Rear seat fixings - I'm stumped!

alanm

alanm

A2OC Donor
A couple of weeks back I got one of the Audi rear drinks holders from Vagparts.com and today I made use of Ben's excellent fitting guide to fit the retaining brackets for the holder. The job was going very smoothly until I unhooked the carpet from the four seat fixings and went to remove the inner bolt from the nearside seat fixing. The head of the bolt had a piece of gaffer tape over it and when I peeled this off I found that the bolt was loose and could be pulled out by about 1cm. I've tried unscrewing it but it feels like the retaining nut, which should be secured to the underside of the car floor, is not secured and just turns with the bolt. The previous owner must have had an interesting rattle from under the rear seats, which was fixed by use of the bit of gaffer tape.

I've looked under the car but where the bolt goes through the floor seems to be above the exhaust pipe and the heat shield above it. Even if I'm very optimistic, looks like it will involve loadsa Audi labour time to rectify - even if the retaining nut is accessible from beneath the car. If, however, it's inside a chassis member a fix will be impossible at any price.

The last thing I want to do is to be reduced to just replacing the gaffer tape and doing without fitting the rear plastic bracket/cover for securing the drinks holder. I'm also concerned that the near side rear seat is unsafe.

Please can anyone advise me as I'm stumped as to what to do or, indeed, whether anything can be done to fix things?

Many thanks - Alan
 
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Hi alanm
As you already realise, if it is a captive nut that has come loose and the panel is double skinned, with no access to the nut, then its back to the gaffer tape.
If you don't have the facilities, go to a good independent garage and get them to put it on a lift and check the underside. The exhaust heat shield may need removing so it could cost you £30 or so, just to have it checked out. If you're lucky the problem captive nut will be accessible and can be replaced so just in case, take the drinks holder bits along so they can be fitted while the car is on the lift.
Sorry there is no magic fix.

Cheers Spike
 
Thanks Spike - fingers crossed the captive nut is accessible.

However, before I go down the remove the heat shield/exhaust route, I wonder if anyone knows whether the captive nut is inside a double skin as that would save needless investigation dosh and I have to accept it's unfixable.

Alan
 
I've had a browse through the workshop manual and the parts catalog and there is no reference to a captive nut.

What I'd do is remove the other bracket screws and bracket and then take a torch and have a really good look to see if there is evidence of there being a captive nut, or if the thread appears continuous, indicating a tapped section.

If you think that it is a captive nut that has come loose, then have a look through the hole to see if you can get a clue as to whether it'd be possible to access it from the rear. In any event, you should get the mount repaired. Let's be honest, if you carry rear seat passengers, then doing so knowing that a seat mount is defective is a little worrying, or it would be to me.

If you think that it is a stripped thread type situation, then these can be repaired by various means.

Cheers,

Mike
 
Mike - I'm also concerned about the safety issue. My latest line of thinking is that front brackets provide little more than a hook and eye type hinge function. The prime security of the seat is dependent on the spring loaded pins that lock into the boot floor and the locking mechanism at the top outer edge of each seat back (both of which work fine). The front bracket in question is still secured by one bolt and in operation the only symptom of the problem is that if you grab the bracket and try to move it there is a slight flexing of it.

Today I'm going to try the following:
1. Remove the second torx bolt from the bracket and suss whether what's behind/beneath the bolt hole is the underside of the car or a double skinned box section.

2. Irrespective of the outcome of (1) I'll mix up some Auto Weld which has a tensile strength of 4000 psi (278kg/cm2) and try and feed some of it behind the hole through which the problematic bolt protrudes.

3. Pull the bolt + the attached (I hope) nut firmly up against the back of the hole so that it sandwiches the Auto Weld between the nut and the underneath of the boot floor around the bolt hole..

4. Keep the bolt firmly up against the boot floor for 24+ hours until the Auto Weld has fully cured and then (fingers crossed) I can unscrew the bolt leaving the nut Auto Welded against the underside of the hole.

5. If I get as far as this stage, I'll then very gently screw in new torx bolt supplied with the drink dispenser bracket. If this works the result will the be a safe fix.

6. If the above doesn't work and the nut is accessible from beneath the car, I'll then implement Spike's advice. If the nut isn't accessible from beneath the car I'll retry my Auto Weld idea again. If still no go - I'm stuffed!

Thanks again for the advice - fingers crossed I can get it sorted!

Alan
 
Sod's Law strikes again!

Bad news - it's the worst case scenario!

I removed the second bolt from the offending bracket to find that behind the bolt is a box section with no access from the underside of the car. The captive nut was orginally welded to the underside of the boot floor but is now detached from the floor and rotates with the bolt.

Unfortunately, the bolt is clearly badly cross-threaded in the nut - which rules out the Auto Weld fix. I reckon this was done when the car was orginally manufactured and that the bolt was cross-threaded upon initial assembly.

Either then, or after the car was retailed, I reckon an attempt was made at tightening or removing the cross-threaded bolt and in the process the weld retaining the nut has failed resulting in a rattly bolt+nut assembly. When this has been investigated and the non- accessibility of the nut from under the car has been sussed, the gaffer tape was applied as a bodge to eliminate the rattle. The customer would have been happy - not knowing what had been done (I didn't discover the gaffer tape until I prised the carpet from around the seat bracket).

So, unless anyone can come up with an alternative (please?!), it looks like my only option is to:

1. Cut through the bolt and remove it.
2. Fill the cavity with Armour Weld so that it makes contact with the severed nut and stops it from rattling.
3. Before the Auto Weld goes off, screw the new oiled bolt into it and allow to set.
4. Once set, unscrew the new bolt so that a new thread is cut in the Auto Weld.
5. Reinsert the new bolt + the drinks holder bracket.

Before doing this I'll wait in hope that someone comes up with a better alternative and, in the meantime, do without the rear bracket for the drinks dispenser.

Looks like I'm the latest victim of Sod's Law!
 
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Sorted!

I used the method I last described and finished the gooey part of the job about 1.30 am and made sure my garage was well warm overnight to help the curing process.

Finished the job off this morning and am amazed at how well it's turned out. In fact the bracket that had the cross-threaded bolt is now more secure than the other 3 that are as original in that you can't get any flex out of it at all. No matter how hard you try to pull/lever it, it is rock solid and the drinks dispenser is now installed. Being ultra cautious, I'm going to leave it for a few days before reinstalling the rear seats to ensure the Auto Weld is deffo fully cured.

If curious, you can find out about Auto Weld at www.jbweld.com and Halfords stock it.

As to its durability/strength, I first used it 3 years back when I stripped the threads in the ends of a set of Durango Profile handlebar extensions I had installed on my mountain bike. Cross threading the retention bolts on these was very easy as they involved a steel bolt going into threaded aluminium. I rebuilt the threaded ends using Autoweld and after 3 years of pretty stressful use they are still rock solid.

I wonder what form Sod's Law will take next time it hits me?!
 
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