My hydraulic emergency brake

[norvalwilhelm]

I did not have a parking brake for years. The old mechanical one was too much trouble so I ditched it and decided to build a hydraulic one.
I raided my sons supply of various brake parts and came up with calipers with 2 live pistons that would fit my 12 inch rear rotor, a master cylinder that was very light, matches the calipers and easy to mount. I also used my old parking brake handle and a 3 inch piece of 2 ½ inch aluminum angle and a 2 ½ inch x 9 ½ inch by 3/16th piece of aluminum to mount the whole thing on.

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I took the stock parking brake handle and added a spur on the back. I bent a piece of 3/16th by 1 inch hot rolled around a ¾ inch pin, machined a little spur from ½ inch material and silver brazed it on the back. I then drove the stock 3/8th spring pin out of the assembly and installed a longer one including mounting my spur at the same time.

Another angle of the spur.

This is the caliper I chose. It has 2 live pistons of good size, it is aluminum so it is light but it was not thick enough so I made aluminum blocks to increase the width. It fits easily around a 12 inch rotor and 100% of the 2 pads ride on the rotor.

This is the assembled unit. The handle works smoothly, the travel of the master and the handle seem about the same. The master bottoms about the same time as the handle runs out of travel. The master has a powerful spring that pushes the handle back smoothly when released. It really feels good.

All I have left it to remove the trailing arms. They were coming out anyway for routine inspection and bearing checking and I will make a nice caliper mount and weld it to the arm. I intend to mount the caliper out front at about 2 oclock on the passengers side and 10 on the drivers side but that could change when I go to mount it.
All I need is some brake line, 2 flex hose and I should be in business.
Marck I am not sure if you can use a hydraulic setup. My son ships argos overseas and they need mechanical emergency brakes.

 

[lone73]

So you're gonna end up with two calipers on each rear rotor? What about unsprung weight issues?
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[norvalwilhelm]

So you're gonna end up with two calipers on each rear rotor? What about unsprung weight issues?
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Yes I do end up with 2 calipers on each wheel. I turned the rear rotor on a lathe and removed the entire center where the old emergency brake road. I cut 3 pounds out of each rotor so with the hydraulic calipers I should be about even in the weight department.
At the time I did all 4 rotors , removing 3 pounds from each or a total of 12 pounds of unsprung weight.
I remove my trailing arms every year or 2 for inspection and I don't want to deal with the stock emergency brake. I feel a couple of short brake lines and 2 rubber flex houses can be neatly tucked in somewhere out of the way. A stock system requires the pulley, a cable and those stiff unflexing lines running up to the trailing arms.

 

[gmjunkie]

Yes I do end up with 2 calipers on each wheel. I turned the rear rotor on a lathe and removed the entire center where the old emergency brake road. I cut 3 pounds out of each rotor so with the hydraulic calipers I should be about even in the weight department.
At the time I did all 4 rotors , removing 3 pounds from each or a total of 12 pounds of unsprung weight.
I remove my trailing arms every year or 2 for inspection and I don't want to deal with the stock emergency brake. I feel a couple of short brake lines and 2 rubber flex houses can be neatly tucked in somewhere out of the way. A stock system requires the pulley, a cable and those stiff unflexing lines running up to the trailing arms.

That's Killer Man!!!I think it's a Great Mod!! Be lot's better than that old Rustin SH*T that didn't work that good New!! junk!!

 

[lone73]

I like the idea of using the hydraulics to actuate the E-brake. I wonder if its possible to just T into the rear brake lines with the new master and use the existing rear calipers rather that add a separate set?

 

[pgtr]

Really interesting approach! I like it. The OE arrangement leaves a lot to be desired to put it mildly. Is this calipre to be mounted as a floating piston arrangement or would the whole calipre need to float? Normally parking or e-brakes use cable. Under nominal conditions - is it possible there can be some hydraulic pressure loss. Let's say over the period of an hour, a day, a week or a month or longer... could hydraulic pressure reduce even slightly over time?

lone73 I can think of several reasons why T-ing wouldn't work. For one - if you pressurize the same hydraulic lines as the normal calipre uses - what holds the pressure up at the master cylinder?

