Braking system upgrade

[Sodo]

Yeah steel wheels have a “raised ring” that presses on the disc at a diameter larger than the hub diameter. This can bow the disc and crack it. Aluminum wheels usually contact “flat”. If your wheel contact surface is flat you’re good.

[MsTaboo]

[SCM]

[MsTaboo]

[?Waldo?]

I have a '91 automatic. I recently had one of the brake switches fail and spring a leak resulting in a complete loss of hydraulic braking while I was driving. The event occurred when I was going ~15-20 MPH with minimal traffic around. The van was still in 1st gear of the 3 speed automatic. I was not in the process of parking, but if I had not used the parking brake to stop I would have hit a car, or building, or run through a solid red light with traffic going the other way. I stopped easily and was happy to use the parking brake in that emergency. Downshifting was not possible. I suppose I could have tried shifting into Park and blown up the transmission instead.

[pomfritz]

Sodo,

I have seen your posts before about the parking brake not working properly on the rear discs. I have talked to,Burley and als Bus Depot and they say the rear brake works fine.

Can you explain why this setup causes yo7 to have an inferior parking brake? Is the cable not activating the pads to hit the discs? What’s the difference between a modern car with rear discs and the Vanagon?
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83.5 233K. GW 2.3, SS exhaust, My German Frau named her Stefi

[Sodo]

Drive 10 mph and pull the brake hard as you can. It should at least skid the tires on gravel.

I’m certainly not the last word on rear disc parking brakes.
I’m basing it ALL on this:

1) doing everything I can to make mine work l, aside from buying new calipers. Which mine were, and never did work. Look at the mechanism inside, its pretty hopeless that it could generate any real squeeze on the pads. It has a dual function, squeeze pads AND self adjust.

So perhaps a little foolish pride, the same pride that didn’t let me buy new drums to make the OEM brakes work, I can’t buy new calipers. I need backing plates, shoes, drums, slaves. . The hydraulic braking is stellar (I think).

2) I drove two other disc braked vans. Both of which I was told the parking brakes worked fine. Driving about 10 - 15 mph I pulled the brake & detected some deceleration. It was detectable so I couldn’t say they didn’t Work at all. It ....was detectable, did I say I could detect “some deceleration?” There was no collusion. But neither disputed my assessment (from the passenger seat).

3) Look on sellers web sites for any description of (Burley or BD or Smallcar) parking brakes performance. They don’t put it in writing. Burley had it for just a little while but its been removed. And it was something weak, like “works as good as can be expected.” Why would they? Customers are satisfied.

4) People are not really willing to even TEST their disc parking brake. If it doesn’t work they don’t wanna know. But I do cuz I park on steep hills etc (Seattle). Or off-road. I pulled my brake at 20 mph and the van rolled something like 260 feet. I think I posted the distance somewhere but can’t find it.

What do new cars have? Many modern vehicles (small trucks etc) have a combination drum brake for parking with disc for the hydraulic (on rear). Some folks say the Girling 60 is OK cuz it was used on the V8 but basically it was dismal on the 2400 lb “passenger car” so clearly it’s gonna be dismal on a 4,5,6000 lb Van. Especially a van with bigger diameter wheels.
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'90 Westy EJ25, 2Peloquins, 3knobs, pressure-oiled GT mainshaft, filtered, cooled gearbox
'87 Tintop w 47k 53k, '12 SmallCar EJ25, cooled filtered gearbox
....KTMs, GasGas, SPOT mtb

[IdahoDoug]

I'd love to have a braking test against some of these upgraded brake systems versus my original braking system. There are a lot of people whipping the "Vanagon brakes suck" bandwagon. How about some facts from a head to head test in Popular Mechanics testing the Vanagon versus 3 competitors? The Vanagon was the heaviest minivan in the process, which means it had the hardest job. Result? Yep, the Vanagon swept the testing. Hot brakes, cold brakes, stopping distance. Crushed them.

I love my stock Vanagon's brakes. They rock, and I salute the VW engineers for the great job they did exhaustively testing, modifying, tweaking and then putting into production a brake system that will suck your eyeballs out.

What? Your Vanagon brakes suck? Let me restate that for you. It's not that VANAGON brakes suck, it's simply that YOUR VANAGON brakes suck.

