Sunday 16 January 2022

Removing Underseal From The Underside Of The Chassis (Part Two)

More of the same really. And there may even be a 'Part Three'!

As you will realise, my car is up on axle stands at the moment. I wanted the car jacked up high in anticipation of needing to get under it. But I didn't want to jack the car up one corner at a time and twist or destabilise the chassis. 
Up high

I used a single wooden beam across the width of the rear end, to jack the car up from a central point.

Rather than that beam put pressure on floor of the car, I fixed pads to each end that aligned to the square reinforcing pads on the chassis - just in front of the rear wheel arches. To give the car the height I wanted I just slipped my axle stands under the beam and pads. Easy!
Jack and beam under the rear suspension

Except that when it came to scraping the underside of the car where the torsion bar is, that beam and the jacks were now in the way.....Using another jack beam just behind the first beam, I was able to lift the cart and free the axle stands. This time I've relocated the axle stands to the rear swinging arms - giving me better access to scrape the boot floor. The 'cups' of the axle stands sit nicely at the ends of the arms and nestled against the axles - so are not going to slip off. 
Relocated axle stand

As I lowered my jack the arms, of course, moved up until the bump stops bottomed-out, so I needed to raise my axle stands on bricks to give me enough scraping room underneath. I wasn't very happy about using bricks, so used some tyre and scraps of wood to make a 'safety cushion' at the rear end: if the car fell off it's jacks, it would be (part) propped up by the tyre stack.
Tyres under the boot floor for added safety

Scraping was pretty much as before. Again I found areas where the underseal came off relatively easily in big, long, satisfying curls, and other areas where it came off only in stubborn little flakes that got everywhere.

There is a lot of time to think when doing this job and I found myself studying the underside of the car. There are lots of holes on the underside. the ones under the fuel tanks are lflanged around the edges and eft unplugged - perhaps to allow air to circulate or moisture to drain out - although there are also crescent shaped vents under the tank area? I found a couple of different style of bungs elsewhere: there were flat rubber plugs/ grommets with a reinforcing 'X' on the back covering large holes under the torsion bar area......

These are also used to cover glass adjustment tracks in the doors, and the the greasing points in the wheel arches - areas where you insert a tool so that may account for a couple of the bungs under the torsion bar. Though not all four lined-up. This type of bung is also found in the rear face of the boot behind the rear lights. Nothing to do with greasing or adjusting when used there though?

I also found larger, spongey bungs that look like doughnuts with a conical tip - under the fuel tank area. I'm assuming that at least some of these holes are something to do with allowing spot-welder access when the cars were assembled, or maybe holding panels in a jig, but I don't really know.
Bungs and grommets in the floor

The parts book for my car says there are twelve bungs of the same design in the boot floor - part DS.744-129. These are the 'doughnut' ones. They seem to perish and go spongey and sticky. You sometimes mysteriously find the doughnut 'head' under your car when they perished and fall off.
Perished bungs

While the Citroen catalogue says there are twelve of these plugs, the Franzose website says only five are needed for a car. 
Floor sealing plugs

I can account for eleven: seven under the torsion bar box, one under the fuel tank box, three under the front footwell. I'm still hunting for the hole for the twelfth one. I also found four other holes - telltale signs of a towbar having been fitted to the car in past years. At least they had had grommets put in them.
Towbar mounting holes?

Interestingly, the area of floor around the the hole and closing piece for the rear light cable had surface rust underneath it in a very regular shape. It looked as though it had been masked off while the rest of the chassis was dipped or painted to protect it? I'm not really sure?
Unprotected area around the light cable tube?

There were some other details to work around which were fiddly but, as before, this was just the first pass to get the majority of stuff off. I will go over it with a 3M abrasive pad on an air tool and a wire brush on a drill to clean out corners and joints.

I've still got the boot floor/ rear suspension area to do AND the engine bay/ front tusks....