Non-power brakes?

[gigaz2]

pedal feel gets REAL hard, but will continue to brake

[riddleyo]

My vacuum pump is leaking so sometimes I will get a soft pedal feel with good stopping, and sometimes I will have to put my whole body into the brake pedal to stop the car. I've been wondering how to get rid of the vacuum assist also to get a consistent pedal feel and free up a tiny bit of weight and power. And a cleaner engine bay.

So all that is needed is a manual brake pedal setup and a smaller master cylinder?

[clbanman]

If you don't want to reduce your car's braking performance, you have to look at the whole system.  Only use the smaller master cylinder if it is factory matched to the pedal setup.  If you don't change your calipers, putting in a smaller master cylinder will reduce your brake force UNLESS you increase the travel of the piston in the master cylinder.  You could keep your existing master cylinder and change the lever point on your brake pedal (mechanical advantage) to retain similar braking performance without greatly increased pedal effort.  I don't know VW's well enough to know what factory available setups there were with manual brakes.  Ideally you would use a complete system from a car with similar or higher weight, or properly engineer it from aftermarket parts to increase braking performance.  The cheapest way is usually to get an entire system from a factory higher performance version of the car you are driving, or a similar but heavier car made by the same manufacturer.   Some brands have more mix and match choices than others.

[TedV]

So all that is needed is a manual brake pedal setup and a smaller master cylinder?

pretty much,  just get all the manual parts off a Mk1 Rabbit.  Use stock front calipers, no need to hunt down front drums.

The Rabbit I drove at the Atlanta Doublecross, Pro Solo has the manual pedal, manual master, rabbit gti kelsey hayes front caliper, (same as Mk2 caliper) drum rear, a manual proportioning valve to adjust bias, and forgot what pads.  Might be Hawk HP plus or HP street or carbotech panther.  Granted the car weighs less than a Mk2 by A LOT!!!, but the pedal feel was just fine and the car did stop.

[BlackTieTD]

yes the early mkIs came that way, non-power brakes. yes you can fit those parts just fine (pedal cluster, non-power master cylinder) but i believe it will also involve bending new brakes lines for the new MC position. totally reasonable and safe modification. i'm with you... less stuff to break, better feel. as mentioned, the majority of the competitive mkIs use non-power brakes (but not the VW stuff).

[molgrips]

I can't believe people are talking about wanting NON servo assisted brakes...   :shock:

I used to have a 92 VW Polo (small small car, think it's smaller than a rabbit) which didn't have servo brakes.  It seemed okay at the time but when I drove it after having driven again a car with proper brakes, it was scary.

Non servo brakes might seem fine when driving normally but during an emergency stop under load on a steep downhill, you'll be crapping yourself.  Just before you die, that is.  That's why almost every car sold in over here in about the last 30 years has servo brakes.  My Polo was an anachronism in that respect even when it was new.

[clbanman]

On a properly designed system, power brakes only provide reduced pedal effort.  Like power steering, automatic transmissions, etc.  it makes for less effort, not necessarily more safety.  Power assist is just that, an assist.  The pressure seen between the pad and rotor just requires more pressure from your foot.  Again, if properly designed, it doesn't require an unsafe or impossible amount of effort.  Just because you can lock up all four wheels with say 10 pounds of force on a power assisted brake system doesn't mean that a manual system requiring 20 pounds of force is unsafe, it just means the driver input required is different.  I know my numbers aren't reality, it's just an example.  It's more a case of driver preference.  One of the reasons many racers use manual brakes is that there is more feedback from the pedal.  I personally prefer the manual feel. I also don't have any difficulty exerting enough pressure on a manual brake pedal to lock up all four wheels instantly, so now the braking capacity becomes a matter of the friction of the tire contact patch and my ability to judge the maximum braking available from the car/brake system without locking up a single tire.  This is the same capacity available if the car has power brakes, the only difference is driver effort input.

[molgrips]

I personally prefer the manual feel. I also don't have any difficulty exerting enough pressure on a manual brake pedal to lock up all four wheels instantly

I have to disagree with this.  I may be a novice when it comes to cars, but this is the kind of question that comes up when talking about bikes all the time (the pedal variety).

You may be able to lock up all four wheels when driving along on a flat road, but when you're going down a steep hill there'll be more weight over the front wheels, so they will tend not to lock.  Then you'll be straining on the pedal as hard as you can wondering why that hairpin bend/brick wall/tree is still coming towards you...  I speak from experience (with cars this time).

