Which calipers for disc conversion

[JWNathan]

With my 1028 being my daily driver Im going to put discs in the rear. I know I need K20 calipers, my question is which ones? On RockAuto they have two to choose from, The difference being piston diameter, one is 3.15" and the other is 2.94". Im thinking Ill go with the larger bore size to drop down the pressure being applied to the pads. Though I dont think it will be low enough to not run a proportioning valve aswell. Any guidance and oppinions would be great, thank you.
-Jesse

 

[dstang97]

I dont think it matters the bolt patter is the same and the bigger bore has bigger pads if i remember corectly

 

[JWNathan]

Correct. the Larger bore style is actually the same as the fronts on a K30 aswell. Well atleast use the same pads that is.
-Jesse

 

[puppy]

Force increases with bore size. Larger bore = more force applied to the pads.

 

[Bunkerbuilder]

I used a std dana 60 single piston caliper but am thinking about using a 4 or 6 piston caliper from wilwood that will fit the dana 60 dualy rotor.

I posted links to pics of my 14 bolt conversion here.

http://www.steelsoldiers.com/cucv/43382-mico-brake-lever-lock-where-mount.html

I plan to use
A caliper like shown in the pics below disreguard everything but the caliper and mounting for it.

ETA: the mounting shown in these 3 pics below isnt correct for the 14 bolt axle flange, im working on the correct bracket for the Wilwood caliper on the 14 Bolt FF Axle.

As soon as I figure out the offset and bracket dimentions I will give out that info if anyone is interested.

 

[POOR WHITE BOY]

I used calipers from a 1979 k20 .they worked perfect. Front calipers from a k30 will not work

 

[JWNathan]

Im just going off of RockAuto right now but they list the same part numbers for both applications. I didnt realize that puppy, I was thinking smaller bore size increases pressure like in the master cylinder. **** fluid dynamics are beyond me!
-Jesse

 

[Bunkerbuilder]

See the thread I posted in a earlier post in this thread.

I used the K30 dually rotors for the reason that the stud holes could be drilled out to the correct size for the appropriate inference fit to mate with the stock studs.

Those who say it can't be done should not interrupt those who are doing it.

I used calipers from a 1979 k20 .they worked perfect. Front calipers from a k30 will not work

 

[Cucvnut]

there is a guy on pirate 4x4 who is selling everything you need to convert your 14ff to rear disks for 315 shipped

 

[puppy]

I used to use Great Lake Offroad, LLC ~ Disc Brake Convertion Kits brackets but they went cheap with some angle iron spacers that I do not like.

My last set I got from Disc Brake Adapters, but have not used them yet. I like this design.

GM Chevy 14-Bolt Full Floater Rear Disc Brake Brackets makes a nice kit but is expensive.

 

[JWNathan]

I was looking at the Ruff Stuff brackets, mainly because they are a local company.
14 Bolt Disc Brake Caliper Mounting Bracket (Standard SRW) [6090031] - $50.00

I should be able to get everything for the swap for around $270. Looks like it wont take to long to do either, looks very straight forward. I think I even still have enough DOT5 for the swp and brake flush. Thanks guys.
-Jesse

 

[Cucvnut]

Dana 60 or 14 bolt disc brake kit $315 shipped - Pirate4x4.Com Bulletin Board

 

[POOR WHITE BOY]

see the thread i posted in a earlier post in this thread.

i used the k30 dually rotors for the reason that the stud holes could be drilled out to the correct size for the appropriate inference fit to mate with the stock studs.

those who say it can't be done should not interrupt those who are doing it.

1979 k20 rotors and calipers work correctly without drilling holes - lets see how you mount the k30 calipers on a 14 bolt ?those who donot know the correct parts to use when doing this swap should not post their azzhole engineering rigging ideas - specially when it comes to a brake system and safety. THE PARTS IN DUMAZZS PHOTOS MAY BE DANA 60 BUT ARE NOT CHEVY K30 ROTORS OR CALIPERS

 

[dstang97]

I did it the conventional way that everyone else did. I did it cheap and my truck stops on a dime


Just throwing this out there I would get the smaller of the two brake pads and see if you have to run a proportioning valve.

