Air brake parts identification questions.

Hi guys, there are some issues with the brakes on my dad's bus.
It's a 1978 IBC Mk3 with a 3208 and auto in the back.
Ever since he's had it, the park brakes take ages to release. Is that likely to be the relay valve? (the only ones I can identify, since they're so obvious).
Lately (it mostly sits around) the service brakes are sticking on and you have to jab the pedal to release them. Any ideas where we should look for that?
Also, could anyone tell me what these pictured things are, please? Just guessing to do with which air tank fills first. It has front and rear wet and dry tanks.
Many thanks, Jarrod.

The top 2 Pics are of a Relay Valve. Pic 3 is a quick release valve, & the bottom 2 are of the Spring Brake control Valve.

Hayseed, excellent, thank you. I actually meant quick release valve was the only one I knew, had my terminology wrong.
I have to find a plumbing diagram for this thing. We tried to follow the hoses, but they just go into a sort of loom (too many).
At least I have something to go off, now.
After this, I have to chase a big leak on the White.....(exhausting heavily out the foot valve all the time - advised it may actually be a chamber)

Thanks again, Jarrod.

Your White will likely need a new kit in the foot valve............one clue for slow maxi blowoff,is to wait until full pressure is up,then push in the valve ......the extra pressure will seal the various valves and stop leaks that happen at low pressure..........the blowoff tank may be too small.........back in the day,you had to be able to release the maxis fully three times with the engine stopped.............might have a leaking diaphragm ,too.

Many moons ago i remember with the westinghouse system , if the diaphram got all saggy in the quick release valve,
it would cover up the exhaust port, making the release very slow...........
A new release valve should fix the situation......
As a quick fix we would pull the quick release valve apart and flip over the diaphram...........
Whether that works with yours i would not know.............

...................Billy..................

Lift the brake pedal up to expose the rubber boot and plunger and sparay sum WD40 to free up the pedal
they all may need a disassmble & clean and any rubber or 'O' rings re install with rubber grease or mums good petroleum jelly
https://cdn11.bigcommerce.com/s-josrcotf/images/stencil/608x608/products/5708/14983/SI932I__05636.1632834748.jpg?c=2
normally a brake shop will not stuff around ........ they fit new valves etc .......for safty reasons .......and the kits for the valves are dearer thsan a new valve
cya

Jarrod, Forget the brake problem. What's with the 3 legs. I see 2 with shoes and socks and one with thongs. Maybe the one is holding the peddle down when you arn't looking.

Jarrod

I replaced both those identical valves on the Renault/Mack. They were leaking and sticking and internally corroded with oily/watery porridge. Action Mechanical used to be called Action Brakes in Northgate Brisbane ordered them in for me and I was very surprised how cheap they were. Took about an hour to chase all the various pipes (mark each and the corresponding valve port as you take them off!!!!) but it was like a new truck afterwards.

Air Brakes in Rocklea will actually rebuild stuff.

As the other blokes who know more than me mentioned could be in the foot valve

asw120 wrote:

After this, I have to chase a big leak on the White.....(exhausting heavily out the foot valve all the time - advised it may actually be a chamber)

Jarrod, does it it only do it with the park Brake off..? or all the time.?

Treadle valve is a pretty frequent culprit and not many mechanics who have yet to retire have ever fitted a kit. A new E6 treadle valve will be around or less that $100. A trade secret from a towie is to squirt your favourite oily stuff down the compressor air intake, instant fix for exhausting treadle valve and other ills.