[Body_Work] 205 1.9 Gti Rust Repairs

[sport1901966 8]

Hi all,

 

Although I have the Mi16 project thread running (incidentally its long overdue an update) I thought I'd put this in its own thread as its not really related to the conversion and I thought it could be interesting in its own right.

 

Anyway, I have finally got around to tackling the cause for the failure of the Mi16’s last MOT back in July 13; a corrosion hole within 30cm of the suspension mount on the driver side wing.

 

 

 

I managed a quick bit of investigation before the cold weather kicked in before Christmas; unfortunately the MOT failure hole was the tip of the iceberg. Looking in to the rear face of the driver side wheel well you can see where Mr MOT man has marked up some other areas of corrosion.

 

 

… and looking at the top of the wheel well we can see the underside of the MOT failure hole.

 

 

So on first appearances there were three main areas of concern – the hole causing the MOT failure at the top of the wheel well/scuttle area panel to chassis leg seam (for the sake of time I’ll refer to it as hole 1), the wheel arch to chassis leg seam – hole 2, and the lower rear wheel arch – hole 3 … not yet a hole but it soon will be!

 

Next step was to get the car ready to work on which meant removing the driver side suspension assembly. I wanted to be able to work on the car both outside the garage and inside the garage, weather dependant, however removing the suspension assembly would render it somewhat immobile, so I designed myself a little axle stand dolly. I don’t have any finished pictures but you get the idea!

 

 

It has worked brilliantly, I can roll the car in and out the garage single handed, and the car has been sitting on it since August last year.

 

With clear access to the wheel arch I could now get on with the real work… and break out the angle grinder! After some flap wheeling and cutting disking I ended up with the below:

 

Hole 2 Before

 

Hole 2 After (plus some zinc primer to prevent any surface rusting of the bare metal)

 

Hole 3 Before

 

Hole 3 After

 

I also got a look at the corrosion from within the drivers footwell side –

 

 

Things starting to look moderately serious now – my main concern being that the seam exposed behind after cutting out hole 3 is also quite corroded. After pulling back the carpet and sound deadening, bubbling paint was revealed running up the other side of this seam, between the bulkhead and the body side and up behind the dash (shown in the footwell picture above, at the right hand edge of the hole I’ve cut). I called it a day at this stage as it was clear I was going to need to do more disassembly – both to see how far the footwell seam bubbling extended, but also to try and get better access to the hole that caused the MOT failure (hole 1) in the first place. I also wanted to research into better tools for cutting, grinding, removing the rust.

 

I ended up picking up a multitude of bits and bobs, a twisted wire attachment for the angle grinder, and one of those rough spongy looking angle grinder attachments, and a few bits for dremel type rotary tools.

 

This brings me up to last weekend where I got a solid few hours on the car. I started off by stripping out the whole of the dash (bar the steering column and wiring harness… for the time being anyway). I then went at it with the twisted wire attachment – this is fantastic for getting rid of rust without thinning down the good metal. As I went on, and more and more metal seemed to be disappearing, I got to the stage where the wing needed to come off and hence the bumper. I was a bit dubious about this because of the bonding on, but careful application of a heat gun combined with a scraper and it came of quite easily – I’d say you have to be very heavy handed with the heat and pulling to damage the paint and/or bend the metal. Anyway, this revealed another (not so) welcome sight:

 

 

 

And… forgive the imagination here… but we’ll call this hole 4!

 

So to bring us up to date:

 

Hole 1 now

… photo taken upward into wheel arch from hub area

 

… from above

 

… and from under the scuttle panel

 

This one is proving very difficult from an access point of view, I think it will need the bonnet removing, and to cut it out I am looking into the possibility of the dremel 90deg attachment (and many many cutting discs) or an air body saw – any tip overcoming this would be really useful!

