[Guna]

My car's (Tiguan Allspace) underbelly scrapped against something hard and a rod/pipe-like piece which is located under the exhaust pipe got dislocated.
This piece s called 'Floor Pan Reinforcement' or 'Tunnel cross-piece' (part no. 5QA802117A).
Folks at VW service centre do not seem to have clear idea on how to fix it back and they are trying to avoid working on it. Before insisting further, I wanted to know if anyone on the forum knows how it is fixed to the body.
My question:
This piece is fixed with the help of 4 bolts. If you notice, the bolts appear as if they are cut rather than broken. Are these bolts fixed to the body with some kind of fusing/welding, which would have given up upon the impact?
Service center folks tell me that the bolts need to be put from inside (which means stripping the carpet, seats etc).
Another thing to be noted is, 'shouldered hex nuts' are also involved.

This is where the piece sits


Piece


Broken bolts on the piece


Other side of the piece


Holes on the car body

[Kosfactor]

Looks they can make a small cut in the carpeting, drill out the broken fastener and replace with one of suitable size. The bracket can be reused as its not mangled out of shape anyways.

[Guna]

Originally Posted by Kosfactor

Looks they can make a small cut in the carpeting, drill out the broken fastener and replace with one of suitable size. The bracket can be reused as its not mangled out of shape anyways.

I would prefer them taking out the carpet instead of making a hole. But I want to see if they can avoid approaching it from inside the car and instead stick/fuse it from outside which seems to be the way it was done originally.

[Sran]

How about welding from outside using some sort of fire blanket/sheet metal? There are also metal glues but how successful they might be, I have no idea.

If in any case a work is done, why not fix a metal plate instead of bracket.

[Jaggu]

Originally Posted by Kosfactor

Looks they can make a small cut in the carpeting, drill out the broken fastener and replace with one of suitable size. The bracket can be reused as its not mangled out of shape anyways.

Originally Posted by Guna

I would prefer them taking out the carpet instead of making a hole. But I want to see if they can avoid approaching it from inside the car and instead stick/fuse it from outside which seems to be the way it was done originally.

The said image is not of interior, it is just the part with the broken bolts, pictured with carpet as background

Looks like some sort of breakaway bolt held in place with some sort of adhesive. Best if for workshop to look at parts manual and then figure what needs to be ordered. Am sure some support from factory can be requested by the workshop if the body shop folks don't have an answer.

[Guna]

Originally Posted by Sran

How about welding from outside using some sort of fire blanket/sheet metal? There are also metal glues but how successful they might be, I have no idea.

If in any case a work is done, why not fix a metal plate instead of bracket.

They are hesitant for welding as it is close to the petrol tank. In any case I think they won't do any juggad work. I think this bracket has a function f reinforcing the tunnel and providing rigidity, so metal plate may not be ideal. I want them to bring it to the original state using stock components.

Originally Posted by Jaggu

Looks like some sort of breakaway bolt held in place with some sort of adhesive. Best if for workshop to look at parts manual and then figure what needs to be ordered. Am sure some support from factory can be requested by the workshop if the body shop folks don't have an answer.

This is a preowned car which I bought. I am also suspecting that the owner had got it cut out for some reason and glued it back. Originally it could be still long bolts inserted from the top (from inside the body). I would be surprised if VW's engineering is so poor that a supportive bracket can come off with a simple nudge, which is so cumbersome to fix back.

[Sran]

Originally Posted by Guna

They are hesitant for welding as it is close to the petrol tank. In any case I think they won't do any juggad work. I think this bracket has a function f reinforcing the tunnel and providing rigidity, so metal plate may not be ideal. I want them to bring it to the original state using stock components.

I am pretty sure these type of brackets are not meant for structural integrity/rigidity. It can be seen that there is extra circular reinforcement around the bolt area. They obviously would have designed it keeping the fail safe mechanism in mind, like what if something clings/hooks to it, then it would rip apart the floor. It is merely some sort of bash equipement, a first line of defense.

