In quest of a SAFE Mechanical E-brake...!!!

[Vette/Berlina-coupe]

---Need for improved Hand-brake....

FYI: ~There is a critical need for an aftermarket improved mechanical C3/Hand-brake (GM referred to it as a 'Parking-brake, because it is frighteningly useless above 3 to 5 mph)!! The lack of effectveness problem resides in the absurdly small/drum-brake with expanding shoes, which necessarily resides concentrically with the rear/Disk-brake Rotors (-which are themselves quite adequate. --once one converts the hydraulic-cyls. to 'O'-ring seals, -instead of the original flange-seals, which can pump air into the hydraulic-system, resulting in catastrophic brake-failure!). As an automotive/Design-engineer i initially contemplated ventilating the drums with a myriad plurality of 3/16"Diam. radial-holes, as was done quite successfully some years ago when all that was available for racing was drum-brakes! However, i am now proposing the somewhat more effective CNC-machining of about 40?/cross-slottings (ie: 1/4"-Wide x 1/16"-Deep transverse-grooves) spaced circumferentially about 3/8"-apart; --thereby serving to increase the gripping-friction approximately 600%(6x) for a significantly improved E-brake(emergency) action, -and likewise greatly improved gripping-friction when parked upon an inclined road such as a steep driveway (-which is presently impossible with the OEM drum configuration). There would be no need for alteration to the Brake-rotor portion, -nor the driver's Hand-lever mechanism whatsoever. Accordingly, i'd like to hear from anyone interested in implementing this up-grading to their C3-Corvette, --perhaps the next time they embark upon a rear-brake overhaul. The ideal senario would be to have a pair of such modified Drum-rotors made-up by a Machine-shop, -so as to have no down-time; -just slap-on the new "Cleated/Drum-rotors TM", --and enjoy significantly safer motoring as a result; --don't leave home without'em!!
~Robair VonHeck (E: robair1@att.net )

 

[80convertible]

I decided to go a different route.. rebuilt trailing arms with stainless steel ebrake hardware. I'm about to order new s/s front and rear cables. I expect (or hope) to have a perfectly functioning ebrake. Even my pos old ones held a little.

 

[Vettehead Mikey]

Drilling holes in your drums will REDUCE the friction area for the shoes, not increase it.

There's not much you can do to a 6" x 1" (approx) drum brake to get it to drag a heavy car like a Corvette to a stop.

Go read Norval's post if you want to see REAL engineering!

 

[WhiteKnight]

You have piqued my interest. I preformed a test of my own hand brake and was unpleasantly surprised at the complete lack of impact afforded to momentum. This was in an empty parking lot at a blistering five MPH. The terrifying feeling was a real eye opener.

I was able to locate many interesting articles on the subject of parking/emergency braking and some on the drilling of drum brakes to improve fade resistance and stopping power. Working similarly as it does with disk brakes, allowing gasses to escape and more shoe to drum surface contact. While your proposal would improve emergency braking, sufficient possibly to actually stop the vehicle when moving. I did not locate any evidence that supported drilled drums providing better parking immobility. What seems to be lacking in the factory system is sufficient leverage from the lever and cable actuation system. I have been thinking of added pulleys to augment leverage. That or keeping a set of chocks in the car.

One article located www.sae.org/events/bce/tutorial-limberg.pdf gave detail on the mechanics and engineering theory. I also found a company the has engineered something similar to Norval's secondary caliper, but employs mechanical actuation at an 80:1 advantage. http://www.precisionbrakescompany.com/

I also saw that some Wilwood caliper systems include a mechanical parking brake mechanism, but was unable to locate details. One advantage of such system would be potential elmination of existing factory e-brake drum internals, offsetting or potentially saving wieght.

At a minimum I intend to bring my currently non-functioning factory system back to specs. Since from your post it appears that something aside from the service brakes was possibly working and prevented obliteration of rice-burners and your Berlina coupe.

-steve

 

[JohnZ]

-wondering if there are any C3'ers that are as concerned as myself about the dangerous ineffectiveness of the stock oem/E-brake

It's NOT an "emergency brake", and was never intended or designed to be able to stop the car while in motion; it's a PARKING BRAKE.

 

[lone73]

I heard that V/B was engineering a retrofit solution from a C5. I don't know if it was to include an improved e-brake system but I had my hopes. Maybe our V/B member will help us out here...
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[ChuckG]

It's NOT an "emergency brake", and was never intended or designed to be able to stop the car while in motion; it's a PARKING BRAKE.

