Parking Brake fail
 

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I had the distinct pleasure of dismantling my rear axles and brakes October last year due to an axle oil seal failure. Brake lining contamination and rotor warping was assumed due to heavy surging/pulsations experienced when braking. Aside from calipers, all of the original equipment brake hardware was replaced with Raybestos Professional Grade components. The above photos are driver side original equipment parking brake shoes etc. (note the thickness of the linings) which would not hold against idle speed in Drive or Reverse beforehand.

Smooth braking action resulted after replacements were completed but the parking brake still would not hold at idle speeds. It passed inspection despite having parking brakes being unable to hold. The mechanic allowed the pass because he knew I had only just done the work and they were still getting dailed-in. Fast forward to this year's inspection (due before end of this month) for which the state now has stricter criteria.

The replacement parking brake shoe linings were and are thinner than the originals which were discarded. Additionally, the lining material on the original shoes cover greater shoe surface area (toward the actuators) than that found on the replacements. Adjusting to the point that the parking brake will work causes dragging brakes that overheat under normal driving. I fear that this already did or will cause warping damage of the top-hat rotors due to overheating at the drum surface.

Doubting my work from a year ago, I took it apart again to confirm parking brake cables were in-fact attached and actuating. They are but actuation travel is minimal (and probably should be) but I can't for the life of me figure out why they won't hold. What gives? Am I missing something? Can anyone point me in the right direction on this dilemma? I want normal parking brake action to pass inspection without over-adjusting the parking brake shoes.

Maybe the parking brake cable is stretched. Still actuates but doesn't provide enough pressure.

I take it you are adjusting that little star adjuster and not the brake cables to get the parking brake to work?

The actuator link in your second photo is what set up on mine. I drove it for 3 years without them until the springs rotted and the shoes started dragging. Then I took out all the parts. When I got my replacement rear axle, it came with good parking brake cables that worked and almost new shoes, so now I've got parking brakes. I'm currently setting the parking brake every night to keep them working.

Make sure the shoes are extending with the drum off. The actuator may be frozen on one side or one shoe on both sides.

This was one of my suspicions but the PO claimed to have rarely or never used the park brake since purchased in 2000. Would the cable(s) still have stretched if practically unused?

Yes, that is the only means for park brake adjustment (unlike prior years where adjustment was accomplished at the equalizer) which led to dragging shoes and heated rear brakes (both sides). Backed-off shortly after the assemblies cooled.

What do you mean by "set up"? Did your actuator link bind on one or both of its two outward directions of travel (upper vs. lower shoe)? Do the actuators articulate in that manner? Is my situation simply a matter of cleaning and lubricating the actuators? When my helper cycled the park brake lever I observed one (upper) shoe actuating (at each wheel) by as much as 3/16' travel but the other (lower) shoe did not move - except when I thumped my fist downward against the extended upper. I attributed that action (or lack thereof) as being due to having no drum there to counter the upward/outward push against the drum face, that if a drum was present then the force would be distributed equally to both shoes. Must both shoes actuate when no drum is present?

Good question. You could always try these to take up the slack and see if it works better.

Good concept but clearances are lacking for a piece like that. The only exposed cables are in the junction box beneath the rear seat. The cables are jacketed everywhere else. Assuming stretched cables, I pondered inserting (slotted-puck-like) shims/spacers to the cable ends where they key/couple onto the equalizer bar...or even inverting/reversing the equalizer if possible. You see, if I did something like that and I would have to set the star adjusters to minimum, then it might cause shoe extension anyway and subsequent shoe-dragging. I'm sure you've got the mechanical aptitude so, are you getting the visuals that I'm trying to describe?

What happened with mine was the actuators didn't move at all. The cables applied tension, but the handle in the cab only moved a tiny bit. The shoes never moved at all. IDK how the actuators are made or how they function internally. I would assume they move both shoes at once and with the drum off, only one would move until it contacted the the drum, then the other would move. The cables are braided steel and I doubt they would stretch enough to not function. I think your actuators are rusted enough to not move far enough. With the cables disconnected from the actuators, the brake handle in the cab should come up almost vertical.

Even the FSM doesn't show the actuator disassembled. All it shows is how to hook the cable up to it.

You can try lubing the **** out of the actuators in the hopes of freeing them up. Once you get them free, force some brake grease into them.

Y'see, now that's what I'm talking about. I think you just nailed it, Dave1123! You've definitely earned a top ten spot on Santa's "nice" list. Oh yeah, and thanks to you too, rgr4475, for your contribution. Valid input/concept for sure.

My park brake handle does move, but only as much as ~20 degrees (max guesstimation) from the down position. Pulling up really hard for a click or two beyond that will get you a very weak park brake action. And like I said before, there is a little brake shoe movement with no drum present. I'll dismantle them again to clean/lube/free the actuators and hope that it's the cure. Nothing else makes any sense based on what I've done and seen.

