MGB Sponge Brakes

During the various test drives as I solved for the various leaks I described in my last post, the brakes have been spongy. If I lightly pumped the brakes a couple of times before using them, I could stop well, but that's not a safe situation. Before I could go on a real test drive, I'd need to fix them for real. Today's post covers that.

Master Cylinder pre-fill
The brakes were spongy since I completely re-did them. after bleeding and re-bleeding the system at the wheels, I concluded that there was air in the master cylinder. I hadn't bench-bled the master before install, so it seemed pretty likely that the issue was there. In retrospect, I should have pre-loaded the master cylinder with brake fluid by the process folks call a "bench bleed". This is where the master cylinder is set in a vice with the shipping plugs still in it. Using a pair of pliers, the activation lever is moved back and forth while brake fluid is added through the reservoir. Once the chambers are filled, the master cylinder is installed into the car. In the MGB, the master cylinder fits onto the end of the brake booster, so this could have been done.

Getting the hard lines attached can be an interesting challenge. As I look back on my efforts to get my master cylinder in, I suspect I would have leaked brake fluid all over the engine compartment. So, while I probably could have done it the "right" way, I think the way I solved it could actually have saved the paint on my driver inner fender.

de-Sponge
So, since I didn't do the bench bleed, nor think much about air in the system at all other than pulling it out at the wheels, I figured it had to be air in the master cylinder. To solve, I took the bleeder hose from the MityVac kit. It's about 3 feet (1 meter) long. I put a coffee filter on one end to catch particles from the hard lines and dipped it into the master cylinder reservoir. I put the other end on the driver-side front wheel bleeder. Then, I pumped the brakes moving brake from the reservoir through the master cylinder, down the hard line, then the soft line to the brake caliper. From there, it passed out the bleeder into the clear hose and traveled back up into the reservoir. The key here is to keep the coffee-filter end in the fluid in the reservoir. Without that, air stays in the system. So, keep topping off the reservoir and keep pumping the brakes until there wasn't any air in the clear hose.

This worked great, except I couldn't close the bleeder without re-introducing air. I tried 3 times before I had spread brake fluid all over the inside of the tire and the garage floor. I succumbed to the obvious: remove the tire first. Yes, I failed to both mention and do that above. At any point before you connect the clear line to the bleeder screw you should remove the driver side front wheel. Why yes, that does sound obvious. If you don't, you'll be like me and try to do this with limited success because getting the bleeder closed without letting in air when the wheel is still on is virtually impossible.... especially if your car is on the ground (not on a lift), and its on the ground in a garage that's full of projects, parts and tools... and sports equipment... and camping gear... and laundry machines.

Anyway, after washing off the brake fluid, I set up again, and had the line bubble-free on my fourth attempt. This time, I was able to get the bleeder closed. I proceeded to quick-bleed the other 3 corners, but virtually no air bubbled appeared. Another test drive, and the brakes were nice and responsive. I haven't tried the stomp-on-the-brakes test that the car shows on Velocity TV do, but I will be next time I take the little car out.

That's it for this time. Thanks, as always for following along--

MGB - master cylinders (Part 3)

Today, we finish up the master cylinders in the MGB. In Part 1, we removed the old ones, complete with the pedal box and pedals. In Part 2, I covered disassembly, parts and re-assembly. Today, we'll get everything back together again. When we left off, the pedal box was put back together with the brake booster on one end and the clutch master cylinder (MC) on the other. The box is hovering over the hole in the engine bay where the pedals dangle into the driver footwell.

Box Seal

wrestling in the pedal box

Once the pedals were over the hole, I loosened the clutch pedal pivot bolt and pulled it partway out, testing for enough play to fit the pedals through the hole as I did. Once the pedals made it through, I pushed the bolt back into place and tightened it down. With some twisting, (and moving the heater hose out of the way), the box dropped into place.

Getting the box in-place is the hard part. Of course, I got my box as far as I described above and then realized that I hadn't gotten my bottom seal in. To get it in, I sent it from below, stretching it around the pedals and then fiddling with it to get it in the right spot to seal. Frankly, I think I was sent the wrong seal (it is square, the hole is not), but it will work well enough.

