1 ton calipers?

[bpodskalny]

newer member here, ive been reading alot of threads here and this is byfar the best tahoe specific forum around. i am an ASE master mechanic, and work as a toyota technician. i am very well versed in auto tech, however its all involving yotas.

the wifes truck is a 99 tahoe 1500 4dr 4wd. it has front disc and rear drum brakes, and the kelsey hayes anti braking system (not a typo)

brakes on my tahoe suck, and its esepecially apparent because i myself have a 2wd 06 silverado as a daily driver. im not talking about towing, i mean just out running errands. brakes seem to lag, then grab suddenly. but only at certain times. rear brakes have been adjusted, and brake fluid has been changed with no effect.

i got to thinking. why not upgrade both with calipers from a higher rated truck/van?

i searched the forum and elsewhere, and wasnt able to find a the info i needed. i did find a thread stating that it is possible to use 8500gvw 3/4 ton calipers

ive found many overlaps in GMs caliper usage. for example, most 1500 series trucks/suvs use the same calipers. even 2500 trucks use them in many common instances. however...

99 police package tahoe calipers =
99 3500 single rear wheel (non-dually) =
99 2500 suburban 8600 GVW.

so these are the larger ones im looking for.

The 1500 7700gvw caliper cups have a 2.95 inch bore (75mm) and the 2500 8800gvw had a 3.1 (79mm) inch bore.

they have the same size brake hose inlet, and as far as i can tell they are direct boltons.

however! if my knowledge of hydraulics serves me right, a larger diameter piston cup will exert more force at the expense of more pedal travel. and im having a much harder time finding the right stats about front brake rotor, mastercylinder, and rear brake cylinder specs/swap info.

has anyone done/seen this performed? any helpful fitament info?

 

[96ProCompTahoe]

i'd like to know this as well. be another nice upgrade.

 

[SunlitComet]

Wouldn't performance rotors and pads be more cost effective for you and less hassle to change out? I would think if you change the caliper size your master cylinder and ABS effectiveness would change.

 

[96ProCompTahoe]

welll... abs wouldn't change anything on mine. i have read that the 3/4 ton calipers are a direct swap, basically the piston is a little bigger but still works with the master. parts are cheap as well.

 

[bai78]

Would the 1 tons have hydroboost versus the 1/2 tons?

 

[99Yuk]

I personally have recently done the 3/4ton caliper upgrade.
My shop was worried too about brake pedal travel due to the bigger pistons.

Due to an ordering error, I ended up with 3/4ton Hawk performance ceramic pads.
But for a three week period until the 3/4ton pads were ground down to fit, I was running a cheapo set of 1/2ton pads.

While running the cheap pads, my pedal sucked sh*t, it was very soft. After changing to the Hawk pads it feels good.. Hard. Not quite to the top as my wife's Jimmy, but good enough that I feel confident about braking again.

My rears are fully adjusted, front rotors are new, etc.

Long story short. Don't worry about pedal travel using 3/4ton calipers. It's the pads that make a difference. Can't say enough good things about the mod.
See this thread...

Now a 1ton caliper...would that fit?

 

[bpodskalny]

so your saying that you have swapped on the larger piston calipers, and the extra brake pedal travel wasnt noticable?

 

[99Yuk]

so your saying that you have swapped on the larger piston calipers, and the extra brake pedal travel wasnt noticable?

It's a yes and no answer.
I did the rotors, cheap pads and calipers on the same day.

The Hawks pads are 1/8" thicker each than cheapo pads for a total of 1/4" per side thicker than normal pads.

So with cheap new pads, I didn't like the pedal travel, sunk to far down for my tastes, worse than when I started. So I had the shop bleed them three times, still no dice. But with the thicker pads, I do like the pedal travel - firmed it right up closer to the top, and braking is solid with no fade.

I don't think it's the bigger caliper piston making the difference, I think it's the pads.
Or put another way, if the bigger piston is a problem, then the thicker Hawks pads offset the difference and then some.

