Make the bus stop - custom Vanagon brakes

I have a VW Vanagon Westfalia that I very much enjoy. It's no dynamic masterpiece but it handles better than any other house I own. The problem is the brakes aren't awesome. It's got a two-piston fixed front caliper with 11" solid rotors and drums in the rear. One weird thing is that the front rotors are actually part of the front hub.

I'm not the first to think this could be improved upon. There are "big" brake kits on the market that repurpose OE bits from other German cars such as Audis. What they're really doing is going to vented front rotors, not so much larger diameter. They also tend to have really big pistons. One popular swap uses pistons that are 40% larger than stock. Apparently the pedal feels a little squishy - no kidding.

There's just one problem with the available BBKs - they're all designed to bolt on to a later spindle design. Used spindles are amazingly expensive. 

I'm mostly looking for a better pedal feel and better single-stop behavior. Heat management hasn't been a big problem for me, as I can simply engine brake on the long downhills. The only time I've ever managed to get the brakes hot was creeping down Pike's Peak after the race, and a steep traffic jam is a pretty rare occurrence.

So I'm thinking of using the Little Big Brake Kit concept that I came up with at Flyin' Miata. Basically, Wilwood calipers on stock rotors. It would be nice to have fat vented rotors but that's mostly for heat management. If I use a bigger pad and an alloy caliper in place of the tiny pads and iron calipers, that'll get me slightly better heat capacity and heat radiation than stock, and if it's really bad I'll just do some brake ducting. I'd rather use Wilwood calipers over some random OE because, well, I trust them on a 500 hp track Miata.

One of my stock calipers just seized, so obviously the best thing to do is to redesign the whole brake system. I'm just starting down this road, so let's figure it out.

Let's get this out of the way - it's a 1985 that has a Subaru "frankenmotor" in it. That's a 2.5 with a 2.2 head. Loads of torque. It's made the van quite perky compared to the Subaru 2.2 that committed suicide in the middle of Utah a while back. It's got 100W of solar panel on the roof, a proper electric fridge, LED lights inside and out, Koni shocks and Ronal R9 wheels. Yes, we use the sun to make ice cubes, it feels like cheating. We've taken it on a few longer road trips but it's often used for weekend getaways off the grid.

I have an '85 as well, no subaru motor yet. I like this thread.

So there's that out of the way.

Why stick with a solid rotor? Mostly because it's easy. In order to fit a vented rotor, I need to either make a custom hub (ie, machine off the rotor part of a stock one) or buy one of the custom hubs on the market. Then find an appropriate rotor, etc. But I think my plan will get me the best wheel clearance (adding a rotor to the existing hub will push the wheels out, which I do not need) and will be the easiest to implement both for myself and for anyone who wants to follow in my footsteps.

Instead of adapting an OE caliper with the difficulties in matching up bolt pattern (it can be done, but only on the later spindles), I'm going to do this exactly the same way we do on the Miatas. Wilwood caliper, custom bracket, done.

Here's stock, pads removed.

Bad picture of mounting. Interesting that this is a fixed caliper. I believe the later vans went to sliding calipers.

As best as I can tell, that's a pair of 2" pistons. That means 3.14 square inches of piston area. If I go to a four piston setup, I'm looking for 1.38" (3.00 square inches) or 1.50" (3.54). If I go with the smaller size, I can use an inexpensive Dynapro or even a Dynalite. But I'm tempted by the greater brake torque of the slightly bigger setup, and I can get that with a radial mount caliper that's got better weather sealing than the usual race calipers: the "Dynapro Dust Seal Radial Mount". Available to fit a 0.50" rotor (!) and in the size I want. It's not the cheapest option, but the calipers alone will be less money than a set of junkyard spindles and I only have to buy them once.

So I'll look into ordering some calipers tomorrow, then we'll see what I can mock up for a bracket. Wilwood unfortunately doesn't have drawings on their site for this particular radial mount design, but I'm pretty confident I can make it fit.  

If I wanted to use Dynapros with a lug mount, I could be mocking that up tomorrow! And a lug mount would be easier to make a DIY bracket for. But I think I'll try the radial, I like the sizing a bit better.

