Project MG Midget

This issue, the front suspension, steering and brakes of our Mk3 project Midget are stripped, assessed and then built back up.

As we explained last issue, after the extensive bodywork repairs to date, we need to pick up the pace on this Midget project if we are to bring it to a conclusion in the planned 12 chapters. That means skipping ahead on some of the mechanical aspects, but that is no big deal because these are adequately covered in the workshop manual. So instead of attempting to recreate the whole stepby-step sequence of each job, we will aim instead to give a flavour of the work, and to highlight any issues we found or any little tips that might help you.

This time around we are looking at the front brakes and suspension. Overall, the mechanical condition of the Midget was pretty good, and a credit to the previous long-term owner. We did find one or two aspects that could be improved, and we also replaced a few items with new that could reasonably have been salvaged – sometimes you do have to calculate the work involved in reclamation compared to replacement, and often the conclusion you reach will depend on your mood at the time, or how many big bills you have just paid out! There is also the danger of mission creep that we have mentioned previously, with standards rising and some

items being discarded because new parts will look better rather than because the old ones positively need to be replaced.

It was back in the March issue that we decided the front suspension and steering had to come off the car so that the entire engine bay could be grit blasted back to bare metal. Each side came off as a complete unit of wishbone, stub axle, brake caliper and disc, kingpin and trunnion link. I separated the lever arm dampers which formed the top links and removed the springs – these were inspected, but found to be fine and so just cleaned up and painted. The rest of the assemblies were taken to the work bench for further dismantling.

One general tip when working on items like this that have not been disturbed for many years and lived in a particularly harsh environment is to use a six-point socket rather than a 12-point one whenever you can to reduce the chances of it slipping and rounding off a rusty fixing. Before even attempting to undo anything stubborn though, clean off any exposed threads with a wire brush in a drill, and spray on plenty of penetrating fluid. Then, after this has had time to soak in, use a breaker bar or long ratchet and see if it will turn – heat and/or shock tactics might be needed, but a long bar will often do the trick, allowing you to apply firm and sustained pressure to loosen things off without needing to resort to anything more potentially destructive. However, if that doesn’t work and you don’t have a gas torch to apply high and concentrated heat, try shocking it free with an impact screwdriver, then undo the fixing a couple of flats, wind it back on, spray on more fluid, then undo it a couple more turns. It is a slow and laborious process, but generally much quicker than having to drill out a fixing that has sheared.

Another tip is never to throw anything out until the entire job is done, even if something is certain to be replaced. That’s because it could be useful to refer back to the old part and ensure the new one

is correct, or to spot any differences if something is reluctant to go back as it should. The old bits will also have various wear and grime marks that can aid with the correct orientation of parts and reminding you how they fit together.

With everything cleaned on our suspension, the parts could be checked and either replaced or prepped and painted as necessary. The king pins and bushes were a nice snug fit together, so they could go back in. The dampers were in good shape too, with plenty of smooth resistance when the arms were moved by hand. The springs and seats were also good to go, although – as detailed in the pictures – new wishbones were fitted.

I also intended to fit new wishbone bushes, but the ones I’d bought did not fit between the mounting flanges on the body. I tried adding red grease to the faces of the bushes to help them slide in, really squeezing the bushes hard and levering the mounting brackets slightly further apart, but all this did was damage the paint. After half an hour of fruitless toil, I took the wishbone back to the bench and compared the new bushes with the old ones. It turns out that the lip of the new bushes was at least twice as thick as the old ones had been. Since the old bushes were actually in good shape and I only replaced them for the sake of completeness, I swapped them back over and the wishbone slipped into the mounting lugs with just enough pressure to create a nice, snug fit.

With the wishbone finally fitted, I took the upright that I had previously built up and attached that to the outer end of the wishbone at the bottom and to the damper arm at the top. There is a pinch bolt that goes through the end of the damper arm, and a corresponding groove in the trunnion pin. As this can be hard to

see through the hole with all the grease in there, I marked the pin head with a dot of Tippex so that I knew when the groove was facing in the right direction.

I now wanted to fit the spring, and realised I had to take the lower spring seat back off the wishbone. That’s because there is an ingenious way of fitting the front spring on a Midget that doesn’t require the use of spring compressors.

I had already bought some high tensile bolts the same diameter as the spring seat bolts, but much longer at 4½in. The trick then is to insert the spring up through the hole in the wishbone and into its seat around the bumpstop at the top. The lower seat is then attached underneath the wishbone with the two long bolts in diagonally opposite securing holes, and tightening these up evenly pulls the seat up against the wishbone, compressing the spring in the process. Once metal was against metal, I could fit two of the regular bolts in the remaining two holes, before removing the long bolts and replacing them with two more regular ones.

