My name is Dale.
I would suggest that you have the vehicle aligned properly first. The Caster on any vehicle can make it extremely difficult to turn, especially if it is manual steering.
This may or may not be the problem but you should have this done before you start working on the steering gear, etc.
I hope this helps you resolve the problem.
PS-I am partially disabled and I subsidize my income by the earnings I get from my customers. I am available about 50% of the time and I must rest when I am not working for you.
Thank You for that information.
Here is the Adobe PDF link for the alignment specifications for your MGB Midget.
All MG models are equipped with rack and pinion steering.
If they all have rack and pinion steering there is no steering box.
Here is a picture and a statement from the factory that might help a bit:
MGB front suspension
The MG Midget and MGB independent front suspensions utilize lever-type shock absorbers and coil springs. The shock absorber lever acts as the upper control arm while the lower control arm is a conventional pressed steel A-frame. Kingpins are used, rather than ball joints, to locate the front hubs and allow them to swivel. An anti-roll bar is installed as an option on some models. The MGC suspension consists of pressed steel upper and lower control arms and telescopic shock absorbers. Torsion bars are used in place of coil springs.
In my opinion, it is more likely that the king pins are binding. Here is the complete king pin replacement procedure including the tolerances. The tolerances are very important for this type of a steering and suspension set up.
Place a jack under the lower control arm and raise and remove the wheel.
Disconnect the tie-rod from the steering arm.
Unbolt the brake caliper and support it clear of the hub.
Remove the hub and brake disc assembly.
Remove the top kingpin pivot bolt and swing the stub axle down.
On the Midget, remove the nut from the lower pivot locating pin and drive the pin completely out. Unscrew the pivot end plug (core plug on later models) and unscrew the pivot using a screwdriver.
On the MGB and MGC, unscrew the nut from the lower pivot bolt and remove the bolt.
Withdraw the stub axle and kingpin assembly from the lower control arm.
Unscrew the nut from the top of the stub axle and kingpin assembly and remove the kingpin, washers, and seals.
Press the bushings out from the bottom of the axle.
Anti-sway bar components-MGB (most models similar)
Install the new bushings, taking care that the open end of the oil groove enters first and that the hole in the bushings is in line with the lubrication channel in the axle.
On the MGB and MGC the bushings must be line-bored after installation (most machine shops can perform this operation).
The bushings should be machined to these dimensions:
MGB-top bushings: 0.7815-0.7820 in. bottom bushing: 0.9075-0.9080 in.
MGC-top bushing: 0.8125-0.8130 in. bottom bushing: 0.9375-0.9380 in.
On the Midget the kingpin bushings do not require reaming. However, the kingpin should be lubricated and installed to check the fit. If it takes excessive effort to rotate the kingpin, the bushing surfaces may be refinished using a brake cylinder hone.
Install the kingpin in the axle body along with the washers and seals, as removed, and tighten the nut.
Lubricate the bushings via the grease fittings using a high pressure grease gun, and check the resistance of the kingpin to rotation. If it is excessively stiff, remove the nut and substitute a thinner floating thrust washer (MGB and MGC) or a thicker adjustment washer (Midget).
From this point on, installation is in reverse order of removal.
If it in fact has a steering box then the data I have on your MGB Midget is wrong. If it has rack and pinion steering and the king pins were replaced and lubed properly, then I would be looking into the steering rack. The steering racks as a rule are replaced as an assembly.
I hope this helps you find the problem within the steering of your MGB Midget.
PS- I have been thinking about this. One other thing that might cause hard steering is if some of the steering and/or suspension components are bent and this will show up if you put it on an alignment machine and check the Camber, Caster and Toe-in against the chart i sent you. If it is off it will point you in that direction.
Thank You for your response and information. If you will read what I sent you I told you that it could have a steering box or it could be equiped with rack & pinion steering (The data shows both) ! I think at this point you would be best served if I OPTED-OUT of your question andrelisted the question with your comments and mine for a different expert to handle.
I am sorry that I was not able to help you more with you MGB Midget.
Best of Luck with resolving this issue.