Sills and crossmember replacement

[GavinL]

So both sills require replacing. Now I've got the car rolled over the crossmember also needs replacing - there are various patches on it,and it is spreading. I'll replace the sills a side at a time, question is when do I remove the crossmember - before or after replacing the sills. Do I cut the ends off the crossmember to allow the sills to be fitted and replace it after replacing the sills? What do others recommend?Body is braced with angle welded across the door openings and between B pillars.

[philthehill]

If I was doing the job I would cut off one end of cross member where it attaches to the sill - replace the sill and what ever other body parts are required and then do the same on the other side of the car and then lastly remove the centre remains of old cross member clean up the underside of the floor and then fit the new cross member.
Unless there is a requirement for the jacking points I would leave them off as all they do is trap the crud thrown up from the wheels.
Cross bracing the door openings and doing one side at a time is the way to go as there is less chance of the body distorting.
When I replaced the original cross member on my Minor (not that it was rusted away but had been modified) I used a spot weld cutter from the inside to cut out the cross member spot welds so as to separate the cross member from the floor and when the new cross member was in place puddle welded the cross member to the floor through the spot weld holes which could be seen in the photo below if only I could post the photo - even though the picture has been drastically reduced to be in line with the requirements. Most frustrating....

[GavinL]

Thanks Phil, that was much as I thought. Removing the existing crossmember may be interesting as it appears to have a number of extra welds underneath where it has been reattached to the floor. I'm lucky that there appears to be just about enough of the flanges at the rear of the chassis legs with the torsion bar hole left which I hope to be able to retain to help locate the crossmember in due course.

On a related matter, do you know the dimensions of the stepped washer that replaces the torsion bar horseshoe washer, as I was going to turn up a couple - I think about 3mm or 1/8" thick to match the horseshoe washer, and stepped down to match the rear stepped washer and 3mm deep where it fits inside the crossmember? Not forgetting the countersink where it meets the end of the torsion bar.

[philthehill]

Regarding the horseshoe washer.

When rebuilding the suspension I replace the horseshoe washer with a stepped washer (Pt No: AAA1485) so that there is a stepped washer either side of the cross member which give good location and security to the rear of the torsion bar.

I invariably find that the stepped washer does not have a good right angle to the step and therefore does not seat well into the cross member. I machine the washer(s) to ensure that the step has a good square root to it.

Dimensions of the stepped washer:-
O.D. ................................................................1 5/16"
O.D of step.......................................................1 1/16" (machine to have good press fit into the cross member).
Overall thickness of the stepped washer.............1/4".
I.D. of stepped washer centre hole.....................1/2" (clearance).
Depth of the step...............................................1/16" (fits into the cross member).
It only needs a light countersink in the stepped washer to accommodate the transition of and where it fits up against the torsion bar.
The stepped washer (against the torsion bar) will have to be reduced in diameter to 1 1/4" so as to be able to fit into the recess of the reaction lever (Pt No: AAA1483) located at the rear of the torsion bar.

The horseshoe washer is 3/16" thick x 1 1/4" O.D.
The reason for the horseshoe washer is that its removal allows in theory for the torsion bar to be removed rearwards through the torsion bar.
Phil

[Mark Wilson]

I did manage to retain some of the chassis leg flanges when I removed my crossmember, but the torsion bar holes are flimsy and I strongly recommend making really good templates to cross check where they should be. I did the sills first, then most of the crossmember, with the car still the right way up. I cut a strip of floor out and (purists look away now) cut through the transmission tunnel which I welded back in afterwards. I finished the welding with the car on the rotissserie (in fact after doing all this I decided to replace the chassis legs as well.....)

[GavinL]

Phil, thanks for the dimensions. I had a short length of 1 1/4" BMS left over from a previous project so turned the washers up yesterday - I've added them to the box of bits awaiting zinc plating when the weather warms up a bit.

Mark, thanks, I suspect I'm being a bit optimistic thinking I can retain the torsion bar flange, it looks paper thin, so will be taking measurements, photos and making a template as you suggest.