TheSamba.com :: View topic - Hydraulic brake line lock instead of current parking brake?

Thu Dec 30, 2021 9:50 am

Hydraulic brake line lock instead of current parking brake?

https://www.amazon.com/gp/aw/d/B0932PBR9C/ref=sspa_mw_detail_0?ie=UTF8&psc=1

Even JEGS sells it for various applications like staying locked on drag strips. https://www.jegs.com/i/Allstar+Performance/049/ALL...dsQAvD_BwE

My parking brake never works well (even when adjusted, PLEASE let's keep those comments for a different thread)

And, since I'll be putting in a SubaruGears Auto trans with a cable shifter I will be eliminating the manual shift rod so could open up the whole middle floor for storage if I remove the parking brake rod assembly.

Thu Dec 30, 2021 10:00 am

So you'd open the solenoid (it remains open by default), push the brakes down, close the solenoid, release the brakes. The pressure is now held in the brakes. I don't see why it wouldn't work. Line locks have been around forever. This is how electric parking brakes work, except you don't need to hold the brakes down, the pump does it. And you'd have front parking brakes too.

You could install it at the front brake T if I am recalling it correctly without too much rework, maybe even none, of the brake lines.

Thu Dec 30, 2021 10:03 am

It would keep pressure on the rubber calipers seals on all the time. With the quality of rubber these days I'm not sure I'd want that.

Thu Dec 30, 2021 10:08 am

Yeah, I considered that too. But electric parking brakes uses the calipers via the ABS system, right? This would be no different.

Thu Dec 30, 2021 10:14 am

Steve M. wrote: It would keep pressure on the rubber calipers seals on all the time. With the quality of rubber these days I'm not sure I'd want that.

Only when using the parking brake.... Which now I don't ever use since it doesn't work.... So yeah, when I park in a hill or something, yes it would be engaged. Would not be engaged when I'm driving or regularly parked in my driveway - though, what about using this as a covert anti-theft device :)

Thu Dec 30, 2021 10:19 am

vanis13 wrote:

And, since I'll be putting in a SubaruGears Auto trans with a cable shifter I will be eliminating the manual shift rod so could open up the whole middle floor for storage if I remove the parking brake rod assembly.

And! I could eliminate the parking brake lever and put the Subi shifter there! There's already a hike in the floor.

And 2, why not install this even if one has a good OEM parking brake as a backup or for F Wheels?

Thu Dec 30, 2021 10:30 am

https://www.pirate4x4.com/threads/line-lock-parking-brake.926774/

Already a discussion on it. Plenty on the internet after a quick search. Looks like the idea is good, but using a line lock is not.

Thu Dec 30, 2021 10:46 am

4Gears4Tires wrote: https://www.pirate4x4.com/threads/line-lock-parking-brake.926774/

Already a discussion on it. Plenty on the internet after a quick search. Looks like the idea is good, but using a line lock is not.

Yes,,,,,and many on there also report years a good service even having them on engaged for months at a time.

and then there is this - a parking brake add-on remote cable actuator that pulls to 600 PSI

https://www.estopp.com/

https://www.estopp.com/faq

Thu Dec 30, 2021 11:01 am

One post on there was concerning. The line lock activated accidentally and the driver suddenly had no ability to brake. That's straight up scary.

Thu Dec 30, 2021 12:27 pm

4Gears4Tires wrote: Yeah, I considered that too. But electric parking brakes uses the calipers via the ABS system, right? This would be no different.
I have not seen an electric brake, but skills@ mentioned that it was a screw-jack.
Which would not release the car if hydraulic pressure (or 12v) was lost.
With the battery disconnected, how would you release the parking brake?
There could be ways..... but..... I bet its managed by a control unit, that you can't just hotwire to reverse the polarity. Just a guess.

On big trucks, a spring holds the braking pressure, and air forces AGAINST that spring pressure to release the truck to roll.
That way if there is an air pressure loss, the brakes fail 'holding' rather than 'released'.

An OEM would never rely upon pressure held, for a safety device.

============

Here's my reasoning why I would never do a parking brake like this.
Maybe on a race car, short term, but not on a normal car.

