News:

The Org - Serving W116 Enthusiasts for over 20 years!

Main Menu

Water leak / pooling in rear passenger footwell.

Started by Alex, 13 May 2024, 06:27 PM

Alex

Morning or afternoon,

So I'll cut to the gist, I was driving last night, car was in the rain a bit.
Come home, and see the rear passenger carpet is waterlogged entirely.

I dried it up and took out the mat for today.

This morning the footwell is filling with water again, despite being sunny.



I suspect water is pooled behind the back seats somewhere, where could that be? Is it coming from the rear chrome air vents? If so, how does one clean them??

Cheers,
77' 280SE Classic White (198,000km)

Alex

I checked all the seals, they are fine.
I ran water in the filler door, air vents front and rear, the fusebox. and nothing. bone dry.
thoughts?
77' 280SE Classic White (198,000km)

Randys01

Remove the back seat squab...is it already wet in here?  Can you see evidence of any water anywhere? Get the hose and thoroughly spray down the back window seal/glass etc. Is the rear hat/ parcel shelf wet?
Check the boot for moisture.
If these all check out OK, take the car to a Car Wash  and observe if you can see where water ingress is occurring.
One suspect is water getting  in the door via the glass ./weather belt strip and leaking thru the door trim in to cabin and rear footwell.

Alex

There is no water in the boot, that's for sure.
There is a very minor amount of "damp" beneath the bench (in the underneath area). But I couldn't observe flowing water in that spot.
I'll check the door glass, the windows specifically, it could be that.
77' 280SE Classic White (198,000km)

Randys01

Some dampness beneath the bench is curious..........is the ponding limited to one rear footwell? 
Check the adjacent ront footwell. As I recall water in the front can migrate  into the back footwell.

daantjie

Indeed the dreaded firewall rust from behind the fuse box can cause water ingress which can easily run backwards and pool in the rear footwells.
Daniel
1977 450 SEL 6.9 - Astralsilber

Alex

Quote from: daantjie on 15 May 2024, 08:55 AMIndeed the dreaded firewall rust from behind the fuse box can cause water ingress which can easily run backwards and pool in the rear footwells.

Nah not that, I tested it, and no water came back.. it all drained out nicely.

Quote from: Randys01 on 15 May 2024, 01:43 AMSome dampness beneath the bench is curious..........is the ponding limited to one rear footwell? 
Check the adjacent ront footwell. As I recall water in the front can migrate  into the back footwell.

It is mostly in the right rear footwell, there is a minor amount in the left, and some in the front right. Most of the water is contained generally to the right side of the car, but despite my best efforts, I cannot recreate the rain ingress with a hose.
77' 280SE Classic White (198,000km)

Alex

Quote from: daantjie on 15 May 2024, 08:55 AMIndeed the dreaded firewall rust from behind the fuse box can cause water ingress which can easily run backwards and pool in the rear footwells.

Nah not that, I tested it, and no water came back.. it all drained out nicely.

Quote from: Randys01 on 15 May 2024, 01:43 AMSome dampness beneath the bench is curious..........is the ponding limited to one rear footwell? 
Check the adjacent ront footwell. As I recall water in the front can migrate  into the back footwell.

It is mostly in the right rear footwell, there is a minor amount in the left, and some in the front right. Most of the water is contained generally to the right side of the car, but despite my best efforts, I cannot recreate the rain ingress with a hose.

There is generally more water in the rear than the front. It may be entering from beneath the front seats but not in the front well, somewhere- if I had to say.
77' 280SE Classic White (198,000km)

daantjie

Check sunroof drains.  The rear ones drain from behind the chrome trim on the C pillar.

Open sunroof completely, then park on an incline with front wheels higher than rear.

Then pour water into the pan channel.  It should rapidly drain out of the drain hose behind the trim.

Front drain exits in the A pillar lower part, you'll see it with front door open.
Daniel
1977 450 SEL 6.9 - Astralsilber

Alex

Quote from: daantjie on 18 May 2024, 03:34 PMCheck sunroof drains.  The rear ones drain from behind the chrome trim on the C pillar.

Open sunroof completely, then park on an incline with front wheels higher than rear.

Then pour water into the pan channel.  It should rapidly drain out of the drain hose behind the trim.

Front drain exits in the A pillar lower part, you'll see it with front door open.

no sunroof
77' 280SE Classic White (198,000km)

daantjie

Only other tip I can offer is to sit in the car while someone else sprays water on the car and maybe see if you can actively see the ingress.  Water leaks suck big time as the place you see the pooling is seldom where the actual leak is.
Daniel
1977 450 SEL 6.9 - Astralsilber

Alex

Quote from: daantjie on 19 May 2024, 12:00 PMOnly other tip I can offer is to sit in the car while someone else sprays water on the car and maybe see if you can actively see the ingress.  Water leaks suck big time as the place you see the pooling is seldom where the actual leak is.

Yeah, that's where I'm at now. I'll keep doing that in new places- see how I go. I did a bit before and nothing... I shall report back.
77' 280SE Classic White (198,000km)

NGK

Hey Alex, I had exactly same issue for ages, couldn't find the reason. Then I did three things:
1. checked the rubber boot where the bonnet cable come out of the fire wall for cracking or gaps
2. unblocked the a/c drainage channels (accessing from under the car)
3. check seal around antenna

The rubber boot was pretty shot so I replaced it. This I'm pretty sure did the trick, although its on the left side I had the most amount of water pooling.

Cheers
NGK

Alex

Quote from: NGK on 27 June 2024, 11:49 PMHey Alex, I had exactly same issue for ages, couldn't find the reason. Then I did three things:
1. checked the rubber boot where the bonnet cable come out of the fire wall for cracking or gaps
2. unblocked the a/c drainage channels (accessing from under the car)
3. check seal around antenna

The rubber boot was pretty shot so I replaced it. This I'm pretty sure did the trick, although its on the left side I had the most amount of water pooling.

Hi mate, I need to get on with this job haha.
So far, my investigation leads me to believe that the majority of water ingress is from the fuse box side (RHD Drivers), where there is a small rust hole. It then pools up beneath the carpet, then works its way back through the car.

The left side of the car is pretty clean.

I am currently trying to figure out a good way to clean up the rust hole, and fix it (fibreglass or bondo type stuff), in the tiny little crevice it is in.

My hands are too bloody big to do the job.



Cheers
NGK
77' 280SE Classic White (198,000km)