Tuesday, June 13, 2017

MGB - Front Suspension Refresh (Part 2)

Continuing from my last post, I'm focusing this group of posts on the rebuild of the MGB front end. Today, we get down to the beam, and get it removed from the car. I'll evaluate parts, and talk about replacement bushing options. Part I can be found here.

While the beam is in, and you have access to your front shocks is the best time to evaluate them. On the right side, the shock responded relatively well to my efforts to move the arm up and down. It resisted in both directions, but not as much as I would have liked. Still, I probably could have left it alone. The shock on the left (driver) side, however, offered virtually no resistance to my attempts to move it. In fact, I could push it to the top of it's motion and it would slowly drop down. That shock is shot. Suspension shops usually recommend replacing both fronts and/or both rears at the same time. For a front-end like this one, where the shock absorber is also playing the part of the upper control arm, it is all the more important. These are held in place by 4 bolts. The two against the inner wheel well can be difficult to get to, but you can address them with the most basic spanners and ratchet/sockets. Similar to the engine mount replacement (see MGB - engine mounts), a good supply patience is welcomed here.

Set the shocks aside with the lower arms and pans. To protect the threaded holes, finger the old bolts back into the holes. I took one with me to Orchards and found replacement grade 8 stainless steel ones for the reassembly. I strongly recommend replacing fasteners with stainless steel or zinc coated to reduce the rusted-on effect.

Beam Down
image swiped from 'net,
but that's a stock beam
Now, the front beam should only be connected to the car by 4 bolts. Nothing else should be tying them together. No brake lines, steering bits, etc. but it never hurts to stupid-check (so-called for those moments when you don't check, something bad happens and call yourself stupid for not checking).

I used an ATV / transmission jack, but a more standard wheeled floor jack should work; it will just take more patience with balance. The ATV / transmission jack is nice in that it has two long arms to spread the weight, and improve the balance. Still, with the front end way in the air, and the rear on the ground, the bottom of the beam is not parallel to the floor. So, I slid a 2x4 under the front of the beam when the ATV / transmission jack reached the underside of the beam to make uniform contact. Raise the jack until it is holding some weight, but not much. You want the car stable on it's jack stands.

Relieve the torque on the 4 bolts by cracking the 4 bolts on top. you shouldn't need to hold the bottom nuts at all for this. I used the breaker bar with an assortment of extensions. Once cracked, do the same on the bottom nuts, just so they are not rusted in place. Whether you remove the nuts on top or the bottom or a mixture doesn't really matter. In the end, all 4 bolts need to be un-nutted on both ends. You would think that once the nuts have been removed from the bolts, they would just fall out. Fat chance. How about lowering the jack a little bit? Nope. To free the bolts, the top nut needs to be removed. Then, using a socket extension so you can address the bolt, rap the bolt from above with a rubber mallet. When this doesn't work, use a framing hammer, but be very careful with those bolts. They are not normal and if the threads are damaged, you'll need to order new ones.

Once the bolts fall out, either through banging or playing with your jack or maybe you got lucky and they just fell out... you'll see that these bolts are 2 different lengths and that the longer bolts (that fell out of the front) have a lump in the middle like a poorly rolled spliff. I retained all of this hardware, choosing to not try to find replacements, though I thought about it. Simply lower the jack, and the beam will lower with it. Pull out the front under the radiator and bumper.

Parts and More Parts
At this point, I was pretty spent. From the start of the prior posting to the beam on the ground was at least 2 days. Now that I've done it once, though, I could do it again in 1/3 of the time or faster. As I set with a beer, I looked at the pile of parts and the zip-lock baggies of fasteners. The fasteners were all bare steel, and they had plenty of rust on them. I chose to replace all of them except the beam-to-frame nuts and bolts. I added 4 fender washers to fit between the beam and the lower control arms. I felt this would help the bushings last longer. The fasteners probably put me back $50. Then, I turned to the pile of parts:

front shock absorber /
upper control arm
Front Shock Absorbers (2) New, these are crazy expensive. Moss has them for over $330 each. Instead, I found World Wide Auto Parts in Madison, WI who rebuilds originals. After some research I bought a pair from them at $99 each plus core which was returned when I sent my old ones back to them. They really look great, and if they work as well as they look, I just may go back for replacements of the rears instead of doing the swap-out for non-MGB rear shocks that so many folks do. The paint chips off without much effort, so if you're going for a show-car experience, I'd recommend repainting them.