 

Hole 2 now

 

 

… and from in the footwell

 

 

Hole 3 now

 

 

.. and shown from the cavity that is usually covered by the wing (some more surface rust to clear under here as well)

 

 

 

So as far as I can see the next steps are:

• Hole 1 - Remove bonnet to gain better access to clean up and see what needs cutting out
• 
  
• Hole 2 – Cut out metal to give a clean hole so a repair section can be made up and get some tool to clean up inside of angled section (surface rust on inner face can be seen in photo taken from wheel arch, outer face can be seen in photo taken in wheel arch)
• 
  
• Hole 3 – Cut out corroded seam behind hole by approaching from cavity that was covered by the wing with an air body saw, weld in replacement patch for seam, then weld in patch to fill hole 3
• 
  
• Hole 4 – Cut out clean hole then replace with repair patch.
• 
  

 

In all cases my idea is to treat with a rust converter before adding any new metal. Does anyone have any recommendations for proven converters (i.e. rust hasn’t reappeared over a long time)?

 

Some of the holes and hence cuts will be very close to some seams – e.g. seam behind hole 3, and hole 4, does anyone have any recommendations how to ensure all the rust is removed in these areas?

 

Has anyone got any recommendations based on experience on how they would approach the holes i.e. where they would cut, what order they would rebuild points where a seam joins a flat section (e.g hole 2) etc?

 

P.S. If any of the pictures aren't clear (subject/angle) let me know and I'll label them up - I know how frustrating it can be reading through a rust repair thread and have no idea what you are looking it!

[sport1901966 8]

Actually - one more question - what means of protecting the sides of replacement patches that will be inaccessible once welded would people recommend?

 

Obviously I will spray with weld through primer on the repair sections, but I am dubious this will be sufficient to maintain corrosion resistance over the long term...

[sport1901966 8]

I've read that this rust converter is good -

 

Does any have any experience with it - did it keep the rust at bay (obviously in conjunction with good paint protection)?

Edited February 13, 2014 by sport1901966

[johniban 59 1 Cars]

I didn't bother with any of that rust remover. I just wire wheeled everything cut out and replaced and bad rust. Then prepared and sprayed

[sport1901966 8]

Its just the seams that I would worry about or the deep/inaccessible areas that I cant get to with a wire wheel or any other tool

[DamirGTI 342]

Actually - one more question - what means of protecting the sides of replacement patches that will be inaccessible once welded would people recommend?

 

 

Weld thru primer .. just spray on both sides prior to welding .

 

But try to find an good quality weld thru primer , personally i've been using 3M :

http://www.ebay.com/itm/3M-WELD-THRU-2-Weld-Thru-Primer-05917-/131113862878

 

Also , almost all the backsides of the panels can be reached with a cavity wax injection gun with long adapter/straw , as most of the panels and panel joints are hollow or have some kind of passage to reach the back side once welded in just guide the wax injection gun trough and you'll reach most of them if not maybe even all of them .. good quality injection gun has nozzle with multiple hole cuts/outlets so it sprays in all directions all the way round 360 degrees so when pushed inside enclosed body structure it'll spray all around coating entire inner surface ..

After the weld thru primer , and after the welding , buy some cavity wax and said gun for application and treat the insides with wax .

 

D

[sport1901966 8]

Cheers for the info Damir (I was hoping you might come along with your input having seen your resto thread!)

 

With regards to the weld through primer, I have a couple of the UPOL cans like this - http://www.halfords.com/webapp/wcs/stores/servlet/product_storeId_10001_catalogId_10151_productId_170878_langId_-1_categoryId_165625'>UPOL Weld #2 Do you have any experience with this?

 

The cavity wax gun sounds like the way forward, you have reminded me as I have heard of those before. Any recommendations? Trying to google this stuff everyone has there opinion - but very few reports on results a good few years after application.

 

I've been looking into protection of the underbody areas. From a brief bit of research there seems to be 4 main products/product types people refer to -

 

Stonechip - Remains elastic, Paintable (although some say it dries hard/can crack - cracking of whatever was applied to my car seems to be the cause of the rust in my case)

 

Shultz - Remains tacky

 

Waxoil - Remains soft/waxy (mainly for water repelling rather than mechanical protection?)