 

[Bunkerbuilder]

My design works and it was given the thumbs up by 2 brake industry engineers one that works for Bendix in that capacity and the other that works for Bosch as a brake engineer.

The design that uses 3/4 Ton brake rotors IMO are what professionals called African engineered and has several faults that are not dealt with by those that sell the kits.

If you measure the stock stud used and the stud hole in the brake rotor you will notice a gap of between .020 to .025. this means the studs arent pressed into the rotors.

According to 3 brake engineers I have had correspondence with the stud should have a slight interference fit in both the hub and rotor.

And since they aren’t hub centric in the stock configuration and they also don’t mount with the correct index on the studs they are a loose fit.

If you would have bothered to check out the pics you would have already seen how the I mounted the K30 Calipers on the 14 bolt axle.

The new solid mount calipers will have a better mount compared to the K30 calipers.

If you’re speaking of my photos they are not entirely my ideas they are the ideas of 3 brake engineers and myself.

They are not the standard K20 rotors that are a thrown together setup that only work marginally, IE are not correctly engineered.

The setup I built was designed from Bendix and Bosch blueprints the same cannot be said for the kit with 3/4 Ton rotors and calipers with brackets bent or with the 4 spacers. With a bit more engineering that 3/4 Ton kit could be a quality kit but they stopped short of getting it right IMO.

1979 k20 rotors and calipers work correctly without drilling holes - lets see how you mount the k30 calipers on a 14 bolt ?those who donot know the correct parts to use when doing this swap should not post their azzhole engineering rigging ideas - specially when it comes to a brake system and safety. THE PARTS IN DUMAZZS PHOTOS MAY BE DANA 60 BUT ARE NOT CHEVY K30 ROTORS OR CALIPERS

 

[4bogginchevys]

14 bolt disc brakes

My design works and it was given the thumbs up by 2 brake industry engineers one that works for Bendix in that capacity and the other that works for Bosch as a brake engineer.

The design that uses 3/4 Ton brake rotors IMO are what professionals called African engineered and has several faults that are not dealt with by those that sell the kits.

If you measure the stock stud used and the stud hole in the brake rotor you will notice a gap of between .020 to .025. this means the studs arent pressed into the rotors.

According to 3 brake engineers I have had correspondence with the stud should have a slight interference fit in both the hub and rotor.

And since they aren’t hub centric in the stock configuration and they also don’t mount with the correct index on the studs they are a loose fit.

If you would have bothered to check out the pics you would have already seen how the I mounted the K30 Calipers on the 14 bolt axle.

The new solid mount calipers will have a better mount compared to the K30 calipers.

If you’re speaking of my photos they are not entirely my ideas they are the ideas of 3 brake engineers and myself.

They are not the standard K20 rotors that are a thrown together setup that only work marginally, IE are not correctly engineered.

The setup I built was designed from Bendix and Bosch blueprints the same cannot be said for the kit with 3/4 Ton rotors and calipers with brackets bent or with the 4 spacers. With a bit more engineering that 3/4 Ton kit could be a quality kit but they stopped short of getting it right IMO.

Care to share how you've done it, i'd really like to make all mine disc......Thanks

 

[StreetbikeDepot]

All the 14 bolt conversions I have seen use mid 70's Chevy 8 lug rotors and calipers. You have to be carefull, there are two thickensses of rotors so be sure to get the pair that work together.

And for the 3rd time......you can't beat that price anywhere.

Dana 60 or 14 bolt disc brake kit $315 shipped - Pirate4x4.Com Bulletin Board

 

[Bunkerbuilder]

Care to share how you've done it, i'd really like to make all mine disc......Thanks

Here is the link where I Pasted all of the part #'s.
This pretty much explains both how I built this conversion and the problems in using a 3/4T rotor in any build that uses a 1 ton rear hub.
http://www.steelsoldiers.com/cucv/43382-mico-brake-lever-lock-where-mount.html

The rotors and hubs are the same from the first build and the build I am now in the middle of.

