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Apple fanboy

macrumors Ivy Bridge
Feb 21, 2012
57,110
56,164
Behind the Lens, UK
Another work post, for those so inclined to skip it.

BTW, I should also mention that most of what I've been doing to the car recently falls under the category of "routine maintenance" and not actual repairs. There's just a lot more to maintain on an old car than on a new car.

I wrote up the brake job a page or so back, but said I didn't want to tackle the rotors despite having them on hand.

For anyone who's done a brake job on a modern car, you know that changing the rotors isn't much more involved than just changing pads. Typically, you'll unbolt the entire caliper mounting bracket(which is normally two bolts separate from the ones you take out to just swap the pads) and move it out of the way. From the factory, a lot of cars will have a screw or two holding the rotors to the hub, but it's my understanding that their main function is to keep the rotors in place as the car moves through the assembly line. If something crazy happens like one strips out or is stuck, I've never stressed over replacing it if I had to drill it out. In any case, though, if those screws are present and removed, the rotor just pulls right off the wheel studs. In operation, it's held in place by being "sandwiched" between the hub and wheels and consequently just held on the studs by the lug nuts.

The MG uses an arrangement that I understand is common to older disk brake systems of any origin. Basically, rather than resting in front of the hub, the rotor is bolted to the back of it, and consequently replacing the rotor requires removing the hub.

This actually isn't a huge deal. If you've only dealt with newer cars, you've probably never serviced hubs, but maybe replaced them they wore really badly. On modern cars(and by modern I'm stretching back to probably the 80s on some designs-what was left mostly went away in the 90s), they're a sealed unit that is just replaced in its entirety if it ever wears out. In reality, unless something crazy happens to physically damage it, a sealed hub will easily make 400K+ miles.

There again, this isn't a setup unique to MGs, but is something that was used on American cars and I'm sure others from probably the 50s going forward. Basically, the entire hub assembly fits onto something called a "stub axle" that, in operation, is held under tension. Riding on the stub axle are a pair of tapered roller bearing races along with spacers and the like to keep everything where it should be. The hubs, in turn, have the outer bearing races pressed into them, so the hub turns on the bearings. The entire assembly is grease packed, so it's a good idea to occasionally break it down, clean out the old grease, and repack it with fresh grease. Replacing the rotors is a good time to do that since you're taking it apart anyway.

So, here's how all of this works:

Once the caliper is removed(in this photo I have it zip tied to the top of the suspension A-arm), the dust cap in the center of the hub needs to be removed also. This exposes a castle nut, also called a castellated nut, that is helded from turning by a cotter pin that fits in the grooves of the "castle" and through a hole in the stub axle. Notice also that there's a lot of grease in there.

View attachment 1744358

After removing the cotter pin, the castle nut is unscrewed, and the hub pulled off. I didn't photograph everything, but basically you get these parts off

View attachment 1744360

Not shown here are the bearing races, as I handled those separately. There are two, an inner and outer. Also, somehow or another, I missed photographing the spacer.

That leaves behind the stub axle. Normally the brake backing plate is here also, but I removed it to clean it up and paint it.

View attachment 1744359

I'm showing it here with a grease gun attached to one of the Zerks(grease nipples) on the kingpins. The kingpins are the swiveling part of the steering knuckle, and need to be greased periodically. This is done by connecting a grease gun to each of the Zerks in turn and forcing grease in. As fresh grease is forced in, old grease will be seen oozing out of any joint it can find. When fresh, clean grease starts oozing out, you know you've added enough. There are 3 Zerks on this car's kingpin, and I opted to do them here since they're easy to access and see. I had a bit of a diversion in that when pumping grease into the center Zerk, I got a nice steady stream out of the bottom one. Fortunately, these are a generic part, and $3 bought a half dozen of the correct replacements from NAPA.

I spent a while working on intermediate steps that I didn't photograph, but basically I decided to wirebrush, de-rust, and paint both the backing plate and the hub. That took a while, but I'm happy with the results even with my messy rattle can paint job. I'm more going for rust prevention than anything.

View attachment 1744369

The bearings need a bit of extra attention. First of all, I'd bought replacement outers at Autozone since they were $7 each. On advice, though, I opted instead to clean and reuse the original Timken "Made in England" bearings.

View attachment 1744368

Timken invented this type of bearing, and these stay well enough greased that they're unlikely to go bad. Modern bearings, even those marked Timken, are of unknown origin and quality.