 

Underseal - Maybe a combination of mechanical protection (like stonechip) and a waxoil type substance??

 

It's all about as clear as mud, and I dont know how much is just marketing speak from different brands for products that are essentially the same chemically, and what are actually different products with different characteristics/applications.

 

It would be great if someone with some experience could shed some light on this! I want to make sure the repairs last.

[DamirGTI 342]

Haven't tried anything made by UPOL myself .. seems like it's mainly UK based brand so we don't get they're stuff over here , at least i didn't see any of them UPOL products on the sale here ..

But reading various projects/topics over here it seems like it's good quality firm

 

Just a few important notes while welding patch panels - as said , prior to welding spray the patch with weld thru primer (spray a little bit more a few more layers on the back side) , and after the welding is completed clean up the welds with wire wheel and spray some zinc primer over the welds .. in fact spray entire patch panel once welded in , but the welds are the most important so keep an rattle can of zinc primer near you so that once you end with the welding , while the weld cools down and you clean them with the wire wheel - spray the welds/patch panel as soon as possible with zinc primer .. do not leave it over night or worse few days before protecting ! especially if working outside .

If you run out of time or you just had enough for the day and you end up with semi completed patch panel - spray no matter if it's fully completed/welded or not and just use cellulose thinner the day after to wash/clean up the area which was left for finishing the job .

 

Welds and bare metal areas closest to the welds are the most prone to rusting (most of the rusting which , if not treated , starts from the actual weld or the welded area) , so make sure that you seal them asap ! same goes for all the bare metal areas , if left for just a day or few they'll start rusting microscopically (obviously you wont be able to see the rusting process but it'll start pretty fast) especially if touched with bare hands .

 

When done with the welding complete patch panel and after spaying it with zinc primer - use PU (polyurethane) brushable seam sealer and cover/brush on all the weld areas (but after painting , do not apply seam sealer on the bare metal or bare welds !) , this'll add further protection over the weld areas as no matter how good you weld there will always be left some pin holes inside the welds which needs sealing to prevent rust formation .

 

Rust converters , again , i don't have experience with the one you've posted .. need to be careful not to dip the brush inside the bottle and use them like that cos what will happened is after you've been working with it for a while and dip the brush inside on which the converter has already started reacting it'll pollute entire solution inside the bottle ! ie. it'll trigger polymerization process on the entire bottle content and thus the protective efficiency of the product will be considerably lowered , not entirely but quite a bit ..

So when working with rust converter , use some clean container/pot and pour inside as much as you'll be using for the repair .. if some lefts on the end - throw it away do not pour it back inside the bottle for the same reasons as mentioned .

When applying converter first , wipe clean the surface free from oil based stuff and dirt , and make sure that you cover all the rusted areas cos if you miss some those will start rusting progressive worse !

 

Also , theres two types of rust converters , theres some difference in content (can't remember now ?!) .. anyway , one is repaintable and another isn't .. though that'll be noted in product instructions so read trough before buying/use . Mainly all of them on the market are repaintable , but then theres also few of them which aren't (i think they're for industrial use) .

 

Underbody protection .. from what i know theres just two of them - rubber resin based , and bitumen/asphalt based . So "Stonechip" and "Underseal" should be same ie. rubber resin based while "Shutz" is bitumen/asphalt based , and usually they all contain rust inhibitor additives also .

Stonechip/Underseal is repaintable and to some extent elastic , Shutz remains tacky/kinda greasy as it's oil based and as such it's not repaintable .

True i also had problems with Stonechip/Underseal cracking , i think it was because of the actual ambient temp. when applied , to heavy layer application at once , badly prepaired surfece - dunno to be honest , but yes it tends to crack sometimes . For this very reason i use both - Stonechip/Underseal first , and then to add even more protection (especially for the wheel arches area) to cover the Stonechip/Underseal area in case it has cracked somewhere or will start cracking in the future i add top final layer of Shutz ..