I have done a panic stop with cold brakes on an undulating country road (deer) and the Syncro was beautiful and stable despite being loaded for a week long trip. Missed the deer by inches. I have horsed around on icy, slick roads with patches of sand and bare pavement creating massive friction differences - straight controllable stops exhibiting stellar brake balance and modulation of locked tires. I have gone down countless mountain passes. I have missed a driveway on a gravel road and hammered the Vanagon's brakes. Always impressive, my Vanagon has been a paragon of accurate, fade-free, quick acting braking under all conditions.

If your Vanagon is having brake problems, consider simply going through the stock system and bringing it up to optimal conditions.

Doug
_________________
1987 2WD Wolfsburg Vanagon Weekender "Mango", two fully locked 80 Series LandCruisers. 2017 Subaru Outback boxer. 1990 Audi 90 Quattro 20V with rear locking differential, 1990 burgundy parts Vanagon. 1984 Porsche 944, 1988 Toyota Supra 5 speed targa, 2002 BMW 325iX, 1982 Toyota Sunrader

[Sodo]

Popular mod is put on wheels/tires that are 10% bigger, thus braking performance drops by 10%, probably noticeable. Folks are inclined to restore braking by increasing disc size. Stock vanagon discs are not vented thus have a lower capacity for long downhil braking especially if loaded.
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'90 Westy EJ25, 2Peloquins, 3knobs, pressure-oiled GT mainshaft, filtered, cooled gearbox
'87 Tintop w 47k 53k, '12 SmallCar EJ25, cooled filtered gearbox
....KTMs, GasGas, SPOT mtb

[MsTaboo]

If the stock Vanagon brakes are so great then why did VW upgrade the Syncro 16" to the LT brakes? And why did VW of SA upgrade to larger calipers and vented rotors?
The stock brakes are ok, but that doesn't mean they can't be better.
That being said, I've haven't felt the need to spend the money on rear disk brakes, at least with any of the kits I've seen for sale.

My Alfa had all wheel disc brakes and for the rear emergency hand brake it had a small separate drum brake. My partners 2015 Nissan Frontier Pro4x has this type of setup also. The other choice setup used has two rear calipers on each axle, one as major, the other for parking/emergency.
My Audi TT just has the rear disc brakes with a parking brake cable pulling on the single caliper, but it's a fairly small vehicle, I think for our larger vans a separate parking/emergency system like an extra caliper or drum is needed.
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Currently:
'90 Syncro Westy 3 knob w/Zetec

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[IdahoDoug]

Careful, Sodo - you are using actual logic and physics here and it may confuse people. Yes, that is exactly correct, of course. Put on 16" low profile tires that are 27" ish in diameter and you just reduced the ability of your stock brakes to apply stopping power to the tire contact patch on the ground. Because the ground just got 10% farther away from the axle center and the brake pad/rotor interface. So those vans would be cake for me to beat. Bring em.

But then you're going to put larger brake rotors on? OK. Better be sure the brake pads are also contacting the rotor in a 10% larger circle. They are? Great. So now lets settle something.

If I can lock my tires at 70 (I can), and so can your modified system (lets assume you can) then neither of our systems lack power. What's going to provide the shorter stopping distance is going to be the subtle factors. Whose front caliper and disc and rear drum (or in a modified system a rear caliper and disc) when mashed suddenly will go to max threshold braking instantly on all four tires? And whose will briefly lock a tire and require modulation? Because the brief tire lock and need for modulation will cause a longer stop. Maybe by 6 feet. Maybe by 21 feet. While modulating, you might be using the front brakes at only 80% of their stopping power because the rears locked and you had to back off your foot pressure on the brake to unlock them.

What the people who modify their brakes are saying is "I think this rear disc brake and this random Audi/Jaguar/BMW/Porsche rear caliper I got off a car in the junkyard will provide the perfect amount of friction to bring the rear tire contact patches immediately to threshold maximum braking. Without requiring additional pressure that will lock one of the front brake rotors which I also got out of a junkyard from an Audi/Jaguar/BMW/Porsche." And it will do it on a wet curve at night. And it will do it on a snowy road. And it will do it when you drop two tires off the edge of the road with a full expedition load, and stomp the brakes in a panic. And when your girlfriend is driving and a deer jumps out.