Lower Control Arms (4) These looked okay, but without tight tolerance measuring tools, I couldn't tell if any of the important holes on the ends were out of round. Replacements for all 4 was $70 with OEM British steel, and the originals could have been worn from the bad seals, so I coughed up the $70.

lower control arms
Spring Pans (2) Like the arms, I couldn't tell for sure if the mounting holes were out of round, but on very close examination none of the holes looked oval. Since no pivoting happens with these pan holes, even a little out of round probably wouldn't matter so I chose to keep the spring pans, and just clean them up instead. New-steel replacements are $32 each at Moss, so they're a little steep cost-wise compared to some of the other bits. Still, if the spring pan won't firmly attach to the arms, your suspension won't be safe, so spend the $64. In the end, there was 0 play after everything was put back together, so my assessment was correct.

Front End Rebuild Kit (1) This was the whole point of this work. I found a few different suppliers for this kit, and resolved to buy from British Parts Northwest for $120. While their return policy is crap, their price is $35 less than Moss. These kits include:
- king-pin set and bushings. These run vertically between the arms and through your swivels
- upper control arm nut/bolts. They call them "fulcrum pin and hardware" and they attach the top of the swivel to the control arm / front shock absorber.
- upper control arm bushings (rubber or all-poly). These pair with the upper control arm nut/bolts to complete the set. I ended up swapping out the kit-supplied ones with some Poly/Graphite bushings I got from a new friend, Basil, in California ($6)

- lower control arm to swivel bolt/nut and bushings. They call these "Lower Trunnion Kits".
- lower control arm to beam ("A-Arm") bushings and bolts (rubber or all-poly). Again, I went with Poly/Graphite ($20) from Basil instead of the kit-supplied ones.

To do the front end rebuild, that's really all you need. I decided, though, that as long as its open, replace the beam-to-frame bushings.... and the sway bar bushings. Again, I sourced these from my friend in California. frame bushings ran $23 and the sway bar bushes were $10. When I consider there was no extra labor for the beam bushings, and very little on the sway bars, this was a very low cost to get the front end as rock-solid stable as possible.

Rubber, Poly and Poly/Graphite
Just for an aside, I wanted to touch on the differences between these three types of bushing. As a general rule, it's best that you pick one and stick with it through the front end. Since they behave a little differently from each other, the front end could be less predictable if your lowers and uppers are not the same material and respond to stresses differently.

Rubber - this is what you had originally. When squeezed between two pieces of steel which want to twist, the rubber twists with it. This smooths out the twisting motion, giving an easy, forgiving ride. For a cruiser, this is great material.

beam to frame bushings
Poly - this is the more common "upgraded" bushing. Unlike the rubber, the poly does not twist with the steel; it resists the twisting motion. This resistance reduces the degree of the twist, allowing more of the force through to the ride. This is a much less forgiving ride, but gives you a much stronger "sense of the road". Installing these bushings can be very difficult, requiring water-based lube or other tricks, maybe the use of a shop press. Once installed, most owners report loving them.

Poly/Graphite - this is in-between the Poly and Rubber in terms of road feel and difficulty of install. Basil described this far better than I could, so I will quote: They look like black plastic that has some give to them. You can put one between your thumb and forefinger and feel it give a little. The polyurethane matrix has a slippery substance called "graphite" (a crystalline form of carbon) in the polymer matrix so a slippery bit is always exposed and thus self-lubricating the bushing. No special install efforts needed.

This post got long again, so I'll continue in another post. At this point, we have the front beam completely torn down, our parts are ordered, and fasteners sourced at the local hardware store. We'll start next time with some painting and then assembly. Thanks, as always, for following along...

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