Let us know what you find. I'm interested to add to my well of knowledge LOL!

I replaced both actuators ($74) with a great deal of cursing but they did not resolve the issue.

I then found a wealth of info/discussions on this issue when I searched in the Jeep forum under the WJ sub-forum. Search parameters included "brake shoes", "Park brake", "emergency brake" and "rear brakes".

After all that reading I finally realize that I'm just plain screwed unless I try to fight city hall over the B-S test they demand for the parking brake to hold (in a 4x4 V8 Jeep with LS axles on Quadra-Drive at 1500 RPM in gear). A ridiculous test expectation even when new. We all know what you get when you try to fight with city hall or state authorities.

This is why my mechanic doesn't test above 1000 rpm. The total swept area of the brake shoes isn't large enough to stall that kind of torque. He says it's an inspector's judgement call anyway. No hard data gets sent to the state computer. The only data that NY demands is ready monitors.

I was wrong to say bad things about Raybestos, have retracted my statements and issued apologies. My complaints and bad-mouthing of their quality were posted out of frustration. Today I had the pleasure of working (via communication over phone and email) with their Customer Service, Quality Engineering and various other Technical Professionals, up to and including their very well-versed Vice President (who called me while on his vacation). Excellent people who take pride in their company and product, all from an excellent American company. I learned a great deal from them, including their discovery of a bad lot of shoe "frames" from one of their vendors. Apparently, I was the recipient of some of the "escaped" bad hardware that was shipped from off-the-shelf in a warehouse somewhere. The frames (the metal structure on which the lining material is attached) had been over-machined by the vendor. Too much material had been cut from the recessed notch where the brake actuator makes contact and THAT is the root cause for the insufficient travel of the brake shoes. The solution was verified by their quality engineering group on several WJ's. They are now overnight shipping new shoes and rotors (tophats) to me with doubly-verified dimensions/specifications. Once again, you get more bees with honey. Will advise (them and you all) with results after new hardware is installed and state inspection passed.

Okay then! I just checked mine and it holds up til 1200 rpm, then it creeps. That's a 4.0 in 4wd. I either have Raybestos or Bendix on mine. Can't remember which.

Both are top names in replacement brake hardware. I still think that the test is wrong, that 1500RPM creates too much torque for even a healthy set of parking brakes on a V8 QuadraDrive WJ. I will challenge the inspection mechanic to think on this at the right time. (QuadraDrive or QuadraTracII, eh, whatever.)

I can't figure out why they want to test it with almost 75 HORSE POWER pulling or pushing on this thing. Do they have any idea how a many horses it takes to make 75 horse power? 75 Horses could pull one of these down the road with all the wheels locked up tight. When is a "parking brake" ever going to actually need to hold back 75 horse power??? lol

You just beat me to the same question... lol :)

This is not a competition. We are obviously of the same mind on this. Have you faced a similar challenge?

I understood that, and was only taking your six about your very good rational common sense question.

I wish I could be faced with this... This would become a legal issue. I am in Az and they still tend to lean more towards common sense with the crap other states come up with and reject them as impractical and ignorant. Some politician put his good for nothing nephew though school and then put him in a position to write such nonsense as this even though he was asleep through all of his physics classes. :)

Legal shmegal
 

Hey bugout4x4, why go legal unless someone got hurt? Luckily that hasn't happened here. Annoyed, yes, but no injury and they are acting in good faith. You get more bees with honey, if you know what I mean...

Check it out
 

This is swee-eet!

Tom,

Below is your UPS tracking number. I had to send UPS ground due to the rotors but you should have it by end of day Saturday. I verified the shoes are correct and also fixed the steel for you so the adjuster will fit right out of the box. If you have any other questions or concerns please let me know and I will help any way I can.

UPS Tracking number 1Z2xxxxxxxxxxxxx

Thank you,
Jim xxxxxxx
Quality Technician

These guys are bending over backwards to please me! Good 'ol American folks doing it the American way!

Stay well my boys, keep the shiny side up,
Tom

First prove an injury... How many cases do they have that support need for this regulation? One? So all the rest of us have to spend money we can't afford and get shut down on our constitutional right to travel because of the one? Bet there wasn't even one case to support this crap.

Same thing with Propane cans and OPD devises. and the three handed gas cans. It was all about money and an attempt to help out a nephew who happens to own a brass foundry make some money.

On it's face it is a lesson in non-physics... On the ranch... We used to pull start engines that had been seized from sitting and the cylinders got rusted up with only two or three horses, REAL HORSES, 75 horses will pull a train.

Look if you fall for their justification good for you. But it does not make any sense and folks should not be loosing their jobs, be late on rent, or can't feed their kids because they can't drive to work because of this ignorant crap.