Thoughts?

preach said:

I have an '85 as well, no subaru motor yet. I like this thread.

Even better, I have a Subaru 6-speed that's ready to bolt in when I get around to it. It'll give me a gear between the current 3rd and 4th (big hole there on stock VW transmissions) as well as a total cruiser interstate gear that I'll probably need the 2.5 to pull. But that's for another day...

Forgot to mention, if I have overheating problems I'll add brake ducting. Which would be entertaining to see.

More thoughts on sizing.

My options are 3.00 or 3.54 square inches. Stock is, as noted, 3.14. The 3.00 is what we use on Miata calipers. It'll give a slightly firmer pedal but require a little more pressure for the same brake torque. Not much, probably not enough to notice. The bigger caliper will have a little more travel but will generate more brake torque for a given pressure. The bigger one is radial mount (more difficult bracket) and better sealed, the smaller one is less expensive and easier to mount. I think I know what the right answer is here, but any thoughts would be appreciated.

Some of the other big brake kits out there are running as big as 4.4, which is ridiculous.

Keith Tanner said:

preach said:

I have an '85 as well, no subaru motor yet. I like this thread.

Even better, I have a Subaru 6-speed that's ready to bolt in when I get around to it. It'll give me a gear between the current 3rd and 4th 

Did you change the ring and pinion to reverse the 6 speeds direction ?

Yes, thoughts.  I probably won’t say anything you haven’t already thought, but maybe hearing it from someone else will help things percolate.

define what “better pedal feel” means to you, in this specific vehicle.

define what “better single-stop performance” means to you, in this specific vehicle.

i like your choice of the 1.5” pistons.  You improve gain (output vs input) in two ways (assuming pads for new calipers have same friction characteristics LOL as pads for old calipers):  (1) more piston area = more clamp force for same line pressure.  In this case, effective piston area increases by [(1.5^2)*2]/(2^2)] = 12.5%; (2) increased effective radius because center of pistons is closer to outer edge of rotor.  For example (mostly for everyone else, because I know Keith already knows this), assuming outer edge of pistons is on outer edge of rotor, your current effective radius = [ 5.5” rotor radius - 1” piston radius] = 4.5”. Your new effective radius will be [ 5.5” - 0.75” new piston radius ] = 4.75”.  So effective radius increases by (4.75/4.5) = 5.5%.  Then your new gain = ( old gain *1.125 *1.055 ) =  1.187 or about + 19% brake output for the same pedal force input.

however, at that same pedal force input, your pedal travel will be longer by some amount, because you’re back-filling larger bores to make those pistons clamp.

you are also changing the vehicle-level brake balance, because you’re increasing front brake output by almost 19% without increasing rear brake output.  If you were already locking fronts first, you’ll still lock fronts first but at an even lower total vehicle decel, because the fronts will reach lockup at a lower line pressure than before, and that means the rears will also be at a lower line pressure than before.

so yeah, thoughts.

Thanks for chiming in, Angry. I was hoping you'd show up.

I'll admit that some of my goals really should be stated as "this would be cool" and I'm trying to justify my decisions :) I would like a firmer pedal, greater stopping power and perfect proportioning, of course! But the current brakes suck, and it's not just because they're probably made of fairly old components. I'm not even sure I can lock the front brakes. The pads are small, the pedal feel is bad and parts are not super-easy to come by. I also only have one functioning front caliper at the moment.

So what I'd like is more braking power for a given pedal pressure, to give me the impression that the van might actually stop if I so desire. A stiff caliper (I'm not sure that's a problem with the current setup) to give a firm "base" at the bottom of the travel would help as well.

I did just find out that the front pistons went from 54mm to 60mm in 1986, but the master did not change. For those following along, that means a 3.58 square inch piston area and a 4.4 inch. Which explains the sizing of some of the big brake kits, and makes my choice of the 1.5" pistons basically the same as stock. So I could bump up to a bigger piston, but my next available option is 1.75" pistons which is 4.80 square inches. I do not want the longer, softer travel that will come along with that.