Theres no adhesion problems in between the two , the Stonechip/Underseal and Shutz , they bond on nicely and afterwards you'll have double protective layer !

Another note about Stonechip/Underseal particulary - all the areas which where seam sealed need to be left for a few days maybe even a week for the seam sealer fully settle down otherwise the Stonechip/Underseal wont bond properly onto the seam sealed areas and will peel off .. with Shutz you wont have said problems .

 

Waxoil is mainly for use in enclosed body spaces - insides of the sills , insides of the chassis rails and stuff like that .. closed body structures .. you don't want to use it where you intend to paint cos you'll have serious paint adhesion problems ..

 

For Stonechip/Underseal/Waxoil application it's best to buy yourself an UBS gun , like this one (can get them with even longer tips/straws for deep waxoil application) :

http://www.ebay.co.uk/itm/UNDERBODY-COATING-GUN-UNDERSEAL-WAXOYL-WAX-OIL-STONECHIP-SCHUTZ-SPRAY-GUN-/230974566850

.. and use it in conjunction with Stonechip/Underseal/Waxoil in cartridge form ie. UBS cans (they all have universal attachment system so one gun will cover all the brands/makes as long as you buy them in cartridges/UBS cans ..) , and obviously you'll need an air compressor .

Don't waste money on Stonechip/Underseal/Waxoil in rattle cans cos they're not as near potent as the stuff in cartridges/UBS cans .. rattle can stuff is usually heavily thinned in order to be sprayable and thus less potent . Cartridges/UBS cans cost a little bit more but worth every penny .

 

Good trick when using Stonechip/Underseal/Waxoil cartridges is to put them in the bucked of warm water and let them sit for a few min. before use so that the content can be mixed more thoroughly and it wont be as goopy/thick when you start spraying , here's a nice read about that :

http://www.mig-welding.co.uk/stonechip.htm

 

For all the above , use the best products which you can get - Wurth , Dinitrol (been using Dinitrol stuff a lot and it's great quality stuff !) 3M , Loctite/Teroson and the likes ..

 

A bit long post but i hope i've answered to some of your questions

 

 

Have fun !

 

D

Edited February 14, 2014 by DamirGTI

[sport1901966 8]

What can I say?! That's one of the most informative posts I have read. After a few days of reading I have only managed to find at most 2 thirds of the info you have managed to fit in one post. Certainly worth being made into a forum article as far as I'm concerned.

 

Certainly with you with keeping the working areas protected, I've been coating with galvanising spray after doing any work and it's definitely doing the job

 

The rust converters seem to either by phosphoric acid based, essentially giving a phosphate coat which is part of the body prep OEMS use (although it's electro-coated so not exactly comparable) and the other type convert to iron tannate, from what I've read the later is meant for getting at rust in seams/internal cavities.

 

Looks like I better find a good supplier for all these materials, and get the compressor back in action.

 

Thank you for taking the time!

[DamirGTI 342]

Regarding the rust converters , they're all tannic acid and polymer resin based .. they don't contain phosphoric acid . Rust removers contain phosphoric acid

 

You can distinguish them (other than the labels on the package "rust converter" vs "rust remover") by the colour - rust converters are thicker milky fluids with kinda plastic smell and once they start reacting on the surface of the rust layer (polymerization) they turn from milky white to dark blue and in the end black . Rust removers are usually light transparent (like water) or brownish colour fluids with strong acid odour , as they contain phosphoric acid .. apart from fluid , you can also get them in jelly form .

 

Rust converter , once it's done the reaction process (turned from milky white to black) must not be wiped with solvent or sanded , the black protective polymer layer which lefts after the reaction process is actually really good primer surface and it has very good adhesion properties thus it's meant for painting straight on top over the black hardened layer . So priming is not needed , just apply paint on top .

