Water Leaks LH 1/4 panel and LH door

First of all, let me say the smartest thing I ever did when I bought my first 1998 Riviera was found a complete set of factory GM shop manuals for 30 bucks on ebay in brand new condition.  It has helped me take apart many things without breaking them and helped me ID wiring throughout this car. It is not an ordinary car. It was built using gm's latest tech of the day. It infact uses UART (Universal asynchronous receive/transmit) data transfer lines for the different body control modules and the PCM to communicate, including the radio and the hvac in the conversation. And the body structure is unique as well. GM wanted to attain a body resonance of 27khz so consequently the body shell is sold and multilayered spot welded steel panels with many , many body seams and body clip holes through the bodywork sheetmetal.Armed with this knowledge, I have taken on some big tasks on this car from stereo swaps, amp installs and  I have even swapped the supercharger pulley down to a 3.2 inch and rewritten the transmission and torque tables of the ECM/PCM , of course turning off all speed governors and setting the transmission to shift to 4th gear under full throttle at 125 mph!

But there is nothing more challenging than hunting a water leak.

There is a thread or 2 on water leaks here but I have been working on mine for a couple of weeks as time allows. It all started while wiring in a new eq/amp setup I found a lake under and in the foam padding under the carpet. The carpet has 30 mm (over 1 inch) of foam rubber attached under it for sound deadening and it works exactly like a car wash sponge... soaking up the water. Out came the interior (all) and the carpet was left to dry on the arm of a hoist in my shop for a few days with the air mover under it. So i thought I would share what I found and Ill upload some pictures later. As soon as the floor dried I wire wheel and disc sanded it clean of all the rust from the water sitting in there. I etched primed it and repainted drivers side  floor entirely.  I will respray it and add the sound deadener to the panels when I am done. I am considering a vapour barrier as well they would travel up the sills to prevent a sponger effect in the future...

So far its still in the works. I found the water rolling into the car at the area of the LH 1/4 panel where it meets the driver door. The carpet foam had a water stain running into the rear foot well, LH side where the rear of the drivers door meets the 1/4 panel. So I pulled the rear seat and the LH inner 1/4 trim and ran a hose ( made from a hose nozzle clamped to a post bolted to an old brake rotor, zap strap to hold the nozzle open)

SO so far, I found this:
Water is leaking into the LH 1/4 panel through the clips on the moldings. In other words there is no sealant or gasket around the holes in the body or doors. So I pulled the moldings (all on both sides) wiped down the body and the moldings, applied sealant and reinstalled all  the moldings. This has remedied these leaks. A second water test, and water is draining out of the b pillar around the small openings in the sheet metal under the seat belt upper anchor. So I am pulling all the mouldings and trim on the upper door opening tonite and trying to find that leak. I will add photos and keep everyone posted as I find the solution.

Ok well, I worked on the problem for a few hours after work tonight.  There are many leak sources in these cars, so mine is no exception. For starters I pulled all the weatherstrip off the body around the door opening. Next, I remove the retainer that the weatherstrip was held in place. Its screwed into the body and had a foam weatherstrip stuck to its backside like a gasket. Source of leak there is the upper rear corner...there is a 1 mm gap in the chrome drip moulding right above the rear top corner of the door glas, so water slides right into the body there. SO I apply generous amounts of autobody sealant to the area where the molding channel will mount to and seal this leak. Reassemble and retest....

Leaking still, but this time water is somehow getting into the body where the weatherstrip rides down the rear of the door?? I see a tiny gap at the front lower corner of the 1/4 glass in there glass weatherstrip. More sealant !!!

water test again... OK.. in that spot.

So I set up the water test again and move further out to take in the side of the car from the a pillar to the middle of the door... And wtf, there is water pooling up in the rear floorpan....seemingly coming from the rear floorpan brace (that forms the front part of the seat cushion support) Now I am scratching my head... How the heck is a leak up front causing water in the rear... And allot.

So to be sure I blow out the sunroof drains and clean the seal, close the roof up.  To pinpoint where the leak is, I start at the top and tape up the windshield moldings and tape up the sunroof and the roof seams from front to back... to eliminate the possibility of those being the source, test again; leaks! So  I am thinking water must be travelling in the rocker and draining into the rear of the car as its just polling from the seam at the rear brace but somehow also running out of the rear brace that the drivers seat bolts to. WTF???

I keep moving the test rig around untill i am spray water in a localized area only ( i forgot to say each time i test, I vacuum up the water off the floor so I can see when it start to drain into the rear)

Ok so 2 more sources of the leak....1 is the lower rocker panel trim... the little gaskets around all the clip holes are mostly gone. This is letting water into the rocker panel but that is mostly draining out of the drain holes But I can make the water poll up in the car by pointing the hose at the rock.

