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Post by valhalla on Nov 28, 2020 0:36:04 GMT 1
Yes, another of my questions about subframe repair, instead of replacement.
Is anyone familiar enough with the welded construction on the Passat B5 subframe, to say whether or not it is likely to be OK to weld-repair?
By the letter of the manual, I understand that a welded construction structural component can be repaired legitimately, whereas a pressed item cannot, yet in the case of the Passat, what you have is two pressings that are welded back-to-back to give the tubular box, and it is right next to that welded seam that I need to repair. So it falls into both camps?
I would not normally entertain a repair on one of these, as subframes are supposed to be ten-a-penny, however, with the UK under the influence of "Boris's big holiday" aka lockdown, it seems that nobody wants to handle getting a large item like this up here....  |
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remmington
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Post by remmington on Nov 28, 2020 6:06:42 GMT 1
Yes, another of my questions about subframe repair, instead of replacement. Is anyone familiar enough with the welded construction on the Passat B5 subframe, to say whether or not it is likely to be OK to weld-repair? By the letter of the manual, I understand that a welded construction structural component can be repaired legitimately, whereas a pressed item cannot, yet in the case of the Passat, what you have is two pressings that are welded back-to-back to give the tubular box, and it is right next to that welded seam that I need to repair. So it falls into both camps? I would not normally entertain a repair on one of these, as subframes are supposed to be ten-a-penny, however, with the UK under the influence of "Boris's big holiday" aka lockdown, it seems that nobody wants to handle getting a large item like this up here.... I doubt I would go thru an MOT. Most testers are "funny" about this! Last subframe I was challanged with for the same this - I removed and replaced with a used item. You are right about one thing thou - the rules are a bit "grey" on the subject.  |
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chippie
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Post by chippie on Nov 28, 2020 12:39:08 GMT 1
If the welding meets a prescribed standard why should it not be acceptable? Surely this is no different to welding a sill or chassis member that forms part of the structural integrity of the car?
How does the MoT examiner know a repair has been effected? Is the examiner a coded welder or a structural engineer?
If the area is a 'grey' area, is it not worth discussing with the examiner to reach agreement...?
I once repaired my Fiesta that had failed an MoT on sills, the replacements were brazed on rather than weld, ( I cant gas weld for toffee..) the braze spots were then ground flat and painted over....for all intents and purposes, it looked like a weld repair....
( spurs chinking in the distance.....yeehaw...)
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remmington
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Post by remmington on Nov 28, 2020 20:53:49 GMT 1
If the welding meets a prescribed standard why should it not be acceptable? Surely this is no different to welding a sill or chassis member that forms part of the structural integrity of the car?How does the MoT examiner know a repair has been effected? Is the examiner a coded welder or a structural engineer? If the area is a 'grey' area, is it not worth discussing with the examiner to reach agreement...? I once repaired my Fiesta that had failed an MoT on sills, the replacements were brazed on rather than weld, ( I cant gas weld for toffee..) the braze spots were then ground flat and painted over....for all intents and purposes, it looked like a weld repair.... ( spurs chinking in the distance.....yeehaw...) But if you read the rules - it does sort of give you some leeway...  The rules from the manual are: (it is a grey area) "The severity of corrosion in highly stressed components, such as steering and suspension arms, rods and levers, can be assessed by lightly tapping or scraping with the corrosion assessment tool.
In places that cannot be reached by the corrosion assessment tool, an alternative blunt instrument may be used.
A highly stressed component should be rejected if corrosion has resulted in serious reduction in the overall thickness of the material or has caused a hole or split.
Welded repairs to highly stressed components are not normally acceptable, other than where the component is made up of sections that are welded together. To pass, the repair should appear to be as strong as the original design."
"It’s common for vehicles to use thin gauge pressings for certain steering and suspension components, mountings, sub-frames and cross members. These are prone to serious and often very localised corrosion.
Corrosion in these components can be difficult to see and may require close inspection." |
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chippie
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Post by chippie on Nov 28, 2020 21:35:21 GMT 1
So from the text in the manual, my interpretation is that subframes, where such are made up from welded sub-assemblies can be welded to effect a repair as long as such a repair is as strong as the original....
But again,if there is a welded repair, how can its integrity be verified if the examiner isnt a coded welder or have access to dye pen or mpi and be able to interpret the results?
But what I find bemusing, cars built using the monocoque principle, can have, say floor section repairs, and be passed as fit for service....
I remember years ago, Mini subframes were a popular welded repair.....
Bit of a minefield.....?
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Post by givusaclue on Nov 28, 2020 23:43:44 GMT 1
I wouldn’t generally accept a welding repaired subframe.
regarding the mini rear subframe, if they fitted the complete repair panel rather than a home cut patch panel, then I would accept that assuming it was fitted seemingly correctly.
a welded in home made patch which may or may not be an equal or thicker gauge steel which has subsequently been dressed with a grinder to hide the seagull excrement would not fill me with enthusiasm to sign a pass certificate.
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Post by valhalla on Nov 29, 2020 1:15:55 GMT 1
Yes, it's certainly a minefield!
I think that I will try to get a photo of this, as it stands, posted up here, as I'm sure I can make a good repair here. For a start, it will be cut right back to unblemished (inside, as well as out) steel, but more importantly, I will dip into my steel-stock that normally furnishes the chassis repairs I do on Landrover chassis.
