107 SL leak! Please help

[ifzal]

Ive bought myself a 1976 350SL. Finding water is leaking into the passenger side footwells. Having stripped out the dash have found the water trickling out from behind the top of the heater inside the car. I understand this is a common problem on these cars.

Can someone please practically advise me how I can resolve this problem.

Does anyone know if it is necessary for me to remove the heater from inside the car in order to weld? if so, how do i remove the heater?

I serious need some help because this problem does not seem to go away.

Many thanks and relying on someone out there to guide this Merc virgin.

 

[43722]

I had the same problem with my 280sl. first unblock drain hoses rubber from bulk head through tunnel reach under gearbox and break up blockage, what I did then was made a plate for under the heater blower< i fitted it with self tappers sealed with waxoil underseal. I rust treated the underneath and then used a bit of fibreglass from ontop around the housing I then used loads of waxoil underseal and covered the bulk head making a seal. Its not the most proffesional fix but it has been waterproof for over 12 months and the car is not garaged.

 

[ifzal]

Thanks for the advice.

Are you saying that your plate covered the air intake flaps in the blower motor bay? [ie creating a barrier between the blower motor and the 2 air intakes?] did this effect the heat in the car?

where did you rust treat? inside the car?

Many thanks again.

 

[43722]

no, I cut out the shape so it had two holes in it, then made it so it fit under the rubber seal that already fits between the body and the heater motor.

Another place to check for leaks is each corner below the hinge boxes for the bonnet this is a real rust trap. you can do it by removing the plastic covers under the dash, the passenger side is easier if you disconect the wiper linkage ( only one bolt ) then peal back sound deadening. The drivers side is underneath a load of wires.

 

[43722]

I rust treated inside and out, it is still going to need welding but hopefully it should last five years or so. Enough time to save up as it is an expensive job to sort properly.

 

[ifzal]

thanks for the tips. I have welded around the wiper motor/ battery tray area.

Do you have any idea of how I can remove the heater motor/box [inside the car?]

I took off the 4 nuts inside the car but the heater box did not want to move. :???:

 

[43722]

No I looked at it myself and it looks a big job, first thing to do is remove centre console which is easy , however I think you may need to remove the dash board, but I am not sure.