Next up, the hub and disc brake went back on, followed by the brake caliper. I had new calipers and dust shields, and could not get the two mounting bolts to engage in the corresponding threaded holes in the stub axle. It was a little tricky anyway because the bolt goes through a tab washer, brake hose lock plate, dust shield tab and the caliper itself before reaching the hub, and you have little hope of being able to see where the threaded hole is through all these. The picture sequence shows where my problems lay.

After finding and fixing this problem, everything went back on fine and I was on the home straight, but not quite finished yet. The next problem was of my own making, because I had already assembled the steering rack and fitted that, but now the track rods would not drop down far enough for me to insert the track rod end up and into the steering arm. Naturally enough I was not keen on dismantling anything again, so I hit on the easiest solution: I removed the TRE, fitted this to the steering arm and then wound the track rod itself into the TRE.

3 You can’t remove the flexihose yet though, because it won’t pull past the hose lock plate. That is secured by the caliper-to- stub- axle bolts, which in turn are locked in place by a tab washer that needs to be knocked back and replaced.

2 The banjo bolt for the brake hose has two different sizes of copper washer – a larger one by the head, and a smaller ID one for the other side of the pipe. It pays to keep adding items that need replacing to a list and then order them all together.

1 This is how the suspension and steering came off on each side – the only fixings that needed removing were at the wide end of the wishbone where it attaches to the body, the brake flexihose, the anti- roll bar, track rod end and damper arm.

8 After removing the steering arm (another lock tab to be ordered!), Simon next decided to separate the upright from the wishbone. The first step is to remove a small cotter pin between the outer ends of the bottom wishbone. The nut on this appeared to be 1/8 Whitworth.

7 There is no one single order in which the things have to be disassembled, so next Simon removed the trunnion fulcrum pin and its bushes – this was already loose from the removal of the damper. Note how dry it is in the bushes, though.

4 It will save time during reassembly if you keep groups of bolts/fixings/brackets etc together in resealable bags. This is a new lock tab. The hose lock plate will go in there too, but first went in the box of parts to be cleaned, rustproofed and painted.

5 The pistons were pushed out of the caliper with an air gun, using rags to stop brake fluid from being sprayed everywhere. Don’t get your fingers anywhere near the path of the piston, as it can pop out like a bullet.

6 The piston was rusty, so Simon opted to fit new calipers on both sides. With the caliper and hose off and stored safely out of the way, he threw away the rags and gloves so that he couldn’t inadvertently touch a car with brake fluid on his hands.

10 That cotter pin goes through a groove in the fulcrum pin, which goes through the two outer ends of the bottom wishbone, and through the bottom of the king pin between them. On one end there is just a regular grease nipple, but on the other end is this more complex plug.

13 The lower spring seat could then be removed after soaking its four retaining nuts and bolts in penetrating fluid and using a six- point socket and long breaker bar to undo them. New saddles are a not inconsiderable £30 each, so these were cleaned, checked and painted.

11 Then you have to unscrew the fulcrum pin using the slot which is now revealed. This needs a flat blade that is wider than a normal screwdriver, but not any thicker. Simon found the best tool he had was one of the bits from his impact screwdriver attached to a ratchet spanner.

9 With the nut loosened but still protecting the threads, a tap on that nut with a copper hammer got the pin moving. It didn’t need much persuasion, and with the nut then removed, Simon could push it out with a small drift.

12 The wishbone can then be separated from the upright, along with two cork washers that sit either side of the king pin – that is what’s being pulled out of the accumulated grease. Note on reassembly that one cork seal is larger than the other!

20 Returning to the workbench, it quickly became clear that the shoulder on the new wishbone bushes was much thicker than it had been on the old ones. Add four of these to a wishbone and it was never going to fit, so the old ones went back in.

16 After cleaning off the accumulated grease, Simon secured the king pin assembly in a vice, removed the 5/8in nut from the top of the kingpin and tapped the king pin out of the top trunnion and the hub with a copper hammer.

17 When you remove the top trunnion, keep it with its thrust washer. Check at this point whether there is an adjustment shim on the top of the king pin and make a note. The king pin can then be pulled out of the housing.

18 When removing the kingpin, remember that there is a sealing ring (an O- ring) in the bottom of the housing. That then just leaves these upper and lower link pin bushes and the spring between them to be removed for cleaning.

15 Moving on to the hub and the upright, under the grease cap there is a split pin, a 15/16in nut and a retaining washer. The hub then pushes off the stub axle assembly, giving access to remove the final bolt on the brake dust shield.

19 Moving on now to the reassembly, the first problem Simon encountered was that the wishbones with their new rubber bushes would not fit into the sockets on the car’s frame. Neither using red grease nor leverage helped.

14 However, although the wishbones were in pretty good shape overall, rust had started to eat away inside where the lower link bushes were pressed in, so new aftermarket wishbones were bought at the cost of £70 each.