake buddy.(Learn alot new everyday on this site) It is brute force but works really good. I have probably pulled an extended Ford Aerostar 30k+ miles with it.  Tom

[edroelle]

You have identified one of the faults of many of the toad brake systems (those with air cylinders at the brake pedal).

If you leave vacuum in your booster, your toad will brake heavily and try to slow the bus.

Vehicle firewalls are not designed for continual no-power (no vacuum) braking.  Dependent of the number of brake applies and the force, cracking or deformation of the firewall could occur.

With no vacuum in the brake booster, toad brake effectiveness is severely limited, or excessive pedal pressure is required.

Ed Roelle
Flint, MI

[Barn Owl]

This post has some links to various brake systems:

http://www.busconversions.com/bbs/index.php?topic=3117.msg27832#msg27832

[Sojourner]

Amen...to Ed Roelle's post.

Master cylinder with vacuum chamber assy will flex more up & down then with vacuum on while pushing pedal.
Another word without vacuum is like panic applied pressure every time using air-cylinder. Have someone push pedal without vacuum while you watch end of master-cylinder for up & down "plane" movement.
One thing for sure....it will be slower apply move than added special air-cylinder in between master to boaster unit. I believe this system has a "one-way" piston rod movement so it is still normal pedal pressure movement while driving car.

FWIW

Sojourn for Christ, Jerry