For proportioning, I figure what I'll do is deal with the fronts and then play with rear proportioning. I have no desire to trade out a functioning (?) rear drum setup for discs with the challenges that entails, so I'll probably just chuck a proportioning valve at it if the plumbing allows. The van is taller than stock and the Westies uses the same brakes as the tintops, so a little more front brake is probably not a terrible thing. A new set of rear shoes are probably overdue as well, which will help.

I've got an 87 Westy I've owned for almost 20 years, always happy to see vanagon content.

Edit: I just remembered, my original date of purchase/registration for the Westy was 9/11/2000. So 19 years ago, today.

I'd be tempted to to with the larger radial mount caliper. The bracket will be a pain, but as long as it fits under the wheels it should be a one time deal. Pad availability is good for both calipers? I'm running the Polymatrix Q on the Accord right now which should be the mildest compound that I can find for the Wilwoods I have and it's still right on the hairy edge of being socially offensive from a noise standpoint. In contrast, whatever compound is on Rufus is very civilized. 

You could machine down the stock hub/rotor to accept a Wide-5 brake rotor. Then you need the appropriate caliper to handle a 1.25" thick rotor and a bracket to hold the caliper. This won't move the rotor much distance from the stock location. Winters 11.75"diameter rotors are $40 each.

Edit: You can also buy the rotors in an 0.810" thickness, which makes more sense.

My boring comment is that I have never experienced a stock, semi-modern, type-approved car that cannot lock the front brakes when everything is in working order. I think new good quality pads, possibly new brake hoses, is all you "need".

In Swedish we sometimes use an expression that is "villhöver", a combination of want (vill) and need (behöver). The meaning is you want something so bad that you really need it. But I'm not sure it works in English. Weed? Nant? Waed? Nent?

Anyway, let's settle for that you villhöver a brake upgrade (much like I'm starting to suspect I feel the same for the newly launched Focus ST), I would make sure that you choose a really stiff caliper. The "lighter" Wilwoods are made for light cars and are known to flex and open up quite a bit when stressed.

Gustaf

Gustaf - the original brakes on this van were designed for a 70 hp vehicle that could carry a half dozen passengers. Now it's making between 2-3 times that power and has been converted into a camper. Even in stock form, the brakes are acknowledged to be sub-par and VW re-engineered them the year after mine were made. New pads would undoubtedly be an improvement but they'd still be tiny pads. One caliper is seized up, so really both calipers should be rebuilt. That's why I'm looking to do this now. The lines are new stainless steel, so that's not a problem. I am proposing that I take the old, obsolete and relatively rare parts and replace them with modern stronger parts that are easily sourced and have a wide variety of pads available. 

The calipers I'm looking to use are Dynapros, which are a caliper I know pretty well and are stiffer than the cheaper, more common Dynalites. Pad availability borders on the ridiculous. I've been happy with them on high-power track cars, which see some pretty stresses.

Seth, Rufus is running the BP-20 up front. The old "letter" compounds are older ones, the BP-xx are newer and pretty impressive.

I'm wondering how much can be done with compounds while remaining appropriate for the vehicle.

I just did an inadvertent and unscientific test with the MGB when I pressed it into parts fetching duty with the rear switched to Porterfield R4S shoes and 205 Conti ECSs, while the fronts we're unknown pads stopping 16 year old 185 Toyos. I was impressed that even without proper bedding, the R4Ss were howling the Contis under moderate braking. Makes me really curious about what it'll be like when I get the HP+ pads on. But in this context, I wonder whether you could use relatively aggressive shoes to regain balance after increasing the front brake torque.

tremm said:

Cool, what kind of mpg do you get when not babying it, and what's the comfortable cruising speed? The tire OD seems tiny. All I've heard about VW vans is how much people love them, & how slow they are lol. Seems like you've done a ton of work to make it an even greater outdoors travel vehicle

I haven't had a chance to get a feel for the new 2.5 on a road trip yet. The old 2.2 was about 18 mpg, and would cruise at 75 mph at 5000' elevation (with 18% power loss).

People love these for good reason - there's no modern equivalent. They're considerably smaller than a Sprinter but more useful than something like a minivan with a tent in a roof pod. You can drive them around a city easily but you can still camp for an extended period. And they're just plain interesting. Prices have shot up pretty dramatically, mine's easily worth double what I paid for it a few years back.

