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 I was apparently a brake-system sinner before, letting it get so outdated.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
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.
|LR image from theSamba|
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|
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.