So for all you detailers out there, what do you use to clean years of grime from the under side of the car?

More specifically, I'll be spending some time under my 99 firebird and would just like it a little nicer while i'm down there working and was just trying to figure out if there are any trouble spots to watch out for, like is the rear end vented? I drove a work van a few years back and it got caught in a flood (up to the floor boards) which allowed water to get into the rear end (since it had a "vented" design) that tore up like 400 bucks of parts and labor and don't want to do that to my car.

 

are you planning to put the car in the bath tub lol? should be fine, have caution around elect,plugs etc, just as you would with a engine bay, you pretty much can go to town, for sure put old towels down etc, it can get very messy pending on how you do it,

 

Just take your time, and be prepared to deal with little rust spots while you're under there.

 

You'll definitely want a creeper for the job, lots of gloves, and get the car high up off the ground. I didn't read any write ups or anything, I just went about the job something like the steps below. I was only cleaning the body itself, exhaust and such would have to be treated differently. Id suggest removing/ disassembling as much as possible.. if you're gonna take the time to do a job like this you might as well be thorough about it. Remove the wheels and as much suspension as you can. Clean those things separately. Drop the exhaust of its a simple setup. The more you remove, the better the job you will do of cleaning.

1) pressure washer to start out
2) completely douse the underside with Purple Power cleaner/degreaser
3) allow to sit for about 15 minutes... Go relax or do something else while the cleaner goes to work

4) repeat steps 1-3. While it's sitting this time go put some hot water in a bucket with some dawn dish soap or some other cleaner. And get some Scotch brite pads (I used red), green isn't as abrasive, but also won't scuff the paint as bad, which is good if you want to keep the paint looking better. I personally wanted to scuff the paint to prep for paint, and the red cleans quicker since it's a more abrasive pad.
5) repeat steps 1-2 again.. Instead of allowing to sit this time, get to work with the hot soapy water and your scrubbing pads. Start at one corner and slowly work down one side of the car and then back up the other side.

6) repeat step 5 focusing on any areas still needing attention.
7) final pressure wash
8) dry everything up.

This was performed outside on the side of the house, definitely not a garage job with all the water and how messy it got. Several times I got out the big push broom to sweep away all of the water.

I did this with a 35+ year old car and brought back the original paint in a way that I never expected. I then followed that with a clear coat which brought the paint back to life. Crazy how big of a difference it made. Unfortunately, I'm holding out on pics till I get the build thread done. But I pretty much followed those exact steps and got it looking damn good, especially considering the age.

 

Second vote for Purple Power. That stuff is amazing, just don't get it on your hands

 

Pressure washer and floor jack. It will eat right through the grime.

Bring a floor jack to the car wash and six dollars in quarters