 

[Mac]

norval, once again, you amaze me with your fabricating skills and unique ideas!!

-Mac

 

[norvalwilhelm]

I like the idea of using the hydraulics to actuate the E-brake. I wonder if its possible to just T into the rear brake lines with the new master and use the existing rear calipers rather that add a separate set?

No way. If you Tee into the main line when you apply the emergency brake the fluid would just go back to the main master cylinder and not activate the brakes. If you put a check valve in the main line your main brakes wouldn't release because the fluid couldn't flow back.
No you need a second caliper.

 

[norvalwilhelm]

Really interesting approach! I like it. The OE arrangement leaves a lot to be desired to put it mildly. Is this calipre to be mounted as a floating piston arrangement or would the whole calipre need to float? Normally parking or e-brakes use cable. Under nominal conditions - is it possible there can be some hydraulic pressure loss. Let's say over the period of an hour, a day, a week or a month or longer... could hydraulic pressure reduce even slightly over time?

lone73 I can think of several reasons why T-ing wouldn't work. For one - if you pressurize the same hydraulic lines as the normal calipre uses - what holds the pressure up at the master cylinder?

The caliper is rigidly mounted and it has 2 live pistons, one on each side.
Yes the pressure will drop over a short time. I have not tested it but I bet after as little as 1/2 hour the brakes are starting to let go.
My idea with the emergency brake is if you main brakes fail and my main braking system is modified into two completely seperate system, if one fails the other is isolated.
My emergency brake is for safety checks and spot checks by the cops. It should work great in any test except the test of time. Over time it will fail.
I leave the car in gear anyway and would never use it for parking.
I drove starndard trucks all the time and never once used an emergency brake,
Again just for safeties and spot checks.
It is very smooth operation.

 

[norvalwilhelm]

norval, once again, you amaze me with your fabricating skills and unique ideas!!

-Mac

Thanks Mac but my son gave me the idea. We just took the parts out of his bins and applied them to my application.

 

[gmjunkie]

No way. If you Tee into the main line when you apply the emergency brake the fluid would just go back to the main master cylinder and not activate the brakes. If you put a check valve in the main line your main brakes wouldn't release because the fluid couldn't flow back.
No you need a second caliper.

No, You could Just put a Micro Lock Syst.for a tow Truck!! Put micro switch on Emg. Brake Handle!! Push Brake,Pull handle,Turn off Key!! All 4 wheel's Locked!! It ain't Move'n with out key!! Or you could put a Hidden Power Switch for Micro Lock,and Nobody is Move'n it even with a key but You!! But I Like the Idea of Ind. Hydro rear Emg.Brake!! Think of the Bat Turns you could do with That!!! Keep it up I think it's In-O-Vateve!! junk!!

 

[pgtr]

OK gotcha - so it's dedicated purpose is ebrake - NOT parking.

Just curious what the calipres are off of? - Most newer 2 piston calipres I'm familiar with are floating calipres vs floating piston.

Again - really interesting stuff you're doing there.

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BTW - while on the topic and with the advent of dual brake cylinders around '67 or so - can anyone explain to me just how 'indepedent' the 2 cylinders are in a modern car - that is a hydraulic leak on one side and it's affect or not to the other side?

 

[gmjunkie]

BTW - while on the topic and with the advent of dual brake cylinders around '67 or so - can anyone explain to me just how 'indepedent' the 2 cylinders are in a modern car - that is a hydraulic leak on one side and it's affect or not to the other side?

If you brake a line in Back,you still have Front Brakes!! If you brake a line in Front you still have Brakes on Back!! You will Still have Some Brakes,Not as Good but can stop it!! junk!!

 

[norvalwilhelm]

No, You could Just put a Micro Lock Syst.for a tow Truck!! Put micro switch on Emg. Brake Handle!! Push Brake,Pull handle,Turn off Key!! All 4 wheel's Locked!! It ain't Move'n with out key!! Or you could put a Hidden Power Switch for Micro Lock,and Nobody is Move'n it even with a key but You!! But I Like the Idea of Ind. Hydro rear Emg.Brake!! Think of the Bat Turns you could do with That!!! Keep it up I think it's In-O-Vateve!! junk!!

