Brake Fluid Replaced

When I had the wheels off, I tested the brakes, replaced some parts and replaced the brake fluid. Today's post covers that adventure.

Brake Check
The wheel saga I just recently posted about all started because the camping festival season is coming and I wanted to make sure my brakes were up for another season. I had remembered that my old rear hydraulics were bad and I hadn't checked the wear since the beginning of last season. Even then, it was a visual without removing the rims. So, after I got the wheels off, I checked things off.
Front pads: 60% remaining
Rear shoes: 70% remaining
Front rotors: unblemished along friction surface, rust along outside edge
Rear Drums: some scoring
Front calipers: unblemished, bleeder caps missing
Rear hydraulics: some surface rust, one bleeder cap missing

This was a far better state than I feared. I knew, however, that the brake fluid hadn't been changed in a long time. I couldn't remember doing it, but I must have when I replaced the rubber lines on the corners. That would have been 8+ years ago, so that fluid is way past due.

DOT3 or DOT4
Sometimes, I think the internet is the great religion creator. If you have a relatively straightforward yes/no question, you can find all kinds of long treatises waxing the pro's and con's but getting a real yes or no can be nearly impossible. In the case of DOT3 or DOT4 brake fluid, I have found some level of consistency, which I found rather surprising. So...can your older car which required DOT3 brake fluid can use DOT4: Yes. Can your newer-ish car which required DOT4 use DOT3? Only in tiny quantities, with the expectation that the system will be bleed-filled with DOT4 later. In other words, if you are running low on fluid and somewhere that you cannot buy DOT4, you can put in some DOT3 to get you back to civilization. DOT3 cannot handle as much heat as DOT4, so to prevent failure of your DOT4-requiring system, you should stick to DOT4.

As to me, and the old bus, I can run either. DOT4 can handle higher temps. Some folks say the DOT4 absorbs less water (and that's why it can handle higher temps), so you can change it less often. Like any good pseudo-science, there are great theories (sometimes with great single-experience stories), with little science, to support both of those claims. Enter religion. Regardless of whether they are accurate, I chose DOT4 for the higher temperature tolerance. I will assume that I need to change the fluid on a 3-year interval just like I was supposed to before. I was apparently a brake-system sinner before, letting it get so outdated.

Vacuum or Pedal
Once you decide on the fluid, you need to arrive at a method. If you have a helper, I encourage the pedal method. If you don't have a helper, but you have a MityVac, you can do the fluid change with it. Take ibuprofen first; your wrists and hands are going to hurt later. Regardless of your choice, the pattern is the same:
keep the reservoir topped off with new fluid while bleeding old fluid out of the bleeder furthest from the master cylinder. Once it changes color, and stops changing color, move to the next-furthest bleeder. Don't let air into the system at the bleeder or you will have that to deal with. Move from furthest to closest wheel until you've done all 4.

New Reservoir Hard Hose

I have come to realize that any time I am touching a system on this 50 year old bus that I haven't touched for a long time (or maybe ever), I should assume that any rubber part will need to be replaced. And, I should assume that I may touch something else that will fall apart on contact while the one thing I'm trying to get apart will require acts of God to get them separated. Never was this more true than the little rubber bushings that snug the connections between the hard plastic hose and the 2 brake fluid reservoirs. Yes, this bus has 2 of them. There is one sitting on top of the master cylinder like any normal car. We'll call this the lower reservoir (LR). Attached to the side of this is a plastic hose which runs up behind the driver seat to another reservoir. We'll call that the upper reservoir (UR). To be fair, it is much easier to add fluid up there, so that's probably why they designed it that way. The hard plastic hose stays connected to the hard plastic reservoir because there is a little rubber bushing between the plastic parts and then the whole thing is cinched together with a plastic thing that looks like a hose clamp with a slotted screw holding it together. Very sketchy. I figured the rubber bits on mine were gone, and that the damage to the steel behind and under the driver seat was caused by leaking brake fluid. The fact that fluid didn't stay in the UR for very long supported this theory. Knowing that parts on this old bus are either falling apart, rusted or otherwise seized, I got replacements for the hose, the rubbers and even the UR. I only ordered one grommet, and it turns out I needed 2. Check twice, order once. Don't assume the websites know your bus; you have to look yourself.

NLA
Unfortunately, the hard hose in its original length is no longer available (NLA). Only the Vanagon hose is available, and it is at least 8 inches longer. Longer is better than shorter, I suppose. That's definitely true for summer days and early Dark Star's, but this is a hard hose, so putting a few bends in it to make up the slack is not an option. On each end, the hose is fluted to fit around the nipple on the reservoir, so even though the web sites all say to cut the hose to length, that's all fine until you want to install it, and then the cut end won't fit on the nipple. And, because you cut it, it is not returnable. So, I suggest you don't cut it and do something clever... like I did.

You have 2 options:
(1) cut 8" out of the hose in the middle and figure out a way of joining the 2 ends without creating a new leak source or
(2) keep the hose the way it is and figure out a new way to attach the UR to the short wall behind the driver seat.

I went with option 2, knowing I could always fall back to option 1 if I couldn't get it where I liked it. The UR is basically a cube with a filler cap along one edge, pointing away from the dead-center of the cube at a 45* angle. Originally attached with the cap facing forward, this made filling easier than having it smack on top. We can use this angle to our advantage. If we rotate the reservoir 90* so the filler cap faces the center of the bus and then tilt the hose towards the door frame, eventually the cap faces straight up. It can be mounted to the wall like that. Before you get too far down this path, assemble the hose, rubber bits, plastic hose clamps, etc to the various reservoirs. Connecting to the LR is swear-word generating-ly frustrating, so prepare with a loud radio and sending the kids inside.

Install Hose

LR image from theSamba

I started by threading the one grommet around the hose and then the hose from above down through the hole in the floor. Since I didn't have a second grommet, I did not want to cause the hose to fail prematurely, so I did not thread it through the little hole in the driver seat pedestal. Instead. I routed it through the large square hole immediately in front of it. This may make it more susceptible to getting struck by camping gear, but I rarely put anything behind the seat, so that risk should be low. It also looks quite janky, and I will probably want to solve it properly before I re-install pedestal carpeting. Regardless, I decided to go with option 1 because I wanted to get this on the road for test drives, and knew I could change this fairly easily later.

Anyway, once threaded through the hole in the floor, it settles onto the nipple of the LR. It takes prodding to get it to sit on the LR nipple without damaging the rubber bushing and getting it deep enough that it won't leak. For me, it took wrapping the hose with a rag and grabbing on with channel-lock pliers to force it on that last bit. I found that putting the bushing on the nipple rather than seated in the fluted end of the hose was more effective as well. Tighten on the plastic hose clamp with a slotted screwdriver. Circle-back to check for leaks later, once you've put brake fluid in.

schematic from VWHeritage

The UR is easy to assemble with the hose, if you don't cut off the end. Placement of the reservoir, in my case, is temporary while I figure out a better long term solution. Ultimately, I will probably do option 2, and cut out a section in the middle. If I can do it right, I'll make the cut between the floor and the driver pedestal so the cut solution is not visible once the pedestal carpet is re-installed.

That's it for today. We got the DOT4 through out the system, using the vacuum method for the rear and the pedal-pump for the front. While the vacuum works, I greatly prefer the pedal-pump method. It is much faster and you get to hang out with a friend while you do it. After a test drive, the brakes settled down into a predictable response as the air worked it's way back through the master cylinder and up through the reservoirs. After several longer drives, the UR fluid level has remained unchanged, and the brakes are consistent. The brakes are ready for another season.

Thanks, as always, for following along.