Some laws are just... Most are not...

It's outright extortion...

Didn't mean to go off like that... But until you have been to court MANY times over to protect everything you own over stuff like this, you would probably never understand. First prove an injury... I have lawyers retained to ask his very question every time it comes up.

It's okay, we all have our reasons. I guess I struck a nerve and I'm sorry for that. My courtroom experiences are few and I hope to keep it that way. My issue obviously pales by comparison but if I "walked a mile in your shoes" then I would probably get the bigger picture and would perhaps be less forgiving. For now my friend, stay well, have peace and keep the shiny side up.

Lol... Seriously...I apologize. I just get upset when folks have to deal with stupid crap like this. I have seen single mothers lose their jobs over crap like this and it just ain't right. If it truly served a justified purpose I might feel different. But this test is extraneous and beyond the engineering capability of the system it's self. Some idiot came up with this in a thesis at college to get a grade even though he slept through physics, and now it is law... Far too many of these hurting this country and economy...

My mechanic buddy looks at it this way. It's designed as a PARKING brake to keep the car from rolling when parked, NOT as an EMERGENCY brake! It would have to be much larger to stop a car from any normal driving speed. Therefore he is a little less worried about how well it works.

My 62 Chrysler convertible with the 413 only had a parking brake, no park lock in the transmission. It was only a 6x2" drum on the trans tailshaft. It HAD to work or you couldn't drive it and expect to find it after you parked it! Being a young kid at the time, I was stopped at a State Police road checkpoint they do sometimes right after inspections are due. The officer told me to set the parking brake and give it gas. I brought it up to 1000 rpm and he said "More!" Of course it moved. He said "Fix it! You can go." What an ***hole! I think he was trying to show his authority to the people behind me.

Know what Dave? He is right... The industry actually relabeled it from "emergency brake" to "parking brake" for a reason. Because they were not an actual effective emergency brake by that term and label they changed it to protect themselves from liabilities. So even the auto manufacturers know they are not designed or effective enough for this type of use or test.

Parking Brake pass
 

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Old Raybestos 807PG park brake shoes had out-of-spec ~0.5" deep actuator pocket.

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New Raybestos 807PG park brake shoes, shown here with new actuators (which I really didn't need after-all), will have gap at bump-stop.

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Side-by-side comparo of Raybestos 807PG park brake shoes new (left) vs. old (right). The deeper actuator pocket is what engineers found coming from their Mexican vendor.

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New Raybestos 807PG park brake shoes have in-spec ~0.25" deep actuator pocket.

Received new replacement hardware (807 shoes and 76794 top-hat rotors) from Raybestos on Saturday, installed this morning (rainy Wednesday) and passed MA inspection this afternoon. Even with new hardware properly adjusted she began to roll at ~1250RPM. I was wrong about the 1500RPM requirement. The Massatwo****s parking/emergency brake requirement actually states that the brake must hold up-to something between 1200RPM-1300RPM and/or must stop the vehicle from 20MPH within 80 feet so I guess you could say we nailed it! :gunsmilie:

IDK if I posted this or not, but mine starts to creep at 1200. According to Chrysler, that's about 205 lb/ft of torque PLUS gear reduction.

I'm still mad that they even ask this...

So it looks like I was close with my 75 HP estimate with this test? :)

Your mechanic buddy is wrong, unless the laws have changed recently.

We don't have these inspections; how do they do that test with a manual trans?

Here's the history of it from Wikipedia for reference...

Emergency brake

The emergency brake was originally intended for one particular emergency and that was "no way to stop", as was the case when the footbrake suddenly failed. Drivers had to respond when brakes failed, so they were expected to learn how to stop a speeding vehicle using the emergency brake alone. Safety regulations became almost universal by 1980, so modern brake systems are very reliable, using dual-circuit hydraulics and more recently low-brake-fluid sensors. As modern brakes no longer cause emergencies (a brake warning light comes on after the first sign of trouble), it is no longer necessary for the average driver to learn to use this brake for emergencies. Some drivers benefiting from the "park" function on their automatic transmissions do not this brake at all(daily use of the park brake is recommended). After a lack of recent history with braking emergencies, automakers stopped using the term and started calling it by it's other use, the "parking brake" even though the ability to function at a high speed was still there. On an increasing number of modern vehicles, the park brake can only be engaged when the vehicle is at a stop, they no longer have an emergency brake.

I think this applies to automatic trans (at-least in my case it does), but if I could guess at how the test would be performed for a manual trans, then I imagine they would use first gear from a stand-still and ride the clutch to affect some forward thrust just short of causing the engine to buck & stall, else they might use the hand-brake to stop the car within a specific distance (like ~80 ft.) from a specific speed (~20 mph).