You are literally saying some random combination of calipers and rotors never tested by a competent automotive engineering staff as a system on the Vanagon, designed for a brake system with a completely different vehicle, a different peak pressure, a different master cylinder, a different tire size and diameter, a different vehicle weight, and a different unsprung weight will through a one in a million conversion of the great cosmos provide ideal braking on your Vanagon by bringing all 4 contact patches up to maximum threshold braking. Cough. Uh huh.

Try my Vanagon. Stock front calipers deglazed with sandpaper last summer, recent rear wheel cylinders, and 31 year old soft lines replaced with Van Cafe versions, on factory wheels and new load rated tires in stock tire size. Jam the brakes and swerve to avoid that deer. Feel the system doing the best it can? Notice the inside front tire did NOT lock? Notice the rears did not lock and snap the Van into dangerous oversteer? That's because one of the finest automotive engineering teams on the planet, including experts from Volkswagen, Audi, Girling, ATE, Bosch, TUV and other major vendors participated in the brake system's design, evaluation of the test data, and agreed upon the final setup. Can you fade a Vanagon's brakes on a long mountain descents if you have old fluid, oversized tires, glazed and thin rotors, and rear brake shoes only contacting with 30% of their surface? Sure. But take mine on that feared pass. No problem.

Brake modifications are serious business. I have been a part of this process from the factory side and have seen how small changes can reduce or increase stopping distances. And these were small changes suggested by experienced prototyping engineers who knew their jobs. So when I see people pulling calipers out of junkyards and making brackets to mount them on their cars, I shake my head. Well meaning changes, I grant. But I am here to tell you that there is a far greater likelihood your modified Vanagon will not stop as fast as it did when it left the factory.

Hill descents are a different matter. Yes adding larger rotors and converting the rear drums to rotors is likely to provide your Vanagon with the ability to shed heat faster and reduce brake fade potential in a steady moderate brake application controlling speed down a long mountain descent. But a brake engineer getting that same brake modification task as a work order would pick up the order from his inbox and see a single bullet point on a single sheet of paper:

• Increase brake system heat shedding ability with no regard for emergency stopping, shortest possible stopping distance, cold stopping, and do not test for balance, brake modulation, brake locking or performance on slippery surfaces. Do not provide any test data, do not experiment with different line pressures, do not call any outside vendors in to test, and do not subject this vehicle to any industry brake system testing of any kind. Thanks - Management.

That's what you are doing with these brake modifications.
_________________
1987 2WD Wolfsburg Vanagon Weekender "Mango", two fully locked 80 Series LandCruisers. 2017 Subaru Outback boxer. 1990 Audi 90 Quattro 20V with rear locking differential, 1990 burgundy parts Vanagon. 1984 Porsche 944, 1988 Toyota Supra 5 speed targa, 2002 BMW 325iX, 1982 Toyota Sunrader

[crazyvwvanman]

Doug, the factory door sticker on my Syncros lists a 27" ish diameter tire, and there is no brake change required or available to use that size. It is a 14" size but the same diameter as 215/65/16 tires.

If the engineering brain trust at VW says that diameter tire is ok to use then why say it is not?

Mark

[dkoesyncro]

Ive been down this black hole before and when I was entertaining rear discs, Sodo talked sense into me. I also went looking for satisfied testimony of users.

Syncro tin top, 3500 lbs two passengers.

My first attack, I reconditioned stock brakes. This was a noticable improvement. I had just got the van on the road after some years of nesting. 14" rims and some passenger tires that were in fair condition.

Wheels and tire upgrade, euro van steelies and 215/75/15 BFG a/t. This combo is about 40 lbs a corner (it's a guess) significantly more than before. This made for a better driver, visualize stopping distance etc... Really pisses folks of in a hurry around you.

Then came the Girling 60 and 288mm rotors with BMW booster, this was a game changer. Stops now!

About 2 years ago I had a questionable looking metal brake line, at this time I replaced the whole system with cupro nickel lines and braided stainless in place of the rubber. Placebo effect says firmer pedal...

I believe the BMW booster will give a better feel and larger brakes/rotors will allow better braking. This is a whole-istic system you can't do one with out the other. Unless starting with the booster.

