Longitudinal Member Assembly repair

[27woodstock]

Please can anybody advise on the implications and possible repair options for rust in a longitudinal member (Workshop manual R36 Item 1 and 2). The rust was not apparent until I remove the gearbox cover. The rust is mainly in the area of tube and reinforcement towards the front of the member. Whilst it is not easy to see several thick layers of rust flakes have come away. Whilst most of the car has had various rust treatments these member do not. Is there a known repair scheme for this area or is it practical to replace the member and if so what would be the rough cost of this as it would have to be a garage job.
As I wish to keep the car for the long term I am more interested in a long term fix if possible. Any advice gratefully received.

[ianmack]

These members can be repaired or replaced. You can buy either a complete one (parts people list them as chassis legs) or just the front half, depending on the extent of the corrosion, or if the hole is small they might be repairable in situ.

I can't help with likely garage costs but if you go for full replacement it's a fair bit of work.

[bmcecosse]

Assuming you refer to the chassis legs - then yes they can be renewed. Quite a big job - but satisfactory long lasting repairs will be possible.

[les]

Longitudinal Member Assembly, and there was me thinking it was just a chassis leg!

[John Naylor]

Took my car to my local garage for a chassis leg repair as I don't have welding equipment. They advised me to get a repair section so I bought the full leg. They backed out when they saw the leg and realised the work involved (over £600 they thought) and did a grand job of repairing the chassis for £35. It is now waxoiled inside and out and the supplier took the new leg back.

[ianmack]

Longitudinal Member Assembly, and there was me thinking it was just a chassis leg!

You're not allowed to call them members any more. Political correctness gone mad!

[27woodstock]

Many thanks for the comments. I think I will get an expert to assess the extent of the damage and the type of repair that will be most appropriate.

Pete B

[moggalot]

I did a short leg replacement on our 4 door last year. You have to be a bit careful with repair patches, especially around the eyebolt hole which had some worrying cracks when I cleared the crud off. My 'five penn'orth' says use a new part and wayxoyl it.[frame][/frame]

[daveyl]

Fair comments above. I did a short leg repair on mine and as said there's quite a lot to it. If the eye bolt is too far gone then a new chassis leg is probably the way to go. Chances are that if the eye bolt section's gone then the rest of it is probably no good either.
I did also have to repair the other chassis leg, which was corroded at the front where the angled 'stay' mount is. I treated the 'U' shaped bottom of the leg as three separate sections and repaired them accordingly with 1.2mm steel.

Whilst welding the 2 parallel sections of the 'U' shape (which were both rotten 2 to 4cm up and cut out), I lap welded both inside and outside the new sections, and then welded in the bottom section to 'Box' it in.
Doesn't look that pretty (and sorry no pics) but, I can confidently Raise it up on a jack and there is no crunching or bending.

[aupickup]

and dont forget drain holes

[daveyl]

Ah yes, well remembered Sir. Also very handy for spraying the old waxoil in.