Brake upgrades

malibu795

malibu795

misspeelleerr
Apr 28, 2007
8,317
624
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in the buckeye state
Chevy1925 said:
Just don’t wanna go too big or you get a rock hard pedal and not much stopping power
Click to expand...

issues I have had, on older vehicles... lines where tooo small... the 800/900 truck run 1/4-6mm lines everywhere vs 3/16 line on the older stuff... swap everything to 1/4" problem fixed or minimized.

and why they neck 1/4" line to 1/8" line for flex hose is still beyond me :confused:

between HYD fluid, lml hydro, fresh calipers, pads, rotors I have no problem slowing down a 6000lb suburban, plan on swapping rubber hose to SS braided lines soon

I put a 1 5/16"(33mm) MC on my G body, I have no problem stopping or hard pedal, and I havent swapped to hydro from vacuum boost yet.... everyone want to run 7/8"-1 1/8" bores for that application..
 
Chevy1925

Chevy1925

don't know sh!t about IFS
Staff member
Oct 21, 2009
21,761
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Phoenix Az
malibu795 said:
issues I have had, on older vehicles... lines where tooo small... the 800/900 truck run 1/4-6mm lines everywhere vs 3/16 line on the older stuff... swap everything to 1/4" problem fixed or minimized.

and why they neck 1/4" line to 1/8" line for flex hose is still beyond me :confused:

between HYD fluid, lml hydro, fresh calipers, pads, rotors I have no problem slowing down a 6000lb suburban, plan on swapping rubber hose to SS braided lines soon

I put a 1 5/16"(33mm) MC on my G body, I have no problem stopping or hard pedal, and I havent swapped to hydro from vacuum boost yet.... everyone want to run 7/8"-1 1/8" bores for that application..
Click to expand...

on the 455, the brake pistons are larger though, arent they? hence the larger master? when you run a smaller master, it takes less pressure from you but a longer throw to get the vehicle to stop. too big and it takes a whole lot more pressure on the peddle but a shorter throw to get the truck to stop.

with a booster, you gain more wiggle room because the booster can make up for the larger master. same reason if you disconnect the booster and try to stop, it takes a shit ton of leg power to get the car to stop. the master is over sized for a non booster application BUT you gain much more fluid/pressure passing through to the calipers so the brakes grab harder/better when the booster is hooked up.

gmduramax said:
But how much is too much. With an upgraded power steering pump it might work. I do agree we have to balance stopping power with pedal effort.
Click to expand...

its harder to find that "too much" with the booster on there. a 37mm stock master to a 40mm is a decent sized jump. i would bet you feel the difference in the peddle assuming everything else stayed the same. the LML booster is most likely bigger (hence why everyone says the feel the peddle moves easier/takes less pressure to push) and would make up for the larger master but if an LML is a 38mm, thats a small increase.

in a non booster situation, the change doesnt take much. 3/4" master and 2 piston brakes at each rear brake on my sand car made for a very hard peddle that took alot of effort to get the brakes to lock up. i changed everything over to wilwood 4 piston calipers and a 7/8" master and its like having power brakes now. easy push will get the car stopping. if i ever added front brakes, the 7/8 master will not push enough fluid to make those work as well so i will either have to up to a 1 1/16" or run a second master with a balance bar. sizing is a big thing in the sand car and off road world as no one runs boosters. same goes for the clutch master and slave.

there are calculators out there that will give you pressure and throw for peddles but you need to know arm leverage/length, hose size, master size, caliper piston size, and so on.

id like to know how the GMT455 master does though. i would think it would be border line between too big or working very well. might be a good upgrade for the larger wheel/tire crowd without needing to change calipers/rotors. just have to make sure the booster and pump are healthy.
 
malibu795

malibu795

misspeelleerr
Apr 28, 2007
8,317
624
113
42
in the buckeye state
gmduramax said:
Do you know the fitting size? I would be willing to try it.
Click to expand...

1/2-20
9/16-18
Inverted fkare

James
It should have been bigger for dual 2.6" piston all around ran 1/4" hard line

I Know bugger mc moves the application up the pedal travel.. for m G-body it went from second/bottom half to top half..
Gnt455 1.568" or 39.3mm
 
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Chevy1925

Chevy1925

don't know sh!t about IFS
Staff member
Oct 21, 2009
21,761
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Phoenix Az
malibu795 said:
1/2-20
9/16-18

James
It should have been bigger for dual 2.6" piston all around ran 1/4" hard line

I Know bugger mc moves the application up the pedal travel.. for m G-body it went from second/bottom half to top half..
Gnt455 1.568" or 39.3mm
Click to expand...

das mo betta then :D :woott:
 
malibu795

malibu795

misspeelleerr
Apr 28, 2007
8,317
624
113
42
in the buckeye state
I'm also working with 20-22" of vacuum in a dual 8" diaphragm booster on the G-body... Obviously that would make for easier pedal than Engine pulling half that vacuum

Been personal preference that I can do an emergency stop with less than 1.5" of brake pedal travel.. most have upwards of 6" of pedal travel...

