buy a Handbrake?

  • Thread starter Thread starter MrDavid5465
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MrDavid5465
If you go for a hydraulic brake, you have to design it like an all drum system to get the right feel. Disc brake systems require a booster to create 1000+ psi
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This depends on how many brake calipers you will hook up I think, which is what I planned to. Buy a set and use one for a handbrake closed loop, and another on a future brake pedal closed loop.
 
In hydraulics, force is equal and unopposed in all directions in a closed system. So it would not matter how many wheel cylinders you would have. and typically the handbrake in a car operates the rear drum brake or inner drum of the rear disc brake via cable. Personally, I would use a drum brake.
 
MrDavid5465
In hydraulics, force is equal and unopposed in all directions in a closed system. So it would not matter how many wheel cylinders you would have. and typically the handbrake in a car operates the rear drum brake or inner drum of the rear disc brake via cable. Personally, I would use a drum brake.
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Cars with a little performance (at least on European and Japanese cars) already have discs all around though.
I dunno about cars in North America though as you guys even put leaf springs on performance vehicles, so I kinda expect drums to be more common good too.

Anyways, I will dive into the matter some more.

On a side note...
A brake caliper would be more useful as without the disc I could use it as a fancy nut cracker. lol :sly:


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I guess I could go for the wire option kit for my hydraulic handbrake and use rear calipers, which would give me the feel of a normal wired handbrake.
The thing is for installation of these types of handbrakes they usually advise to reroute the brake line coming through the tunnel for the rear brakes, into the handbrake master cylinder inlet and then the outlet to the brake lines.

This guy had it installed by a mechanic. I doubt this is boosted though. ;)
 
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Handbrake just arrived with reservoir :)


 
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HoiHman
:gtpflag:Very nice Christiaan:gtpflag:

Mooi tafel kleedje :D lol
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Bruin Café. lol

Went to Brezan today and I have to mail them the details and they will help me with finding the right sensors and stuff.

There is one issue though. If I use the cylinder of a brake drum, they have to push against something else things will start to leak. Using a brake caliper needs a brake booster as said above.

Hrm... it's a pain but that's what you get with these projects.
The handbrake feels nice already though. If only I could use it. ;)
I already am wishing I bought a full hydraulic pedalset instead. lol
 
Well I don't know what's your understanding of braking systems but you certainly don't need a brake booster. You can use a brake caliper just like that. It works just like any other slave cylinder.
 
Jet Badger
Well I don't know what's your understanding of braking systems but you certainly don't need a brake booster. You can use a brake caliper just like that. It works just like any other slave cylinder.
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If that's the case, I am going with a brake caliper. It's much easier to use and will look better as well I suppose.

I will go and draw something up on how I envision hooking this all up.
 
I'm an automotive service technician. You need a booster to apply the sufficient pressure on the discs. A drum brake has a self energizing action that when the shoe is pushed up against the drum, the shoe becomes wedged between the shoe's anchor and the drum. Because of this action, no booster is needed for a drum brake because through self energization, enough force is applied. They are susceptible to many types of fade and lockup is not easily controlled. Disc brakes do not have the self energization action so more pressure through brake boosters is necessary to stop the vehicle. Without the booster you would basically need to stand on the brake to come to a normal stop. Disc brakes are commonly used because they are not as vulnerable to fade as drums are and lockup is more easily controlled. Without a booster though the brake pedal would be very hard. E-brakes that use disc brakes are electronically applied (slave piston is threaded). If not electronically applied on a disc brake, there is usually a small drum on the inside of the rear rotors near the hub.

On another note though. I think I have come to a conclusion as to what i am going to do for my handbrake. Rather than buy one as i originally posted, I am going to build one that is similar to one of the handbrakes that was suggested earlier (first page i think) but instead of a hydraulic cylinder acting as a spring, I am going to use 2 coil springs.
 
MrDavid5465
I'm an automotive service technician. You need a booster to apply the sufficient pressure on the discs. A drum brake has a self energizing action that when the shoe is pushed up against the drum, the shoe becomes wedged between the shoe's anchor and the drum. Because of this action, no booster is needed for a drum brake because through self energization, enough force is applied. They are susceptible to many types of fade and lockup is not easily controlled. Disc brakes do not have the self energization action so more pressure through brake boosters is necessary to stop the vehicle. Without the booster you would basically need to stand on the brake to come to a normal stop. Disc brakes are commonly used because they are not as vulnerable to fade as drums are and lockup is more easily controlled. Without a booster though the brake pedal would be very hard. E-brakes that use disc brakes are electronically applied (slave piston is threaded). If not electronically applied on a disc brake, there is usually a small drum on the inside of the rear rotors near the hub.

