Parking Brakes of Doom: Inspection Tomorrow

[V8BoatBuilder]

I heard some scuttlebutt from a few people, and wanted to confrim myth or truth:

1) The shoes can be installed "backwards." All 4 looked identical, with only a top and bottom..

2) Shoes need to be broken-in for max holding power, but say taking the vehicle up to 30mph and pushing on the pedal slowly till the vehicle stops.

 

[96eb96]

I heard some scuttlebutt from a few people, and wanted to confrim myth or truth:

1) The shoes can be installed "backwards." All 4 looked identical, with only a top and bottom..

2) Shoes need to be broken-in for max holding power, but say taking the vehicle up to 30mph and pushing on the pedal slowly till the vehicle stops.

1) I that find hard to believe(but anything is possible!), since there is no documentation anywhere on this. The explorer, crown vic series, and windstar (various years) use these shoes and there is nothing mentioned in any FSM. There is only a top and bottom.

2) Very possible, especially if your drums aren't newly machined. Imagine if you have a tiny ridge and the shoe is resting on it...

 

[CDW6212R]

All brake pads and linings, rotors an drums need a break in period. The wrong way to do it is to slam on the brakes at any time when they are new, under say 200 miles. Almost as wrong to do is to never use the brakes hard, in that case when they are needed they will smoke or smell and not work at maximum ability.

Best brake power is achieved after a proper break in period/process. Use the brakes as little and lightly as possible when new. Try to use the brakes on purpose at controlled times and places. Add brake pressure over the previous application, for longer periods of time. Do not use the brakes when new unless they have had time to cool, it takes a long time to cool after a decent slow down. Thus it is very hard to gingerly/barely/lightly use the brakes when new.

The best way is to baby them when new, alter your driving habits to allow much more stopping distance for the first 50 miles maybe. Avoid heavy traffic and constant stopping. After a decent period of time, then apply controlled greater braking power, slowly working up to full ABS use. The brakes should create a smell when reaching that maximum temperature the first time, or few times. After done properly, they should never smell again, and last as long as possible. Other than doing that, brakes will not last as long, not give as high of power, and smell(when very hot) if not already broken in. Regards,

 

[V8BoatBuilder]

So in the context of a parking brake on an explorer, what do you recommend?

 

[96eb96]

So in the context of a parking brake on an explorer, what do you recommend?

I know Bendix has a 30/30/30 rule for any main pad or shoe. 30 moderate stops from 30 mph 30 seconds apart. I wouldn't do this for the E brake.


Just be aware of this "troubleshooting tip" straight from the ford service manual - parking brake section. Take it very easy when you brake these in."several dynamic stops" can cause line wear.

Excessive Lining Wear
Brake drag.
CHECK the parking brake cables for binding condition. INSPECT for broken or missing springs.

Rough drum surface of the rear disc brake rotor.
SMOOTH the drum portion of the rear disc brake rotor with emery paper or REPLACE the rear disc brake rotor, if it is badly scored.

Several dynamic stops.
INSPECT the brake shoe and lining. REPLACE as necessary

Reasons for not applying:

Parking Brake Does Not Apply
Clearance prevents complete brake application.
CHECK the brake cable for slack. GO to Pinpoint Test A .

Grease soaked linings.
REPAIR the source of the leak and INSTALL new linings. REFER to the procedure in this section.

Linkage friction.
CHECK for linkage binding and misalignment. LUBRICATE all the friction points.

Linings.
REPLACE the parking brake shoe and lining (2N712). REFER to the procedure in this section. CHECK the rear disc brake rotor (2C026) for scoring and REPLACE as necessary. REFER to Section 206-04 .

 

[CDW6212R]

For parking brake linings you really need to just maintain their quality and finish, and actually use them for a parking brake on inclines. I wouldn't worry about breaking them in like normal pads/linings, they don't work well for any stopping needs. Rely on them for a parking brake, and for an inspection them being as new as possible is best. Regards,

 

[V8BoatBuilder]

Well my problem is solved, I have a valid sticker.

This was the first time I took the truck into a shop to be worked on since I bought her

Thanks to everyone who helped on this thread, now it's on to more pressing issues, like wheeling this weekend and a leaking water pump.

 

[MountaineerGreen]

Did you ask the shop what they did to make it work?

 

[V8BoatBuilder]

Did you ask the shop what they did to make it work?

Mechanic had left for the day when I picked her up, but the receipt just says "adjustment & equalization"

 

[DeRocha]

Mechanic had left for the day when I picked her up, but the receipt just says "adjustment & equalization"

I just hate busting my @$$ trying to fix something for several weeks only to bring it to a shop and have them fix it quickly..

 

[96eb96]

An engineering afterthought

Mechanic had left for the day when I picked her up, but the receipt just says "adjustment & equalization"

Here is one step we may all have been taken for granted.....And proper adjustment solved all my issues. Think of the extreme force you need to hold these rigs in place. Every fraction of a mm that the shoe moves when out of adjustment is probably a loss of thousands of lbs. The 6+" of foot pedal travel is supposed to move the pad not more than 1/100" of an inch! The rest of the movement is all transfered to compressive stress on the shoes and drum.

