Rear Disc Brake Upgrade Update

[John Cunningham]

If anybody wants to go to this setup there was and is only one issue. The caliper bleeding is difficult because the kit I got the caliper bleeder is down around postion 10 oclock. You have to slide that caliper off the mount and get the bleeder up at 12 oclock.
I would find a kit that did that.
Also you have to be careful when buying the rotors. Some of the rotors have a small step that interferes with the caliper and some do not have the little step between the rotor hat and rotor.
Same part numbers with two different machining standards. Took me afternoon to figure that out and I told the guy that I bought the kit from that he had a problem.
I was able to go to autozone and open several boxs to find the rotor without the step. This will save you some greif.

 

[Jglew82]

Good info! What did you do, if anything, about the parking brake?

 

[John Cunningham]

Good info! What did you do, if anything, about the parking brake?

I could have purchased different calipers to have a parking brake.........but its an automatic so I chose to eliminate it because I never use them.
Some folks use them regularly and I cannot remember the last time I used a parking brake for anything, so it was not important for me personally, but the option is there if you need one.

 

[bugdewde]

If you ever saw the "Park" pawl thingy that you're relying on to keep your vehicle "parked" , you would use your parking brake everytime.

I've seen these fail multiple times in mostly high mileage vehicles, and one very low mileage fleet vehicle that rarely went more than a few hundred yards before being parked and then used again dozens of times a day. That pawl & teeth wear.
Everytime a shift from park into gear on a hill or slope increases that leverage and wear. I cringe when i hear a vehicle shift out of park on a slope and the pawl/tooth makes that familiar sound ...... You know what I'm talking about.

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Hate being that internet guy....., but not using a parking brake is very dangerous, not only to you but to your surroundings (people, cars, houses, trees, etc).
Just sayin' ...... Lol.

 

[John Cunningham]

If you ever saw the "Park" pawl thingy that you're relying on to keep your vehicle "parked" , you would use your parking brake everytime.

I've seen these fail multiple times in mostly high mileage vehicles, and one very low mileage fleet vehicle that rarely went more than a few hundred yards before being parked and then used again dozens of times a day. That pawl & teeth wear.
Everytime a shift from park into gear on a hill or slope increases that leverage and wear. I cringe when i hear a vehicle shift out of park on a slope and the pawl/tooth makes that familiar sound ...... You know what I'm talking about.

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Hate being that internet guy....., but not using a parking brake is very dangerous, not only to you but to your surroundings (people, cars, houses, trees, etc).
Just sayin' ...... Lol.

I will say this........I dont live in a state with hills.........none...Florida
I have not used a emergency brake in over 50 years of driving. Nobody I have ever rode with in my entire life puts the emergency brake on when they park. This must be something they must have taught millennials during high school drivers ed?
I have never seen it in my entire lifetime.
I have never had a transmission fail for not using one........never
Now I will say this..........If I were to ever live in San Francisco I would have one for parking on those streets!
Now its called the PARKING GEAR for a reason?
Otherwise why do all Auto manufacturers give us this so called PARK shown in the gear selector? Its called "P"... They should not include the gear in the transmission and only give us Neutral then we would all use the EMERGENCY BRAKE because it would be an emergency! I have never called this a PARKING BRAKE
So we have two different scenarios for this.
I prefer to use the PARKING GEAR when I park
You prefer to use the Emergency Brake when you park

A stroll thru a large parking lot to see how many people set the emergency brake when parking and I doubt I would see 1% of the those parking who would set their emergency brake.
Some new models are now using an power button for the Emergency Brake...which I suppose if you some anxiety over this then it would be good to use it.
But I doubt many people are standing on their emergency brake pedals when pulling into a parking lot.

I give you that San Francisco it would be a good idea....I have maybe parked on a hill a couple times in my life and used the what we all called the Emergency Brake, maybe a couple of times.
If you come to a COMPLETE stop before you select park you will NEVER have a fail....and I mean never. I have never broke the pawl ever in an automatic transmission. I have owned race cars with $7500 auto transmissions and have never broken a pawl. I have seen guys throw their transmissions in reverse at 150 MPH and not break anything except their ego and almost losing their race car. Talking to a few of my friends I asked them how many set their E brake when parking...none of them do except sometimes on a hill or they turn their tires into the curb even better.