The last , I hope leak, is the vapor barrier in the driver's door... water is dripping out ot the door panel under the speaker area , running along the sill and draining into the back of the car . Off comes the door panel (warning... there are no clips in this panel so do not pry it off. Take 2 screws out and the grad handle after you take the inner door handle bezel off and lift the panel up and off. ) and sure enough it's wet in the door and the vapor barrier is no longer adhered to the door. Plus itss all dried up and falling apart. So I will use what's left of it as a template and cut a new one out of polly. Ill get a double gang 120 volt vapour barrier from home depot for the barrier behind the speakers and tuck tap it in. It will be as good as new again!... TO BE CONTINUED> It was time to cleanup and go home.

This is never ending. Its come down to the drivers door weatherstrip. This car has the original , but I know there is an updated part for this. I just need to find one. Anyone know how has these?

dbriviera wrote:

This is never ending. Its come down to the drivers door weatherstrip. This car has the original , but I know there is an updated part for this. I just need to find one. Anyone know how has these?

just a wild guess -- but you may be able to get one thru a dealr parts desk that will order it through GM's parts partner "vintage parts" -- if they have any there at VP.

After much work I managed to solve the water leak... so far. To confirm, I left the cars interior gutted over the course of all the repairs and the last one seemed to be completly dry after sitting for 6 hours in heavy rain.

The main culprits turned out to be:

1-Poor seal contact between drivers door and body contact in areas of the upper door both front and back. ....Diagnosed by using a product made by Worth to detect water leaks and steel to seal contact. Its a spray on liquid that dries to a powder that will leave a "trace line" where the two pars meet when the door is shut. Anything in width less than 3/8" to 1/4" inch on the trace is a potential leak. Some of my traces were less than 1/8"......Fixed by inserting a rubber windshield wash hose inside the weather-strip because I could not obtain one. I sprayed it generously with silicon lube and fed it up the door weather-strip - i made this easier by rigging up a compressed air nozzle in such a way as to blow air into the hose thus expanding the weather strip ahead of it. It took a bit of time and spraying silicone into it all...Also I clamped off the stripping at just above the door belt line as that was as far as the expansion was needed. It made the door tight but I backed off the striker and its working ok.

2-Lack of butyl at required contact point.... Diagnosed by observation... With the interior gutted its easier to see leaks. This car comes apart very easily. So using a water test setup of a hose on a stand, I could watch the water leaks at the source... Water would drip from in behind the weather strip... Both front and rear belt line area. .... The Fix.. Add generous amounts of butyl tape to the body where the belt line transition is (where the top of door meets body area)

3-Upper weather strip channel gasket skip.... I had removed the channel from the upper door opening before .. this is where the weatherstrip locks into place to seal against the very cool piller-less glass. I overlooked a skip in the sealing tape. Plus the old tape was hard and did not look like it was useful anymore. I scraped all the tape off and apply new closed cell foam tape that usually used for the top of a pickup box when a canopy is installed. It was just a matter of trimming off the excess width I didn't need. It worked perfect and sealed the channel. I also took time to flatten out the screw-holes that were a bit deformed from the tightened screw. I replaced with new trim screws with larger flat heads.

4- leaking body side mouldings -- All the gaskets were long gone, so I used urethane to seal them up.. I removed them and cleaned the body and moulding, applied a generous amount of urethane to the moulding and snapped it all back together.

5-body seam drip... I could see in the inside of the LH 1/4 panel a small trace in the dust from water dripping. It was dripping on the inner wheelhouse (from a spot about 4 inches back from the back bottom corner of the 1/4 glass) and running down to the inner most area of the 1/4 panel area; a spot where an open seam exists that allows it to drain under the back sheet sheetmetal , causing water pooling on the pass seat footwell area (this area collected 3 of the leaks of the whole car it turned out) -The fix was to apply a generous amount of seam sealer to the seal from inside the 1/4 panel... not an easy task, and to seal the open seam on the bottom of the inner 1/4 to prevent any other leak from up top getting in there. Also, I drilled a drain hole in the pocket under the seat belt retractor as it was a water accumulation point and I drilled 1/8 drain holes in the very bottom of the 1/4 panel and then primed and painted them for corrosion resistance. (I had the lower outer rocker trim removed at this time) Also I used a hand held video camera to view the inside of the 1/4 panel ... Thats How I could see the open seam.

6-decayed and leaking water vapour barrier in drivers door...I spotted this one when the car was on the hoist with the door opened. It was obvious it was a long time issue. So I removed the door panel and fabricated a vapour barrier out of poly vapour barrier I have for my house project. I made the speaker pocket out of a double gang 120 volt electrical box pocket-seal and tuck-taped it to the barrier (using the old barrier as a template helped)

It took me about 4 hours to completely reassemble the interior myself, including time to finish wiring up the satellite radio to the sound system during the reinstall. Word to the wise... make sure you understand how to disassemble this car before you start. The door panels and made out of plastic, fiber glass i think and foam that is like a pastry my dad used to make from egg whites and sugar... crunchy but melt in you mouth. As a pastry good but as a panel ... the clips can tear off easy. I used a hot melt glue gun with good quality adhesive sticks to repair many broken parts in the trim departments. The door panels lift up and off after some trim screws removed... no clips here so don't try to pry it off.