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MG MGB Technical - Where to place jackstands for sill replacement?

The title says it all. I'm going to replace the outer sills, one side at a time. Where is the best place to support the car on four jackstands for this job?
Greg Bowman

I've been told to place the stands under the A arms in the front and under the front spring mounts at the back. Are you replacing the entire sill or just the outers?Is this a roadster or GT?
william fox

It's a roadster and I'm doing just the outers. I'm also curious as to how the bottom of the A pillar is welded to the outer sill. I don't see any spot welds and the is no welding along the edge. THe bottom of the A Pillar is in good shape as is all of the outer sill except the very front corner and rear corner and I don't want to mess it up.
Greg Bowman

If you look at your new sill, you will see that it fits along the bottom of the A post and also behind it ( the A post ) It is a pain to get out the old outer sill from behind this post if you want to do it properly. The post was spot welded on, 3 or 4 spots on each flange ( how unless it was done off the car I do not know ) The trick is to get the car as high as possible. The three sill sections are welded together behind that post, so if you do not cut the new sill, you will need to get a angle grinder behind the post to get the old part out. The B post bottom is just as much a pain. I suggest if you get the outer off you will find the inner is starting to rot, it is just as easy to to fit a new inner, then you can also clean up the inside of the castle rail.
Tatty

You could remove the flanged portion of the outer sill that would interfer with going behind the A Post. Weld the partially destryoed A Post flanges to to sill top. I say destroyed because the flanges are small and removing the spots will chop them up. I made new angle pieces and plug and seam welded in place. I don't believe any structural integrity will be compromised.

Place the stands as Tatty described.
Mike Zaffarano

Greg,

You will find lots of information on fitting new sills to an MGB in Lindsay Porter's book 'Haynes mgb restoration Manual' ISBN 1 85960 607 5.

It's quite an involved process as it's essential to maintain the shape of the car while you cut away portions, possibly more than you might expect - remember corrosion is allways worse that shows on the suraface - of the structure.

Good luck

Peter
Peter Hills

I've supported my car at the front and under the rear end while replacing the sill. Assuming the rear end is installed, this would distribute the weight better than only under the front spring mount. It would also move the jack stand back and provide more working room.
Rich Stinchcomb

Greg, Place the stands like William said, under the rear end housing as close to the wheels as possible and under the lower a-arms in front also as far outboard as possible. You are trying to make the car set as it would if it were sitting on the ground. I do these all the time in my shop. Good luck, John
p.s. William did his sills in my shop.
John

John, William said put the rear stands under the front spring mounts. Are you saying to put them under the axle?

Thanks.
Greg Bowman

If possible borrow a proper car repair jig/bench, these have special brackets that attach to specific structural points on the car such as gearbox mounts and spring hangers and will also tell you if the car is not to the correct factory dimensions.Greg if you lived nearer Yorkshire you could have borrowed mine as I'am not using it ATM.However without it I ould support the car in as many places as possible and check it supported level and eavenly to maintain the origional dimensions,check against the production dimensions.
Regarding the A post sill lower flanges, if these are still intact and it is just the sill requiring replacing then cut of the sill and leave some metal around the bottom of the A post allowing you to attack the welds from below without damaging the flanges. These can be plug welded back onto the sills.
If you want to spot weld the flanges back to keep 'originality' then there is a way to do that ,if you want to know how to do that let me know.HTH
mike.
mike satur

Thanks for the offer Mike. However, I don't think my wife would find that a good enough reason to move to Yorkshire.
Greg Bowman

Yeah, I guess she wouldn't want to move but we have a few lasses spare ;-)
Mike.
mike

This thread was discussed between 22/01/2003 and 25/01/2003

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