My Rear Disc swap from drums observations

[Urambo Tauro]

I don't want to interrupt the flow of discussion either, but 1BigCarrot touched on an interesting point. While it might not seem all that important whether we call it a parking brake or an emergency brake, I think the terminology has a real effect on how it ends up getting used.

Thinking of it as a parking brake makes you more likely to use it regularly, keeping stress off of the parking pawl and exercising the cables to keep them from seizing up.

"Emergency brake" on the other hand gives the wrong impression and discourages the good habit of using it regularly. True, these brakes can be somewhat useful in an emergency, but only if they're actually working. And for those of us in the rust belt, cables are very likely to break if they are never used outside of emergencies. What's the point if it doesn't work the one time you need it to work?

It's for all of these reasons, as well as the aforementioned concerns about drum adjustment that I prefer to call it parking brake.

 

[Urambo Tauro]

And I'll be the first to admit that I don't use my parking brake enough (gotta work on that more). My driveway is almost level (just enough of a slope to direct rainwater away), and I hardly ever find myself parking on an incline. FWIW, that's well within the parking pawl's ability to keep the vehicle from rolling away.

But I still make a point of retaining parking brake functionality anyway. Because I can't guarantee that I'm never going to find myself having to park in somebody else's steep driveway or something.

It should also be noted that not every car/truck needs to have a parking brake. If you're building a dedicated racecar, it's probably only ever going to be parked in a nice level garage or strapped down to a flatbed trailer. Might as well shed a couple pounds of parking brake components in that case. It's a minimal amount, but every ounce counts, as they say...

But for road-going vehicles, there are also inspections to consider. Many states require a functioning parking brake to pass inspection. Michigan doesn't have such inspections (at least not for non-commercial vehicles). But we still have a law on the books requiring road-going vehicles to have "2 separate means of applying the brakes" (which actually kinda supports the notion of calling it an "emergency brake" but I still prefer to think of it as a parking brake for all the reasons listed earlier).

 

[John Cunningham]

That is the difference between what we call "steerers and drivers". For those of us who have driven professionally, use the brakes to hold the vehicle not the gearbox no matter if it's 40T or 2T. Gearbox is not designed for the way you are using it - period. Just because you have been doing something for years does not make it correct.


A quick google and . . . . you might just find you are in the minority.

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As my Grandfather once said "never try to understand an idiot son, you'll waste your time"

 

[John Cunningham]

That is a interesting opinion from some writer blooger...but not a hot rod car buff mechanic I have ever road with have set the e/parking brake when they park..obviously its a personal choice a d nothing wrong with it for sure.

So this morning I asked several mechanics if thet set the parking brake everytime they park their truck..most replied "for what"

 

[R422b]

Not to interrupt the argument but.....
Did you ever check the line pressure? Just curious what the numbers were.

 

[Frank Enstein]

Lol.. So you replaced malfunctIoning brakes and this confirms your belief that drum brakes are trash.

I agree. The shoes dig a groove in the backing plates and get stuck leading to a high "Wooden" pedal. My 92 K3500 DRW did that too. I ground the grooves smooth, put a LITTLE moly on the rub pads and made sure my calipers could move smoothly. That truck will throw you out on the hood with 1 toe pressure.

That being said I prefer the feel of rear disc brakes. It is more linear. But the grooves and calipers that don't float are a hidden brake problem nobody seems to know about.

 

[Frank Enstein]

There is a reason Class 8 trucks have drums. They Work!

 

[Frank Enstein]

I added some rear discs to a 66 nova about 25 years ago and left the prop valve wide open. Any adjustment I made did not make much difference so I left it wide open and drove that car for years like that.

That is because the rear tires had 3 times the traction that the fronts do.

The only thing a proportioning valve does is prevent premature rear brake lockup in a panic stop.

Without one when the kid runs in front of you chasing a ball and you have both feet on the brake pedal and are bending the steering wheel back the rear brakes lock and you hit the kid with the back bumper!

 

[frito-bandito]

There is a reason Class 8 trucks have drums. They Work!

So do disc brakes, that’s why a lot of newer Class 8 trucks have those now

 

[Gibson]

That is because the rear tires had 3 times the traction that the fronts do.

The only thing a proportioning valve does is prevent premature rear brake lockup in a panic stop.

That's silly, anybody with more than a passing knowledge of vehicle dynamics knows that in a braking situation the vehicles weight shifts forward and causes the rear wheels to have less traction.
Even with the vehicle standing still that Nova still had less weight in the rear
That's why the front brakes do around 60>70% of the braking effort.
It's called a combination valve, it does more than one thing, it can help to lessen rear wheel lock-up, but it will not prevent it in many situations.
An anti-lock system is needed to stop wheel lock-up.