|The MGA With An Attitude
REMOVING DENTS FROM THE ROUND CROSS TUBE - FR-102
The MGA frame tubular cross member that passes under the engine to gearbox joint takes a severe beating, especially when driven on rough roads. Most MGA may have substantial dents in this part of the frame, some being smashed flat for about one third the thickness of the tube. Do not despair, as this damage can often be repaired without cutting and welding.
Notice that this tube is capped on each end - air and water tight. The trick is to apply about 120 psi of air pressure by tapping one end cap and screwing in an air chuck fitting. Once this is done you need only heat the dented areas cherry red and work your way across them with a torch
This may take a little practice. You need to heat a large enough area at one time to allow the material to move in unison. Propane torch will likely not provide enough heat. MAPP gas torch can work, but may be a little slow. The factory shop manual is fond of mentioning the gasoline torch (good old fashion blow torch). Air-acetylene torch would work well. Oxy-acetylene torch makes it a breeze and gives good control. A word of caution: Keep the torch moving to heat large areas, do not heat just a small spot, and in particular, do not blow a hole in the tubing or all bets are off (not to mention that it could be a rather startling experience).
The results as heated can be quite satisfactory for most people. For concours quality a little standard body tapping, filling and filing can work wonders.
See also FR-210-RT2 - FRAME REPAIRS, Round Tube Under Bellhousing.
In July 26, 2015, Daniel Ross in Omaha, Nebraska, USA wrote:
"Removed the dents in the tubular cross member. Heated the dents with oxy acetylene and pumped the tube up with air - it worked really well - the dents popped out".