The tire OD is not tiny, it's actually bigger than stock. It's just not a modern over-tired SUV. One of the pictures I posted was a wide angle one that made the wheels look small, here's what they really look like.

And another, just because it's fun.

Looking forward to seeing your adapter brackets and your whole process!

Jumper K Balls (Trent) said:

Looking forward to seeing your adapter brackets and your whole process!

+1 

I'm going to warn you guys, I do not have access to a big pile of machine tools! The brackets are likely to be fabricated out of steel, not milled out of a sexy piece of aluminum billet.

In reply to Keith Tanner :

I'm sure there are those here that could help make you brackets out of the thexy billetses. 

Rough out the drawing and make some prototypes to verify it all fits and see if someone can lend a hand with their mill.

BTW, this is the perfect solution for a 3D printer, print out sample adapters from cheap plastic to test the fit, etc. then have the design cut out of aluminum, etc.

That's how we'd do it if it was a product for FM. That's exactly how we did the ND brake kit, for example. But that's because it's easier to produce (and sell) sexy aluminum. But a welded up steel bracket will work just as well and I don't care about the sex appeal, so I'm not going to take that route. I'd spend more time dinking around in 3D and trying to get my model right than I would simply cutting, grinding and welding. I tend towards the practical instead. 

A coworker did get himself a mill recently, scored a wicked deal on CL. But I'm not 100% he knows how to use it, while I know how to use my belt sander.

In reply to Keith Tanner :

Well, you did say in the beginning folks could follow along if they wanted to duplicate. Sounds like you're missing an opportunity to create a "Flying Vanagon" division. 

Keith Tanner said:

I'm going to warn you guys, I do not have access to a big pile of machine tools! The brackets are likely to be fabricated out of steel, not milled out of a sexy piece of aluminum billet.

C’mon, send me a picture of a drawing on a paper napkin and we can make you that sexy shiny billet bracket ... 

Keith Tanner said:

Thanks for chiming in, Angry. I was hoping you'd show up.

i heart keith so much, that post was thumb-typed on my phone.

...

So what I'd like is more braking power for a given pedal pressure

we apply force, not pressure, to the pedal.  we've been over this before.  if you call it pedal pressure again, i'm gonna not help you.

A stiff caliper (I'm not sure that's a problem with the current setup) to give a firm "base" at the bottom of the travel would help as well...

I did just find out that the front pistons went from 54mm to 60mm in 1986, but the master did not change. For those following along, that means a 3.58 square inch piston area and a 4.4 inch. Which explains the sizing of some of the big brake kits, and makes my choice of the 1.5" pistons basically the same as stock. So I could bump up to a bigger piston, but my next available option is 1.75" pistons which is 4.80 square inches. I do not want the longer, softer travel that will come along with that.

so go with the 1.75" and increase your MC bore size by 0.0625" or maybe 0.125".  i didn't do the math yet.  but there are tons of OEM tandem MC's out there with bore sizes from 3/4" up to way too big for you.  calculate the percent gain increase for the new front caliper effective piston area, then increase the MC bore size by some percentage less than that.  the result should be more front brake output with less pedal force and somewhere around the same pedal travel that you currently have.

For proportioning, I figure what I'll do is deal with the fronts and then play with rear proportioning. I have no desire to trade out a functioning (?) rear drum setup for discs with the challenges that entails, so I'll probably just chuck a proportioning valve at it if the plumbing allows. The van is taller than stock and the Westies uses the same brakes as the tintops, so a little more front brake is probably not a terrible thing. A new set of rear shoes are probably overdue as well, which will help.

your approach to proportioning is pretty much what i'd do.

I may have missed it but what about rim size? I converted mine to Porsche 5 on 130 via spacers and currently run 15" Phone Dials from a NA 944. I figured on bigger brakes one day and the 5 on 130 opens up a bunch of rim choices.

6MT requires cutting a crossmember I think and I do not know if there is a reverse cut R&P out yet. My plan is 5mt mated to an EZ30 6cyl.