Ergo, I wouldn't hesitate to recommend the bigger caliper with some new Hawks pads, on any new rotor set. Not so much with thinner new pads.

Why I can't directly answer your question is because I changed my pads and callipers at the same time. The ****** brakes may have been the bigger piston, or it may have been thinner new pads. When I realized the Hawks wouldn't fit without grinding, I ordered the cheapest set of pads they had to tide me over. They may have been thinner than OEM, I don't know. So who can say why it was bad.
But I do like it now!

Hope that helps.

 

[bpodskalny]

Wouldn't performance rotors and pads be more cost effective for you and less hassle to change out? I would think if you change the caliper size your master cylinder and ABS effectiveness would change.

calipers for this truck are CHEAP even getting the bigger ones. hawk pads cost more than a set of 8800 gvw calipers.

imo new rotors will give me the least bang for my buck. i have genuine gm rotors on there now, and properly surfaced with properly seated pads they will work just as well except in the most extreme wet situations.

hawk pads are on the way, i know the generic pads that were installed on the vehicle when i purchased it are my major problem. i usually prefer genuine oem pad material, but i am interested if these pads will do all they say.

 

[99Yuk]

calipers for this truck are CHEAP even getting the bigger ones. hawk pads cost more than a set of 8800 gvw calipers.

imo new rotors will give me the least bang for my buck. i have genuine gm rotors on there now, and properly surfaced with properly seated pads they will work just as well except in the most extreme wet situations.

+1
Me too. Upgraded calipers cost less than the hawks pads. 1/3 less.

After this experience, I also don't think that fancy rotors do anything for you.
Although I ended up with ATE Premium slotted, that's because they were on sale, and also cost less than the hawks pads.

hawk pads are on the way, i know the generic pads that were installed on the vehicle when i purchased it are my major problem. i usually prefer genuine oem pad material, but i am interested if these pads will do all they

Now, I'm really curious for someone to measure the thickness of the new Hawks pads vs new OEM pads?

What Hawk part # did you order?
Are you buying the bigger calipers?
How about SS lines? buying those as well? I bought some, but havn't installed them yet. Some guys can tell the difference, some can't. We'll see.

 

[sparg93]

Here are my thougths are the brake upgrades...definitely curious to hear what you guys think:

Pad Upgrade = Big benefit (Hawks seem to be the winner)
Slotted Rotors = OK Benefit (as long as not Chinese crap or cheapos, almost anything is ok)
Steel Lines = Little to no benefit (not sure if I buy the swelling rumor for a set of lines unless they are really old)

What is the benefit to the bigger piston on the larger calipers mentioned above? Is it simply a larger surface area "pushing" against the pad? Any idea on the true benefit?? (not trying to be difficult, I have no idea)

 

[96ProCompTahoe]

pad upgrade- great

but i do have to say i did see a difference with my SS Lines and a HUGE different with the Brembo Slotted Rotors.

 

[99Yuk]

Here are my thougths are the brake upgrades...definitely curious to hear what you guys think:
...
What is the benefit to the bigger piston on the larger calipers mentioned above? Is it simply a larger surface area "pushing" against the pad? Any idea on the true benefit?? (not trying to be difficult, I have no idea)

I'm no rocket scientist, but I think the theory goes like this.
force is the surface area * the pressure
more force on pads = better braking
An example would be 100psi pressure on 1 square inch of surface area = 100 units of force, lets call that the smaller piston. The bigger piston might be 100psi of force on 2 square inches of surface area = 200 units of force.

Now these numbers are clearly not valid for our brakes, but serve to illustrate the thoery behind the bigger calipers. If someone could take accurate measurments of the two surface areas and measure the pressure on the brake lines, we could potentially do the math and get real numbers.

 

[sparg93]

it certainly makes sense...but couldn't our smaller piston calipers exert a similiar force theoretically?