The tiny tiny dynamic seal lip of the pressure cups is where it all happens.
Press and release.

How long can you leave brake pressure cups energized and their delicate, crucial lip pressed hard against the cylinder?
1 hour?
24 hours?
A week?
A year?

Would the lip 'adhere' to the cylinder wall at some point?

Do any OEMs use this method? (no)
If it leaks could your van roll? (yes)
Can it 'fail' your brake pressure cups? (I suspect, YES after some time)

Thu Dec 30, 2021 12:57 pm

Not that I'm an all-out staunch defender of 'The Man', but I'd check local laws - line locks are illegal to run on the street in Canada, even though you can buy them. Plus of course you cannot pass any safety inspections up here with line locks installed. The e-brake has to be an entirely separate system outside of the main hydraulic brakes.

I also don't believe that any hydraulic pressure is used for electric brakes (intentionally, in case of brake fluid loss) - my Audi electric e-brake calipers work even with zero fluid in the system (thus regular brakes inoperative).

Thu Dec 30, 2021 2:06 pm

I agree with the posters above on the dangers of a line lock as a parking brake. I used a line lock (front brakes only) in my Beetle 2180cc drag racer way back when, for burnouts. We had a spring-loaded switch on the shifter (with a red button emphasizing the potential danger) to hold the car at the staging lights. My rear drum brakes were never very good on that car and always leaked a small amount of brake fluid at the wheel slave cylinders. If I held the line lock engaged long enough (only a few minutes if I recall), the leakage would be sufficient to almost disengage the brakes. When you use a front-brake-only system, you also need to abandon the dual-diagonal brake system design).

The danger of the line lock includes accidental application while driving, thus preventing use of the service brakes. If you think accidental application is highly unlikely, remember how accidental pedal misapplication almost killed Audi in North America in the "unintended acceleration" scandal in the 1980's.

I can't say I know this to be a fact, but I think it is likely that the Vanagon brake system was never designed to remain under pressure for any length of time and that the seals and fit and finish of the cylinders, both master and slaves, were all designed only for intermittent use, not long-term use.

Having said that, a system that simply applies spring pressure to the brake pedal itself (to account for any brake fluid leakage), might just work, but not the small amount of residual pressure you would maintain with only a line lock.

Thu Dec 30, 2021 2:13 pm

vanis13 wrote: 4Gears4Tires wrote: https://www.pirate4x4.com/threads/line-lock-parking-brake.926774/

Already a discussion on it. Plenty on the internet after a quick search. Looks like the idea is good, but using a line lock is not.

Yes,,,,,and many on there also report years a good service even having them on engaged for months at a time.

and then there is this - a parking brake add-on remote cable actuator that pulls to 600 PSI

https://www.estopp.com/

https://www.estopp.com/faq

hmm, no comments on this one that pulls the OEM Ebrake cables?

Thu Dec 30, 2021 2:21 pm

I think it has less safety concerns, so less discussion! Sodo's point about if the battery is dead, how do you release the parking brake still holds valid. I think I'd feel way better about the e-stop than a line lock.

Howesight wrote: I agree with the posters above on the dangers of a line lock as a parking brake. I used a line lock (front brakes only) in my Beetle 2180cc drag racer way back when, for burnouts. We had a spring-loaded switch on the shifter (with a red button emphasizing the potential danger) to hold the car at the staging lights. My rear drum brakes were never very good on that car and always leaked a small amount of brake fluid at the wheel slave cylinders. If I held the line lock engaged long enough (only a few minutes if I recall), the leakage would be sufficient to almost disengage the brakes.

I think this is excellent insight. Drum brakes just never cross my mind. I remember when I replaced the drum brake pads and just removing the pads and pushing/pulling/orwhateveriwasdoing on the brake cylinder pistons caused fluid to leak out. I think pairing line lock with a drum brake is a recipe for leakage.