IE it starts with a set of the GM srw hubs and the bearings
Part #'s are GM unless otherwise noted. These are 1 ton parts that are from a DANA 60 front differential IE K30/K35.

3977397 Hubs Rear Wheel
Rotor 1985 Chevy front dually Bendix 141468 # Centric 120.66004
Napa #'s 85822 superceeded by Napa 4885822
WHEEL STUDS 3988538 16
SEAL 469694

Another rotor interchange page.
brake disc rotor number,Brake Disc,Brake Drum PHAETON GROUP

My next build will use a wilwood caliper that uses an adapter to fit the 1 ton dually rotor, a cnc machined insert as shown in the pictures in another post above. http://www.steelsoldiers.com/cucv/46159-calipers-disc-conversion.html#post519141

It would be beneficial for those that are suggesting using the 3/4 Ton brake rotors to measure the studs and stud holes in the 3/4Ton rotors prior to purchasing or using them.

I had hoped the attitude of slap it together and run it wasn’t as prevalent here as it is on other truck forums.

 

[POOR WHITE BOY]

with all these engineers involved in your system - you state 2 in one paragraph and 3 in the next - you think they would have addressed the e-brake when putting k30 calipers on the rear - they must have over looked that - not a safety concern i guess.it is good to know that major brake part manufacturers let their engineers talk about building homemade brake stsyems to the public. Personally i will continue to use the $350. Set up that everybody else uses and works fine. I will use the eldorado calipers for e brake if needed. The studs donot need to be press fitted into the rotor - most all the trucks and cars made today are not - they slide right off - i guess the engineers must have over looked that at all the major truck manufacturers. Still waiting for photo of k30 caliper and rotor mounted on 14 bolt

my design works and it was given the thumbs up by 2 brake industry engineers one that works for bendix in that capacity and the other that works for bosch as a brake engineer.

the design that uses 3/4 ton brake rotors imo are what professionals called african engineered and has several faults that are not dealt with by those that sell the kits.

if you measure the stock stud used and the stud hole in the brake rotor you will notice a gap of between .020 to .025. This means the studs arent pressed into the rotors.

according to 3 brake engineers i have had correspondence with the stud should have a slight interference fit in both the hub and rotor.

and since they aren’t hub centric in the stock configuration and they also don’t mount with the correct index on the studs they are a loose fit.

if you would have bothered to check out the pics you would have already seen how the i mounted the k30 calipers on the 14 bolt axle.

the new solid mount calipers will have a better mount compared to the k30 calipers.

if you’re speaking of my photos they are not entirely my ideas they are the ideas of 3 brake engineers and myself.

they are not the standard k20 rotors that are a thrown together setup that only work marginally, ie are not correctly engineered.

the setup i built was designed from bendix and bosch blueprints the same cannot be said for the kit with 3/4 ton rotors and calipers with brackets bent or with the 4 spacers. With a bit more engineering that 3/4 ton kit could be a quality kit but they stopped short of getting it right imo.

 

[Bunkerbuilder]

Here is one pic.

I posted links to this same pic earlier in the thread I guess you need to be spoon fed.

They did address the E Brake when they put the K30 calibers on the rear with a different rotor.

More about that later.

with all these engineers involved in your system - you state 2 in one paragraph and 3 in the next - you think they would have addressed the e-brake when putting k30 calipers on the rear - they must have over looked that - not a safety concern i guess.it is good to know that major brake part manufacturers let their engineers talk about building homemade brake stsyems to the public. Personally i will continue to use the $350. Set up that everybody else uses and works fine. I will use the eldorado calipers for e brake if needed. The studs donot need to be press fitted into the rotor - most all the trucks and cars made today are not - they slide right off - i guess the engineers must have over looked that at all the major truck manufacturers. Still waiting for photo of k30 caliper and rotor mounted on 14 bolt