Commencing RX7 Brake Upgrade

Just got lucky. Won Ebay Australia auction for a pair of used RX7 FD brake calipers. These babies are essential for the well-known brake upgrade option for AE86 owners. Having 4-pots each, brake fades should be a thing in the past.

Although it's a good idea to rebuilt used calipers before use, i'm going to be cheap and just believe the description on Ebay: Recently had fluid in them and were being used, they will be OK for use without rebuild.

They come without pads so i'm on the hunt for new ones. Figuring that brake pads are somewhat fast-moving spare parts, i don't want to have to preorder everytime i need new ones. I went looking for an alternative available locally and budget-friendly. Obviously you don't see RX7s rolling in Indonesian streets a lot so you can't expect many shops would stock their brake pads. However, thanks to this wonderful Malaysian blog, i learned that 80 series Land Cruiser brake pads should fit with minor mods. Here's the comparison.

Curvy one is LC's. You can see the sides are a tad bigger but that should be an easy fix with a grinder if necessary.

Obviously i'm going to have to find some way to mount these RX7 calipers to my struts. I've been trying to contact AJPS for the last few days but no response so far. AJPS manufactures these equally essential parts..

These slick looking stuff allow me to mount that RX7 caliper on my stock strut, which is identical to AE86 strut. Kinda worried since AJPS haven't responded so far. Why the hurry? Well, i am counting on my cousin to bring me back these stuff from Aussie and he's flying back next week. AJPS is in Adelaide and he's in Sydney. It'll take some time to deliver these parts and that's what i don't have much of. I hope they're not out of stock.. Or, seeing on the bright side if they do, i might have similar bracket machined here for much less. However, this is not something the average machine shop here can make.. with same level of safety and quality anyway.

Anyway, as stated on their website, these adapters are to be matched with 262 x 20mm Honda Civic EG6/EK4 front rotors. Luck is again on my side.. Right in the middle of writing this post, i just made a deal for a set of used EK4 rotors and met with the seller in person. Measuring the dimensions using a ruler, all is perfect. How can i tell that the measurements are correct?

Meet DBA Rotors, taken from their website, Australia's leader in innovative blah blah blah and the production of performance disc brake rotors. The best part of their website is the online catalog where you can check the sizing of many OEM disc brakes. Using this service, i learned that these are the main measurements:

- Rotor Overall Diameter (A)

- Total Height (B)

- Disc Thickness (C)

- Minimum Disc Thickness (D, not shown)

- Center Bore Diameter (E)

- Number of bolts (F)

- PCD (G)

Just from logic, E to G are negligible as we can get them machined to our suit. A to C are the main numbers you need to watch. These are the values for EG6/EK4 rotors for A, B and C.

A = 262 mm

B = 45 mm

C = 21 mm

Thickness is only 1 mm off from AJPS's spec but diameter is perfect. Those values are also what i found on the discs that i bought just 15 minutes ago! They need to be machined to fit the Charmant hub but that's easy work.

Now, the remaining parts are the caliper brackets and brake pads. Brake pads are easy. Only thing left to worry about is the caliper delivery to Indonesia and caliper brackets. If AJPS do ran out of stock, hopefully i can get fabricate one here. Hoping everything will turn out as planned.

One thing i don't understand fully is whether the master cylinder is sufficient for those massive calipers. I've read some say the brake feel will become mushy but some also say it's fine. I can't really tell until i install them but i already got a plan ahead. If i end up having to replace the master cylinders, guess what will be an easy upgrade? Well, again 80 series Land Cruiser to the rescue! They have bigger inner diameter (one inch) which would be perfect for a pair of 4-pot front calipers and it should be a bolt-on work. How accurate is this info? Here's one proof. Head on to one of Bob R's monkeymagic86 blog post and you'll find this pic below.

Those are the stuff that went to Bob's beautiful AE86 (good stuff btw). He's using the same RX7 brake upgrade method. Check the lower-mid part of the pic. See a master cylinder? Bob mentioned that he's using a Land Cruiser master cylinder. Which version? Go to google image for Land Cruiser 80 Series Brake Master Cylinder and match the results with Bob's.

*** edit Feb 10th 2011 ***

Speedhunters just put a write up on Ryan Beal's 3S-GTE powered KE70. Ryan's car is equipped with Land Cruiser calipers and RX7 pads. This just proves even more that the brake pads are interchangeable. Here's the pic.