Tuesday, May 16, 2017

MGB - steering rack

The last collection of posts have been about this project MGB I picked up last Summer/Fall. Today's post covers the efforts of removing, cleaning, and repairing the steering.

Context
The steering on these little British cars is only a hair more complicated than the old VW bus. The bus uses a system called "work and peg", which is definitely not used in modern cars. Without opening up the steering box, consider that there is magic inside this box with two arms coming out it. The arm coming out the top connects to your steering wheel and the arm coming out the back connects to control arms that terminate at each of the front wheels. Within the magic box live the worm and peg. The "peg"  rides on the "worm" that is a threaded bar that looks like an auger. As the steering moves from lock to lock, the worm moves the peg from side to side, causing the front wheels to turn. Simple design.

3-armed monster
The MGB has a rack and pinion style. Rack and pinion has a gear (pinion) at the end of the steering column that rides on a "rack". The rack is simply a toothed bar to which the control arms are attached. In the case of the MG, the control arms and the rack are all one piece. Power steering includes more bits to boost the power of the pinion to move the rack. The MGB doesn't have the power assist, but its a tiny car with little weight, so there isn't much need. One other interesting bit about the MGB steering is that over half of the steering column is part of the steering rack so it has 3 long legs/arms to manage on extract and install.

Getting It Out
just removed. note torn d-side boot
Removing the steering rack from the MGB is actually pretty easy. For me, someone who takes forever to do even the most simple of jobs, that's a big statement. At the ends of the control arms are tapered "ends" that fit into the steering knuckles (sometimes called "swivels"). Since I had already decided to replace the rod ends, I separated the ends from the knuckles with a couple of smacks with a hammer. There are gear remover tools that are more graceful, but if you're replacing the ends and the nuts (always replace the nuts) anyway, a hammer works great.

p-side arm measured
With the ends separated from the knuckles, move up to the steering column part up near the firewall. Mark the way the two ends come together so your steering wheel will align properly on your first re-install effort. I shot the joint with a pop of spraypaint, but that was only because I couldn't find something like a paint pen. You can just see the marks in the picture on the right, here. Once marked, loosen the connection so it doesn't hang up on you later.

In order to easily get to the rack bolts, you may need to remove the little section of cowling between the radiator and the front beam. It is made of glueboard and held on with a couple of nuts. There are metal replacements for the cowling available, if your original is trashed. Once you have access to the rack, it is held on with 4 long-ish bolts. With those bolts removed, the rack can be removed by pulling it forward and down. If it isn't budging, check that the steering column is loosened enough.

Cleaning
p-side arm measurement
My rack was leaking, and was identified as a possible replace item by the shop. K2 and I saw that the bellows on one side were definitely torn, so I ordered a replacement set as well as replacement arm ends. We (step-son K2 helped a bunch here) started with simply cleaning everything up first. K2 used "Simple Green" and a lot of elbow grease to get the arms and main cylinder clean.  You can't put new bellows on while the arm ends are still attached, so when it was clean, I marked the control arm end positions with a shot of spraypaint (use a paint pen if you have one). Once marked, I removed the arm ends, and then the bellows. At this point, K2 doubled down on cleaning. He turned the steering from post to post, cleaning up any gunk that he found in the teeth. We removed the cover plate and looked for broken teeth on the pinion as well.

Repairing
Junk. Don't Buy These
The pinion had no broken teeth and the arms were in great shape. We decided not to replace the steering rack, and just re-seal the cover, refill with oil and replace the bellows. I used a very light application of form-a-gasket to help seal the cover. If you use too much, it gets into the gears, and that detail cleaning needs to be redone (guess how I know that). Before the cover plate is sealed on, the bellows need to be put on. Put a little bit of gear oil on the inside edge of the small end before you start. This allows the small end to slide over the end of the arm without tearing. Attach the wide end to the main cylinder and a-fix with the metal band. Before attaching the small ends, check where they should go so that they don't stretch nor bind when the rack is turned lock to lock. If you have marked the old location, its easy. I didn't but I found that once I started zeroing in on a spot, it actually was the same original position (there were tiny scratches on the arms). Tighten the small ends down with the smaller metal bands. Now, fill the system with gear oil: 90 weight (like the VW bus transaxle). "Fill" is about 8oz.

Ends
OEM. Buy These
Once everything above is done, all that's left are the ends. There are two kinds available out there, and I bought both to see the difference. These cars came with sealed ends that allowed no maintenance. So, if you thought your end needed grease, you can't grease it; you need to buy replacements. These replacements are made in England, though, so you're getting a good OEM part when you go this route. There are also replacements available which have a grease fitting. These are Chinese junk. The concept is great, the execution is appalling. The pair that arrived were rusty and the main rubber seal was falling off. Not only would it not hold grease, the rubber "seal" wouldn't stay on at all. I was only able to find them at the Roadster Factory, but don't shop there. When I alerted them to this poorly built part, and returned it according to their rules, I received no communication nor any money back. Vendor: if you sell garbage and then don't honor your own policy, you're a sham to me and will be called out accordingly: do not shop from The Roadster Factory unless you're willing to accept crap parts with no means of return.

Ends On
The OEM part, as expected, looked perfect and fit as you would expect. I threaded it on to the marks and tightened it down.

I am finishing up some other tasks before re-installing the rack, so I will post again when I have that completed. Thanks, as always, for following along.

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