AMEN, John. I might add that the Parking Brake on my 69 holds just fine. If the shoes are adjusted, and the cables are adjusted, it works "as intended". Chuck

 

[WhiteKnight]

Ok, so GM intended it to be used for parking only.. Got it!


Bob and I were interested in discussing an improvment to the factory design that can be used as both and emergency and parking brake. Unlike Norval's modifications, discussed in another thread, that are intended to provide emergency braking only.

-steve

 

[norvalwilhelm]

My brakes have been divided into two complete seperate systems. I removed the proportioning valve/light and run a seperate line from the rear master to the rear brakes and a seperate line from the front master to the front brakes. They are completely two seperate systems. If one fails the second one is not affected.
I have not tested my hydraulic emergency brakes yet but they have 2 light weight calipers , each with 2 live pistons. It also acts on a 12 rotor.
I do not need it for parking, I leave it in gear but I do want a backup system.

 

[Vette/Berlina-coupe]

fyi: -Here's an article found on Brake-drum "venting"...

----Need for improved Hand-brake.....

 

[JHL]

It's NOT an "emergency brake", and was never intended or designed to be able to stop the car while in motion; it's a PARKING BRAKE.

Unfortunately in the UK your parking brake or hand brake as we call it has to meet a certain level of stopping power on each wheel. It is checked at each yearly inspection on a set of rollers and must provide some stopping force and be an even figure for each wheel, I think from around 5-10mph, the figure is reached by some calculation on the weight of the car. Basically the guy sets the rollers going and yanks on the handbrake. It is the one thing that has given me all sorts of problems over the years at inspection time :ugh

 

[Bill75]

It's NOT an "emergency brake", and was never intended or designed to be able to stop the car while in motion; it's a PARKING BRAKE.

Mine have been rebuilt to factory specs and doesn't hold worth a darn! I would never park this car on a hill and rely on it to hold it as a "parked car", it's a hazard as far as I'm concerned. Any improvement in this area would sure be great! This is really an interesting thread!!

 

[lone73]

Mine have been rebuilt to factory specs and doesn't hold worth a darn! I would never park this car on a hill and rely on it to hold it as a "parked car", it's a hazard as far as I'm concerned. Any improvement in this area would sure be great...

Couldn't agree more.

I guess VB&P has dropped the idea of a C5 brake upgrade for C3's. If I ever do get some "tinkering time" in the next year or so I want to start my own investigation into the feasability of it. Hope somebody else beats me to it. I know someone has done it before but I don't know if they upgraded the so called "parking brake" along with it. Right now my plate is just too full to take on the project.
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[norvalwilhelm]

Reply to MIKEY: -hummmm, no cigar, -as the principle of the radially-vented drum-brake is advantageously entirely mechanical, --wherein the embossing-effect of the 72-holes greatly increases the stopping power; -and anyone who would park their car on a slope using Norvel's clever albeit hazardous Hyd./E-brake would be most foolhardy as even a non-engineer would know (you'd be liable for any damage or loss of life incurred by its leakdown failure).


My system was never meant as a parking brake. It was meant as an emergency brake only. Other then hooking up the lines and bleeding the system it is about ready to go.
I am running DUAL brake master cylinders now, one seperate one for each rotor, The two live pistons per wheel are operating on the outer edge of a 11 3/4 inch rotor.
So for my emergency brake, NOT parking brake I have 4 large live pistons working at the outer edge of our rear rotors and two/2 master cylinders.
Hope it works.
As for parking I have driven standard something all my life and I just leave it is gear. NEVER ever used the emergency brake as a parking brake.

 

[norvalwilhelm]

Is this what you are looking for
This is one of my rotors

 

[Vettehead Mikey]

Reply to MIKEY: .........

I think you've got the wrong guy.

 

[Mac]

I think you've got the wrong guy.

He just grabbed the whole paragraph, Mikey. I don't think he was pointing fingers. The original author was Vette/Berlina-coupe.

-Mac

 

[JohnZ]

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Brake linings aren't compressible - if they were, they'd shred instantly.

 

[norvalwilhelm]

He just grabbed the whole paragraph, Mikey. I don't think he was pointing fingers. The original author was Vette/Berlina-coupe.

-Mac

Your right Mac. I just saw my name and grabbed the whole thing. Certainly no offense ment. Sorry

 

[Vettehead Mikey]

Certainly no offense ment. Sorry

None taken!