Another take on Disc Brakes

[yitzac1990]

DISCLAIMER: This post is for informative purposes only, do this work at your own risk. I am not responsible if you do this and your brakes fail and cause injury or damage to anyone or anything!

I just completed my rear disc brake swap last night (front still in the works) and wanted to post what I did. Here are the parts I used:

caliper - rear caliper and pads from S13 240SX (1989 - 1994)
rotor - rear rotor from 1995 Isuzu Pickup

I will jump right in:

First, you have to get the rotors machined. The center bore needs to be opened up to 4.2", and the lug holes need to be opened up to 0.609"

Second, the axle hub needs to be slightly ground or machined down. I was refurbishing my axles (new seals, axle nuts, lock washers, grease) so I already had the axle shafts out of the housing. I took them to a machine shop, along with one of the rotors and told them to machine down the hub enough to fit into the rotor "hat". You could also use an angle grinder to slightly grind down the outer diameter. This is the surface I am talking about, specifically:



Third, the caliber brackets needs to be made. I have attached the PDF of the bracket, and I will attach a STEP file when I have it made up. CAUTION: THE ATTACHED PDF SHOWS THE BRACKET AT A SCALE OF 3/4! DO NOT JUST CUT IT OUT AND TRACE IT ONTO YOUR METAL TO BE CUT, IT WILL NOT BE THE CORRECT SIZE! It is to be made from 0.25" (1/4") steel plate. I was able to cut out each bracket using just an angle grinder, but obviously having a machine shop CNC it would be way nicer. I printed out the drawing at a scale of 1.0, cut out the shape, traced it onto the steel, and got to grinding/drilling. It came out very accurate the first time and slipped right on!

Forth, attach the bracket to the axle. I used new, shorter nuts on the backplate studs, still using lock washers. very simple and works great. that basically makes this a "bolt-on" disc brake swap

Fifth, install rotor and caliper. Do this as you would any other vehicle, however you need to come up with a spacer of about 0.28" between the caliper and adapter plate. I used Qty 4, M10 washers and it worked perfect. NOTE: I actually installed the calipers backwards; driver caliper on passenger side, and passenger caliper on driver side. This was so the e-brake attachment was behind the axle, instead of in front.

Sixth, plumb your new brake lines, however you see fit for your specific application, and bleed brakes!

Why did I choose that caliper?
A: because i come from the world of drifting, where nissan 240sx's are plentiful and cheap. I got a pair of calipers from a friend for $40 and got some rebuild kits for about $5 each. These calipers also have a built-in parking brake function, which I will work on adding at a later time.

Why did I choose that rotor?
A: because it was similarly sized (thickness) to that of a 240sx rear rotor, so I knew the caliper and pads would fit on it. The outer diameter was also not too huge compared to other rear rotors. It also had the correct lug pattern, obviously.

Good Luck!

[yitzac1990]

Here I have attached a 1.0 scale PDF of the bracket (if you want to print it out, cut it out, and trace onto metal, like I did). If you want the STEP file, please PM me.

[r1lark]

Good stuff yitzak, thanks!!!

[Esteban]

Well done Yitzak, and thanks for sharing the files and your insight into this matter. You work extremely fast also. Congratulations!

[yitzac1990]

One other thing I should mention: when I did my SPOA swap (as you can see in the pics), i rotated the axle to have more pinion angle for better driveshaft angles. MY axle housing, therefore, is rotated more than a stock patrol rear axle. The straight line between caliper mounting bolts is at a 14 degree angle from the straight line between backing plate mounting studs on the patrols axle. I'm 99% sure the caliper will work fine if its a bit higher and at an angle, however keep in mind that your angle may have to be less than 14 degrees in order to keep the caliper completely vertical (refer to picture 2, in the first post).

[yitzac1990]

The front brakes are finished! Let me dive right in:

Calipers used: 1993 Toyota 4Runner (CARDONE 191601, CARDONE 191600)
Rotors used: 2002 Isuzu Rodeo (CENTRIC 121.43018)

First, you have to get the rotors machined. The center bore needs to be opened up to 4.2", and the lug holes need to be opened up to 0.609" (the machine shop actually made my holes too small, so I opened them up to .625" (5/8") and they fit great).

Second, the hubs need to be ground or machined down. I used an angle grinder to slightly grind down the outer diameter. This is similar/same action as the rear hubs, from the first post above.

Third, the caliper brackets need to be made. Unlike the rear bracket, I had these front brackets laser cut for accuracy, mainly to clear the "lip" on the spindle without interference. I can attach a PDF drawing, no problem.

Forth, the threaded inserts need to be made/modified. I used some 1/2-13 coupling nuts (easy and cheap at a home improvement store), and took them to a machine shop to have them turned. These can also be seen in the PDF drawing, second page. The .158 dimension is the critical dimension, as that sets the spacing (inboard or outboard) of the caliper. Here is the result from the brackets and inserts:





Fifth, weld the inserts to the brackets:



I then had to do a "final trim" on the length of the inserts. I put the bracket in a vice and grinded them down so they would not interfere with the rotor. Final insert total length was about 0.615". I then had to grind down the bolts I bought too (I bought long bolts to make sure I had enough thread...you can always cut a bolt, but welding bolts together is a bit harder ) Add some paint, and mount the bracket to the spindle:



The mounting holes in the caliper need to be slightly drilled out, using a 1/2" drill bit. Then put the rotor on and then the caliper! Attach your brake line of choice and bleed the brakes.







Closing remarks:

Why did I choose that caliper?
A: Another member of this board seemed to have good luck with it, so I went with it. They are also pretty common, cheap, and beefy.

Why didnt I use a 240sx front caliper to match the 240sx rear caliper?
A: I really wanted to, believe me. But a patrol is a bit bigger/heavier than a 240sx. I didnt think the 240sx front caliper would be enough for the front of the patrol.

Why did I choose that rotor?
A: Another member of this board seemed to have good luck with it, so I went with it.

Good Luck!

[yitzac1990]

for my next question:

Would anyone be interested in something like a group buy of bracket kits? I can talk to machine shops and see about getting multiple sets of the brackets made, im thinking 10 sets at first? I can ship international as well. I can also have the rotors machined too, but only for domestic orders, as shipping rotors overseas will cost a ton.

Let me know, and if there is enough interest, I can see about helping everyone out.

[yitzac1990]

another thing to consider, before I forget...you will probably need new wheels, at least for the fronts (and rears will have to match front, usually). I dont think I have the OEM wheels on my patrol, but it did come with 15x6 -4 offset wheels. They do not fit over the caliper (diameter is fine, but they hit the front of the caliper). I put on a single 1/4" spacer, no dice, still hits. I put on a 2nd 1/4" spacer, for a total of 1/2" spacing, and they worked, but there was not enough thread left on the stud for me to be comfortable with it.

Keep this in mind. a deeper dish wheel will be needed to have proper lug thread engagement, OR longer studs. And I dont think there are any longer studs available or that will work for the patrol??

edit: could also try some bolt-on 1" wheel spacers. which I might do...

[TasMan]

Nice work, I wonder how much work it would be to adapt GQ patrol disc breaks
.

[yitzac1990]

Nice work, I wonder how much work it would be to adapt GQ patrol disc breaks
.

i think someone on this forum has already done it. as far as i know, GQ parts are super hard to come by in the US.