Water in the cab

[alborz]

I have a peterbilt 387. I have noticed when A/C is running or it rains I see a small amount of water running from behind the glove box to passenger footrest. Also when it’s raining I notice water from under the gauges assembly dripping to driver foot area. It gets the wires around and behind the steering column wet. This happens when actually I’m driving in the rain. I have checked the firewall from engine compartment no openings found. Also the A/C drain tube is ok and unclugged. The A/C and heat system assembly is connected to the firewall just below the windshield outside the cab with few bolts and nuts. How water gets in is a puzzle. [/size][/b]

[Waterloo]

Well, could be from around the windshield. Is that a gasket holding the glass in or is it butyl?

Also where the visor attaches to the roof, that could also be a possible area that water gets in. The other area is around the roof line where the cab roof attaches to the body. Check around those A pillars up near the top of the doors, there is a seam there also.

Our ProStars like to leak like that, I used a case of silicon caulk all around the roof line and where the visor attaches to the cab roof. The leaks have stopped.

The water when the AC is running is something different, sounds almost like the heater core is leaking, but you said it is water, not coolant. Condenser does not sound like it is draining to the outside. I know you said you checked the drain, but maybe something got up in the box and has it plugged from there. Have you gently used say a coat hanger to push up into that drain, all the way into the AC box to clear any blockage? You may have to pull the dash apart to physically get into the condenser box to inspect and clean.

[mmssvv]

Let me share my experience with similar problem.
On my Volvo the windshield is hold in place by a rubber gasket.This rubber originally has two small holes symmetrically located only on the one of the longest(horizontal) sides.
When some morons at Safelite company changed my windshield,they didn't put the right side with those holes on the bottom and I start get some water inside the cab coming out under the dash.
After drilling the new holes on the WRONG installed rubber side the problem was solved.Pay attention
those holes must match the two symmetrical very small canals on the cab body.
That way the water collecting in the rubber will come out instead of overflowing inside.       
Hope this will help somebody.

[Rig Wrench]

Pete's are notorious for the windshields leaking. Whatever your mileage is, if its the flat 2 piece glass, replace em. Make sure the windshield frame is squeaky clean before the new seal is put in. Also, on the ac leak, the condensation drains plug easy, and pushes the water to the cab side. Make sure its clear

[Rig Wrench]

I forgot to add. The windsheilds are only about 70 bux a piece. And only take an hour or so to change both

[Hammerhead]

(02-06-2018 )Rig Wrench Wrote:  Pete's are notorious for the windshields leaking. Whatever your mileage is, if its the flat 2 piece glass, replace em. Make sure the windshield frame is squeaky clean before the new seal is put in. Also, on the ac leak, the condensation drains plug easy, and pushes the water to the cab side. Make sure its clear.

The passenger side during a/c use leak is exactly that, the cores get dusty then the condensation makes goo and when you shut off the a/c the goo sticks to and plugs up the drain, or as I even had one time builds a damn and some water went on the pass side floor and some came out the drain so I didn't think the drain was plugged. Kinda laughed when I took it apart to find that.

The few times when I had Pete windshields last about 3 years without chipping, cracking, or being too sandblasted, they had to be changed because of leaking. The rubber starts to dry out and shrink after so long and then they leak.

Like Wrench says, they're cheap, so just change them out...

If you still get water on the driver's side after new windshields, put some silicone (which I hate), or seam sealer around the plastic hoods that shield the wiring and such where it enters the cab. They don't always lay flush, and they don't have gaskets, they're covers not seals so they will fool you into thinking the firewall shouldn't leak...
The seam sealer stays pliable and you can reseal the covers with it if you ever have to take them off, unlike silicone which is why I hate it.

[Waterloo]

GOOD INFO!