Brake upgrade for the GTX

[GTXKen]

Time for an upgrade from the 10.87 rotors to 11.75 rotors. Spindles came today, I pulled the backing plates and the lower ball joints and I'm throwing them in the parts washer. Caliper brackets are on the way from arizona. Thinking about replacing the upper control arms and the strut rods during this project as well. Heres the first step and first picture.

 

[Meep-Meep]

That should be a good conversion. I'm doing the same on my 69 RR. Are you using the taller spindles that came with the 11.75" donor car? If so then you should get the modified upper control arms because the BJ angle is such a way that it won't put the BJ into a bind when you hit max suspension travel. This is according to Firm Feel.

 

[ga66mopar]

That should be a good conversion. I'm doing the same on my 69 RR. Are you using the taller spindles that came with the 11.75" donor car? If so then you should get the modified upper control arms because the BJ angle is such a way that it won't put the BJ into a bind when you hit max suspension travel. This is according to Firm Feel.

This is a theory that has never happened during testing. There has been tests that suggest the taller spindle may be better. I've used both short and tall spindles and could not tell a difference.

http://www.moparmusclemagazine.com/...apping_a_and_b_disc_brake_spindles/index.html

The Final Outcome
Overall, using the B-spindle will result in geometry changes that are unnoticeable with all but the most aggressive drivers running against a stopwatch. Even at that, there's a good argument that the increased camber gain will have a positive impact on cornering while the increased toe-in through extension will go undetected.

 

[GTXKen]

I'm actually using 73 A body spindles so the geometry stays the same.

 

[GTXKen]

Its been almost 4 months but the plan is coming together. I have UCAs a new set of tie rods coming from Firm feel and the new caliper brackets for the 11.75 rotors coming from Dr. Diff. Time to pull those spindles out of the take and get them painted!

Anybody know where to get fittings for GM metric calipers?

 

[Budnicks]

I went with drilled & slotted rotors 10.87" some time ago, what a difference in stopping. Don't still have the car, but just the rotor change was night & day different. Budnicks

 

[GTXKen]

my new 11.75s are drilled and slotted. I'll take some pics of the parts and post em

 

[SIKPUP]

Where did you get your 11.75s that are drilled and slotted ?

SIKPUP

 

[GTXKen]

Well, started collecting parts in January and finally got it together this past week, got it aligned this morning!

 

[Deleted member 214]

Tell me if I'm wrong, but I thought that you could put the larger rotors on the old spindles if you got the taller caliper bracket off a larger rotor brake car, no need to change the spindle. I was hoping someday to find a set in a boneyard and swap in the bigger rotors. Yes?

 

[GTXKen]

Tell me if I'm wrong, but I thought that you could put the larger rotors on the old spindles if you got the taller caliper bracket off a larger rotor brake car, no need to change the spindle. I was hoping someday to find a set in a boneyard and swap in the bigger rotors. Yes?

The 11.75 rotor has a larger beering, you can use the old spindle if you get a bushing for it. The caliper brackets are a little hard to find unless you have a good mopar junk yard near you.

I used Metric calipers because they are a bit larger and there are better pads made for them.

 

[ga66mopar]

Tell me if I'm wrong, but I thought that you could put the larger rotors on the old spindles if you got the taller caliper bracket off a larger rotor brake car, no need to change the spindle. I was hoping someday to find a set in a boneyard and swap in the bigger rotors. Yes?

You are correct the larger rotors do fit on the spindles that came with the smaller rotors. I have never heard of a spacer being needed. Maybe he's talking about needing a spacer when using a 1967 spindle with the later model rotors?? All you need is to change to the taller caliper bracket. I used the 73-76 a-body disk brake spindle with the larger rotor on my 66. I mounted mine to the rear.

 

[GTXKen]

You are correct the larger rotors do fit on the spindles that came with the smaller rotors. I have never heard of a spacer being needed. Maybe he's talking about needing a spacer when using a 1967 spindle with the later model spindle?? All you need is to change to the taller caliper bracket. I used the 73-76 a-body disk brake spindle with the larger rotor on my 66. I mounted mine to the rear.

Read that again - The caliper brackets fit either spindle but the large 11.75 rotors DO NOT fit the original b-body disk or drum spindles. They do fit the 73-76 A body spindles, thats what I did. If you want to use the b-body spindles you need a bushing so that the rotor fits. Cass (aka...Dr. Diff) in Montana sells them. http://cgi.ebay.com/ebaymotors/70-7...ptZMotorsQ5fCarQ5fTruckQ5fPartsQ5fAccessories

 

[Mopar To Ya]

I did my 10.7" disc swap on a 70 RR about 20 years ago when the swap articles hit the scene and used the pin type calipers like you have. When I discovered my first Mopar Chassis book, I did the 1 inch at a time movement through the entire travel, measured toe, put into a graph just like the book with my original spindles and the A body. Played with lower BJ arms, idler, steering box and finally went to bumpsteer adjusters from Speedway and made my own tie rods (drag only car)

Has anyone out there really found a stock spindle that did not change toe and camber/caster during suspension travel? I want to know which one? I bleed for Mopars but just start measuring some radii on the suspension pieces of any car. They are what they are! Still 1000% better than the 11x3 drums.

 

[GTXKen]

To my knowlege the 73-76 a body spindles are identical except for the size of the rotor they accept. When compating the two all measurements are the same except the diameter of the spindle itself.

For the record I am running GM metric calipers and not Mopar pin type

 

[Mopar To Ya]

Sorry, missed the line about metrics in your earlier post (how dare you) Nice looking swap. My point was simply that although we as Mopar fans has often worshipped our T bar front ends and while I don't recommend anything that is unsafe for street driven vehicles, these suspensions had their limitations by design as all muscle cars did. The parts you added no doubt provide more adjustability/durability than any facotry set up and the work looks awsome. I was more poking some fun at thinking you can pick any stock components that won't produce significant changes in alignment specs througout their travel. Best to ya.

 

[GTXKen]

I had a hard time going to the GM metrics but the wide variety of pad and caliper availiable sold me. This brake set-up stops 100% better than the stock disc brakes did. I feel better driving the car so I will drive it more more!