B post cracking

[stag36587]

Hi

I have a recurring issue with the b post cracking on the outside at the midway point on my 2 door saloon, i.e. where side window frame starts.

I know some people have had this problem before so I'd ge grateful for views in best way to ensure a permanent repair. I've welded it up a couple if times already so assuming I should put some sort of reinforcement?

Thanks

[philthehill]

The cracking in this area of the 'B' post is caused by the body flexing.
I would suggest that you do need to look for a underlying cause i.e. corrosion of the floor pan or sill panels.
The area at the bottom of the 'B' post is comprised of multi layers of metal and it is difficult to see inside the sill panel.
Whilst it may look good on the outside do you know what the metal is like inside the sill.

http://www.moss-europe.co.uk/shop-by-mo ... anels.html

[stag36587]

Hi Phil

I probably should have said - I recently completed a full restoration on the car so all the metalwork is completely solid and corrosion-free in the sill/floor areas. On looking at the car again I wonder if it's the door out of adjustment - I can see some evidence of paint rubbing on top of the door window frame which will need sorting

[philthehill]

Thank you for the additional information.

There should be no cracking in the area you describe even after a full restoration and especially no reoccurrence of the cracking.
Whilst the door may be rubbing on the door frame (a common occurrence) it should have no bearing on the crack and its location as described.
The reason the metal/weld keeps cracking is because that area is under stress. If there is no stress there will be no cracking.
When you undertook the rebuild did you remove the door and strongly cross brace the door opening in both direction and across the body between the door frames?
I suspect that there is a slight misalignment of the body parts which has induced stress into that particular area.
I would also suggest that using the diagram in the Minor wksp manual you do a drop test from the various point as described in the manual and see how your Minor body alignment compares to the manual. Checking must be done on a flat and level surface.
Phil

[stag36587]

Thanks Phil that's very helpful.

I did indeed brace everything before cutting and welding - the car was very rotten indeed and I was actually slightly (ok very) paranoid about the door aperture changing as I made repairs. I'll do some careful measurements etc against the workshop manual bodywork diagram when I can get a spare hour or so, I'm also interested that door frame rubbing is not uncommon

[Fingolfin]

I've got this same problem. New floorpans and sill panels (and a lot more) six years ago (and I just looked at the underbody, it's in sound shape). I've already done the drop test, and the result was that the body alignment is spot-on. Perhaps the cracks began before the body was made sound, and have progressed since due to their weakness?

[stag36587]

A possibility I guess. I think I'll want to find a way to reinforce this area - has anyone done that?

[jagnut66]

Hi,
I had this problem on my last Moggy, as has been already been suggested it is probably due to stress on what is an extremely slender pillar on the two door model.
The only solution I think would be to strip out the interior, open up the pillar from the inside and weld in some reinforcement, then weld it all back together again. Once it's all been repainted I would fill the area with cavity wax for long term protection.
It may seem extreme but allot of two doors I've seen have this problem, it may be caused by failing structure elsewhere but this is a very weak area to start with in my opinion. Doing the above would also provide an 'invisible' solution.
Best wishes,
Mike.

[Fingolfin]

Mike, I think you're quite right about that - but that's pretty daunting on anything but a bare shell! It would help if there were repair panels available for this area. I can fabricate a flat or single-curve patch easily enough, but this is a complex shape.

[Mark Wilson]

There's a bit of room in the B post, so strengthening wouldn't need to be too complex a shape, just a channel or angle. The inner face is plain steel sheet and easily cut and replaced.

I've attached photos of mine as you don't often get to see inside the B post. It's a Traveller, so there's a channel running down the back face (right in the photos) which holds the wood frame attachment captive nuts. Don't know if there's anything at this point in a saloon, could be a suitable location for a strengthener? Angle would be easier to plug weld.

[Fingolfin]

Great photos! Thanks, Mark.

My "complex shape" is the pressed steel that forms the area where the cracks are, at the leading edge base of the side windows. Strengthening the area would probably be a fairly simple matter, but repairing the "skin" to make it look good will be harder (for someone who's very hamfisted with aesthetics).