The light tap with the corrosion-assessment tool was not really a very light tap in this case, more a full-blown swing with a pick to bellow the steel inwards, leaving dimples of fresh-looking steel around the impacts. However, the damage is done now, so I will need to find a way of fixing this car, which is very important for this particular customer's business - and cannot be replaced with a new van on-the-business in under 4months at the moment. The repair needed is a long strip that runs just above the weld-line between the upper and lower pressings, and I doubt that my welding is much inferior to the jointing methods of VW between two such pressings.
The odd thing is; the MoT-tester's screen shows where to find the "trouble" on one of these subframes, which is generally down the righthandside and under the engine mount, but as a stressed area, IMHO, it isn't really a very stressed area at all. I can think of many properly stressed areas such as the one on the little Rover 25 I did earlier this year, near the steering rack mountings, but this one just doesn't figure as such a problem, and certainly nothing in the same league as certain points on a Defender chassis that are often bodged-together by long-distance MiG welding techniques.... 
Access to my 2-post ramps again makes this job possible, so we will see what this week brings.....
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Post by sorted on Nov 29, 2020 3:10:37 GMT 1
You could of course do the repair such that the tester can’t tell there’s been a repair- cut out rust, neat repair panel butt welded and ground back with a coat of stone chip- same as a decent quality body repair. Whether that is ethical is another matter.....
The issue is those who slap a plate over the rust using pigeon poop and prayers.....
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Post by valhalla on Dec 2, 2020 0:40:30 GMT 1
I'll close this one off with some hindsight -
Having got the ramps free of the previous urgent job this lunchtime, I managed to get the Passat up in the air to have a really decent inspection and preparation for welding tonight. Except that when I went in with the tools, the damage was worse than I had anticipated....
I have taken some pictures of the original damage as presented for the MoT, but the lad doing that test was just going by the book, not straying too far from the prescriptive screen. What I found within a few minutes this afternoon was that the corrosion was both below and above the weld-line, but also had extended around the back of the RH engine mount bracket that is welded to the subframe. In other words, the MoT was barely the half of this car's problem.
I took some more photos after the inspection, but the phone does not want to link those as-yet, so that will have to come later, but I have decided that the repair of this subframe is not possible to a decent standard, and that is because; a) I know this car, and therefore I know how fast this corrosion damage has occurred - in other words, this is fatigue-corrosion, and that can only come from stresses b) The internal webbing has disappeared, and that is where a lot of fatigue has been induced c) The upper and lower pressings have thinned from internal scaling over such a large area, it would be difficult to repair this frame to a good standard without virtually rebuilding the entire RHside of the upper and lower pressings. d) There are too many hidden crevices that require repair, meaning that I would have to cut-out a large access plate in the base of the frame to get in with cutters and welding gear
So this car can only be repaired with a new or good secondhand subframe, which is where I stand at the moment.
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Post by valhalla on Dec 5, 2020 1:08:47 GMT 1
Looks like the car is going to be stood a long time - it seems nobody anywhere has a new or good-used front subframe for a B5.5 1.9TDI 5-sp car. All I get these days is "Dear John" letters and Emails each day, briefly to the point, "Sorry Mate, we've got nothing, and we're not all that interested at the moment, as we are all really worried about catching Covid_19 off anything that we might have to handle, so we cannot do car-parts or anything cos we're on Boris's Big Holiday and a fat wallet of compensation to go with it"
Cynical? Never let it be said I'm cynical.....
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Joepublic
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Post by Joepublic on Dec 5, 2020 14:24:33 GMT 1
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Post by valhalla on Dec 6, 2020 1:40:26 GMT 1
I'm not sure about the second one that would work with a courier - something about it looks a bit different near the engine mounts.
Definitely a good idea of yours to look for other VAG frames - I had got a bit fixated on getting an exact match, but the first link above looks possible, albeit the car I am trying to repair is a 2005, so theoretically the subframe is different again. I might just contact them anyway, to see if i could get a courier to pick-up
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Post by Rhubarb on Dec 6, 2020 11:17:29 GMT 1
I'm not sure about the second one that would work with a courier - something about it looks a bit different near the engine mounts. Definitely a good idea of yours to look for other VAG frames - I had got a bit fixated on getting an exact match, but the first link above looks possible, albeit the car I am trying to repair is a 2005, so theoretically the subframe is different again. I might just contact them anyway, to see if i could get a courier to pick-up
I thought the only difference between the B5 and B5.5 was the front wings/lights/bumper?  |
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Joepublic
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Post by Joepublic on Dec 7, 2020 10:56:59 GMT 1
There's someone on fb in Wishaw breaking one, 03 plate
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Post by valhalla on Dec 7, 2020 14:21:49 GMT 1
Well, thanks for all your help, chaps.
What I have is done is go for the really oily one in Bristol that JoePublic linked a couple of days ago. There was a bit of faff with the listing, but he guy sounds genuine, and I'm hoping that he can get it off the car for the next Sunday in-time for my mate to pick it up from him. This is the same mate that comes up for Christmas each year for a few weeks, so logically I should have it on the floor ready to go by the time we are packing-up the tools after our holiday in January, and I think that is the best outcome I could have expected at this stage.
I took a bit of a punt on the B5 and B5.5 business - it looks similar, and if there are any spare brackets to fit, entirely possible on the floor before the new frame is fitted.
As long as the oiliness is not covering-up any dire internal corrosion on the RH rail, I reckon this could well see the recipient Passat out. I know that I will be ladling-on the Waxoyl before it goes anywhere near the car (if it will stick....!!) and that might give it a fighting chance on Skye for a few years. The only risk here is that once the owner has sampled the delights of my V70 TDI for a few months, he may not want to go back....
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