I cleaned these by soaking in kerosene and then blowing out with compressed air. Once clean and dry, they can be packed with grease. They can actually be packed by hand rather easily(you put grease in your palm and force it into the bearing), but why do that when there's a tool for it?

View attachment 1744362

These are not very expensive, and basically hold the bearing while you use a grease gun to inject grease around the bottom of the race and through the top, the same way it would be done by hand.

Finally, I bolted the new rotor to the hub.

View attachment 1744361

I opted for fresh hardware, which was another adventure. The bolts holding the rotor to the hub are 5/16 UNF(5/16-24). I went to the hardware store, and in general the only fine bolts they have are grade 8. Grade 8 fasteners are overkill, but at the same time I'm okay with using a fastener that's stronger than needed. I needed 1 1/4" long bolts, but the ones they had didn't have shoulder. The 1 1/2" ones did, but they only had 7 in stock(I need 8, 4 per side). I debated a bit and gambled on 1 3/4" not being too long, and fortunately I was correct.

As the repair manuals say, assembly is the reverse of disassembly

View attachment 1744364

The most difficult part was getting the hub seal seated correctly, but fortunately it didn't take too much persuasion.

From there comes reinstalling the castle nut. On a typical American front suspension, the procedure for installing this is to tighten the nut until the hub locks, the back off until the cotter pin lines up. The workshop manual for the MGB specifies a bit of a different procedure-the nut should be torqued to 60 ft-lbs and checked for free rotation and also endplay. It should "tunk" slightly when pulled on. If it doesn't under this amount of torque, the shims between the bearings are adjusted. Too much freeplay requires removing shims, while too little requires adding them. Fortunately, mine was dead-on at 60 ft-lbs.
I used to make outer roller bearings for Timkin back in the day. Thank you for the reminder. They were a pig to make. Poor quality tooling as I recall. Not that effected the finished product. The tool just had no ejecter which meant you had to heat it off and hammer it with a copper mallet.
 
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bunnspecial

macrumors G3
May 3, 2014
8,353
6,497
Kentucky
I used to make outer roller bearings for Timkin back in the day. Thank you for the reminder. They were a pig to make. Poor quality tooling as I recall. Not that effected the finished product. The tool just had no ejecter which meant you had to heat it off and hammer it with a copper mallet.

You certainly have done a lot. Am I correct that they are not made in the UK anymore?
 

ericwn

macrumors G5
Apr 24, 2016
12,122
10,914
LOL Yes or do they still do that Citroen C4 Cactus with the eggshell boxes on the doors

Amazing that a company that used to produce a DS or SM or even the CV has gotten into these fake plastic enhancements.

Same thoughts here. How can you let go of the design language if that’s the one thing you really have had going strong.
 

bunnspecial

macrumors G3
May 3, 2014
8,353
6,497
Kentucky
So another bit of an update on my “catch up on maintenance” quest:

I mostly finished the brake rotors/hubs/etc on the front with one exception. Somehow or another I came up short of shims to set proper end float on the hubs. I had the big 30 thou shim and a smaller one, but the other side had I think 5(a mixture of 10, 5, and 3 thou). I only had a 30 and 10 on this one. I went in desperate hunt to make sure it wasn’t buried in a pile of grease on a towel or something, but no such luck. They may just not have been there.

I put it all together, but there’s no end float and with the castle to the spec torque it doesn’t turn as freely as it should. It looks like I need to order shims and spend an afternoon playing to get it right.

Also, I noticed in all of this that my 4 year old rack gaiter boots are shot and the tie rod ball joint boots are split. Unfortunately, reproduction rubber parts are largely junk. I try to use polyurethane wherever it’s available, but it’s not for everything. The options for rack gaiters are “bad” and “slightly less bad” so unfortunately I may have to resign myself to replacing them every few years. The other options I can explore are seeing if I can find a silicone rubber gaiter boot or CV boot that can be made to work. It would be worth modifying one to not have to mess with this again. The gaiter boots themselves aren’t bad to replace, but BMC specced gear oil, not grease, as the lubricant for the steering rack. Filling it is a messy job.
 

nospleen

macrumors 68030
Dec 8, 2002
2,726
1,593
Texas
Just picked up a 2022 Acura MDX A-Spec for my wife. I am pretty impressed. If it has a bit more power, it would be perfect, but it is plenty for her. I bet the Type-S version is going to be nice.
 

