How do I remove the sound deadening mat from the void above

[golf301]

Hi all
Can I get this big black mat and wire retainer out of this void without removing the gearbox?

Got some rust issues behind it that need attending to.

Thanks

[scottbott]

I used bolt cutters to cut the rusty metal away and then pulled the sound deadener off it was full of dust so watch out if you are underneath it when you pull it out,don't ask how I found that out ,never refitted it I sprayed stone chip on the exposed metalwork,there was no rust in mine thankfully never noticed a difference it noise without it fitted back

[Plasticman]

can we have picks of this please as im doing the same this coming week
mm

[golf301]

Brilliant thank you very much. Will give it try in the morning. And try to take some pics mike!

[golf301]

can we have picks of this please as im doing the same this coming week
mm

I'm shocked you haven't done this job before mike. Given the depths you go to!

[Plasticman]

ta,not saying either way but good to see what yours is like to compare as they are both going to be done at same sort of time. and show the inside of the van where its rotten prior to cutting away as need to see the visible sign before the actuality comes screaming home
mm

[boatbuilder]

Just took mine off a few days ago. There are four metal retainers, kinda springy, badly rusted. You can just get them out by hand as the ends of the retainers just push into holes.
Paint was pristine behind most of mine except the top cross member. Soundproofing material cracks if you bend it at all as it has a rigid backing moulded to the body shape and has lost its flexibility over the years. Was going to power wash mine and put it back in. Fiddly to treat rust in there as it's mostly in corners and awkward places. Wouldn't like to try to access it with the gearbox in place, you'll never get to it all.

[golf301]

Got it out this morning with a great deal of cursing! Mine is surprisingly good behind it too but as boat builder said it will be a nightmare to work in there with the gearbox fitted. Shouldn't be too difficult to do the immediate repairs though. Will take the engine and box out next winter and probably use the extra space under there to mount a tank and compressor for my air ride set up [SMILING FACE WITH SMILING EYES].

[boatbuilder]

I'm using a powerfile with 36 grit to remove as much of the rust in there as possible. I don't have holes though, just surface rust so far. Then I'll acid treat it with phosphoric acid for a few hours, wash it off with water, dry well with heat gun and brush on some epoxy primer.

Anyone have any idea on what to use in place of the ancient sound proofing mat?

[golf301]

I will probably get what I can reach low down and blast the rest when the engine is out. I can do the firewall at the same time. I was wondering the same thing. But as scottbott said he doesn't notice any difference in noise. Don't know if he is running a diesel??

[golf301]

How does the phosphoric acid compare to vactan?

[boatbuilder]

I have a blaster but I'm not prepared to wave it around in there as grit would get everywhere again!
Might be hard to find suitable replacement foam with a rigid backing to suit. Normal acoustic foam would just flop down.

[golf301]

This what I ended up with today! Descaled it all and gave it 2 coats of vactan. Will paint it tomorrow and start welding it all up again.

[boatbuilder]

I used vactan once but I'm not a fan. Seems very plasticky to me almost like pva. With the acid you can see what it's doing more.
It bubbles on contact and turns rust black and leaves a grayish etch on the non rusted parts. You scrub it off with water and a scotchbrite pad to reveal the dry treated and etched surface.
I'd have more confidence in painting the treated metal afterwards with a decent primer rather than vactan which I don't think provides as sound a base for paint.

[golf301]

Whoops wrong pic. This is the correct one.