Thu Dec 30, 2021 2:47 pm

I posed this question to my VW mechanic who does my NYS inspections.
since I have a 71 beetle with a park-loc only no Cable brakes. (4wheel discs)
he said NYS inspection is looking for a "Parking Brake" not "Emergency Brake"

he'd have no qualms issuing a NYS safety only inspection on it.
of course YMMV some of the rules are guidelines and left vague to the inspectors experience and digression

Thu Dec 30, 2021 9:02 pm

vanis13 wrote: hmm, no comments on this one that pulls the OEM Ebrake cables?
Thoughts…..
More interesting for a vehicle that doesn’t already have a parking brake system. Levers, cables, etc.
Or a vehicle that you want to delete all that stuff & clear the floor, cut new carpets.
The button adds “modernity”, if that’s some kind of plus….
No battery = no setting the brake (or releasing it).
If it actually “held the van” (& small engine) it could be integrated as a theft deterrent.
Not good for “modulating a Peloquin differential “.

Thu Dec 30, 2021 9:56 pm

I've run line locks on drag cars. They would work. They lock the brakes solid when engaged.

HOWEVER, the biggest issue you're going to have is that they would be pulling on your battery constantly, and the moment your battery voltage gets low your parking brake would release. That could lead to situations where it lets go and rolls away because you expected the brake to hold and it didn't.

Thu Dec 30, 2021 10:02 pm

Sodo wrote: 4Gears4Tires wrote: Yeah, I considered that too. But electric parking brakes uses the calipers via the ABS system, right? This would be no different.

I have not seen an electric brake, but skills@ mentioned that it was a screw-jack.

Which would not release the car if hydraulic pressure (or 12v) was lost.
With the battery disconnected, how would you release the parking brake?

correct. you can see where the motor bolts up here:

no mfgr in the world (that i know of) uses brake pressure for a emergency brake arrangement, as it bleeds off. parking brake? yes...kind of (see below)

now semantics aside I'm a CDL holder with a few endorsements (like air brake and tanker) and federal law on cars (and trucks starting in about 1983) requires brake redundancy. in CDL speak, your service brake (normal brakes) are different than your spring brakes. (emergency brakes)

that said, parking brakes and emergency brakes are defined as you'd expect... parking for parking temporarily (like unloading) and emergency for total loss of your (service) brake system.

from the DOT handbook:

NHTSA published a final rule extending Standard No. 105's parking brake requirements to multipurpose passenger vehicles, trucks, and buses with a GVWR of 4,536 kilograms (10,000 pounds) or less. Among other things, the January 2, 1981 final rule required parking brakes on multipurpose passenger vehicles, trucks, and buses with a GVWR of 4,536 kilograms (10,000 pounds) or less to hold the vehicle stationary, in both forward and reverse directions, for five minutes on a 30 percent grade. In response to three petitions for reconsideration, the agency decided to change the gradient requirement for parking brakes on these vehicles from 30 percent to 20 percent (46 FR 61887, Dec. 21, 1981). Later, the agency established FMVSS No. 135, which originally applied to passenger cars only. In a final rule of September 30, 1997 (62 FR 51064), NHTSA extended the applicability of FMVSS No. 135 to multipurpose passenger vehicles, trucks, and buses

the part in bold goes into how passenger cars have to have 2 different systems, hydraulic and/or mechanical (now electronic) in case 1 system fails.

basically, line lock won't fly federally as an emergency brake. if you pop a brake line, you'll never develop enough pressure to effectively deploy line lock as an emergency brake and as such you'll die in a fiery crash killing yourself and possibly others.

no fucking way would i want a hydraulic emergency brake when my hydraulics fail. cables or electronic brakes please

the only really bad ass thing i know of that ABS is used for is to undetectably pulse the brakes when the wipers are on about every 20-45 seconds to wipe the rotors clean of any water in the rain.

Fri Dec 31, 2021 5:57 am

Yep, what Skills said.

Not legal.

Most have never experienced hydraulic brake failure while driving and probably never will.

But let me tell you, when it happens, you will absolutely LOVE that cable operated brake system.

Dave

Fri Dec 31, 2021 9:49 am

I already tried braking with the handbrake only, well not much happens. Sure it's better than nothing, but at higher speeds it's useless. Downgearing will slow you down and the ebrake will help you get rid of the last 10 or 15 km/h.