undercarriage prep on '69 gtv

roller · #1 (**permalink**) 11-23-2004, 03:34 PM

i'm getting ready to do the degrease-etchant-por15 treatment on the interior floor pans soon. i'm also going to have new springs/shocks/bushings replaced on the suspension.

i'm wondering about what i should do to the underbody. i think it has the stock undercoating (very light). should i remove that undercoating and do
the degrease-etchant-por15 on the underside as well? if the stock undercoating is unbroken, should i still remove it and put a modern undercoat on?

i want to make the right call on this, but am not sure what direction to take. i definitely want to preserve the car, but i'm not planning on turning it into a show car.

john

GTD · #2 (**permalink**) 11-23-2004, 03:58 PM

John
My experience with GTV's and Alfa's in general is that the undercoating the factory applied did little more than trap moisture-from leaks to the interior and rain and salt spray from outside. It's a bear to scrape it off and sandblasting, while effective, is dirty!

I can't recommend a half-way measure which insures long term protection for the metal. Not the answer you want to hear but...it's reality!

roller · #3 (**permalink**) 11-23-2004, 04:26 PM

thanks gtd.

so do most people do the extreme or leave it in it's present state?

the mechanic implored me to let him to the suspension work before
i do anything with an undercoating. i think he didn't want to deal with
the mess.

if i have new undercoating applied over the old, and do por15 from the top,
would that be sufficient to preserve it? the idea is that no more water could get in from the bottom or the top after i'm done.

what do you think?

john

GTD · #4 (**permalink**) 11-23-2004, 04:32 PM

John
Unfortunately, most people cover the mess with more undercoat and leave it for the next guy!

What do I think?
I can't recommend a half-way measure which insures long term protection for the metal. Not the answer you want to hear but...it's reality!

Tito · #5 (**permalink**) 11-23-2004, 04:50 PM

The answer lies in what you want to do with the car. If its a keeper go ahead and have it sandblasted off. The problem with this is that you may find where some rust has started to take it toll on your car. Repair it with metal. Apply POR-15 metal prep and then Por-15 paint then re-undercoat to your hearts content. This will protect it from almost everything. If you are just band-aiding it, buy some decent rubber undercoating from your local auto parts store and spray away.

roller · #6 (**permalink**) 11-23-2004, 05:00 PM

thanks.

i'd like to do a decent job on the car. my take is that if i do the
band-aid and just put new undercoat over it, that it will continue to rot from
the inside? i've had all rust spots in the floor pans welded last month. there are no (that i can see) rust-throughs in the floor pans now.

given that i can treat the top easily, that just leaves the question of what the rest of the undercarriage looks like beneath the undercoat. it seems to be pretty solid. i definitely don't want to just coat over a problem that will eat away from the inside, but i can't put a million into the car either.

i think i'll call the mechanic and see what he thinks about media blasting after the suspension components have been removed.

any other thoughts?

john

**ossodiseppia** · #7 (**permalink**) 11-24-2004, 08:05 AM

Quote:

Originally Posted by roller

i'm wondering about what i should do to the underbody. i think it has the stock undercoating (very light). should i remove that undercoating and do the degrease-etchant-por15 on the underside as well? if the stock undercoating is unbroken, should i still remove it and put a modern undercoat on?

NikosF · #8 (**permalink**) 11-24-2004, 09:35 AM

Apologies for taking this off-topic - but Osso, when is that roundtail going to be finished? Seems to have been in a similar state for a while now. It seems you have already done all the difficult bits. I can't wait to see the finished result!

**ossodiseppia** · #9 (**permalink**) 11-24-2004, 09:45 AM

Quote:

Originally Posted by NikosF

Apologies for taking this off-topic - but Osso, when is that roundtail going to be finished? Seems to have been in a similar state for a while now. It seems you have already done all the difficult bits. I can't wait to see the finished result!

roller · #10 (**permalink**) 11-24-2004, 02:48 PM

i've got to say i'm impressed.

so this is my understanding at this point:

- even tho i welded all rust-thru on the floor pans, if i undercoat over the
existing dealer-installed undercoat/paint, i'm still risking the integrity of the car. if the existing undercoat seems not to be broken, there still could be rust in there that's not visible from the top.

> do i have that right?

john

PSk · #11 (**permalink**) 11-24-2004, 04:41 PM

Quote:

Originally Posted by ossodiseppia

The cars didn't have any undercoating put on at the factory. They didn't even have much paint on the undercarriage. anythihng you see on the car was put on by the dealership.

GTD · #12 (**permalink**) 11-24-2004, 06:04 PM

John
You've got the message. Without pic's all I can suggest is do some scraping around the drain holes in the floors and trunk, ahead and behind each wheel-at the point where the wheel well is welded to the floor pan. Most likely you'll find rust has travelled undetected, beneath the undercoating. How far it extends is largely due the cars environment over the last 35 years.

There is no short cut in keeping an Alfa body strong-you either protect what's still there or replace it later!