Bolting the Banjo

brake calipers - before

While you still have freedom of movement, pull the shipping plug from the clutch MC and attach the banjo bolt. If your new clutch MC was like mine, it did not come with a new banjo bolt, fitting or copper washers. You'll need to re-use your old ones. The banjo bolt and fitting clean up with steel wool. Be sure to get all the little steelie bits out/off before you install. I used brake cleaner after polishing. Also, the copper washers need to be annealed for them to make a good seal. To do that, you need to get them red hot: hold with needle-nose pliers and torch with a propane torch. Once cool, and the brake cleaner wiped and dried, assemble the banjo bolt, fitting and copper washers into the rear of the master cylinder. Tighten down with a 1/2". Unlike the banjo bolt nightmare I had with the steering rack on the Jetta, this was cake.

Wrap the end of the clutch hard-line with plumbers tape and thread it into the fitting. Tighten with a brake flare wrench. I was able to use my 12mm from my VW tools.

Box Final Install
Now, you can attach the pedal box to the car. I started by lining up the holes I could see from above, and loosely threading the bolts in, then moving inside the car (on my back) to get the three from the driver foot-well. Last, I did the 2 that thread in from behind the dashboard. Times like these serve as a great reminder to loosely thread in ALL of the bolts before you tighten any. I, of course, continue to need to learn that, so I had to loosen many bolts in order to get those last two in. Then, tighten them all down.

Last, loop the return springs around their respective holes in the pedal shaft and connect the other end to the underside of the dashboard. I've found that the pedals rebound well without these, but I'm sure the engineers wouldn't have put them in if they weren't necessary... so... I put them back.

Finish Clutch Master Cylinder

clutch MC is hard to reach

Box in? check. Pedals tight? check. Clutch MC plumbed? check. Next, we finish off the clutch master cylinder with DOT4 brake fluid. This sounds simple enough: put fluid in the metal can. Because of it's location up against the firewall, nearest the left-side bonnet hinge, getting a jug or even a really tiny bottle, of brake fluid in a place to pour it is virtually impossible. I imagine the bigger shops, or a place where you have a couple extra pairs of hands and some safe part storage, the bonnet is pulled waaay earlier, so it's not as big of a hassle. No matter. We're inventive. I dug through my old bio-diesel stuff and found a 10ml plastic syringe. With is, I was able to draw fluid from the bottle and add to the metal can without getting a single drop anywhere else.

If you use the syringe on a new master cylinder, expect to add at least 40ml. I filled until I could see the top of the fluid near the lip. Then, I put the cap back on, pumped the clutch pedal like mad and repeated. At one point, I figured out that I could move the master cylinder with a spanner through the top of the pedal box, so I didn't need to move around to get the MC primed. After about 5 syringes, the MC started to give good resistance. I moved to the cabin and worked the pedal with my foot, noting that the car moved in and out of gear with the pedal movement. I topped off the fluid, and called it good. A driveway test drive should shake any little bubbles free.

Prepare Brakes

VHT paint drying

Some like painted calipers. Some don't. Since yucky stuff gets onto surfaces, and looks worse when the yuck is on top of something light colored (like battleship gray unpainted steel calipers), I prefer black. Since I had the calipers off to do the front end rebuild (see parts 1, 2, 3 and 4 if you haven't already), they were ready for paint with very little extra work. For anyone else, you need to remove the calipers, disconnect the brake lines, etc. To me, that's just too much work unless you were in there to do a brake job anyway. I pulled the flexible brake line and pads, taped off the bleeder, plugged the brake line hole and scrubbed them with steel wool. The PO had shot them with some red paint that didn't adhere too well, so that needed to have an edge for the new paint to grip. Feeling the difference on the painted versus unpainted was interesting: the unpainted had a grain that gunk was attaching to where the painted side didn't. As a result, the paint, while not too good, still kept junk from caking on there. Food for thought. Anyway, after they were scrubbed, I blew them out with compressed air and them sprayed them down with brake cleaner to get any little bits of steel wool dust off. After they dried, I wiped them down with some mineral spirits, suspended them with bailing wire and shot them with VHT (very high temperature) flat black paint. They fully cure at 200*, but the off-gassing that happens when you bake-cure makes an oven unusable for anything else again. So, I decided I would let them cure through use. I'll just have to remember that they will smell a little bit the first time I drive on them, so I don't freak out.

