Brake upgrade questions

[retorq]

The way I am reading this is the final stopping distance is lifted, with 2 piston calipers, and hydroboost. It looks to me like the stopping distance was better my almost 40 feet.

I would have liked to see what the stock stopping would have been with the 2 piston and hydroboost.

Yeah I see that it took 40 feet of, which is awesome but it's still not doing what it did stock ... wonder what it would do on a lowered truck.

Retorq - where did you grab that data from? Which member posted it?

The link Adam posted, 2nd to last page in the article.

 

[sparg93]

Where did the 600 psi figure come from?

Just used it as an example b/c I can't figure out why LESS pressure on the pad would result in stopping faster...unless the individual used two different pad materials.

Wouldn't 2 54 mm pistons effectively reduce the pressure more than the bigger than stock single 80mm piston? Maybe I'm not thinking about it the right way.

Keeping everything else the same, I think the x2 54mm pistons would reduce the pressure on the brake pad more then x1 80mm piston.

My thoughts - the pedal is essentially the "lever" for the master cylinder, or the "pump".

As an example, if you push the lever 3", the pump is going to push "x" amount of hydraulic fluid to the caliper. Whether there is one or multiple pistons, they are still voids in which the hydraulic fluid is going to go (the "voids" are the distance between the back of the piston and caliper housing).

If you take an extreme example of x6 54m pistons (300+ total mm), you are going to need a ton of hydraulic fluid to actuate all those pistons. As the pistons are moving forward to clamp on the rotor, fluid is filling the void...the large the void, the more fluid needed.

I'm assuming the PSI rating was established by putting some form of sensor between the brake pad and the rotor...therefore the pad doesn't know there are x2 pistons, just 108mm of a void that was filled with hydraulic fluid.

I'm not sure if that is the best way to view it b/c i'm not a fluids guy...but that's my thoughts

I don't consider replacing 2 rusty/used/abused calipers that are 12-15 years old a waste of money for what they cost....mine were under $75....don't know what you paid. The stainless lines cost me more than that and did absolutely nothing.

I only meant replacing 1/2t calipers with 3/4t calipers was a waste of money w/o hydroboosting the brakes. If someone is NOT going to hydro, I would serioulsy recommend replacing 1/2t calipers with 1/2t calipers...by going to the larger 3/4t calipers, you may increase your stopping distance over the 1/2t calipers you originally were using.

Have you tried pulling the ABS fuse yet?

Not yet, but I will try it this weekend!! The more I thought about it, I don't think pulling the fuse is going to be the fix for me. When I smash on the brakes, the ABS isn't even kicking in until the very end of the stop... it's literally like the calipers are not exerting enough pressure on the rotors to slow them down to the point the ABS kicks in.

 

[steamroller]

Just used it as an example b/c I can't figure out why LESS pressure on the pad would result in stopping faster...unless the individual used two different pad materials.

My guess is the larger piston is applying (even if it's less) pressure over a larger area of the brake pad backing plate. Too many variables and everyones vehicles are set up different, plus what may be good braking for one person may be terrible for another. Try driving an old car or truck with manual brakes and drums on all 4 corners...it will make you appreciate what you've got

Keeping everything else the same, I think the x2 54mm pistons would reduce the pressure on the brake pad more then x1 80mm piston.

I'm assuming the PSI rating was established by putting some form of sensor between the brake pad and the rotor...therefore the pad doesn't know there are x2 pistons, just 108mm of a void that was filled with hydraulic fluid.

I'm not sure if that is the best way to view it b/c i'm not a fluids guy...but that's my thoughts

Haha I'm far from an expert, but at least there is some tech being posted without no one getting hurt feelings lol. That was what I was getting at-the stockers are 75mm and the 3/4 tons are 80mm. So 5mm or 7/32" or so. I would think the pressure loss would be minimal but you gain a somewhat larger apply area over the pad. Everything I could find when looking at this a couple years ago shows the Limiteds and the police package SUV's use the same master cylinder even though the calipers are larger.

In the article they switched to SSBC's overpriced master cylinder and they said there was no pressure or volume difference, even though the piston in there was larger. It just actuated the brakes faster. From what I've been able to find out it's a NBS master with an adapter fitting and looks like they used a pressure gauge screwed into the bleeder port for the testing.

Not yet, but I will try it this weekend!! The more I thought about it, I don't think pulling the fuse is going to be the fix for me. When I smash on the brakes, the ABS isn't even kicking in until the very end of the stop... it's literally like the calipers are not exerting enough pressure on the rotors to slow them down to the point the ABS kicks in.

Hell at least try it out. IIRC it's the only 60 amp fuse in the underhood box. It's too bad no more info was posted in another thread about using the steering knuckles from a NBS so we could adapt the big dual piston calipers...I've even got a new set of the calipers that could be used for mockup.