I have no ideas of how big the MC on my FL60 is...piston are dual f/r 2.6/2.8...hard stop is .75" of travel roughly..
 
gmduramax

gmduramax

Shits broke
Jun 12, 2008
4,082
252
83
Nor cal
Chevy1925 said:
on the 455, the brake pistons are larger though, arent they? hence the larger master? when you run a smaller master, it takes less pressure from you but a longer throw to get the vehicle to stop. too big and it takes a whole lot more pressure on the peddle but a shorter throw to get the truck to stop.

with a booster, you gain more wiggle room because the booster can make up for the larger master. same reason if you disconnect the booster and try to stop, it takes a shit ton of leg power to get the car to stop. the master is over sized for a non booster application BUT you gain much more fluid/pressure passing through to the calipers so the brakes grab harder/better when the booster is hooked up.



its harder to find that "too much" with the booster on there. a 37mm stock master to a 40mm is a decent sized jump. i would bet you feel the difference in the peddle assuming everything else stayed the same. the LML booster is most likely bigger (hence why everyone says the feel the peddle moves easier/takes less pressure to push) and would make up for the larger master but if an LML is a 38mm, thats a small increase.

in a non booster situation, the change doesnt take much. 3/4" master and 2 piston brakes at each rear brake on my sand car made for a very hard peddle that took alot of effort to get the brakes to lock up. i changed everything over to wilwood 4 piston calipers and a 7/8" master and its like having power brakes now. easy push will get the car stopping. if i ever added front brakes, the 7/8 master will not push enough fluid to make those work as well so i will either have to up to a 1 1/16" or run a second master with a balance bar. sizing is a big thing in the sand car and off road world as no one runs boosters. same goes for the clutch master and slave.

there are calculators out there that will give you pressure and throw for peddles but you need to know arm leverage/length, hose size, master size, caliper piston size, and so on.

id like to know how the GMT455 master does though. i would think it would be border line between too big or working very well. might be a good upgrade for the larger wheel/tire crowd without needing to change calipers/rotors. just have to make sure the booster and pump are healthy.
Click to expand...

Even from going 37mm to 38mm it definitely takes more pedal effort to stop the truck. Probably not enough for anyone to notice but I like having a solid pedal and not having to move it as far to get the truck into abs. I do think the 40mm will be too big, but we’ll see I might like it.
 
Chevy1925

Chevy1925

don't know sh!t about IFS
Staff member
Oct 21, 2009
21,761
5,933
113
Phoenix Az
gmduramax said:
Even from going 37mm to 38mm it definitely takes more pedal effort to stop the truck. Probably not enough for anyone to notice but I like having a solid pedal and not having to move it as far to get the truck into abs. I do think the 40mm will be too big, but we’ll see I might like it.
Click to expand...

let me know cause i push right through my damn hydro boost when i panic stop. might as well get more master in there too if i change it.
 
Chevy1925

Chevy1925

don't know sh!t about IFS
Staff member
Oct 21, 2009
21,761
5,933
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Phoenix Az
gmduramax said:
Should with the SSBC three piston calipers.
Click to expand...

might look at those. really i need to fix the trailer brakes. dumb asses at Lipert used the ez grease hubs to pack the hubs full until it came out the seal at the back and screwed my brakes... just something else to fix... :roflmao:
 
gmc502

gmc502

Member
Jan 16, 2011
468
13
18
made it thru a snow storm yesterday,brakes worked great while plowing,,even w/ worn out pads and rotors,good pedal feel.
 
gmduramax

gmduramax

Shits broke
Jun 12, 2008
4,082
252
83
Nor cal
Got new rotors for the rear. Ac delco the slotted ones. Decided to try out ebc yellow pads. Other than theyre yellow and stick out like a sore thumb, I like them so far. Initial bite is much better than the hawk super duty. Modulation is impressive. When it dries up I’m going to see if I can over heat them.
 
gmc502

gmc502

Member
Jan 16, 2011
468
13
18
gmduramax said:
Got new rotors for the rear. Ac delco the slotted ones. Decided to try out ebc yellow pads. Other than theyre yellow and stick out like a sore thumb, I like them so far. Initial bite is much better than the hawk super duty. Modulation is impressive. When it dries up I’m going to see if I can over heat them.
Click to expand...

have a p/n for the ebc's?thanks
 
gmduramax

gmduramax

Shits broke
Jun 12, 2008
4,082
252
83
Nor cal
Front DP41305R
Rear DP41304R

Finally did a panic stop. The ground was still wet, but as soon as I touched the pedal the ABS was active. Much faster initial bite as it never did that before. I can’t wait till it’s dry to try them.
 
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