Upgrade Front Brake Calipers

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454cid

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My experience is only using the DRW calipers on an 8-lug truck with the appropraite upgrades in rotors and pads. There can be issues with clearance using the larger pads on a 6-lug truck, I've read. Then there is also the matter of rotor thickness.
 

Supercharged111

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I run the 8600# GVW calipers on my 1500 and also observed the 2500 pad backing plates grinding away at my rotor hats. I run the 1500 pads, but you need to bend the spring out for the inner pad so it fits tightly in the larger piston. I think the pads ride a smidge too high, so no matter what it's a bit of a mish mash. That, a 9.5" rear, the 8600# GVW master, and hydroboost stop the truck a jillion times better than stock.
 

1998_K1500_Sub

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I run the 8600# GVW calipers on my 1500 and also observed the 2500 pad backing plates grinding away at my rotor hats. I run the 1500 pads, but you need to bend the spring out for the inner pad so it fits tightly in the larger piston. I think the pads ride a smidge too high, so no matter what it's a bit of a mish mash.

Yup, this jibes with my expectations, thanks @Supercharged111.

So @Fileguru, you can try the 8600# pads like I did, but you *may* find you need to grind the outboard pad like I mentioned in a prior post.

Or, as @Supercharged111 notes, you can run the lighter 7200# GVWR pads, but you may have to bend the spring on the inner pad so it stays retained in the larger diameter piston... and, the 7200# pads "ride a smidge too high", meaning they don't sweep the entire rotor width as well the 8600# pads.

If you have access to a grinder, don't hesitate to use 8600# pads just be ready to grind a bit, then trial-fit, in case they touch the hub. You may need to trail fit / grind them a couple of times before you find they no longer rub. The "rubbing" itself is a minor concern, it's mostly an annoyance simply because of the metal-on-metal noise.

Finally, my brakes have vacuum boost and work great... but I don't often pull a trailer, and when I do it's not heavy (aluminum trailer with two ATVs). Although I have most of the parts, I haven't installed the hydroboost system. Others swear by the hydroboost, so take that information as you see fit. I can't comment as it's something I haven't done.
 

1998_K1500_Sub

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does someone know what braided SS brake hoses to get, im now at stock height still but going to get the 4" spindle lift kit later, can i order those longer SS braided hoses for now and use them at stock height too, just route them differently?

@Schurkey comments about stainless brake hoses in his post here (link below), among other things. His comments about the hoses begin with "MOST 'braided stainless' brake hoses don't fit properly" so scan for that paragraph. (edit: The entire thread has some good nuggets throughout).

https://www.gmt400.com/threads/brakes-for-towing.58497/post-1247902

Get the front (2) and rear (1) SS hoses and install all three. @Schurkey and I both noticed improved performance with the all three lines installed vs. just the two in front.

The SS hoses I bought for my Suburban were Russell Performance purchased from Summit Racing but, like @Schurkey notes, the hoses I received were sub-standard in that they didn't have a length of hard-line at their end like the OE hoses do, i.e., where they connect to the caliper banjo bolt. For me, "missing" hard-line wasn't a deal-breaker b/c I was able to route the hoses out of harm's way... and I inspect them often, during other maintenance.

There's a place in Indianapolis, IN (Brownsburg, IN actually) called Technafit that makes custom lines, see two links below. I've bought from them before for another vehicle (not a GMT400). You might want to touch base with them if you have unique needs. I'm sure there are other places that do custom work as well.

https://www.technafitstore.com/
https://techna-fit.com/
 
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Fileguru

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So @Fileguru, you can try the 8600# pads like I did, but you *may* find you need to grind the outboard pad like I mentioned in a prior post.
Yeah if it only needs grinding to fit thats ok im a platesmith/welder i can get them to fit, ill take the 8600# pads then so they sit on better spot on the rotors.

Finally, my brakes have vacuum boost and work great... but I don't often pull a trailer, and when I do it's not heavy (aluminum trailer with two ATVs). Although I have most of the parts, I haven't installed the hydroboost system. Others swear by the hydroboost, so take that information as you see fit. I can't comment as it's something I haven't done.
I looked up for the hydroboost swap, but i would like to rob a ready system from another gmt400 that already has it, but we dont have these trucks so many laying around on junkyards here because it has been a "rare" custom ordered imported vehicle here in Finland... And im trying to keep EVO ps pump so it needs to be from later year gmt400 truck to rob it from.. So i decided that i would now first try to improve this vacuum system as good as i can with GM parts (looked at those big brake kits too but i want to use bigger A/T tyres with smaller rims) so HB swap might happen later if i run into a ready system on the lot but for now ill stick to vacuum..

@Schurkey comments about stainless brake hoses in his post here (link below), among other things. His comments about the hoses begin with "MOST 'braided stainless' brake hoses don't fit properly" so scan for that paragraph. (edit: The entire thread has some good nuggets throughout).

https://www.gmt400.com/threads/brakes-for-towing.58497/post-1247902

Get the front (2) and rear (1) SS hoses and install all three. @Schurkey and I both noticed improved performance with the all three lines installed vs. just the two in front.