If a fire blanket is not used to weld from outside, then the only way is to bolt it from inside.

[crdi]

If VW is not giving a better repair option; maybe drill out the bolt remnants from under the car, and fix the part with an over-sized self-tapping bolt? The part doesn't appear to be needing frequent removal or sustain too much flex.

[yesyeswe]

Why not some self drilling screws are used to drill into the remaining broken part of the screws? In that way there would be no need to remove the broken bolts and the bracket would be put back too, moreover it's not like new holes are made into the body, holes would be into the broken part of the bolts.

[venkyhere]

First Q has to be :
What is the purpose of that cross member ?

A) Structural strength laterally, to improve torsional rigidity

OR

B) Just a barrier protection / backup carrier for the exhaust, in case the weld of the exhaust pipe hook with the body comes off

Unless this answer is found, any comment on 'how to fix it back' is pointless.

[rpunwani]

Originally Posted by Guna

My car's (Tiguan Allspace) underbelly scrapped against something hard and a rod/pipe-like piece which is located under the exhaust pipe got dislocated.
This piece s called 'Floor Pan Reinforcement' or 'Tunnel cross-piece' (part no. 5QA802117A).

My question:
This piece is fixed with the help of 4 bolts. If you notice, the bolts appear as if they are cut rather than broken. Are these bolts fixed to the body with some kind of fusing/welding, which would have given up upon the impact?
Service center folks tell me that the bolts need to be put from inside (which means stripping the carpet, seats etc).
Another thing to be noted is, 'shouldered hex nuts' are also involved.

As the name suggests it is a floor pan reinforcement in the transverse direction. The primary function of the reinforcement is to maintain the shape of the tunnel under transverse loads.

The impact has probably sheared the bolts - can happen if the impact has occurred at a high speed. You can see that the cross piece has twisted a bit. The twist can be straightened.

The bolts should be extracted using a bolt extractor and renewed. If the carpet / seats / plastic moulding has to be removed for access please have it done. I would not recommend any kind of welding. If a spare piece is available at reasonable cost, renew it.

[Vid6639]

Very tricky to remove the bolt left in the body shell. They need a bolt extractor or drill with a small bit into the left over bolt then take the old sheared bolts out. After that fix the new beam and bolt it back on.

Hopefully the threading on the body is not damaged.

[Guna]

Originally Posted by rpunwani

The impact has probably sheared the bolts - can happen if the impact has occurred at a high speed. You can see that the cross piece has twisted a bit. The twist can be straightened.

This happened at crawling speed on a mud road covered with grass. Probably there was a stone hidden under the grass.
Cross piece is not really twisted. In fact there is no sign of any 'hit' on it.

Originally Posted by Vid6639

Very tricky to remove the bolt left in the body shell. They need a bolt extractor or drill with a small bit into the left over bolt then take the old sheared bolts out. After that fix the new beam and bolt it back on.

Hopefully the threading on the body is not damaged.

Car is at the workshop and I should have some answers by tomorrow. Not sure if the body (hole) has any threads. There could be a sleeve with threading on it which takes the bolt which either has a nut of the top (from inside the cabin) or flattened head like a rivet.

[John P Daniel]

It's most likely a fail safe to keep the exhaust from scraping the road and holding it in place if it gets damaged. If sheared bolt is inside the body work, a welder can probably get them unscrewed and use new bolts to fix it.

[AJITHAAA]

Usually there are no loose bolts inserted from the inside of the car body shell. These should be studs welded on the outside of the car body. The entire stud seems to have been dislodged from the body. Looking at the parts catalog on Boodmo/Oriparts the part is a crossmember reinforcement for the tunnel. The nuts used are M8, Item No.22 in the first image and by all probability the weld stud is Item No. 13 in the second image. If this is indeed the part, then its welded from outside. The fuel tank might have to be dismounted before welding if its deemed a fire risk.