Replacing Welded on studs for brake pipes etc. On car floor pan

[Lufbramatt]

Need to cut out a bit of rusty floor pan from my BMW... On the bottom of the bit I need to cut out there are 2 metal studs welded on which the brackets for the brake pipes screw on. Anyone know if you can buy these (they are a kind of "self tapping" thread for plastic brackets rather than a fine bolt thread). What's "best practice" for replacing these? I have a MIG welder but not a stud welding setup.

 

[Swift&Bold]

Cut down some wood screws, it doesn't matter about the thread as you have the plastic 'Top hat' type, as long as they have the same shank diameter they will do the same job.

 

[Crater Creator]

Cut down some wood screws, it doesn't matter about the thread as you have the plastic 'Top hat' type, as long as they have the same shank diameter they will do the same job.

^^^^ this
Then you can drill panel and plug weld from the back for a neat job.

 

[the snooper]

Keep the ones you have and weld them back Into the new plate

 

[Lufbramatt]

The old ones are horrible and crusty so don't really want to weld them on to my nice new steel. Will go down the route suggested above. I guess any plating will have to be ground off the screws to get a good weld?

 

[steveo3002]

another option if its not a show car ...repair the floor then just a stainless self taper to screw on the clips

 

[Cobs]

Re original question, yes you can buy them but bit expensive if you only want a couple:

http://www.ebay.co.uk/itm/251929587262?_trksid=p2060353.m1438.l2649&ssPageName=STRK:MEBIDX:IT

 

[slim_boy_fat]

You don't say which year or version of the e36(?) you have, but I'm pretty sure the bits will still be available from BMW [Dealers are sometimes surprisingly inexpensive for certain components]. Are they something like any of these? I've just chosen a random vehicle spec for example purposes.

http://www.realoem.com/bmw/enUS/showparts?id=CB72-EUR-06-1997-E36-BMW-323i&diagId=41_0982

www.Realoem.com is a great source of info on parts and gives you the relative number and an indication [albeit in $] of the cost(s). You can drill down through the schematics and find any part for any model.

 

[Lufbramatt]

Thanks for the link slim boy fat, I had already been through all the diagrams for the E39 (mine is a 530i) on RealOEM and can't see what I want. I think there might be a diagram missing as I can't see anything for the area I need to repair, which is rear outer corners of the floorpan, just in front of the fuel tank. Water had been sitting under the carpet due to blocked pollen filter drains and it has rotted the floor from the inside. It's a real shame as the car is a lovely spec+colour- techno violet- and overall in really good condition- it's only done 72000 miles.

I've circled them in the pic (not my car, pic borrowed from the internet, original found here http://mukerji.co.uk/e39-m5-update/dsc_0619-3/ )

 

[pedrobedro]

Why not replace them with plastic clips that will not rot again and just need a hole to push into ?

 

[Burdekin]

Could you use a rivnut?

 

[Lufbramatt]

Why not replace them with plastic clips that will not rot again and just need a hole to push into ?

Yep no reason why this wouldn't work, using something like this:

https://www.vwheritage.com/shop/281611767/clip-for-brake-pipe-plastic/

Just have to make sure the edges of the hole were properly sealed. Might do that instead.

 

[pedrobedro]

Yep no reason why this wouldn't work, using something like this:

https://www.vwheritage.com/shop/281611767/clip-for-brake-pipe-plastic/

Just have to make sure the edges of the hole were properly sealed. Might do that instead.

When I used them I just put a blob of mastic on the hole then pushed them through.

 

[slim_boy_fat]

Thanks for the link slim boy fat, I had already been through all the diagrams for the E39 (mine is a 530i) on RealOEM and can't see what I want. I think there might be a diagram missing as I can't see anything for the area I need to repair, which is rear outer corners of the floorpan, just in front of the fuel tank. Water had been sitting under the carpet due to blocked pollen filter drains and it has rotted the floor from the inside. It's a real shame as the car is a lovely spec+colour- techno violet- and overall in really good condition- it's only done 72000 miles.

I've circled them in the pic (not my car, pic borrowed from the internet, original found here http://mukerji.co.uk/e39-m5-update/dsc_0619-3/ )

Part #21 here?? [or one of the others listed] http://www.realoem.com/bmw/enUS/showparts?id=DT62-EUR-09-2002-E39-BMW-530i&diagId=34_1043

Failing that, print out that pic and pop into your nearest main Dealers with it, those clips will cost you just a few pounds I'll bet.

My last BMW was a 528iSE with the manual 'box, I still miss that car. I'm more than happy with her replacement 'though...a 530i e60, again with manual'box and virtually ALL the toys.

 

[Lufbramatt]

It's the actual metal stud that those clips attach to that's the issue, as they are welded to the bit of floor I need to chop out, but yes those are the right clips :-) Actually the clips are in pretty good nick as the previous owner had all the rear brake pipes replaced just before I bought it.

 

[the snooper]

these have a pretty course thread and they are cheap

 

[slim_boy_fat]

It's the actual metal stud that those clips attach to that's the issue, as they are welded to the bit of floor I need to chop out, but yes those are the right clips :-) Actually the clips are in pretty good nick as the previous owner had all the rear brake pipes replaced just before I bought it.

Ah, I misunderstood the bit you meant. They'd be factory welded on to the bare shell, can you not just plug weld a suitably bent piece of steel on then fit the oem clips to them?

 

[optima21]

when I replaced the studs on the floor of my car I tacked the heads of some M5 bolts against the floorpan.

the original studs may be what are known as "xmas tree" studs (well they were when I was buying them 20 years ago)

http://www.advanced-studwelding.co.uk/specs-cd.html#CFS