More work done, more work needed!

[ekafant]

Well, got done with engine mounts, engine shocks, trans cooler lines, and vacuum modulator on the 300TD last Friday. Vibration free and shifting is great! While the car was up on the lift, I started poking around and found soft undercoat on the bottom of the car, on the left side of the drivers floor, where it meets the inner rocker. Pushed harder and heard crunching noises. Pulled the floor mats up and found that all there was was undercoating in the "valley" that is there. Poked around on the other side, and hard steel. Poked around the entire bottom, wheel wells, etc. The rest of the car is fine at this point. I am counting my blessings on that one. The rust is localized and was very dry and scaly, which tells me it rusted a long time ago and has been dry a long time. Removed the plugs underneath and was able to examine some and the metal is fine. So, since it was minor, I POR 15ed the area, and am just going to lay a little fiberglass, more POR 15, use spray chipguard underneath and call it a day. Since it is not structural, it should be OK. My MGB that I just sold had a similair repair 30 years ago, and is still sound! Not the best way, in my opinion, but it does work. Only thing I can think is that the undercoating got some moisture behind it in that area a long time ago, and the moisture had nowhere to go. I am going to blow all the drains out just to be sure though! I assume that the cowl drains, and sunroof drains empty into the rockers and drain through the rubber plug with the holes in the bottom middle of the rocker. Is this correct?

[Chad300tdt]

If it's a w123, the cowls drain into the engine bay through the bent hoses with the pinched ends on the fire wall, the front sunroof drains out behind the front door along the A pillar and the rear sunroof drains out behind the drip rail between the quarter window and the hatch.

[ekafant]

Chad, yes it is a W123 and thank you very much for the info. Just an update. I let the POR15 dry overnight, and this evening I laid the fiberglass/resin mixture over the damage. After that, I reapplied POR15 on both sides of the fiberglass. When I get home tommorrow I am going to apply the chipguard and be done. I am going to apply inner body cavity wax in the rockers for extra measure also. I work for Volvo, and we have an inner body cavity spray that is a heavy wax, designed to rust proof inner body cavities. It is pretty good stuff. I am going to remove the plugs under the rocker panels and spray like there is no tommorrow. If anyone is interested, I can get the pt. #. I told my wife this car needs to last us at least 20 years, and I believe it will! I am only at 172k, so I believe this is possible!

[Chad300tdt]

Good luck with everything.

Here's a few threads I posted with photos that might help. You can see by these posts that the w123s have common problem areas. Make sure you check out under the battery tray, in the hood hinge drains and behind the plastic fender liners.

Hood Hinge Drain Rust Repair

Remove the window seals to repair the rust

I'm helping a friend keep another 123 on the road