The SS hoses I bought for my Suburban were Russell Performance purchased from Summit Racing but, like @Schurkey notes, the hoses I received were sub-standard in that they didn't have a length of hard-line at their end like the OE hoses do, i.e., where they connect to the caliper banjo bolt. For me, "missing" hard-line wasn't a deal-breaker b/c I was able to route the hoses out of harm's way... and I inspect them often, during other maintenance.

There's a place in Indianapolis, IN (Brownsburg, IN actually) called Technafit that makes custom lines, see two links below. I've bought from them before for another vehicle (not a GMT400). You might want to touch base with them if you have unique needs. I'm sure there are other places that do custom work as well.

https://www.technafitstore.com/
https://techna-fit.com/

Ok i just thought if someone would have made same thing with readily available ss baided hoses, ill order some that will fit now, the lift im after isnt gonna happen soon (LS swap, my '68 Impala and other projects + family life and damn inflation and million other things eating all my money already lol). Yeah we have good shops here that will make quality custom brake lines too if necessary.

Thank you all again for helping me out on this.

PS off topic: a month ago i went to fill up my 'burban, gas price was 2,70€/Litre on 95E (compares to your regular quality) so it was at currency rate that time $11,20 a Gallon! So for $50 u got 4,5 gallons of gas, nice thing for my 16mpg consumption, great time being a working family man haha! Luckily its now at 2,25€/litre but we fear at winter it can get up to 3€/litre because of the f***ing russian (*soviets!!) war in ukraine.. time will see...
 

Suburbanman

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My 1996 5.7 K1500 Burb is getting its second life. I have vacuum assist and anti-locks that are still stock. I need to get the brakes sorted out. I have already swapped a NBS rear end out of a 1500 pickup to get disks in the back. I am going to put Stainless brake lines front and rear, but after that I don't really know what works best.

Master cylinder swap and calipers? Bigger rotors? I kind of want to use stock GMC parts for ease of getting things when they break. Point me to the right thread, and all suggestions will be appreciated!
 

1998_K1500_Sub

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1996 5.7 K1500 Burb ... vacuum assist and anti-locks that are still stock. I need to get the brakes sorted out. I have already swapped a NBS rear end out of a 1500 pickup to get disks in the back. I am going to put Stainless brake lines front and rear, but after that I don't really know what works best.

Master cylinder swap and calipers? Bigger rotors? I kind of want to use stock GMC parts for ease of getting things when they break. Point me to the right thread, and all suggestions will be appreciated!

Simply start at the beginning of this thread and read through it.

Then, read through this thread, which likely has redundant information but certainly some clarifying points...

https://www.gmt400.com/threads/early-abs-hydraulic-unit-rwal.58975/

Also peruse any threads referenced within those above, and the threads referenced within those referenced (did you get that?). It may seem like a lot of reading, but you'll benefit from the multiple perspectives given to the front brakes.

Finally, look through this short thread about front rotors:

Please comment on your GMT800 rear disc conversion.
 
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Treb

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I finished my brake upgrade on my 88 GMC K2500 6 lug (7200lbs). I up graded the front caliper's to 3.15" and pads from a K2500 8 lug (8600lbs) Had to grind the front outer pads just like Nitro Junkie posted on one of the pervious pages. Rear wheel cylinders from a K3500 duel rear wheel 1.1875. New hoses. New master cylinder from a 2002 Chevy Silverado 1500. Brakes work great. A noticeable difference. It is worth the upgrade. I entered the parts I used from Rock Auto for this project.

ACDELCO 18FR741N (New - Uncoated) Gold / Professional Info
Front Right; 8600 lb. GVW
ACDELCO 18FR742N (New - Uncoated) Gold / Professional Info
Front Left; 8600 lb. GVW
RAYBESTOS SP370TRH (Heavy Duty (Long Life, Truck & Tow)) Specialty - Truck; Metallic; Includes Hardw
ACDELCO 18E1362 (Daily Driver) Gold / Professional Info
Rear; with Dual Rear Wheels
ACDELCO 18M1159 (Daily Driver) Gold / Professional Info
with Vacuum Booster
ACDELCO 18J2064 (Standard Replacement) Gold / Professional Info
Rear Center
ACDELCO 18J2068 (Standard Replacement) Gold / Professional Info
Front Right; with 7200lb GVW
ACDELCO 18J676 (Standard Replacement) Gold / Professional Info
Front Left; with 7200lb GVW
 

Suburbanman

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Simply start at the beginning of this thread and read through it.

Then, read through this thread, which likely has redundant information but certainly some clarifying points...

https://www.gmt400.com/threads/early-abs-hydraulic-unit-rwal.58975/

Also peruse any threads referenced within those above, and the threads referenced within those referenced (did you get that?). It may seem like a lot of reading, but you'll benefit from the multiple perspectives given to the front brakes.

Finally, look through this short thread about front rotors:

Please comment on your GMT800 rear disc conversion.
No problem reading through all the threads and links, but its going to take a while... I better get some snacks and a drink or two.

I will give a complete run through of my rear break swap, pictures coming too.
 
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