Freightliner FL60 dash warning light

[Opi]

My buddy just bought an fl60 crane truck and this warning light is on the dash accompanied by a terrible annoying buzzing that doesnt go away, except for maybe a second or two once and a while. for you guys that know air brakes its almost exactly like the buzzer that goes off until you hit 60psi. the thing doesnt have air brakes though. heres a picture. any idea what it could be?



thanks

[bushpilot]

Brake Fluid Warning Light <Low Fluid> !

Its probably "blinking" off on RARE occasion because
the fluid level is bouncing as you go down the road...if not
then its cause the fluid level "sloshes" front to rear when he
takes off or comes to a stop.

[ford_trck]

It is something with the primary brakes.
Does the hydroboost motor kick on when the brake is pressed and engine not running? (Sometimes the key has to be on.)
Or it could be something easy like low brake fluid.

[Opi]

Originally Posted by bushpilot

Brake Fluid Warning Light <Low Fluid> !

Its probably "blinking" off on RARE occasion because
the fluid level is bouncing as you go down the road...if not
then its cause the fluid level "sloshes" front to rear when he
takes off or comes to a stop.

we checked the fluid, theres really no clear markings but this is where the fluid is, i think it seems low




also this line is slightly pinched i dont remember specifically what it was off of, but it was leading into the powersteering resevoir i believe.. just snapped a picture of it incase that has anything to do with it. didnt seem like anything was really leaking anywhere though

Originally Posted by ford_trck

It is something with the primary brakes.
Does the hydroboost motor kick on when the brake is pressed and engine not running? (Sometimes the key has to be on.)
Or it could be something easy like low brake fluid.

it does without it being keyed on, i think its low fluid, also, there was a can of dot4 fluid in the truck, empty and the resevoir clearly states dot3 is that that big of a deal or no

[bushpilot]

1st im not a big rig or otr owner/driver....but that symbol is universal for
conventional cars/trucks etc.

I would agree that the brake fluid looks low....it would seem that its barely
1/3 full...but theres the thing...

as pads/shoes wear, the brake fluid "takes up the slack"...and as a
result of pads/shoes wear it can give the appearance that brake fluid is low.

In a sealed system (assuming no leaks) BRAKE FLUID goes low as the
pads/shoes wear...i dont recommend ADDING brake fluid w/out full knowledge
of the conditions and thickness of the brake pads/shoes as well as checking
ALL the lines for leaks.

as soon as you put new pads/shoes on a vehicle w/ "low" brake fluid, the fluid
level will rise (less slack)

[dixie123]

YES THE BRAKE FLUID IS LOW.IF YOU TAKE CAP OFF THE MASTER CYLENDER . THERE WILL BE A SPLIT RING EXTENDING DOWN INTO THE RESIVOIR. THE FLUID SHOULD BE UP TO THAT RING. AS FOR THE HOSE IT IS A RETURN HOSE. YOUR POWER STEERING AND BRAKE BOOSTER OFF THE SAME PUMP. THAT LIGHT AND BUZZER INDECATE LOW PRESSURE IN THE SYSTEM. IF YOU STEP ON THE BRAKE AND TRY TO TURN THE STEERING WHEEL ? IS IT HARD TO TURN? THERE IS A SENSOR IN THE BOOSTER MAKE SURE IT IS PLUGGED IN.

[tc2]

there are 3 things that will cause this light to come on:
1. low brake fluid
2. a leak in the front or rear brakes causing a difference in pressure between the front and rear system.
3. a lack of flow through the hydromax or hydroboost system (the power steering lines that supply power assist to your brakes.

There are switches that monitor all 3 parts of the system.
1. on the fluid reservoir
2. on the master cylinder
3. behind the master cylinder on the booster.