Sew it Up
Once dry, pull the tape and brake line plug, re-assemble the pads and retainer bits. Thread the flexible brake hose back in, and install the calipers back onto their respective swivels. If you can't remember which is which, consider that the brake bleeder bolt should point up (so the air bubbles can work their way out). Thread the flexible hose into the hard lines and check your wheel movement isn't compromised by the brake lines. I've never had this be an issue, but my experience is limited compared to others, so maybe this is a thing. I figure it's always better to be careful and have all of your surprises be pleasant ones.

a little scrubbing goes a long way

There are a few little mop-up things to do. The pedal box cover needs to be put back on. This takes 1/2" #6 sheet metal screws. I recommend replacing the seal that sits beneath, if yours is original. Or missing. Bleed the brakes with the MityVac. Verify the hand brake works. And last, give it a test drive. I haven't gotten to that last part yet, since I still need to get the fuel tank in. Oh, and I need to do something with the cooling system. I'll get to those here shortly, and post soon after that. I know I'm running against time, if I want to get a drive in before the weather changes to solid rain as it does here in the fall. We usually have until right around Columbus Day, but the clouds we've seen lately lead me to believe that the weather will shift early this year. We'll see.

As always, thanks for following along.

MGB - master cylinders (Part 2)

Today, we continue documenting the work on the master cylinders, and perhaps more importantly, the pedal box between them. In Part 1, I covered removal and disassembly. Today, I'll cover clean-up, painting and re-assembly. Unlike so many of my posts lately, this one might be a little shorter.

Parts Order

before

With the various major components apart, its time to consider the condition of your bits and pieces, and place a parts order. We're starting with the 2 master cylinders (MC). The whole point was replacing them, so let's start there. As of today, a clutch MC costs about $35. A brake MC costs anywhere from $60 for an aftermarket (read: Chinese) up to $220 for an Original Equipment Manufacturer (OEM) part. I like OEM, but I don't like spending a premium if I can avoid it. Look around. Moss isn't the only supplier, and you can find the OEM for less than that.... like my new friend Basil.

How does your brake booster look? Does it look like mine, all rusty and nasty? Considering a new one is $250, you may want to consider cleaning and maybe even painting your original.

I get new fasteners when I see rusty ones, and fasteners around brake fluid always rust up, so I encourage new bolts for holding the box to the car, and screws for the lid. You will probably need 2 new cotter pins. I found that the bolts and nuts dedicated to the pivoting of the pedals were perfect, so I didn't replace those. You may want to. Get new pedal pads; they're like $3. Depending on condition, your pedal return springs (which I forgot to mention in step 1) might need replacing. Mine were rusty, so I got replacements. Consider that there is supposed to be a seal both above the box and under the lid. These are also cheap, so get these too.

My parts list was the 2 master cylinders, pedal pads, seals and a couple of handfuls of fasteners. All in, I was under $150. I got the MC's from Basil, pedal pads and seals from Moss and everything else from Ace Hardware.

Prep and Paint

assembled box, from behind

First, complete the dis-assembly, if you didn't as part of your parts order step above. Remove the pedals from the box and then the sleeves from the pedals. Remove the pedal pads if you didn't during the pedal box removal. Remove the seal from the top of the pedal box / bottom of the lid (depending on which one it is stuck to). The pedals, box and lid should now be bare. I scuffed the remaining original paint from those pieces with a mostly-spent 100-grit sanding pad after removing the rust with 60-grit sandpaper. The mostly-spent pad removed the deep scratches from the 60-grit and created and edge for the paint to adhere to. I shot the pieces with Simple Green to get the sanding dust off and then wiped them down with Mineral Spirits before shooting them with a basic gloss black. I have found that shooting smaller pieces in one shot is efficient without sacrificing the finish. For the pedals, I run a short stretch of wire through the pivot hole and hold it by the wire so I get full coverage. I did the same thing with the pedal box and lid, but short the pieces in stages, shooting the inside first and then following with the outside after the inside had dried. I left these pieces cure for a long time since it was about here when I discovered the floors were rusted out... or it was about here when I discovered that the front suspension was bushed with window insulation.

Polish

after

I didn't mention the brake booster in the paint list. When I painted the other pieces, I was still considering my options. I decided I would try to give the original piece some love and see if I could bring it back to looking fairly good first. I started with the same pattern of low-grit paper on the rust and 100-grit pad everywhere. It took a couple of hours, but the rust came off and the whole piece started to glow. After the spent 100-grit pad, I started polishing with steel wool. This was the magic. The steel wool took away the tiny scratches left behind by the spent pad, and removed the little bits of grime that the other efforts didn't. The end result is pretty incredible. I thought about shooting it with clearcoat, and concluded that it survived years in a barn and many more years of weather and still returned to such fine condition without it. It could go another 40 without it.