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jeyf

macrumors 68020
Jan 20, 2009
2,173
1,044
new drivers
the all time minium age here is ~16y. We have a gofundme effort to get them all used 1 liter sport bikes as their first vehicle.

iu
 

bunnspecial

macrumors G3
May 3, 2014
8,353
6,497
Kentucky
My favorite car of all time. 1956 Austin Healy 100-4. 4 Cylinder, 4 speed. Had the pleasure of driving this all through my senior year in high school.

I LOVE all the Big Healeys. I think the 100-4 is the best looking of them, but if I were to go out and buy one it would have to be a 3000 BJ-8. There's a certain "rawness" to all of them, and especially the 100-4.

With that said, every time I drive one or really even ride in one, they hit me with two things. The first is how hot they are, and the second is how rattly/noisy they are. They really do put the whole "Collection of parts moving together" saying into practice. The MGA/TR3/TR4 and the others of that age all feel that way to me, and the next generation of cars like the MGB and TR6 definitely feel more solid.

Still, though, IMO the Big Healeys as a group are the best looking of all the British sportscars of the 50s-70s. The MGA is a close second to me, although I admit a slight bias(and I will probably own an MGA before I have a Big Healey).
 
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Allyance

Contributor
Sep 29, 2017
2,075
7,692
East Bay, CA
I LOVE all the Big Healeys. I think the 100-4 is the best looking of them, but if I were to go out and buy one it would have to be a 3000 BJ-8. There's a certain "rawness" to all of them, and especially the 100-4.

With that said, every time I drive one or really even ride in one, they hit me with two things. The first is how hot they are, and the second is how rattly/noisy they are. They really do put the whole "Collection of parts moving together" saying into practice. The MGA/TR3/TR4 and the others of that age all feel that way to me, and the next generation of cars like the MGB and TR6 definitely feel more solid.

Still, though, IMO the Big Healeys as a group are the best looking of all the British sportscars of the 50s-70s. The MGA is a close second to me, although I admit a slight bias(and I will probably own an MGA before I have a Big Healey).
I agree they were hot. I solved the problem by installing a layer of asbestos (not a problem when I was in high school in the stone age) covered by a layer of aluminum foil. It cut down on the transmitted heat and the aluminum foil reflected what was left. Worked like a charm. Always got a kick out of some of the terminology in the owners manual, like for more fresh air, "remove the grommets from the scuttle valence".
 

Allyance

Contributor
Sep 29, 2017
2,075
7,692
East Bay, CA
My most disappointing car was my 1951 XK120. I had 3.4 sedan in college and bought a new 3.8S a few years later. I liked the sedans, 3.4 was a stick, but died from rust. 3.8S was a beautiful light metallic blue with dark blue leather. Sold my MG-TF to get the XK120, big mistake. The 120 drove like a truck, not fun at all. I always said a dog could run in front of you and come out 2 days later, because the hood was so big!
1951 XK120.jpg

Unripe apple green with dark green leather.
 
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Allyance

Contributor
Sep 29, 2017
2,075
7,692
East Bay, CA
One more vintage photo of another car I loved, it too died from cancer of the frame. I loved the car but got taken by the used car dealer, after trying to get into Canada after live back the USA for I while, I learned about it's history being imported to the US from Germany. It had air bag suspension that leaked air slowly, so I always carried a brick to stick under front frame to keep it from going completely to the ground! Great ride, always rode the same no matter how many people in the car. Always felt good to see that star on the hood, now my ML350 just has a badge.
1971 300SEL.jpg
 

bunnspecial

macrumors G3
May 3, 2014
8,353
6,497
Kentucky
I agree they were hot. I solved the problem by installing a layer of asbestos (not a problem when I was in high school in the stone age) covered by a layer of aluminum foil. It cut down on the transmitted heat and the aluminum foil reflected what was left. Worked like a charm. Always got a kick out of some of the terminology in the owners manual, like for more fresh air, "remove the grommets from the scuttle valence".

One of the constant debates on the MG forum is that MGBs shipped with a nice woven asbestos mat under the carpet around the gearstick/over the transmission tunnel. Many people find it pulling the carpet up or even just poking around under the gaiter boot. I've seen more than a few loose their heads over a 2'x2' piece of asbestos blanket. Personally, I leave it be-I've never seen one that was anything close to degrading, and it sure helps the heat in that area.

Now the MGA guys at least usually line things with a material called Hushmat, which is a thin silvery(mylar?) insulation. It's supposed to do wonders for both heat and sound and not weigh very much, but it's also expensive.

British cars are fun when you really get into the service manuals, and you can at times almost need a dictionary to make sense of them. What is the old saying about two countries separated by a common language?
 
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