Now go back to the 50's and you had a simple two speed transmission and yes they had a P on the selector. They also had a emergency brake that you would reach down and pull up with your arm and it would ratchet up thru some teeth...then you would turn it to get it to release and then on its own it would bang back to the dash....Nobody used them because of that and then the mechanical cables would rust and jamb it was over with, because if you did use it , it might not return and then you were in a real jamb.. I never seen my mom & dad at the time ever pull up on that lever and later never stepped down on the E brake pedal..People might say " Dont forget to set your "EMERGENCY BRAKE" when parking on a hill! "
So for now we can even call it the Auxiliary brake if you want to...
But I will never stand on that left pedal in order to park especially on flat land, and none of my friends do either.

signed: A VERY DANGEROUS GUY

 

[bugdewde]

signed: A VERY DANGEROUS GUY

Well, I doubt you are very dangerous down there in FLA. LOL. Unless you're in Howie & the Hills, or Zepher Hills. All 110 feet above sea level. I have several folks down there (Sanibel Is, Lakeland & Winter Park).

While I would have to agree with you on the people's infrequent use of the "Parking Brake", it is just something that is taught up here (or used to be).

I also have had several '79-'81 Trans Ams over the years with WS6 4 wheel disc brakes. Those rear calipers (also Caddy Sevilles) will seize up and not work at all if the "Parking Brake" isn't routinely applied. It's the bane of most of these old car's braking issues.

You would crap if you saw the hills I have to climb just to get to my houses & the hills where I grew up.
400 feet of elevation change (730' at lake & 1100' at top of subdivision) in just a few blocks (3 tiers).

Current house has a subdivision access road that is too steep for the county to annex. It's relegated to being a "Private Drive" maintained by the current land owners.


Those parking pawls get a very abusive workout up here if the "Parking Brake" isn't used. Lol.

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[bugdewde]

Hell, just my front yard has more elevation change than the whole state of Florida.

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This is called a "flat spot" where I live.... a good place to stop & rest, get out & stretch your legs.

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[letitsnow]

Haven't we heard this argument, maybe like 100 times already?

 

[Gibson]

Haven't we heard this argument, maybe like 100 times already?

Yeah we have,, and I've taken flack for suggesting that people not completely rely upon a pawl in the trans,,.
However, one makes a choice, and takes ones chances with their own decision,, but, their are states where a parking brake is required to pass a vehicle inspection.
My old model squarebody, a '66 1 ton panel, had a great set-up. It used a drum behind the trans, that had a friction band wrapped around it, so its effort was multiplied thru the diff gearing.
With 5:13 gears in the rear, that brake would really hold good.

 

[bugdewde]

Haven't we heard this argument, maybe like 100 times already?

My apologies ….. not wanting to hi-jack the thread, just indicating that were I to do this upgrade, a "Parking Brake" would be a necessity (where I live) …..

As I originally stated in my original post about the pawl: …. " I hate being THAT internet guy " …. because of the ensuing point and counter point that ALWAYS seem to follow.

Where I'm at, …… without the PROPER use of the "Parking Brake" (it can be engaged incorrectly) , it wears the pawl and teeth to the point it can release or move out of "Park" all by itself …. such is the case of the fleet vehicle that rolled down a hill, off a short retaining wall and wedged itself in a gully. Whole thing was caught on the plant's video surveillance ….. the thing is, the video clearly shows the driver (my co-worker) applying the "Parking Brake" …. which was practically ineffective upon the ensuing investigation.

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Once again, my apologies ….

If you come to a COMPLETE stop before you select park you will NEVER have a fail....and I mean never.

John, that is simply not true, as indicated by my co-worker's incident stated above.
……. It's not engaging "Park" that wears the pawl/teeth … it's pulling it "OUT" of park when bound up under a load. The two bound up metal pieces makes an all to familiar "pinging" sound when forced to release. Wearing, chipping and even breaking the pawl and/or teeth.

Even the Owner's Manual (my '95) has a section regarding the use of the "Parking Brake" while on a hill ….. It's to avoid "Torque Lock" , where the load of the vehicle can bind the pawl and keep it from releasing and prevents shifting out of Park because of the load on the pawl.
Manual states "you may need to have another vehicle push yours a little uphill to take some of the pressure from the transmission so you can pull the shift lever out of Park (P).


I'm not wanting to continue this on this thread (hi-jack) but I simply wanted to let John know there is a possibility of that pawl breaking or wearing, as it does happen …. I wasn't smart enough to see his location …. He's right, probably won't ever need it down there in flat land.

Once again, my apologies … for being THAT internet guy. Lol.....

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Back on topic, though.
I really like this idea of the rear disc upgrade …..
I've had really poor luck/results out of both of the GMT400 Suburbans I've owned. Both 14-bolt rears with HUGE drum brakes … that just seemed to never adjust themselves and always caused a lot of pedal travel.
John, thank you for all the info you've provided … I hope to have disc brakes on mine one day. I appreciate your efforts and knowledge on the subject.​