View Full Version : Brake Tank Pressure Gauges

Joe Camper
04-04-2013, 12:27 PM
Are you still chasing brake tank pressure loss and ran out of places to look.

Well did you try looking here?


This is a shot of the lower back corner of the steering bay

Joe Camper
04-04-2013, 12:42 PM
For those who haven't needed to yet, There are very very very tiny air lines prevo uses to feed the gauges. Normally 1/4 in plastic is the smallest stuff you will find on a truck. These lines are less than 1/4 the size of that, crazy tiny lines. They make problems many times the fittings at the back of the gauges are leaking. You will NEVER fine these ANYWHERE but prevo so dont even try, fittings as well. Take 1 to a truck parts place and ask for the fitting they will think you are from Mars.

If you find your leaking at the fitting on the back of the gauge DO NOT attempt to tighten them unless you have a replacement fitting in hand. Otherwise you risk running without a gauge till you replace what youve dammaged trying to tighten on an old brittle plastic tube.


Here is a close up view of the first photo. There is a manifold of sorts at that location and that is where those tiny lines for the air pressure gauges are fed from. They have the same tiny prone to leaking fittings as on the back of the gauges you may or may not have already replaced. You will not see these points from just looking in you need to get your head into the compartment to see these. I almost always see bubbles here. DO NOT ATTEMPT any adjustments without new components in hand.

Joe Camper
04-04-2013, 12:56 PM
While your down there soap up the white plastic sending units that are threaded out of the front of the same small aluminum block the air lines are coming out of. These are your the sending units for the low air pressure warning system thereare 2 of those and a 3rd one too that one is for the brake light signal switch.

These are prone to leaking Ive seen MANY MANY leaking. There are 2 small screws holding them togeather that sometimes are loose and can be tightened and slow the leak but usually not stop the bubbles completly . DO NOT get carried away with tightening without replacements in hand. Bad photo but it is the little white plastic piece the first photo shows it too.


04-04-2013, 10:47 PM
Them small lines a avalible at any parts store they are often used for oil preasure gauges

Joe Camper
04-05-2013, 08:35 AM

The photos are larger than actuall. If you can come up with this line at a local parts place you definatly win a cookie.:o

I would be willing to risk a bet they are even smaller than that too but I certianly could be wrong.