Re-assemble

inside the pedal box

After the paint had cured (sat idle without people poking at it for a few days), I put the new rubber pedal pads on first. You could do this at the end, but the box goes in the same whether the pads are on or not, and (a) I wanted to see how they looked semi-finished and (b) I was able to make sure they were completely seated without having to lie on my back under the steering wheel to do it. I used a paint can opener to help the rubber lip around the edge of the pedal. After admiring the new pads, I mounted the brake booster to the box. Next, I attached the brake pedal to the brake booster with the clevis pin and cotter pin. Then, I attached the pivot bolt, and tightened it down.

The clutch master cylinder is next. For consistency of appearance, I threaded both bolts from the outside of the box in, so the top bolt which threads into a nut, has the nut inside the box. Next, I moved to the clutch pedal, attaching only the clevis pin and cotter pin to the MC, leaving the pivot bolt to last. For this, I put all the parts together and lightly threaded it into the captured nut inside This was just to get the box into position.

I'll cover the install in another post, so that's it for today. As always, thanks for following along...

MGB - master cylinders (Part 1)

Another post about the ongoing work on the MGB. Today's post covers the removal of the brake and clutch master cylinders. This got long, like so many of my posts these days, so I split it into two, with the follow-up post covering the re-assembly and re-install. It should be noted that sometimes I revert back to a sworn-at previous owner (SAPO) and start removing things without taking pictures. This is one of those times, so the pictures are from either the re-assembly or the internet. Sorry. Sometimes I suck too.

Why?
This is as logical a place to start as any. "After the list of other things that have been done why the (expletive) would you open up yet another system?" Yeah.. that's a really great question. It's not because I'm sadistic. You see, I started with the brakes. Long before I discovered the rust-thru on the floors, or learned about the front suspension having window insulation acting as bushings, I tried to fix the brakes. I completely redid them at the wheels. I even replaced the hoses with nice new ones, but I couldn't get the rear's to bleed. Turned out, the master cylinder wasn't pushing fluid to the rear, so it had to go. After some reading, I learned that for some weird flaw of nature the clutch master cylinder fails within 6 months of replacing the brake master cylinder if you don't replace them at the same time. Rather than tempt Murphy's Law, I figured I'd just get after it. Besides, winter was coming so the little car was going into the garage anyway.....

Remove the Brake Master Cylinder (MC)

my engine bay - before

After I tried all sorts of combinations of efforts to remove things, I figured out that it wasn't nearly as complicated as I (and the internets) was making it. First, remove the electrical bits: the pressure sensor and the brake-light switch. The first unplugs, the second unthreads. Then, remove the brake hard-lines from the master cylinder. There are three, two head to each of the front wheels and one heads for the rear. Put a small catch-pan under the master cylinder before you start opening these or you'll get brake fluid dripping all over the driver side of your engine bay. It is a really small space under there, so I used a washed out yogurt container as a catch-pan. I taped plastic on the brake line ends to keep some water out (and brake fluid in), but after the front end suspension work, the lines are completely clear. If you're just pulling one and slapping a new one in, It might be worth doing. I didn't see the downside except consuming 10 minutes of my time. Once the fluid lines are detached, remove the two nut/bolts which hold it to the brake booster. With a wiggle, it should come right out.

Remove Brake Booster?

not mine, but better angle

With the brake MC out of the way, the next in line is the brake booster. This unit takes vacuum from the engine and uses it to help you stop. Very clever. First thing to remove is the hose from the engine to the brake booster. If your rubber is as old as mine, make a note of replacing it. The booster is held onto what's called the pedal box from within the box, so before we can go any further, we need to pull the lid off the box. It is held on with a bunch of little fasteners. Depending on how much your car was messed with, these could be bolts or screws, Phillips head, slotted or hex. Or a combination. Mad love for prior owners. Someone will be cursing me this way one day. Anyway, remove the fasteners and the lid on top. Inside is the magic where the pedal action is translated into brake or clutch motion. In here, you can see how the brake pedal actuates a lever that runs forward into the brake booster and how the clutch pedal hinges on a pin connected to the clutch MC between the pedal box and the firewall. Whoa. So.. maybe this is why everyone says to replace the clutch MC at the same time as the brake. You have to get so deep anyway, you just might as well.

So, how do you get this thing out? You can try starting by removing the pin connecting the brake pedal to the lever. This is a royal PITA. You need inhuman fingers to do this. Same goes for the clutch pedal/MC and even getting the brake booster off. After the fact, I figured out that you don't need to separate the brake booster from the pedal box at this point. You can just remove the booster with box all at once. Whaaa???

