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Underdog Inc · 10-04-2023, 12:33 PM

Hello,
I have a 1992 Gulf Stream Sun Clipper 8313 Diesel. There is an open port on what I believe is called a Bendix. I could be wrong. Due to the air coming out of this port it is causing my compressor & air dryer to continuously cycle. When I connect a piece of vacuum line to the open port that has air coming out if it and kink the line a vacuum line pops off on a ball shaped vacuum canister located next to the bendex/open port. I’m assuming that this port connects to something but I have been unable to locate what it goes to. I’ll attach a few pics of the items in question. Any help would be appreciated. I new to this type of system & learning.
Thanks
Josh

Hufficon · 10-05-2023, 08:50 PM

Could be a perforated biscuit in the brake actuator. The actuator is connected by linkage to the brake backing plate at the wheel. Usually 2 bowl shaped pieces held together by a bolt on clamp. The biscuit is a round rubber bowl shaped disk between the 2 halves.

THenne1713 · 10-05-2023, 11:57 PM

Suspect you need to research/ study air brake operation sequence? I have always understood with air brakes, the air releases brakes and springs engage the brakes, = Pressure required to be able to roll. So air has to DUMP/ bleed to apply brakes? (Experts, feel free to correct my statement if wrong?)... but, yeah, pressure coming OUT of a VACUUM CANISTER ball does sound wrong, like lines crossed or something blown?

twinboat · 10-06-2023, 05:43 AM

Quote:

Originally Posted by THenne1713

Suspect you need to research/ study air brake operation sequence? I have always understood with air brakes, the air releases brakes and springs engage the brakes, = Pressure required to be able to roll. So air has to DUMP/ bleed to apply brakes? (Experts, feel free to correct my statement if wrong?)... but, yeah, pressure coming OUT of a VACUUM CANISTER ball does sound wrong, like lines crossed or something blown?

Wrong.

Air releases parking brake only.
Air applies service brakes.

twinboat · 10-06-2023, 05:44 AM

Quote:

Originally Posted by Hufficon

Could be a perforated biscuit in the brake actuator. The actuator is connected by linkage to the brake backing plate at the wheel. Usually 2 bowl shaped pieces held together by a bolt on clamp. The biscuit is a round rubber bowl shaped disk between the 2 halves.

Biscuits in bowls, not helpful.

twinboat · 10-06-2023, 05:47 AM

That port does not do to a vacuum port.

The pictures show an adjustablr pressure regulator that controller air flow to something but not to anything with push on fittings.

Your going to need some professional help on figuring out what's missing.

Hufficon · 10-08-2023, 04:25 PM

Quote:

Originally Posted by twinboat

Biscuits in bowls, not helpful.

Sorry I was just trying to describe what OP may have been looking for. Calling the diaphragm a biscuit was a carry-over from my mechanic days and what they called it in the parts store where I worked before I opened my shop. I should have been more clear. Here are a couple of examples of the shapes I was referring to.

https://www.irv2.com/photopost/showfull.php?photo=38297

Underdog Inc · 05-08-2024, 04:00 PM

Someone told me today that this is a valve somehow tied to the cruise control. It does have a vacuum line that runs to the cruise control servo. Maybe that helps???? Any ideas???