On another note though. I think I have come to a conclusion as to what i am going to do for my handbrake. Rather than buy one as i originally posted, I am going to build one that is similar to one of the handbrakes that was suggested earlier (first page i think) but instead of a hydraulic cylinder acting as a spring, I am going to use 2 coil springs.
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David would a booster like any of these help to put after the master cylinder? Can't be in front due to the handbrake design.
Maybe you know a better solution?

http://modiparts.en.alibaba.com/product/764833671-210645203/Univeral_Auto_Hydraulic_Handbrake.html
http://www.aliexpress.com/store/pro...st-wholesale-and-retail/511899_674208302.html


This is how I have it hooked up in my mind as of now:

Hydraulic Handbrake for PC by LogiForce, on Flickr
 
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This is how a car's brake "booster"/servo looks like:

cutaway%20servo.JPG


It is only needed for real road cars where you can't put a 2 ton vehicle to stop with only the pressure from an elderly lady's foot. Though it's the first thing that is thrown away when preparing a car for racing.

For a sim application like yours you only need to read the pressure applied to the lever/pedal. It can be in a 0-100psi, 0-228psi, 0-556,0245psi etc... or whatever range you can squeeze out of your muscles that, when calibrated, will be the 0-100% braking. You do not need a brake booster.
 
Well, the point is to get the feel of the real thing by having to apply the correct amount of pressure as in a real car.

If this feel can be achieved without calipers,slave cylinders and boosters. The better.
However, my understanding is that I need a slave cylinder to get travel on my handbrake lever. The longer the travel, the longer it takes to get to full pressure.

Now my understanding from what I read is that about 1000-1200 psi is needed in a car for full lock of the rear tyres (at the brakes that is). This is pressure created on a certain amount of travel depending on the bore of the pistons in the brakes (slave cylinders).

If I used a 0.675" inch bore master cylinder it would be easier to create a higher pressure, but it needs a longer travel to push the piston of the slave cylinder out the same distance.

The issue is that I haven't looked into the piston sizes of different calipers yet, but I reckon this trick goes the other way as well.
Since I have a 0.7" inch bore master, if I get a large bore slave it should give a bigger travel with higher pressure.
I just don't know if the input strength in Nm (newton meters) would go down in this case as well.
 
You dont need a brake booster because you are not doing any actual braking...this is for a sim... You just need it to feel right regardless of what the actual pressure is. Have a look through the sim brake thoughts thread, and also pilmats g27 hyraulic conversion thread. Its the same principal and you will find all the info you need to build you're handbrake.

I'm not sure why you are going the hydraulic route anyway to be honest, the handbrakes in rally and drift cars are designed to lock the wheels and not be modulated, a suitably stiff spring/elastomer and microswitch would give the required feel for a lot less cost and hassle....
 
ravey1981
You dont need a brake booster because you are not doing any actual braking...this is for a sim... You just need it to feel right regardless of what the actual pressure is. Have a look through the sim brake thoughts thread, and also pilmats g27 hyraulic conversion thread. Its the same principal and you will find all the info you need to build you're handbrake.

I'm not sure why you are going the hydraulic route anyway to be honest, the handbrakes in rally and drift cars are designed to lock the wheels and not be modulated, a suitably stiff spring/elastomer and microswitch would give the required feel for a lot less cost and hassle....
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You're right. Found some more info.
The brake calipers and drum brakes are out.

Pilmat used a clutch slave cylinder that was used on VolksWagen Transporter Type 2 (T2). I won't be able to get the same as easy, but I will be damned if I can't get a VW part when I live in a country next to Germany. ;)

So it's now: Master Cylinder > Brake hose > 4-way piece with 2 sensors (switch and pressure) > Brake Hose (if needed)> Clutch Slave Cylinder VW T2 with skateboard bushing

I just hope I won't run into the throw issue. Initially Pilmat used a .750 bore master and now has a .625 on there. While I have a .700 bore master cylinder.


Oh and I want to go this route for a couple of reasons.
- To learn and use the knowledge in future projects (also car and not just sim related, but remains to be seen)
- To have something that is different
- Just having something to do
- Simply doing things the hard way has its own fun sides ;)

Besides a microswitch is not progressive.
With the current setup I can switch with the flick of a switch and just reassigning... wait a second. Why don't I just use a single joystick axis in the code, saves me time reassigning. *facepalms himself for not thinking of this before*
I still need the physical switch to switch between sensors though, or else I need to make a driver in which i can switch modes (which is something I can't do if I want to make it PS3 compatible). Besides having a physical switch is more convenient as I don't need to leave the game.

Ah well, I will get this to work somehow. I am having fun and that's what I care about the most. :)
 
Finally got all parts and have the system working. Quite happy with it in fact. I'm sure with a lot more effort and expense I could have gone for calipers/hoses etc to add to the feeling, but just the 500 psi transducer seems well good for the purpose. Again, there was nothing wrong with my LC handbrake before, but this feels a lot more like a real hydraulic handbrake, perhaps because it really is part of one :)
The biggest downside was realising threads are different on the transducer and the master cylinder, so i had to order an additional thread adapter and wait for 2 more weeks for shipment from US, having waited weeks before for the transducer itself :) but all is good that ends... well

Many thanks to people who helped/, especially Derek for his original links and further email advice

Not best pics, but they show it all in place, only the cable management left to do but it's all connected and tested for a couple of RBR runs and maybe get a nicer looking brake fluid reservoir cap. Glad I went with cheap brake fluid, as I dot' believe it would make any difference in this very short brake chain and w/o real calipers and temps



 
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