60Patrol

Phase 1 -- Complete! My adventure du jour!

First, my new lathe kicks butt! Makes it so easy to turn material. Tons of power make pretty deep cuts possible and it's super rigid so even while making those deep cuts, I get a decent finish quality!

So, this is one of the hubs my buddy cleaned up for me. I had asked him to take as little as possible to give a good register for the rotor... turns out that the two hubs ended up being slightly different diameters. I want them to be the same so the rotors can be used on either side.


Nailed it! The plan is to turn the hubs to 4.125" and I got it. It's kinda odd working in such small values. A thousandth of an inch is barely visible and then only in perfect lighting! It's actually quite a challenge to get the hub set up on the lathe! I used the 4-jaw chuck, then went round and round with an indicator tightening and loosening until it was perfectly aligned, then round and round again to make sure the front of the hub is also perfectly aligned -- turn, measure, turn, measure turn, measure, tap, measure, tap, measure, tap, measure, Repeat, repeat, repeat until it's perfect!


ACTION SHOT! Next is to face the hub to clean it up -- I cut just 0.002"s to make it look extra pretty


Considering how little I took off, this looks awesome and confirms that the face is perpendicular to the rotating axis


This is the brand new, stock, GM front rotor (yea, not Nissan)


The stock hub register on that brake rotor is 3.062 -- I'd guess that the hub that is designed for it would be right at 3" in diameter. To fit the Patrol hubs I just machined, I want to open it up to 4.127" (+2 to 3 thousandths is my target).


Setting the rotor up on the lathe is easier than the hub for a variety of reasons... it's easier to grab and the bore is much, much shorter so front to back alignment is less critical (not to say it's not... it's just a little less). I have my Test Indicator in place on the stock register (which, by definition, is perfectly concentric with the axle). The zero is irrelevant, what matters in this set up is the difference between the min and max readings. This is the minimum reading


And this is the max reading! It took awhile but using that 4-jaw chuck, I was able to get it super close!


ACTION SHOT! Boring! The outside edge of the black marker circle is just a hair under 4" -- it's there to keep me from opening it up too much in all my excitement!


FINISHED! Hubs and rotors fitted together perfectly! They slide together nicely, but have no movement once all the way down. Next stop, the caliper brackets...


In case anyone wants to do the same conversion on the front brakes -- for reference:
Turn hubs to 4.125" to create a register to seat and center the brake rotors
Use the rotors from a 2003 Chevy Silverado Pickup (ACDelco Silver 18A925A Front Disc Brake Rotor) - Open center hole to 4.127"

Measuring with a caliper is a chore! I must have re-measured 100 times just to make sure I was getting the right measurement! My next purchase will be a 5" micrometer!

On another note, I love my 1969 vintage lathe and am looking for excuses to use it. If anyone needs help getting the hubs and rotors turned, ping me!

John

Very cool.

Never let it be said that I take the easy route!

I've been sorting, tidying, and getting rid of stuff for the past few weeks just to get some space... Today, my work bench moved inside from the backyard temp carport! I don't think it's ever actually been inside and then inside with an intent to stay inside! I am very excited! Time to start putting Aerogirl back together!


This is the first time that the disk brake rotors have been installed on the axle! So, I spent much of the day measuring and drawing up the brake and caliper in CAD so I can design a caliper bracket... I am learning Fusion 360 for 3D cad... I am very slow at this point.


I set the caliper onto the rotor to get accurate dimensions, the angle that the caliper must sit to fit... you know, all the important things.

Then -- I notice something. The caliper and brake rotor combination that I planned on using... will NEVER work. And, I should have seen it long ago. I simply wasn't focused on that side of the rotor!


The caliper mounting bracket stands way proud of the wheel mounting face meaning there is no way to mount a wheel (sans a 3/4" spacer or something like that.

Dang! Well, at least our own @jwgreen is working on the same problem and posted his way more successful findings! See viewtopic.php?p=50178#p50178

Tonight I ordered the calipers and rotors straight off his list! I guess I do it right, 'cause I do it twice!

Have a happy Sunday!

j

I had to run a 3/8 spacer with my 4runner 4 piston calipers. It still uses the original length studs. Anything over 3/8 you would have to change out the lug studs.

Also I am using land cruiser rims, the offset is different.

rdarnell wrote:Also I am using land cruiser rims, the offset is different.