So maybe this is a better way to think about it...b/c at the end of the day we want to stop our rigs faster and a big part of that is how long the brake needs to travel in order to stop the damn thing.

If we push our brake pedal down 3" (just an example) will the smaller caliper exert the same force as the large caliper? Technically (someone correct me if i'm wrong) by pushing on the brake a hydraulic pump pushes fluid that pushes the piston within the caliper outward against the pad.

By pushing 3", are both the larger caliper and smaller caliper exerting the same force? My thought would be yes b/c the pump is exerting the same force on the liquid...but I have ZERO science to back up my idea...anyone much smarter than me that can chime in?

 

[SunlitComet]

+1
Me too. Upgraded calipers cost less than the hawks pads. 1/3 less.

After this experience, I also don't think that fancy rotors do anything for you.
Although I ended up with ATE Premium slotted, that's because they were on sale, and also cost less than the hawks pads.




Now, I'm really curious for someone to measure the thickness of the new Hawks pads vs new OEM pads?

What Hawk part # did you order?
Are you buying the bigger calipers?
How about SS lines? buying those as well? I bought some, but havn't installed them yet. Some guys can tell the difference, some can't. We'll see.

I personally bought hawk HB332P.654 which are .654in or 17mm.
They will be installed with powerslot slotted in the next 30 days.
No new lines or calipers.

 

[sparg93]

96ProComp.

The SS lines, the end of the line that attaches to the caliper, was it identical to the originals or more of a universal fit?

 

[99Yuk]

it certainly makes sense...but couldn't our smaller piston calipers exert a similiar force theoretically?

So maybe this is a better way to think about it...b/c at the end of the day we want to stop our rigs faster and a big part of that is how long the brake needs to travel in order to stop the damn thing.

If we push our brake pedal down 3" (just an example) will the smaller caliper exert the same force as the large caliper? Technically (someone correct me if i'm wrong) by pushing on the brake a hydraulic pump pushes fluid that pushes the piston within the caliper outward against the pad.

By pushing 3", are both the larger caliper and smaller caliper exerting the same force? My thought would be yes b/c the pump is exerting the same force on the liquid...but I have ZERO science to back up my idea...anyone much smarter than me that can chime in?

I'm not an expert at this either, but your correct. The pressure on the pistons regardless of size is the same for the 3" of pedal travel. Ok, thats the pressure in the equation. Now the surface area of the pistons is different, which would change the actual force measured in pounds exerted on the pads.

The actual pressure exerted on the pads is different because the size of the surface area of each piston is different even though the fluid pressure on each piston is the same.

That's how an air hoist works. It's still only 100psi in the hoist, but the surface area is much bigger, so bigger surface area * pressure = force, which has enough force to lift a vehicle.

I guess we would need to know how big round is each caliper piston, then we could use 800psi fluid pressure and then we could have some real numbers!
I guess I'll google the piston sizes.



EDIT: Dope! bpodskalny gave us the piston sizes in the first post! 75 and 79mm bore sizes.
Step1. Convert mm to inches. 75mm=2.952755905515 inches and 79mm=3.1102362204758003 inches.
Step2. Determine surface area in inches. Use formula A=pi*r2 reference found here

r=2.952755905515/2=1.4763779527575
r2=2.17969185938842690185380625
A=3.14159265*2.17969185938842690185380625=6.8477039247195154499261890895241
Surface area of the smaller piston is 6.85 square inches.

r=3.1102362204758003/2=1.55511811023790015
r2=2.41839233678989776333002948137
A=3.14159265*2.41839233678989776333002948137=7.5976035900754674075290601429554
Surface area of the larger piston is 7.60 square inches.

So now all we need is the psi pressure number on the piston due to pedal travel.
Lets say it's 800psi.
So let's do some math. 800*6.85 = 5480 pounds of force on the pads for the 1/2ton caliper, and 800*7.60=6080 pounds of force on the pads for the 3/4ton caliper.