[IdahoDoug]

Mark,

I agree. If it is on the sticker, then the brain trust at VW has tested the vehicle fully and under all conditions that it will perform properly. Thanks for pointing it out. It is common for one vehicle to be available with different size tires.

Doug
_________________
1987 2WD Wolfsburg Vanagon Weekender "Mango", two fully locked 80 Series LandCruisers. 2017 Subaru Outback boxer. 1990 Audi 90 Quattro 20V with rear locking differential, 1990 burgundy parts Vanagon. 1984 Porsche 944, 1988 Toyota Supra 5 speed targa, 2002 BMW 325iX, 1982 Toyota Sunrader

[OddN]

Sufficient hand brake function was an important factor when I upgraded the brakes on my syncro. And Ive read many posts about how bad the handbrake function became when converting to rear discs.

So I went with the original syncro 16 larger rear drums. And even with 245/75R-16 (roughly a 31 inch tyre) I can still lock the rear wheels when engaging the handbrake going 10 mph on dry asphalt (with decoupler of course). Id like to see a rear disc brake kit do that

As far as emergency brake systems are concerned, the regulations here in Europe (where the Vanagon was produced) says that the remaining circuit of a two-circuit braking system (when one circuit fails) can function as the emergency brake. And it must be able to stop the car in a certain distance from a set speed. If it does, the hand brake does not have to comply with the emergency brake regulations, only with the parking brake regulations which only require the hand brake to hold the car still in a certain incline, not to stop it from any speed.

It is really uncommon for both brake circuits to fail at the same time so this was good enough for the officials.

Some 4x4 cars, like the Range Rover Classic and the Lada Niva has the parking brake mounted directly on the rear output shaft of the gearbox, thus only holding the prop shaft still. The owners manual clearly says that the parking brake must not be applied at any speed due to this construction. And when parking on really uneven ground, or with one rear wheel on tarmac and the other on ice with such a car, it will not hold still since the parking brake isnt holding any of the wheels, only the prop shaft.

In the early 1960s cars with single circuit brake systems were more common, and then the hand brake also had to function as the emergency brake.
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1991 VW Multivan syncro 1,9 TD

[IdahoDoug]

We have a new Subaru Outback and one feature I don't like is the parking brake lever has been replaced with a small electric lever that engages the parking brakes. It's an all or nothing thing - you can't gently engage it to slow the car down. It goes on fully and harshly with no adjustment.

However, I discovered something impressive a couple days ago. Leaving a coffee meeting with friends, in the parking lot I tried to spin the Subaru with the parking brake. Stopped us briskly with only the rears and the ABS was even engaged! Huh? Screwed around a little more and realized it's actually engaging all 4 brakes, plus utilizing the ABS function. Amazing. I love the added safety here and would gladly trade it off for no ability to slide the tail around. I must be getting old......

Doug
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1987 2WD Wolfsburg Vanagon Weekender "Mango", two fully locked 80 Series LandCruisers. 2017 Subaru Outback boxer. 1990 Audi 90 Quattro 20V with rear locking differential, 1990 burgundy parts Vanagon. 1984 Porsche 944, 1988 Toyota Supra 5 speed targa, 2002 BMW 325iX, 1982 Toyota Sunrader

[Merian]

It's not that VANAGON brakes suck, it's simply that YOUR FAILURE TO PROPERLY MAINTAIN VANAGON brakes sucks.
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[Sodo]

I kinda feel like I just ended up with a good braking system that deleted my parking brake.

I agree it would be wise, and probably should be mandatory periodical driving test to practice for, and prove you are capable of a panic stop.
_________________


'90 Westy EJ25, 2Peloquins, 3knobs, pressure-oiled GT mainshaft, filtered, cooled gearbox
'87 Tintop w 47k 53k, '12 SmallCar EJ25, cooled filtered gearbox
....KTMs, GasGas, SPOT mtb

[Pcforno]

