Difference between revisions of "Areas that rust - Rear cross-member"

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== Repair section ==
== Repair section ==
Due to bad drainage, the outer sections (dajavent to the javking points) of the cross-members can(eventually) rust enough to seriously reduce it's thickness. Ditto the thick metal of the jacking points too.
The rear cross member box-section is made of 2mm thick steel and is 50mm outside dimension.
Here is a section I made up to cut-out the rust and weld in at the outermost end of one, just over 4" long with sides about 2 1/2" deep. By careful setting out and bending, with a bit of adjustment and trueing up, I managed to get a good match, the box width ending up less than 20 thou out at either end. I've done a lot of bending in the vice and bench using makeshift tooling, but was more than pleased with that - will make welding it in a lot easier.
Also, note that I've swaged-in a drain hole, and that this is the correct way around, unlike VW's effort they put in about 5" from the outside edge, which allows water in but stops it draining out !!
[[File:X_Memb_Repair_02.jpg]]
[[File:X_Memb_Repair_01.jpg]]


==Tools==
==Tools==

Revision as of 22:26, 7 October 2009

Main

Diamond Hell: A while ago I spent a lot of time with a screwdriver and a wire brush searching out corrosion on the latest thing to occupy garage space at that time.

Now the T25 I have has obviously been used off road for some of it's life, but I was turned on to this corrosion trap back awhile when I visited Mercus and found him giving the cross-member in question in his yellow post van a good seeing to with a screwdriver. This is the cross-member in question, from ETKA:

Rust RCM 01.jpg

For those of you with diagram allergies it's the one where the rear jacking points are. This is one of the main structural members of the van and HAS to be sound for the rest of the van to be sound!

So, here's what I was looking at, after I'd attacked one of the outriggers:

Rust RCM 02.jpg

That doesn't look TOO bad - I mean it looks like I've just hacked out the steel over the cross member for no reason.... errr no actually. I ran a wire brush over what appeared to be a perfectly good panel and it FELL IN on itself!

That's right - this is an invisible killer - it will rot your bus from the inside out and you ain't gonna know owt about it until one day you tread on the floor and your foot goes right through! If you've got a camper you might not even notice until the stuff under your bed starts getting wet, cos this is the bit under your bed.

Having had this happen on one side I unzipped the other side. Here's what I found:

Rust RCM 03.jpg

M'mmmmmmmmm, looks tasty, doesn't it, kids? I might add that when I unzipped this panel with the angle grinder I found that although the top of the corrugation was sound the sides were wafer thin.

So, having opened Pandora's box it's rude not to see what's inside, isn't it? Let's get digging with something that fits in there, so as not to lacerate ourselves on the nasty, sharp edges, eh?

Here's what came out. when looking at this bear in mind that the mud is just from the outrigger on one side! There's a whole load more on the other side of the vehicle on the floor and more to come out where the loom passes through the cross member:

Rust RCM 04.jpg

Here's a better view of that pile of filth - LOOK at the size of it!

Rust RCM 05.jpg

Here's what it looks like with most of the filth removed:

Rust RCM 06.jpg

The holes at the bottom of that are drain holes. Unfortunately they are also 'fill' holes. Every time you immerse your Syncro in water God kills a kitten..... no, no sorry, wrong forum. Every time you give it a dunking silt will come in. Think of what water you drive through is normally like - all churned up with muck in it. When the water gets forced up into the cross member it comes in with filth. The filth then sinks to the bottom and the water drains out. Repeat this over and over and 'oh look' your cross member is full of silt! Silt holds water, which when it warms up causes water vapour, which condenses on the floor of the van.... not to mention the horrible things that the nasty stuff is doing at the bottom of the cross member, where cold, salty water is being pressed against the cross member on a permanent basis.

So, how do we stop this happening, without all cutting the floor open and clearing it out? By my reckoning it'll be best to wait until summer and get a garden hose and force it into the drain holes in your cross member and give the thing a right royal enema. You'll need to do it both sides and once you've done it you need to get some heat in there to dry it out - this is gonna take some time so it'd best be a nice gentle heat.

Once you're convinced it's reasonably dry (the dryer the better though!) then you want to get some waxoyl in there and quick - really give it a good hosing through all of the drain holes

For those who don't bother and use their van off road I'd give you four or five years, tops.

You have been warned.

Cleaning

HarryMann Thanks Thomas. If you don't want to completely unzip the cross-member capping panel like DH, then it'll be a powerful vacuum jobbie with lengths of rubber vac hose attached, and hours prodding with bent bits of fencing wire (loop the end right round round to avoid getting it jammed and round-off the edge. (to avoid scratching everything inside). A screwdriver doesn't quite cut it! Dry summer weather is best, and doing this over a few days helps as you uncover more and more damp stuff, let it dry overnight and go again, you'll be amazed! Or get the hot-air gun in there, but on alow setting for setting.

It's also not difficult to attach a length of heater rubber hose to the 'crevice attachment' on your vacuum, wedge off the end of hose and slide it right into any sections. Occasional large flakes will block, but again, you'll be amazed how much you can suck out... and it is of course detritus that hold the moisture and so prevents drying out that acceleartes continued corrosion, ne'st pas?

Others favour a running hose or jet wash in there - your choice (but not mine :-)

Repair section

Due to bad drainage, the outer sections (dajavent to the javking points) of the cross-members can(eventually) rust enough to seriously reduce it's thickness. Ditto the thick metal of the jacking points too.
The rear cross member box-section is made of 2mm thick steel and is 50mm outside dimension.
Here is a section I made up to cut-out the rust and weld in at the outermost end of one, just over 4" long with sides about 2 1/2" deep. By careful setting out and bending, with a bit of adjustment and trueing up, I managed to get a good match, the box width ending up less than 20 thou out at either end. I've done a lot of bending in the vice and bench using makeshift tooling, but was more than pleased with that - will make welding it in a lot easier.

Also, note that I've swaged-in a drain hole, and that this is the correct way around, unlike VW's effort they put in about 5" from the outside edge, which allows water in but stops it draining out !!

X Memb Repair 02.jpg

X Memb Repair 01.jpg

Tools