So the larger caliper exerts 600 more pounds of pressure which stops your truck better.
Whew! Hope that helps at least someone!

 

[sparg93]

Some info on the 1 ton caliper:
http://www.azrockcrawler.com/_images/tech/2005/10-14-0534tonbrakes/34tonbrakeconv.html

This gentleman stated the 1 tons were pretty heavy and w/o significant brake boost, took too much travel for them to grab.

Question:
With the rotors you ordered...did you order 3/4 ton sized discs? Is there a difference between our stock discs and the 3/4 version? (per the article, he states the 3/4 are thinner then the 1 ton... so I thought the 3/4 may be thicker than our stocklers)

 

[sparg93]

I can't find the link now, but someone mentioned the 3/4 discs were the same size as our 1/2 ton, but were "thicker"

I'm still torn on the fluid against the piston and the amount of travel by the pedal...at least for the 1 ton caliper I know it's a problem without boost....so wouldn't the 3/4 suffer from a similiar fate, just not as severe?

Shouldn't it take more fluid against the piston to push the piston against the pad? (i.e more pedal travel for the pad to rub against the disc).

The reason I bring this up - is spending the extra $$ on the 3/4 worth it? Keeping all things equal (Hawk pads or high quality equiv), will the 3/4 caliper stop the truck faster then a 1/2 IF you need to push the pedal slightly harder on the 3/4?

I apologize for laboring this issue!!

Additional Info: The discs for the K2500 (i.e 3/4) are 8 lug and I believe our 1/2 ton are 6 lug

 

[99Yuk]

I can't find the link now, but someone mentioned the 3/4 discs were the same size as our 1/2 ton, but were "thicker"

IDK, I ordered 1/2ton rotors. I havn't seen or read anything about using 3/4ton rotors on our trucks, and I didn't want to be the first. hehe.

I'm still torn on the fluid against the piston and the amount of travel by the pedal...at least for the 1 ton caliper I know it's a problem without boost....so wouldn't the 3/4 suffer from a similiar fate, just not as severe?

Shouldn't it take more fluid against the piston to push the piston against the pad? (i.e more pedal travel for the pad to rub against the disc).

Yes, technically you are correct. The pedal will travel down more on 3/4ton calipers than 1/2ton calipers....when using cheap pads. You won't like it. However, when offset by the Hawks thicker pads, you will like it. That particular combo works for me. It feels better than when I started, which is what I was after.

The reason I bring this up - is spending the extra $$ on the 3/4 worth it? Keeping all things equal (Hawk pads or high quality equiv), will the 3/4 caliper stop the truck faster then a 1/2 IF you need to push the pedal slightly harder on the 3/4?

Honestly, I didn't find much of a difference in price in calipers sizes. A few bucks at most. The 3/4ton calipers were one of the cheapest componants. And to answer your question, Yes. IMHO it's worth it. When those Hawk pads heat up and start to grab, you can really feel it, and I actually have to back off the brake pedal. That could be the pads, could be the calipers, rotors, who knows. But I really like this combo. Makes me wish I had done this earlier.

I apologize for laboring this issue!!

No need to apologize man. That's what this place is about. Helping someone until they are happy with the answers.

I think that much like shocks, braking is a personal experience. We can talk about it for some time, but eventually you'll have to take the plunge and try it. And let's say that for what ever reason, you don't like it. Your only out less than $80 for a set of calipers, and an afternoon to swap the 1/2ton back in. You can reuse all your other new parts, then sell your 3/4ton set here. That's the cool part of running these trucks. Most mods can be reversed easily and cheaply if you don't like em.

---------- Post added at 07:25 PM ---------- Previous post was at 07:22 PM ----------

I personally bought hawk HB332P.654 which are .654in or 17mm.
They will be installed with powerslot slotted in the next 30 days.
No new lines or calipers.

Hey, I was just curious, are you in a position to measure new OEM 1/2ton pads thickness?