I'm discovering more and more fit-issues as I get further along in my - what has become - engineering on the fly brake project

Any chance you have a picture from the other side of the wheel? I'd like to see how the brake rotor and caliper fit in the rims

j

There are a bunch of pics in my build forum 1967 patina and I also posted all the photos in the modifications forum under disc brakes

I found them -- Thanks! Super helpful

For reference -- https://60patrol.com/forum/viewtopic.ph ... r&start=10

j

I was taking measurements -- running back and forth between the shop and my office when I discovered that someone had decided to come in for a visit! He now has a new home in the garden OUTSIDE


So - some good news... I was wrong about the caliper not fitting due to it overhanging the rotor face... Seems that is not uncommon. This means that my current options are not dead in the water (at least for that reason)


This is the challenge du jour -- fitting the disk brake assembly inside the stock Patrol rim. Not a lot of room in there. There is only 13" of clearance deep down in the rim... it widens out to about 14.5" about 2" up from the mounting flange. But it would take some crazy thick spacers to get there. Right now, I really, really wish I had 16" rims and tires... that would make all the difference. But since I spent a small fortune on 5 new tires shortly before the crash, I'd like to design the disk brake system to actually fit inside them... I mean, I'd be surprised if those tires have 300 miles on them total!


One of the rotor choices is the 18A258 from a mid-90s Chevy K2500 (the one jwgreen is using)... It is slightly smaller in diameter (11.6") than my other options, but it's thicker with a discard thickness of just over 1.2". The hat diameter is also slightly larger than the other option... that that may be an issue. It's total height (2.6") is slightly more than the other option - meaning the disk sits further back toward the wide part of the wheel.


The 2003 Chevy Silverado rotor (18A925A) is another option, it's 12" in diameter, but thinner at just over 1". The hat is 0.1" thinner too... which may be a factor. Its not quite as high as the previous option at only 2.3".


This is the "best case" of the 1980-ish GMC K1500 Brake Caliper (again, the same as jwgreen is using and probably the most common choice for many conversions for more common vehicles) - it's mounting flanges are really easy to make brackets for... which is awesome. But the cylinder is large diameter and may cause problems fitting over the axle. This combination will require at least 13.5" of rim clearance (this is with the caliper bottomed out, so in reality, there will be another 1/4" or more of needed room -- adding 1/8" to the radius for clearance).


Even on the 11.6" rotor, I wouldn't expect any additional clearance as the caliper's piston area hits the patrol axle when bottomed onto the 12" rotor. There's just not any room to grind for additional clearance


The best case using the 2003 Chevy caliper requires the same wheel clearance as the previous one. Plus it has some flanges that could be ground away to yield a bit more clearance if needed (again, this is with the caliper bottomed out, so in reality, there will be another 1/4" or more of needed room -- adding 1/8" to the radius for clearance).


But the 2003 Chevy caliper has more room around it before it hits the axle. Grinding those flanges and using the smaller mid-90s Chevy rotor (11.6") may yield a bunch more room -- maybe a quarter inch?


The 2016 Nissan Frontier calipers -- my original choice -- sits higher on the rotor. It's needs 13-5/8" of wheel diameter to clear again, this is with the caliper bottomed out, so in reality, there will be another 1/4" or more of needed room -- adding 1/8" to the radius for clearance.


The 2016 Nissan Frontier caliper doesn't have much clearance when using the 12" rotor... and not much room to grind out some additional space either.


Also, the 2016 Nissan Frontier caliper has a narrow opening for it's standard 1.024" discard thickness rotor so it's really unlikely that the 11.6" x 1.215" discard thickness rotor would fit at all anyway.


So... I dunno. I'm thinking that the 12", 2003 Chevy Silverado rotor (18A925A) mated with either caliper is my best choice. I like the 12" from the same vehicle better as they would be perfectly compatible with each other... but there is no way it will fit in the stock 15" rim without a silly 2" spacer (not actually considering a 2" spacer). As for the 11.6" but thicker rotor? I don't expect that the 11.6" rotor will yield enough space to fit in the rim either. So, there's that...

So, my choices:
1) Test fit another 15" rim to see if that would provide enough clearance. (rdarnell had disk success with landcruiser steel rims)

2) Give up on disk brakes and rebuild the drum brakes (but with a dual master of course)

3) Bite the bullet and sell the 15" rims/tires (nearly new tires too!) and buy a set of 16" rims and tires

This weekend, I'll head to Pick-n-Pull and grab a 15" rim and a 16" rim to do some test fits -- I mean, rims are something like $11 each... way cheaper than committing to a new set of tires!

Always having fun...
j

when I started my build on the brakes I was using my spare split 15" wheel for clearance mockup. Later I decided to move away from the problems of split rims and tubes in favor of a regular tubeless wheel from a 70's Toyota Land Cruiser. I still had to use a spacer on the LC wheels and I think I would have had to use a thicker spacer if I used the original rim. I have some details of the differences in the offsets between stock 15" split rim and 1970's Land Cruiser rims in the modification area under "Patrol vs Land Cruiser rim offset" ... https://60patrol.com/forum/viewtopic.php?f=7&t=6107