Step 8 in the maunal:
Use a Brake Adjusting Gauge to set the rear brake shoe and lining diameter to 0.0508 mm(sic .508mm) (0.020 in) less than the inside diameter of the drum portion of the rear disc brake rotor.

Each shoe has to sit a maximum 1/4 of a mm from the drum. That is just about 2 dust mites or less than a pixel on your monitor

(wikipedia)
# 100 micrometre is equal to

* 1/10th of a millimetre,
* 0.00394 inches.

# 125 µm — length of a dust mite
# 200 µm — typical length of Paramecium caudatum, a ciliate protist
# 340 µm — length of a single pixel on a 17" monitor with a resolution of 1024*768.
# 100-400 µm — length of Demodex mites living in human hair follicles
# 500 µm — MEMS micro-engine
# 500 µm — diameter of a human ovum
# 500 µm — typical length of Amoeba proteus, an amoeboid protist


Hopefully this thread will help someone else in the future.

 

[V8BoatBuilder]

I just hate busting my @$$ trying to fix something for several weeks only to bring it to a shop and have them fix it quickly..

Ditto. The guys seemed nice and honest. I just wish I had been able to make that "adjustment" on my own.

 

[CDW6212R]

The adjustment is a short process. Install the rotor and feel the resistance to installing it, and spinning the rotor. If the rotor doesn't go on, you obviously loosen the brakes. If it does not drag over the pads at all when you install the rotor, tighten the adjustment. When it does drag a little putting on the rotor, the rotor should spin easily, but not completely free of brake lining friction. You want a small amount of resistance when turning the rotor, not a ton, but a little. The interference will be gone within 100 feet of driving if it isn't way too tight. Then the linings will be as close as possible to the rotor.

 

[V8BoatBuilder]

So it's two years later of course, my e-brake doesn't work. Well, it never did, even after I took it too the shop. They just gave it the old college try followed by the old New Jersey "awww screw it" and slapped a sticker on.

Well now I'm lifted, so I NEED to go through state and can't go to a private garage and it HAS to work.

Here are some things I found:
1) RH (passenger) rear Raybestos cable had partially seized. It works when out of the vehicle, but bent, it's jammed. I replaced it with a Dorman Cable from Rock Auto which seems much, much better. I didn't need to dremel the eyelet, for starters.

2) Shoes. I used Autozone shoes last time, so I swapped them out for new ones using the Warranty. Still no good. So I installed Wagner shoes, which LOOK much better, and what do you know, hold much better, too.

3) Rotors. Didn't replace this go around, but I sanded the heck out of them with 150 grit paper. Look at the photos below (next post) of the new Autozone shoes, which didn't have more than 1 mile on them. They seem "glazed." Thoughts?

 

[CDW6212R]

Aaron, are you adjusting the shoes tight, so the rotor drags slightly the first time you put it on? How is the hardware, does it all seem clean and not corroded? I bought all new parts for my Mountaineer when I first got it in 2003. Being up North it was all bad, the hardware I got at Autozone I think.

The cables are the only thing I haven't ever had to replace, I think using them often keeps them working.

 

[V8BoatBuilder]

Don,

I'm wondering if the shoes were too tight, hence the glazing.

For "take 2" with my Rock Auto parts, I'm using all new springs, and I wire-brushed the adjusters clean and reassembled with lube. I also sanded the rotors with 150 grit paper, relatively shiny. Right now, the brake is the best its been in years, but could be better for the inspection. I do have 4.56 gears, so there is more torque to the wheels, but that's no excuse for the state of NJ.

 

[V8BoatBuilder]

Here's what I'm talking about. This is the Autozone shoe with less than 1 mile on it. As I stare at this photo, it looks like the shoes were not (are still not?) contacting the drums as they should. Perhaps new drums /rotors are in order??? I'm confused at the "wear pattern" displayed here.

 

[V8BoatBuilder]

Rotors, tough to see the inside where it counts.

 

[CDW6212R]

Those rotors don't look too bad, mine were very pitted and it ate the old pads/linings.

I did forget to mention, when you install the parking brake linings, apply that parking brake pedal lightly at low speeds. That rotors should be dragging just slightly(when installed) to be sure the linings are close, that gives you more pedal when you apply them. It gives you more holding power on a hill.

Remember that they don't adjust automatically like old drum brakes. They wear down and you notice it by the pedal moving farther down each time you set it. But set them up tight when fresh, and lightly apply that pedal to seat them. It will not take much to knock off a little of the lining, which then provides enough clearance.

I think that lining you pictured is so so. It is a little slick, but it isn't touching fully either. I think just applying the pedal at slow speeds will quickly smooth it out. I agree that if they are set up too tight the would keep touching at all speeds, which would be more likely to glaze them. The material should be soft, and easy to rough sand it and make it good.

So yes w don't want them to touch when the pedal isn't pressed. We do want them as smooth and close fitting as possible. Apply them at very low speeds moderately when new. They don't provide much stopping power, so I worry more about making them work for parking. Does that help or make sense?

 

[V8BoatBuilder]

Don,

Thanks for the info. The drum surface looked pretty good after the light sanding, no ridges, pits or gouges. The rotors are only 2 years/6,000 miles old!!

I'll try applying them at slow speed to break them in gently by putting the axle on stands and running the truck in place.