Rust removers on the other hand mostly need to be neutralized ie. the surface treated with rust remover needs to be washed off with mixture of baking soda and water and dried before applying the paint on top . The reason being the phosphoric acid which if left and painted over will eventually lift off the paint layer . Though on some of them theres written in the instructions that they must not be washed off/neutralized , so need to read instruction first ! mainly all of them need to be neutralization before repainting but yes there's a few which don't .

 

Factory E-coated panels are entirely different process , they use various metals and resins along with electric current process to apply them on the metal surface (E-coated panels are usually black)

 

What i like to do with getting rid of the rust is using both - the rust remover and rust converter .

First , i use wire wheel to grind off as much of the rust as i can , then i apply rust remover and start rubbing the rusted area soaked in rust remover by hand with wire brush , dish washing wire mesh or 80grt. sanding paper .. depends on the surface access , i soak it with rust remover and rub until all the brown/black crap lifts off from the rusted area (extremely important : wear gloves , long shirt with long sleeves and protective eye goggles !) .. After that's done , i use baking soda with water mixture and wash off and dry the surface to remove all remains of phosphoric acid . On the end when that's done , i apply two layers of rust converter , and paint on top when the rust converter does it's job .

 

Glad to be helpful , good luck with your project !

 

D

Edited February 15, 2014 by DamirGTI

[sport1901966 8]

Thanks again Damir, more information worth its weight in gold. I certainly don't think there is much more you can do to remove rust than the method you describe (where cutting and replacing is not feasible anyway).

 

I had a chance to spend a bit more time in the garage over the weekend so thought I'd have a go at repairing the hole on the chassis leg (hole 4 as it were!)

 

So for a quick reminder - this was the current condition

 

 

Then out came the angle grinder

 

 

 

 

This section seems to be double layered - on the inner side is sheet of approx 1.5-2mm thickness, the outer sheet is more like 0.8mm. You can see a section of the cut I made facing upward and rearwards from the hub position.

 

 

The shape of the sheets are also different, so I decided I would repair it in 2 sections (firstly the thicker inner skin, then the thin outer skin) to keep to the original design as much as possible.

 

Thicker skin welded in place with welds ground down

 

 

Then coated with some zinc primer to protect the bare metal until I am ready for the proper painting/under sealing process

 

 

And from further out

 

 

The welds certainly arent the prettiest in the world, but definitely will do the job, I have since played around with the wire wheel spindle break and the wire feed has improved significantly so hopefully the welds should improve from here on out.

 

I came up with some lighting solutions to help visibility when working in the garage (overhead lights are a bit dim), I had made some 12V led strip light panels (the larger one was initially intended for use in footwells when working up behind the dash). A bit of duck tape to mount it to the garage wall and this illuminated the wheel well superbly.

 

 

For the actual welding I have always struggled with visibility when starting up the weld - well no more! -

 

 

 

If anyone has any suggestions about where to make the cuts for the other holes, especially where they are along seams I'd very much appreciate it. Thanks!

Edited February 20, 2014 by sport1901966

[sport1901966 8]

Managed to get some more time on the car over the last couple of weekends. I had pretty much assessed the extent of the rust in the wheelarch/footwell so decided the next step was investigate the cause of the MOT failure... aka hole 1!. I had been considering what would be the best approach to access and remove whatever extent of rust I would find. Initially I picked up an air body saw, but it has since become clear that my compressor isnt up to the job of running it. My backup was to use a dremel with the 38mm cutting discs, but I was dubious about this as I had heard people found they just weren't any good for cutting bodywork. However my experience was that the Dremel was brilliant for the job, of course you will go through a stack of discs, but coupled with the 90 degree attachment I could make some really precise cuts in very awkward places! I would go as far as saying it is a must have for sorting awkward access areas.

 

Anyway, so initially the rust at the seam looked like this

 

 

 

After a while with the dremel it ended up like this! -

 

 

 

And from the footwell, previously I left it like this -

 

 

And it became this -

 

 

As you can see the weight saving effort is gaining momentum -

 

 

Its going to be interesting when I get to the stage of re-sculpting this all, but the rust had taken hold so it had to come out. I have lots of pictures, and am keeping all the cut outs to aid me as templates so we will see!

