500 SEC problem

[richard.curtislewis@tesco]

I have recently noticed that water starts to pool in the rear n/s footwell after heavy rain. I have searched in vain to find the cause, and the point of ingress. Anybody have any ideas?

 

[supercharger]

i would go for the sunroof drains they are common on the w126,s .you will nedd to take down the roof lining and inspect the four corners of the casette. there is a metal pipe coming from each corner which then has rubber drain pipes over them going down to the sills to drain .these often rust and then obviously leak i have repaired them in the past.


supercharger

 

[television]

And I would say look in the air intake box in front of the windscreen, the drains block up and let water in via the heater

 

[lepton]

Drain blockage often causes corrosion. Look for a hole in the firewall above the drain. Water is channeled to the rear footwell via electrical trunking.
Alan

 

[richard.curtislewis@tesco]

Would it be the trunking that has perished, or the metal pipe that has corroded? Forgive my ignorance, but if it was the metal pipe, wouldn't it be showing in the ceiling? Does the trunking go from metal in the roof to metal in the sills?
By the way thanks for taking the time to help.

 

[lepton]

The plastic trunking is in a channel under the carpet next to the near side doors. It is easily visible when the carpet is lifted. It carries wiring (and water) from the front to the back of the car. My 300 SE leaked when it rained and at first I couldn't work out why the front passenger side was only wet while the rear footwell was flooded with several inches of water. However, I found a hole in the firewall (caused by corrosion) just above a blocked, nearside, windscreen drain. Water getting in here would flood the rear by travelling through the trunking. I also found that the drain in the rear floor pan was blocked while the front was relatively clear, explaining why the rear was wetter than the front. The problem was completely cured by sealing the hole in the firewall with fibreglass. This appears to be quite a common problem on the w126. There was certainly a lot of threads on this problem a couple of years back.
Regards Alan