 

[AtomicHoe094]

you guys reallllly know how to lose me!! shit haha

 

[Monstar_est87]

O shit... Damn u guys have been busy... But yea im wit every1 on the hydroboost... I shoulda listened 2 atomic... He posted part #s on page 2 4 every1... And sparg, I cant wait 2 see ur write-up on the hydroboost setup... Ill b sure 2 reference it wen im doing mine...

 

[sparg93]

My guess is the larger piston is applying (even if it's less) pressure over a larger area of the brake pad backing plate. Too many variables and everyones vehicles are set up different, plus what may be good braking for one person may be terrible for another. Try driving an old car or truck with manual brakes and drums on all 4 corners...it will make you appreciate what you've got

I can only imagine...i was pretty close to buying a '69 Camaro with a 454 yrs ago...my dad joked about how I planned to slow the damn thing down!

Everything I could find when looking at this a couple years ago shows the Limiteds and the police package SUV's use the same master cylinder even though the calipers are larger.

I found a parts catalog through AC Delco that had a hydroboost system for a '99 Police Package 5.7L and as you mentioned above, the 3/4t calipers....it made me believe that it (hydro) was at the very least an option on the police package for that yr...any ideas?

In the article they switched to SSBC's overpriced master cylinder and they said there was no pressure or volume difference, even though the piston in there was larger. It just actuated the brakes faster. From what I've been able to find out it's a NBS master with an adapter fitting and looks like they used a pressure gauge screwed into the bleeder port for the testing.

Hmm...if there is no pressure difference with the SSBC's master cyclinder, then the vacuum system seems to be the most important part of the equation. When you switch from vacuum to hydro, it instantly generates more pressure. My head is turning with ideas, do you mind sending me the link to the article?

Hell at least try it out. IIRC it's the only 60 amp fuse in the underhood box.

Absolutely - I like using my hoe to confirm/deny ideas so hopefully one day I can put together an article that has some real numbers to back it up!

It's too bad no more info was posted in another thread about using the steering knuckles from a NBS so we could adapt the big dual piston calipers...I've even got a new set of the calipers that could be used for mockup.

My wallet can not handle anymore ideas...but damnit, now you have me thinking! I can honestly say, if this hydraboost system significantly drops my braking distance, I'm moving on to some other component of the truck's hardware to mess with!!

After I finish the hydro setup I promise to post all of the stopping distances.

As a side note: I even put the tires/rims back on from when i first tested my stock 1/2t calipers...to keep everything constant. The second I'm done with installing the hydra setup and testing, the new rims and tires are coming on!! (this yr i switched to winter tires with all the snow in the area for a few months)

 

[steamroller]

if you want more info check out this thread
http://www.truckinweb.com/tech/0807tr_ssbc_truck_force_10_brake_kit/index.html

do you mind sending me the link to the article?

Quoted it for you. Another thing they did was completely eliminate the ABS all together, but didn't recomend it for liability purposes I assume. I could see where it useful in certain weather conditions but like the article says I believe it has alot to do with the pedal feel they have........Dad's C10 has the same size calipers on his 85 C10 and the brakes work pretty good on it, almost seem too touchy the few times I've driven it. It's much lighter than mine too though so that could play a factor in it.

I did some cross referencing when looking at this stuff using VIN's from Ebay and punching them in on Compnine's website.
http://www.compnine.com/vid.php

There Tahoes/Yukons stop at 1996 I think if you're looking for exploded diagrams and part #'s....The OBS Escalade/Denalis are listed under the 2000 model year IIRC. As far as I know there were only 3 size master cylinders used 1 1/8" for JB5, 1 1/4" for JB6 and the Hydroboost master-don't remember the size on it.

Keep us updated on the swap, I've put off any other brake upgrades until I find a front axle for the SAS......Otherwise I would be looking harder at trying to make the NBS knuckles/rotors/brakes work on mine along with adding Hydroboost

 

[sparg93]

Atomic - you posted part numbers for the hydro setup.

I've found two hoses (power steering to hydro) that are required, but I can't tell if I need any extra brackets, fittings, etc (other then the plate on the firewall).

If you look at Whipple's setup, he purchased a $200 hose kit from hydratech and it came with a bunch of fittings and other parts...any idea what they are for??

 

[AtomicHoe094]

those fittings are just for the hoses that hydratech made. You can make your own lines instead of buying new ones..
check out Anplumbing.com
Theyll have everything for you..

Brackets, im sure you dont need anything.
Those 2 silver things in the package with the circles. look like they are just hose clampers. Kinda like spark plug wire separator things.. You know what i mean.. Just to make it more "clean" install and not having zip ties or something..

 

[sparg93]

ok, that's what I was thinking.

AC Delco on those two hoses are like $30/ea...i can't figure out why that setup (Hydratech) is $200 for two hoses and some fittings that I can't see the benefit of!!