[Slave2School]

I wouldn't recommend going that way, imagine the insurance implications if you ever have an accident (even if the conversion is done correctly I can't see it ending well).

If manual brakes were all the jazz we'd probably use them on the C17 to save complication  Instead we apply ~ 4000psi to 12 sets of massive brakes

Take care and don't kill yourself!

[BlackTieTD]

new cars also have paddle shifters and seats that auto adjust 14 different ways. is that necessary as well?

a couple important points: early rabbits came from the factory with non-assist brakes. going this route, its not as much a conversion as a retro-fit. also, the guys who seriously compete using the mkI body almost always have a non-assist brake setup (non-oem components, tilton MCs for example).

with proper hydraulic ratio there is no solid argument against non-assist brakes. its up to driver preference. they are less complicated and provide more driver feedback. the cost may be increased effort, but the resulting braking force, when setup properly, is the same or can even be better than a power-assist arrangement.

its about the hydraulic ratio. on a C17 is it possible to manually apply 4000psi to 12 sets of brakes by a single operator in a safe and easily-repeatable fashion? i have not operated a C17, but likely not. in a sub-2000lb tin-can of a car? all day long  :mrgreen:

[Slave2School]

If this swap is completed I want to see before and after panic stop videos from 60mph and the braking distances for each.

If Douglas decided to put a huge lever system in place....I don't think a human could provide enough power to stop an aircraft like that because of the volume of fluid required to be moved.  Much of the braking is from the TR anyway.  

I also wanted to note for the record, my czech status symbol 1987 Skoda 120GLS even had power assisted brakes...ahem...this should tell us something.  That car was only 1968lbs and I was glad to have it.  Power steering would have been nice as an option too when the "trunk" was fully loaded.

Screw it, let's all get horses.  Back to the dark ages!  No really, time for another beer and some drunken buggery.   :lol:

[molgrips]

My Polo's brakes were crap.  That's about all I can tell you with certainty

[gldgti]

wow.

non-assisted brakes aren't any worse performance wise than assisted - for light cars! the more mechanical advantage you need to build in with non-assisted, the more unrealistic the control job becomes - large pedal travel, etc.

there's plenty of a1 golfs getting around with non-assisted brakes, for rally and tarmac events - for all the reasons listed above.

however, something that noone has mentioned is that Joe Idiot, owner of motor vehicle, needs to be accounted for by motor vehicle manufacturer. Joe idiot doenst understand much about anything at all - so if he sees something in his way on the road - he slams on the brakes and swerves - which is why new cars have ESP and ABS, and over-assisted brakes - so that with one deft press of the pedal, Joe I is no longer in control - the cars ABS and ESP systems are doing his job for him, trying to stop the car in the least dangerous fashion they can.

For the discerning driver, who may be highly trained or well travelled, non-assisted brakes might be great - but for plebs, we have assisted brakes because its EASIER for us to apply the brakes without thinking too much.

Just look at the pedal effort required to use the brakes, compared with whether a vehicle is fitted with ABS or not - its pretty clear whats going on. more to the point - look at the brakes fitted to cars over time, against the advance of tyre/tire technology.

[smutts]

If you ever drove a VW MK2 Polo, you would have had all the answers you ever needed. Excellent antilock braking system though, if you get what I mean, nope, no ABS. :shock:
MK2 Golf is 400lbs or so heavier, good luck. :wink:

My Polo's brakes were crap. That's about all I can tell you with certainty Smile

Amen!

[jaed_43725]

Is there any update to this. Did OP put on a manual system? If so what parts were used?

I am thinking about doing this because my power brakes only work when they want. I went through the entire vacuum system, even have a new MC on there and the booster checked fine. But if I dont slow down while in gear to keep the revs up I have no vacuum. The factory vacuum system is crap to say the least. Its probably a worn IM shaft, and I am not changing that.

I have looked at Wilwood and that other company but I would have to call them to see if they have anything that fits. Also does anyone know of where to get the proper booster delete. I seen some old threads on vortex (google search, not a member) where a guy was selling some he made. What about my pedal travel? Do I need to MK1 pedals, or will the MK2 work with the proper MC?

Will this work: http://www.jbugs.com/product/17-2808.html?Category_Code=vw-dual-circut-master