Hydraulic Lock Parking Brake. Any issues or concerns from those who have used them?

scotch737

scotch737

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Greensboro
Like the title states, I'm just searching for feedback from those of you who use them or have used them in the past. Looking to set this up on a street/trail rig that will be driven "daily" occasionally. As a mechanic, the only things I think of that could fail would be caliper stuff, or a rusty brake line of course. Or would this in any way cause more strain on seals in master cylinder.. etc. But all the brake lines are stainless and new braided. So any thoughts? You likey or no likey? Thanks.
 
From what I've read the Jamar manual lock works great.

Push pedal, lock valve, release pedal. It holds pressure in the system.

Only complaints I've read is that it can be difficult at times to get it to release, and I'll explain why.

When you deactivate the lock switch, it remains engaged until you press the brake pedal again. The force of pressure against it keeps it engaged until you push the pedal again.

This would also ensure if you engage it, and bump the lock into disengaged position while exiting, it would still be active, ensuring that your foot is on the brake pedal to disengage.

Not that big of a deal normally, but from what I've read, can be annoying on the trail. You push the pedal hard to get good holding power when parked on a hill, then it becomes difficult to get it to release as the pressure was so high when engaged.

But still has to beat no e brake.

I have no experience, but I like that it is mechanical, and I like that it uses all my normal lines and components ensuring that the capacity is there in the system to hold the vehicle.

I don't know how that would fail any sooner than the braking system under normal use anyway.
 
I've been running the Original "Mico Lever Lock", for 2-3 years. This lock has been used for Years, on heavy trucks, & equipment. It is Not intended to be a Parking Brake, but Hell, that's what it's used for! I had a work truck once, with the Electric lock, like Mac5005 describes, & That is why I don't like them. Least, not for the Trail. The Mico & other manual / lever style locks, just have a 1/2 turn lever, that can be unlocked, without having to reapply brake pressure. It's Perfect for holding on a hill, while getting recranked or in gear, & not needing 3 feet! Some claim it can or will leak the pressure off, & Sure, that's possible. But I expect that to be on a worn out valve. If I HAD to leave mine on a hill for an Extended time, Yes, I would scotch it or secure it some other way. But as a test, I'd had mine on for 3-4 days, & the pressure hasn't leaked down. Of course I don't use it that much, so it's still tight. Like as Said, it beats the Crap, out of No parking brake! ://www.mico.com/products/brake-actuation/brake-locks/lever-lock
 
My 93 topkick work truck has a e brake lever and hydraulic brake the brake lever won't hold it alone but other together I park on step hills with 11000# on a 16' trailer and never had it roll! I scotch tires regardless tho if out of truck!
 
I've had a Jamar hydraulic lock on mine since 2001. It's a great supplement, but I don't trust it. It's only rolled away once. I've come back to it many times, and a soon as I pushed the clutch in, it moved. So the pressure was not holding. Then other times, it's held fine for a month or more of being parked, and was very difficult to get disengaged. The biggest problem is the inconsistency, which is why I don't trust it.
 
I guess, being so freaking picky... Relying on ONE single valve/seal to hold brake pressure (which in a way sounds absurd, because well I wont go there) Having a true mechanical friction force on the rotors in the rear, regardless if it's pads or the parking brakes themselves. It's still really the same. But I've never heard of a cable system giving way after engaged. This is the only thing that makes me skeptical about the hyrdolock. But.. really it's the same thing....
 
We had them on our fire trucks at one point. (showing my age!). They worked great if you chocked the tires. If not just remember to go get the truck in a few min.
 
Mac5005 said:
I don't know how that would fail any sooner than the braking system under normal use anyway.
Click to expand...

It still relies on hydraulic pressure, and that pressure isn't reliable if there is even a very slow leak somewhere in the system. Normal braking is such a short amount of time that a small seal leak, etc., isn't that big of a deal, but when you pressurize the system and then statically hold that pressure with a lockoff valve, any leak will start to bleed the pressure down with time, and then you have no E-brake. If you lock off a certain section of the hydraulic system, you have even less system volume to hold pressure versus time, so any given sized leak will lose pressure faster than if the entire system volume was pressurized.

You're trusting the brake lock to not leak or fail, and every other seal and fitting in your entire brake system to not leak or fail as well, including all lines, flares, banjos, caliper piston seals, etc.

It works great until it doesn't work great, and then your rig rolls down a hill, or into the street, or whatever. I'd probably trust it for short term use (like a few minutes or whatever), but it's just too risky to engage and walk away from for any length of time.

There's not much that can go wrong with a cable-type system or other mechanical system. The cable can break, and there's low risk of that happening just sitting there if it didn't break when tension was initially applied. The cable isn't going to stretch an appreciable amount during the time that it spends under tension (unless you park for years at a time) so that's not an issue either. There are very sound reasons behind using cable actuated park brakes in OEM applications.
 
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A leak is a leak no matter the size.

A leak will allow pressure to bleed off, but more importantly it will allow air to enter the system on pedal return. This will render that half of the system useless, or both systems useless once the fluid is drained from the master.

I agree completely a separate mechanical system is safer.

I thought we were talking about a trail rig as a supplement to shutting off in gear or in park?

How about instead, just get a front and rear winch and use that as a trail parking brake.

Either ways it's trusting a additional mechanical caliper or drum that may or may not hold, or using the hydraulic system that may or may not hold. I thought that's why we use multiple ways to secure.

Park, e brake, and wheel chocks.

Or shut off in gear, e brake and chocks.

I say best solution is a driveline mounted cable operated brake caliper with adjustable locking handle.


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As I mentioned earlier. I have no experience with the Jamar, but I would prefer the 1/4 valve.

When I park on the trail, I shut off in 1st gear, chock the wheels, and usually find a tree to put a tire or axle against for safety. At times I've ran the rope out for added safety.

I've hear of d300 coming out of gear when parked, and th350 breaking the park and rolling away nearly hurting people on two occasions.

I think that for safety the best solution is more than one separate systems, however that may not be the most practical or affordable.
 
If you've got a picky inspection officer, it won't pass. In NC, you're required to have a mechanical backup, is my understanding. Add to the fact that they can and will leak down. The compound that with the fact that if you blow a line on the trail or on the road, there goes your brakes completely. Brakes are one area where I like to have a redundant system in place in case of failure. It's not that hard to incorporate a driveline or e-brake caliper. I'd go that route before hydraulics every day.
 
The driveline cable in work truck stretches if used regularly mines failed before bc I hadn't tightened it enough and truck and trailer rolled to nice stopping point against a tree! Mine has adjustable handle on it to tighten each time before engaging tho technically it was human error
 
As for "Liability", all these hyd locks, state, "Not to be used for a perking brake", yet for Years Heavy work trucks had them, though as aftermarket.
And last I knew of NC inspection does Not accept them as a Parking Brake.
When I had my AMC20 rear, Big drums, New shoes, drums, & hardware, the Factory park brake held just a little, on level ground, Forward. Not in reverse.
Changed out to Scout D44, Big Drums, New shoes & hardware. If you lean on that SOB, on level ground, it will roll!
There-for, I have a Mico Lever Lock, & 4-wheel drive x T-18 >6.32 x 1.
 
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