MGB - Front Suspension Refresh (Part 1)

Before I took the little British car to a shop for review, I did the brakes on all 4 corners (See MGB - Brake Job). While I had the front end on jack stands, I noticed some weirdness with the front end suspension. Today's post starts the documenting of that work.

Well, That's Not Right

weather stripping?

So, I had the front end in the air and the front wheels off, trying to get after the bolts which hold the calipers onto the front swivels. On my back, lying under the front right (passenger) fender, or wing in British car parlance, I noticed that the front of lower control arm was attached to the front beam, but it looked like the bushing had been replaced with a strip of window insulation. Huh? I pushed and pulled up and down on the arm and it wiggled. Yikes. I looked at the point where the front shock attached to the top of the swivel, and that bushing looked old and tired: brittle and cracked. The top connection didn't wiggle, but something that brittle was at end-of-life. I slid around to the left (driver) side. There, I found more dust and more surface rust, but both the top and bottom bushes on the swivels looked like the top of the passenger side: old, brittle and tired. This front end needed a complete re-bushing before being driven very hard.

Getting Down to the Beam
I had a few weeks between jobs around the holidays, so I thought it was a perfect window of opportunity to do the front end. I did spend some focused time during those weeks, but I also took advantage of an amazing snow season by hitting the mountain a few times, I visited with family, etc, so I didn't exactly get this done within the window. As usual, this took me longer than it would probably take most folks to do.

Since we're working on the front end, we start with loosening the lug nuts and then putting the front end on jack stands. This time, get the front end as high as you can get it without getting nervous about how high it is. The key here is having it high enough so the lower control arms can hang straight down once disconnected. Figure, that's at least 16 inches at the rear of the lower control arm. Once on the stands, remove the wheels and stow them out of your way.

Disconnect the brakes. Start with loosening and then removing the calipers. You may need to pull the pads before the calipers will come free. I was able to remove everything as a unit but I just did these pads. I ultimately needed to disconnect the front brake lines so I'd suggest you completely remove the calipers from the car now. Once the calipers are free, disconnect the brake hard-line from the front beam. Remember that brake fluid is corrosive, so wear gloves, use a catch-pan and dispose of safely. Its nasty stuff on your paint too, so basically, have it avoid everything but the pan.

get it way up in the air

Remove the steering rack. I already had mine off (See MGB - Steering Rack), which was one reason why I jumped into this over the winter.

Disconnect the front sway bar from the control arms. In the picture above, you can see them still connected to the lower control arms out near the wheels. Once the nut is removed on each end, coax the threaded end out the front. Sounds easy, and the second side is. The first side can be a bear.

Orienting on the Lower Control Arms
If you have ideas about doing more than just replacing the beam-to-frame mounting rubber, there's more to do. If not, I get to dropping the beam in my next post. Since I aim to refresh the whole front end, I kept going.

First, pick a side. If you are space-constrained like I usually am, pick the side where you have more room first so you get a feel for the work and don't lose your patience as quickly. If you consider the lower control arm is a capital "V" lying on its face, there are 2 bolts holding it on: one at the bottom and one across the top. The one at the bottom attaches the arms to the wheel assembly (often referred to as the swivel). The one at the top attaches them to the front beam. Extending our capital letter metaphor, the spring comes from above and lands into the middle of that "V", making it more of an "A". Where the spring reaches the arm there is a round cup for the spring to sit in. It is not held in place by any fasteners; this last bit is an important safety consideration during removal.

Pop Goes the Front Spring

bottom of the "V"

Start with putting your floor jack under the spring cup in the lower control arm. Set it far enough to the outside where it will grab the cup edge but not so far out that you can't get a spanner or socket onto the bolt/nut because the jack is in the way. Raise the jack just enough to take some of the energy out of the springs. There is a debate on the internet about how pressurized these springs are and whether there is reason for concern for them launching when the arm is removed. They are under reasonable pressure and there is reason for concern. Take a couple of zip-ties and zip-tie the top of the spring to the beam. If you don't, it will take off in an unpredictable direction when the lower arm is lowered.

Back to the removal... there is a cotter pin running through the castle nut, so remove that. Take note that replacement cotter pins are NOT included in any of the rebuild kits available out there, so either get some independently or do like I did and use bailing wire at install-time. Crack, loosen and then remove the nut/bolt that runs across the bottom of the "V" I described above in Orienting on the Lower Control Arms. The bolt can be hard to remove. Unlike the cotter pins, replacement castle nuts are included in the kit so you can use your old castle nut on the end of the bolt as a target for your hammer. The castle nut doesn't take punishment as well as a standard nut, so you still need to be careful: once the bolt breaks free, you still need to be able to thread the castle nut off the bolt to get it completely out. With the bolt out, the jack is all that is holding the spring under pressure. Make sure the top is zip-tied to the front beam! Slowly lower the arm until the spring pops out of the cup. If you raised the car high enough, you will be able to completely lower the jack and the arm will hang straight down. Sometimes the swivel gets hung up in the arm, so you may need to coax the 2 pieces apart. If you find this necessary, be mindful of how much spring tension is supported by the jack. It will unload quickly if not contained by the jack.

Once the arm is hanging free, cut the zip-ties and move the spring out of the way. You may choose to paint or powder coat them as long a they're out. I shot mine with paint, thinking I didn't have time (nor money, the paint was free leftover in my cabinet) to powder coat.

Spring Pan
Removing the rest of the arm assembly isn't terribly difficult, even for me. The spring pan is held to the arm with 3 nut:bolt combinations. If I remember correctly, they are all 1/2" drive. There are two on the rear and one facing front. The front one was paired with a threaded end of the sway bar which we removed earlier. With the bolt:nut combinations removed, the arms and spring pan should fall to pieces. Set the spring pan aside.

Remove the Lower Control Arms
The inner end of the control arms are held to the front beam with large castle nuts. The nuts are held in place with cotter pins. Like the pins at the other end of the arm, these do NOT appear in any of the kits available out there, so either acquire some elsewhere (local hardware store) or use bailing wire like I did for install. So, remove the cotter pins that hold the castle nuts, then remove the nuts. There are replacement nuts and washers in the kit. Set the arms with the spring pan for inspection.

Upper Control Arm... Er.. Shocks

left swivel top

Unlike lots of other cars, these little British cars don't have a traditional upper control arm and piston-style shock absorber. Instead, the shock and upper control are are one kinda weird unit, but it works. They are oil-filled, and for space purposes, it makes the most of what's available. The top of the swivel is attached in a similar way to all of the others in this job: castle nut, cotter pin,
long-ish bolt that needs to get banged out with a hammer. The rebuild kits also provide parts the same way: all bolts, washers and nuts are provided. NO cotter pins. The swivel is kind of heavy, so put something kind of soft to catch it when you get the bolt removed. If your experience is like mine, you'll be banging away on the bolt and then without any real sign it will suddenly pop out and the swivel will topple. Without something to cushion it's fall, a drop onto the concrete of your garage could damage something.

Now, do the other side. Whee!

At this point, your lower control arms are removed, and your front swivels are as well. Your front shocks are still on the beam, and the beam is still in the car. This is when I will pick it up next time where I'll cover removing the front shocks, evaluating them, the spring pan, and control arms for re-use, buying parts and of course, lowering the front beam.

Thanks for following along. This series of posts represents one of the longest, biggest things I've done since I rebuilt the front end on the bus: the post that launched this blog.