Updating the Rear Suspension in the MG

Ever since I built the MG, I’ve been having issues with the rear suspension. First the springs were too weak to handle the torque, so I build some traction bars to help. That only got me so far, so I ended up getting a kit that mounts to the top of the axle… which helped a ton.

But then the suspension started to sag in the rear. I guess ~200 lbs of batteries were a bit much for the old springs after a few years. So I decided to get some new, uprated springs.

Turns out they don’t exist. And even if they did, there are quality issues with most of the leaf springs that are available, so I’d probably be dealing with the same thing in a year.

I added some VW helper springs with built-in shocks, which carried me through to this point. They’re OK, but the suspension feels unpredictable at times.

It’s time for a better solution…

Building a new suspension from scratch?

Having looked at several suspension options, now, Some kind of 3 or 4 link is probably the best and simplest choice for the car. That’s because of my unique spring rate and height requirements for the rear in tandem with the much-higher-than-stock torque. A 3 or 4 link suspension system gives me the option of adding adjustable coilovers to the mix, allowing me to mix and match spring and shock rates to get something that functions well.

The trick is that no one offers a 3 or 4 link kit for an MG Midget anymore. The one or two that I found pictures of haven’t been available for years, and they cost thousands of dollars in 2008… so I have to get creative.

Scouring the Facebook Marketplace

I’m not a big fan of Facebook, but it’s hard to deny that you can buy a lot of random stuff for cheap on the marketplace. Since no kits are available for an MG Midget, the next best thing is to adapt a kit from another car. I picked up a 4 link designed for a 40’s Ford truck. The links were very thick and very long for my application, but the price was right. It will end up overbuilt, but that’s OK since I’m not running the 60hp 4-banger anymore. The kit set me back $140.

The kit as I got it from the seller.

Adapting the kit

Since the links are all too long and the brackets too large, the first order of business is to reduce everything down to a more usable size. With the suspension completely remove from the vehicle and the axle positioned below it, it’s pretty easy to measure everything out and mock it up. All told, the length of each link was reduced by about 40%. I shortened the links by cutting a chunk out of the center, and then using a sleeve of DOM tube (Drawn of Mandrel; no weld to clean up on this inside of the tube) to join the two parts. Two holes were drilled in the sleeve for a rosette weld, and the ends were fully welded.

  • The arms shortened with both ends inserted into the tube before welding.

I also had to cut the original brackets and adapt them to fit in the MG. The front, lower, weld-in frame brackets from the kit were pretty easy: I cut the bottom plate off and tacked it to the front leaf spring mount from the MG. I had to cut the original “ears” off of the leaf spring mount, and then I flipped it over. I split the nuts off the bottom and put them on the bottom again once the mount was flipped over.

The rear brackets for the underside of the axle required a little more work. I decided to weld them to the bottom of the shock plate, allowing the lower link to be entirely bolt-in. The front is retained by the original bolts for the leaf spring mount, and the rear is held to the axle by shortened ubolts in a similar fashion to the original setup.

Fitting the lower arms

With the lower brackets made, I could fit the lower arms. A few things were a little finnicky, but it went together right! I had to be careful about welding everything on straight. Any amount that I was off on my brackets and arms would have an impact on the location of my axle, and could even cause binding. This is especially true for the much longer lower arms.

3 to go…

Welding the upper brackets

The upper brackets all had to be welded. There are two brackets on the axle, and two on the car. These brackets were a little trickier to place, since they are triangulated. I couldn’t weld them flat and straight to a big hunk of steel. Instead, they had to be cut and ground and cut and ground and cut and ground until they fit properly and could be welded in place on the axle. The brackets on the body were easy, being that they were cut to go into a corner. I simply welded them to the inner fender. This area will get some reinforcement on the opposite side, in the wheel well. That vertical reinforcement is surprisingly stout… it has to be something like 12ga or 14ga sheet metal, but I’d like the forces to transfer into some more structure.

The bracket fit nicely in the corner. As an aside, my old differential had a leaky pinion seal. I replaced it, but the carnage is still obvious.

Adding the coilovers

Without the leaf springs, I needed to add some coilovers to actually hold the car up. I sourced some QA1 shocks (DS404s for those who are curious) from Facebook for a reasonable discount. I used the remainder of the axle bracket to mount them. It will need some reinforcement to wrap around the rest of the axle, since the bracket was designed for a ~3″ tube, and the Midget axle is closer to 2.25″. I coupled these coilovers with a set of 150 lb springs. The rate of the stock leaf springs is less than 100 lbs.

The coilovers are adjustable (to dramatic effect!), which will go a long way to dialing in a comfortable ride.

What’s next?

I need to figure out the upper mount for the coilovers, and then firmly weld all of the brackets, which are currently tacked on. After that it’s paint for a final assembly and some test drives!

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