I feel compelled to comment.
ID Doug - I don’t think anyone would argue that the stock braking system is fine for a stock vehicle. But when you start adding weight and bigger tires things change. I’m sure your tin top 2wd stops on a dime. I have a syncro westy with add ons and modified engine. I know how to maintain a brake system. I refreshed everything in my brake system - pads, rotors, drums, lines, bleed, etc. performance was ok but made me nervous due to fade on long passes and poor emergency stop performance. I did my upgrades stepwise. Installed G60 upfront with 288 rotors. - noticed immediate improvement in emergency stopping distance and felt better with fade on the passes. I did notice problems with needing more pedal pressure however. Next I put on rear discs which helped more with fade on hills and a little on emergency stops. Mushy pedal got worse. Then I did the larger brake booster. System is awesome now and feels safe, stops on a dime, and no fade. I’m not gonna say it feels like my 2018 outback but it’s not far behind. As far as the parking brake, I did new cables and spent a lot of time adjusting the calipers on the rear discs and it works great. It’ll skid on gravel but not on concrete, and there isn’t a hill that I’ve found that it can’t hold (including steep off road stuff).
So yes I get your engineering comments (I’m not one, nor even a real mechanic) but For me it’s a big improvement. I really like nearly all the mods I’ve made to my van. Yes it’s a well engineered machine for 30 yrs ago and leaving it stock is great. But so are mods. That’s kinda what most people read the samba for. My .02

[IdahoDoug]

PCforno,

Thanks for your input, and it sounds like you've put a lot of effort, time and money into changes to your brake system. I want to preface what I'm about to say with something. This is an earnest and heartfelt insight with protection of the Samba folks in mind. Though it may take the wind out of your sails a bit, it could be that your particular system is a great match and increased your overall safety. The intent is greater good here.

I have personally been a part of studies at GM where the engineering staff put larger disc brakes on the GM "F" chassis (Firebird/Camaro) - a rear wheel drive sporty chassis that has a low center of gravity, no ABS and good handling characteristics. There were others - many others but this will serve as an example.

They put these larger brakes on to prepare for a performance model, brought it out to the braking test area and put it through its paces. Faster bite and harder initial braking, and better multiple stop performance, but longer stopping distances because the rears locked up. And modulation (the ability to ease pedal pressure to unlock a tire without easing so much braking must be reduced too much before the tire rolls and you can bear down again) was terrible. It was not a surprise, just Day 1 of a brake upgrade.

In order to tune these larger brakes, it took weeks of instrumented testing and documented changes. Dozens of different combinations of brake master changes, F/R line pressure balance adjustments, changes to brake pad materials, different calipers, etc to bring the car back to a safe vehicle after plugging in larger brakes with greater heat shedding.

You did the same - put on different rotors, different calipers, and then rear rotors replacing the drum. But you did zero instrumented testing. And I believe you when you say they "feel" better. However, I'm here to tell you that unless you are the luckiest guy in our solar system, you got an increase in total heat shedding, but you gave away emergency braking on a wet curvy road. Your stopping distances on dry pavement are actually longer. Your front brakes will lock too easily on a gravel road emergency. Who knows? I sure don't.

My point here is that people who do heavy brake modifications uniformly report their systems are "better". Is it a surprise that someone who spent perhaps $1000 and hours of their time wants others to believe it was a good idea? A wise investment? I find it odd that nobody who's done this has gotten back on Samba and said "Wow they don't fade on Vail pass anymore, but in the winter I've discovered that the rears are practically useless on snow - they just lock up and the Van sucks. Does anyone have any suggestions?" Or "Holy crap. I love how firm the brake pedal feels but a deer walked out on a rainy country road yesterday and when I hit the brakes, the fronts locked up and I had a hell of a time regaining control."

So the impression others get is these brake upgrades are a sure thing. 100% better braking performance in all respects. Perfectly engineered plug in.

I just want to weigh in and say that there is no way on God's green earth these brake modifications are not creating ill handling monsters under emergency braking maneuvers, or low friction surfaces, etc. Those modified Vanagons are on Day 1 of a brake upgrade program, and there will be no Day 2.

Doug
_________________
1987 2WD Wolfsburg Vanagon Weekender "Mango", two fully locked 80 Series LandCruisers. 2017 Subaru Outback boxer. 1990 Audi 90 Quattro 20V with rear locking differential, 1990 burgundy parts Vanagon. 1984 Porsche 944, 1988 Toyota Supra 5 speed targa, 2002 BMW 325iX, 1982 Toyota Sunrader