 

Starting to look a little sorry for itself!

 

Edited March 3, 2014 by sport1901966

[welshpug 1,656]

one thing I would recommend when fixing bits like that in the chassis is to support it as flat as possible, i.e two axle stands under the subframe for example, you would be surprised how much a tired 205 will flex when you jack one corner up, so if you weld some bits in when its like that it might not go back straight!

[sport1901966 8]

This weekend just gone I decided to have a look over things as they are now all the rust is removed and start to come up with a plan of how I intend to repair the areas that have been cut, and the areas that will require more cutting.

 

After giving things a bit more of a poke from the footwell it became clear the rust had breached the chassis leg seam and I had actually got through to the seam sealer in the engine bay area below where the brake servo is located.

 

After a brief period of denial I accepted the engine was going to have to come out if I was going to do a proper repair . This presented the next challenge... How to go about doing this. The problem I have is there isn't enough room to get the engine out with the car in the garage, so this means pushing it either halfway or fully out onto the driveway. The problem then is that once the engine is out, and hence wheels off its stuck in situ (as the offside suspension leg will not be fitted). Leaving it out on the driveway isnt really an option as the driveway is in use, and with in progress rust repairs wouldnt be ideal even if it wasnt.

 

I needed to be able to roll it back into the garage, at whatever stage of removal the engine may be so my solution was this... fabricate a second rolling axle stand! And here it is - very pleased with this one, no weld finishing required at all, since sorting the wire feed on the welder the quality of my welds have massively improved. I was very pleased with the fabrication time; from having the bare materials (1x 20mmx20mmx2m Square Tube, 1x 20mmx20mmx1m square tube and 4 heavy duty nylon casters) to a painted rolling axle stand was about 2.5 hours with a cost of £50 for the materials.

 

 

 

 

The added bonus with this is no steering capability is required, and even better, when in the garage, all I have to do is pull it one way or the other and I can access both sides of the car to work on!

[sport1901966 8]

one thing I would recommend when fixing bits like that in the chassis is to support it as flat as possible, i.e two axle stands under the subframe for example, you would be surprised how much a tired 205 will flex when you jack one corner up, so if you weld some bits in when its like that it might not go back straight!

 

Thanks its a very good point, I was getting concious about how much material was coming away from the bulkhead to chassis leg region - fortunately my last post should mean that won't be so much of a concern from a twisting point of view!

[welshpug 1,656]

ha, excellent, oh for a smooth floor!

[sport1901966 8]

ha, excellent, oh for a smooth floor!

Everytime I enter/leave the garage I am grateful for it I tell you! When I first did the conversion it was on a driveway that was a combination of mud and gravel - I would hate the count the number of hours I spent looking for dropped bolts/nuts!

[BenC 6]

It might be a bit late but r.e rust converters I have used Bilt Hamber Deox-C gel and Hydrate 80 with good effect when I had a patch welded on my boot floor (made sense to treat other areas of the underside which had surface rust at the same time). I went over this with Bilt Hamber Electrox Zinc primer (90% zinc) and then top coated with POR15.

 

That was just over 2 years ago and results have been excellent - no sign of any rust coming back through. Obviously as I have used several products it's impossible for me to say if one has worked better than the others/hasn't worked but as a combination they seem to have done the job very well. I'm really impressed by the POR 15 as a top coat, it hasn't chipped or cracked at all. I would definitely recommend it on non-visible areas. Not cheap though but worth it. I got mine from Frosts.

[sport1901966 8]

Thats good news, I just bought some of the electrox primer and have got some of deox-c in the garage I was planning on using. Its great to hear from someone that has used it and had a good period of time to check the long term results.

 

I have some epoxy mastic from Bilt Hamber which is similar stuff to the POR-15 so hopefully with some stonechip and waxoil in the right areas should provide long lasting protection.