Under Dash water leak

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DragginMAster

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I read once a while back on some guys dart restoration website about a "common leak" found on the firewall of darts and other a bodies.

of course I cannot find that site anymore, and I think he mentioned it being at a seam of the firewall / cowl.

well.

My car has a under dash leak on the driver side. When I had the dash tore apart I inspected the wiper pivots they show no sign of being the source.

one of the bolts for the voltage regulator was missing and I could not get another to thread back in, bolts of the corrects size would not stay tight and could not fit a bigger one. so I smeared a dab of silicone over the hole for a quick leak preventative. it has not rained since and I have not had time to venture to the carwash to see how that did for the leak. there is a bit of surface rust inside on the firewall around and below where the master cylinder is. could that be the source? would it be worth my time to remove the master cylinder clean things up and reinstall the master cylinder with some sillycone?

or is there an actual mystical common leakage that others have suffered and conquered? having the leak prevents me wanting to put new carpet in.
 
I have never heard of that before, but I would say if it is around your master cylinder i would be checking it for a leaking seal. And I still wouldn't rule out the wiper pivots either. Just my 2 cents on this. i am sure some will come along that might know more tham me on this subject.
 
I'd try replacing the wiper pivot seals anyway. The master cylinder probably has rust around it from the fluid leaking and eating away the paint, hence allowing the area to rust. I'd also check the cowl area for a blockage in the drain holes. If you get a lot of crap in there water will build up and find it's way in.
 
If it's not from the wiper pivot seals, then it's probably from the windshield seal gasket. Mine leaked between the gasket and bottom passenger side corner of the windshield frame and pooled at the front of the passener foot well.
 
Well here go's nothing.
Put a water sprinkler under the car on the drivers side and let it hit the fire wall.
let it run for 15 to 20 min if it don't leak put a slow running water hose on the wind sheild on the drivers side and jack up the passenger side.
If it still don't leak then do the other side the same way.
Just thought I would give you my 10 cents worth

This is how we find water leaks in new car's
 
H22A4 said:
If it's not from the wiper pivot seals, then it's probably from the windshield seal gasket. Mine leaked between the gasket and bottom passenger side corner of the windshield frame and pooled at the front of the passener foot well.
Click to expand...


Yeah, the windshield gasket...If it's ever had new glass installed, it could be thinner than the original glass and allow water to enter around the glass. Seen it happen more than once.
 
thanks for dispelling my mythical leak, will change the seals and check other things. I have had the glass replaced, but the leak was there before the new glass.
 
chances are it's the windshield. the correct way to seal it is with a urethane sealant. you'll need to remove the chrome trim, start by squeezing the end of the nozzle between the glass and gasket and filling all around the perimeter of the glass. next back fill the area on the outside of the car between the gasket and body. i know some people use silicone for this but ive been an auto glass tech for 9 years and i can tell you if you use silicone between the body and gasket and there is any bare metal (even scratches) the acid (vinegar) in the silicone will quickly cause rust issues. oh and gts340 is 100% correct about windshields being thinner then original, even on new cars we're finding the glass to be too thin when replaced and the moldings and cowl leave gaps between themselves and the glass. (damned outsourced production)
 
thanks for the link, useful info.

bentsixscamp, is there a urethane sealant you would recommend?

i got a nice rain ... thunder... torrential rainstorm... tsunami today and poked my head underneath the dash with my feet stickin out in the rain (small car, big guy) and have narrowed it down to the windshield seal.
 
I installed my windshield myself and what I did was sand down and paint all the metal around the window channel. I found two drains in the lower channel that drain into the cowl area. But initially the drains were covered with glue and are not very visible with the gasket in place. Anyway, I cleared the drains and with installed the winshield with no sealer. No a drop comes in.
 
i was present during and assissted the tech who showed me and answered all of my questiosn for installation and removal, we actually did both. we removed the old, installed the window then the next day took it back out and installed it again because he was not satisfied with the stuff the company wanted him to use between the seal and the metal of the car along the bottom edge.

the drains were not obstructed.

the original gasket has had plenty of silicone or similar sealant around the driver side corner where the leak is coming from. now I think I know why.
 
Can someone out there please show a close up photo of these drains, where they are located and what they look like? My '69 (well it's not mine technically any more) had bad rust that we fixed, but we didn't add any drains..oops.

thanks.
Neil.
 
as far as sealant is concerned i would call the local glass companies and see if someone will sell you a tube of urethane brands like sika, essex, and titan will do you well. you can also use the stuff from the auto parts store, it just costs a little more. a word to the wise always use gloves and if you get any on a visible body panel use the "hand scrubs in a bucket" that are readily available at the parts store. those will take off the urethane without exposing your paint to harsh chemicals.
 
i found a place online that sells sika stuff, not sure which one to go with though, so many different types and only about $7 a tube
 
65s said:
Can someone out there please show a close up photo of these drains, where they are located and what they look like? My '69 (well it's not mine technically any more) had bad rust that we fixed, but we didn't add any drains..oops.

thanks.
Neil.
Click to expand...

windshield drains.jpg
 
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