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--

Transition to the New Transmission

This should be brief today, but every time I say that it's long anyway. Hahaha... It's been a productive and fun few weeks, but I'll focus on bus stuff today, particularly on the test drives and changes I made.  Next time, I'll post on the current run of Furthur shows I hit this past weekend.  I think I left off with the transaxle in, but before any driving.  Let's start there...

Where's that Confounded Gear?

I figured when everything aligned on install that the shifting would be relatively close.  It was... Until it wasn't.  The initial drive away from MS's house was triumphant, but starting in second.  I couldn't find first.  Down the hill we went (Boo following in a chase car), and had to pull left onto a busy road at the bottom from a dead stop.  After fiddling a bit, I found 1st, moved through 2nd and 3rd to a cruising speed of 35mph at an engine speed in the mid 2000's.  Perfect.  The whole drive home followed a similar pattern of 1st gear going missing.  We hit a short stretch of freeway and I got up to 60mph on the entry ramp but near 3k on the tach, though.  I had some coolant leaking challenges that left the bus stationary while I thought on how to fix.

Wheeler Dealer

When I chose to watch something on tv that isn't sports or a movie, it's usually either Family Guy or this British show called Wheeler Dealers (on Velocity).  If you aren't familiar with the show, one host works the buy and sell end of the used car market while his partner fixes them up in between (Wiki Link).  It was while watching this show that I realized my mistakes with the cooling system.  They showed how they bled the air from the cooling system by getting the engine up to temperature, opening up the heater and then removing the cap from the overflow bottle.  The key is leaving the engine running during this process, and letting the air bubble up through the overflow bottle.  Keep adding coolant/water until it stops bubbling, and it stays at the full line.  After I did this, I stopped having coolant leak issues and odd pressurization happening.

Shift the Shifter

bubble wrapped 002 on my carpet

While I was solving the leak issue, I continued to test drive the bus, but the gear seeking got worse.  I decided that the limited-throw Skat shifter wasn't helping and it could actually have been harming the break-in of the transaxle. Fortunately, I'd only driven less than 20 miles, but I bought a replacement original gear shifter unit from Always VeeDub in Portland.  By following the instructions in the Bentley (hold the shifter between the seats near the floor and set the ball & pin first, then tilt the shifter upright while holding the base firm), the shifter set in within 15 minutes.  I was able to adjust the shift action somewhat, though I will need to do more.  Currently, I can find all gears consistently, though it does pop out of 2nd when I rev up and then pull my foot off the pedal.  When I get some time, I'll mess around with that some more.

Now, I have an old transaxle sitting in my living room, with a Scat short-throw shifter a-top it.  I'll probably sell the shifter, but I need to get rid of the transaxle.  It's a runnable gearbox, and a suitable rebuild candidate / core, so I should be able to find someone who can use it.  I have driven the bus to work every day this week, as well as to the Further shows in Troutdale all last weekend.  Lots of time grinning behind the wheel for sure.  That's it for today.  More next time.

braking better

In my last post, I mentioned that I was working on the brakes while alternating between charging and attempting to start the bus. I have continued to do that, and now have the rear brakes completed. I'll cover that work today. I did get the engine to run for about 15 seconds, though, so that's a break-through.

Ain't Broke, Don't Fix it, but are you sure it Ain't Broke?
Brakes on these old buses are not that complicated, but they do require regualr attention, even if everything seems fine. They slowly become less responsive over time if they aren't regularly adjusted, for example. The rubber flex-hoses fail from the inside-out, so you can't see that they are slowly restricting the brake fluid. The fluid itself attracts water moisture, so it needs to be changed every few years. Many times, none of these areas are looked at. "The bus stops (eventually) when I step on the brake pedal, and its old, so I know its supposed to talk a while to completely stop", you may think. That is just dangerous thinking; waiting for a failure.

Brake Fluid
The VW Bus required DOT3 brake fluid. It needs to be bled (air bubbles removed) out of the lines when you perform your oil changes. You're gonna be there when you do your brake adjusting anyway. The old bus brake system is not perfectly sealed, no matter how well maintained it is. This allows moisture into the system, and into the fluid. This reduces its boiling point considerably which lowers its ability to stop you after a few hours of driving. So, when you're getting tired, so are your brakes. To resolve this, every 3 years, the fluid should be changed. This is done by using the same process used to bleed the brakes only much more fluid is removed at the wheel cylinder while the new stuff is fed in at the top (behind the driver seat in the '72.

Adjusting Stars
The old bus has drum brakes on the rear. This was typical in its day. These older brakes were adjusted manually - as the brake shoe wears down, the wear needs to be adjusted in the placement of the shoe against the drum. The biggest pain is knowing which way to turn the star. Follow this:

to move the shoe towards the drum (opposite direction to move away)...
right wheel front: turn down
right wheel rear: turn up
left wheel front : turn up
left wheel rear: turn down

When adjusting, have the wheel raised so you can tell when the brake shoe is against the drum (by turning it). Once you've hit that spot, crank the adjusting star the other direction 3 'clicks'. The wheel should rotate well, though there may be some dragging noise, the brake is well adjusted.

Flex-Hoses and Wheel Cylinders
The rubber lines that connect the hard lines together are rarely replaced by owners anymore. They should be replaced every 10 years or so, but that knowledge is fleeting. The work is not mentally hard, but the lines differ from year to year and wheel to wheel, so order carefully. Most hoses are held into the bus by rusty clips, and the mate point with the hard lines is usually rusty too. PB Blaster everything before you open the system. Get the flare wrench - it will protect your hard line unlike a typical open-end 11mm wrench. Replace the lines and the wheel cylinders one at a time, and do it if you don't know when it was done last. Allow yourself plenty of time.

Baby needs new shoes
I knew the rear shoes hadn't been replaced since I bought my bus 7 or 8 years ago. I did the front brakes when I re-did the front end 3 or 4 years ago. It was that job that spawned this blog, actually. Anyway, 1972 is a switch-over year for rear shoes, and my bus has the "later" model shoes. This is good, as most bay window buses have these, so they should be getting manufactured longer. Unfortunately, I had the older version on-hand, so I need to unload them. The process for replacing drum shoes is pretty well documented in the Bentley book as well as online, so in the interest of length I won't go into it here. I do encourage anyone reading this to buy new adjusting stars, the spring set and wheel cylinders if this is the first time you're doing this bus.

Well, that's it for this time. I need to replace the flex-lines on the front, get the fluid in, bleed the lines etc before the brakes are fully done, but its close. Figure another few hours. Like I said, I was able to get the engine running for about 15 seconds, but that's it. We'll see if I can get more than that. I should have a whole post celebrating that, but I'll hold off until it actually runs for a couple of minutes.