Remove the Clutch Hydraulics and Pedal Box

thank you eBay for your blurry picture

Skipping over the brake booster, we move to the clutch master cylinder (MC). Disconnect the hydraulic line that runs along the firewall. Again, I wrapped it in plastic wrap and then taped it sealed. Now, the only thing that is holding the clutch master cylinder, the brake booster, and the pedals in the car are the little bolts which are holding the pedal box in. Many of them are addressed from the driver footwell. Only a couple (those on the engine-side of the box) are removed from above. They are different sizes, which is a little weird. Anyway, once the box is free, the entire unit can be coaxed out of the car.... but wait: the pedals are too wide to fit through the hole! Lift the box and pedals as a unit and once you have it up as high as it will go straight up, twist it counter-clockwise while you lift and you can get another inch or so. That little bit is enough for you to get access to the clutch pivot bolt. The bolthead is sticking out the left side of the box. 1/2" socket will remove it, and the pedal will be free enough for you to get the unit out. Seriously, it works. The pedal will dangle a little strangely, but the 2 pedals will fit out of the hole this way, even with brand new pads.

Separate
With the box on your bench, you can easily pull the various parts off. The brake booster is held on with 4 1/2" nuts, and the pin from the brake pedal is easier to get to when you're not leaning over a wing (fender). The clutch MC is held on with 2 1/2" bolts. One of them twists into a fixed nut, the other needs a wrench on the nut on the inside. Like the brake pin, the clutch pin is easier to get off at this point. I found needle-nose pliers to be up to the task.

Now, your pedal box, master cylinders, brake booster and pedals are all apart. In part 2, I'll cover cleaning, painting and re-assembly. Thanks, as always, for following along.

MGB master cylinder(s) - started

Continuing on the MGB project, today is all about the removal of the master cylinders. This is the logical continuation of the prior post about MGB brakes where I did all four corners and the rubber lines but I was unable to successfully bleed the rear brakes.

How Works MGB Brakes

pic swiped from MGB forum

I briefly touched on this in the MGB brakes job posting (See: MGB Brake Job). The brake hydraulic system is very simple. From the pedal under your foot, a level presses against the vacuum-assist brake booster which activates the brake master cylinder. That's typical of any modern car. The MGB master cylinder is split into 2 halves, the front and the rear, with a rod connecting them so that when you press on the pedal and the brake booster activates the master cylinder, fluid is pressed out of two chambers. The chambers correspond to either the front or rear. This is a protection in case there is a failure in your brake system, keeping the other system intact so you can stop. Safety Fast!

Bleed Fail
This brings us to our brake problem, I did the four corners, and bled the front system. The rear system, though, would not bleed. First, the air bubbles would not stop and finally, the fluid stopped passing through. I thought I had fouled the rubber line install so I removed it and still couldn't get fluid. Rules out rubber line. Then I put it all back together again, and went to the master cylinder end. I disconnected the one hard line that ran to the back of the car and it could hold vacuum. So, the hard line is good. The master cylinder must have failed.

Master Cylinder
Again, the internet has opinions when it comes to brakes. Okay, pretty much that's true when it comes to anything, but in this case, there's a strong urging from the MGB community to replace the clutch master cylinder when you replace the brake master cylinder. That's because they stack-up against one another and removing just the master cylinder for the brake requires so much disassembly, it's one of those jobs you only really want to do once. There is even a reported odd circumstance where both master cylinders fail around the same time, so even if you avoid doing both, you find yourself replacing the other one within 6 months. I mentioned the rust/patina condition of this little car in my part 2 posting (See: Little British Car (Part 2)) about buying it. The patina on the brake booster was pretty bad, and the pedal box looked pretty bad. There were leaves, and other filth all up in there too. So, I decided that I'd pull all of it out, clean it up and paint what I could. That may have been just one sentence, but many weeks of effort.

Pedal Box

swiped from britishv8.org

The brake and clutch pedals attach to the car in a combined steel box that is attached to the inside of the engine compartment. There is a rectangular hole through which the pedals pass into the driver foot-well. Once the hydraulics are disconnected, the pedals are removed as a unit, still attached to the box. Once removed from the car, I disassembled the pedals, cleaned, sanded, wiped down, etched, primed, re-sanded, re-wiped and painted them (black). I did the same to the pedal box.

I have ordered and since received the brake and clutch master cylinders. I have not installed them yet, though, as other projects have jumped in front of this. The posts on these other projects will keep coming, and as they complete, re-assembly will start, and then I'll come back to the master cylinders. The picture on the right here from britishv8.org is very much what I am aiming for. I've bookmarked this guy's project page for inspiration. Very nice build.

As always, thanks for following along, and I'll post more soon-