Yes I could. I even have a spare line lock sitting on the shelf but I actually want to try and be as close to legal as possible. I don't want to be hauled into a safety lane, have a mechanic pull the lever and find I was cheating on my system. It could also be dangerous in that the line lock is left on and my rear brakes no longer function. In a panic stop if the switch was bumped or left on the rear brakes would not work.
NO I am trying to make everything right so anyone can drive the car.
It is no big deal to fabricate another caliper mount and weld it to the trailing arm. I do pull my trailing arms regularly for routine inspection. It keeps everything well lubed, prevent seizing up and keeps my skill at pulling them apart undated.
I will just weld/fabricate a bracket with the assembly sitting on the bench.

 

[Vette/Berlina-coupe]

Nice try 'norvalwilhelm' -but no cigar, just a brass-ring---

-probably a couple of years ago i posted about some ideas for improving the pathetic E-brake non-effectiveness (but was aghast that nobody here seemed to care about this extremely critical issue of which GM should actually be held liable for the danger it poses), -indeed, my own awareness was prompted by my having almost wiped-out a hord of rice-burners when my hydraulic's went-out for the typical 'pumping-air' reason; --which was remedied by the fine SS-sleeves & O-rings fix. However, it certainly brought to my panic'ed attention the pathetic ineffectiveness of my E-brake/Park-brake, -which is basically simply to small for a heavy Vette. While your Hyd.E-brake apparatus is clearly very professionally executed, it still does not adaquately address the need for a reliable/dependable mechanical Parking-brake for those of us having a Manual-transmission. The only safe E-brake apparatus is still necessarily a mechanical-type; --which is why i have urged the application of Metal-spray to coat the faces of the oem-rear/Brake-drums with something like Aluminum-oxide/60-grit like sandpaper-finish which would present a high-friction surface. A viable alternative which i most favor, -would be to install a myriad plurality of 1/4"Radial-holes in the drum-faces (in combination with soft/shoe-lining to enhance embossment-like bite into the holes you see!), -tantamount to drilling of racing/disk-brakes! There are Stainless-steel Shoe-brackets and SS-linkage available, so that obviates problems with rust, --thus if anyone has possibly experimented with my proposed means of increasing the stopping-friction of the puny 6"/Brake-drums as a viable solution to the quest for a safe combination Emergency & Parking -Brake not facilitated by 'norvalwilhelm's admirable experimental iteration. -Would love to hear more on this important topic, as i am seeking a Mechanical-brake which will have the ability to skiddddd the rear-tires when i yank it on (hence, holding the car parked on a steep-hill as well, which the stock-version will not do.)!!! As i said earlier, there is a huge-market for the enterprising person that can provide a Mechanical-brake 'PosiStop-Kit' that up-dates the pathetic factory-version (sorry friends, -but the hydraulic approach offers no viable-merit/provision for "safe-parking on a hill/sloped-driveway")....... ~Bob vH

 

[norvalwilhelm]

OK gotcha - so it's dedicated purpose is ebrake - NOT parking.

Just curious what the calipres are off of? - Most newer 2 piston calipres I'm familiar with are floating calipres vs floating piston.

Again - really interesting stuff you're doing there.

---

BTW - while on the topic and with the advent of dual brake cylinders around '67 or so - can anyone explain to me just how 'indepedent' the 2 cylinders are in a modern car - that is a hydraulic leak on one side and it's affect or not to the other side?

Yes it's only purpose is if the other brake fails for some reason I have something to fall back on , That a the cops stop for a roadside inspection and I can pull that emergency brake and the car will not move. Weather it rolls away in 15 minutes is not a concern.

The calipers are aluminum and rigid just like our stock calipers. The are off an off road vehicle called an Argo. It is a go anywhere 6 or 8 wheel vehicle designed to carry about 1000 pounds through water, mud rock or anthing else you encounter. Same with the master cylinder.
My son supplies me with them.

If one side looses pressure due to leakage the other side is affected. Line pressure drops off unless you are steadily pushing on the pedal