Suspension TECH Including Brakes, Wheels and tires

          
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  #1  
Old 02-15-2024, 12:20 PM
joes455 joes455 is offline
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Default Rear drum to disc

76 ta ,I have the disc backing plate,from a 80 ta,I want to use the s10 calipers (as recommended).Question is do I use the stock rotors for a 80 ta?E brake not required.Im doing this conversion just to feel the difference before I buy the $300 plus calipers and to make sure there is no problem with the Moser axles as far as rotor centering with calipers.Any other tips welcomed.I aware of axle centering hub being shallow at .500 ,I'm using 10" rally2.

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Old 02-15-2024, 12:58 PM
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Honestly, if you want discs on the rear, I'd just go ahead and buy the kit you're looking at, instead of trying to put something together very cheaply just to see if you will like them. That last part being the issue. You're not going to "feel a difference" with a basic disc setup in the rear of the car.

The front brakes do the vast majority of the actual braking on these cars. The weight up front and the dive dynamics mean the rear wheels do relatively little. In fact as you start putting big powerful brakes on the back of these cars, managing brake lock-up becomes somewhat difficult.

The advantage of disc brakes on the rear don't really have much to do with outright stopping performance. Especially if the tire package isn't changing. The advantages show up in less unsprung weight, better heat dissipation for more repeatability and in my opinion, better looks.

Your car isn't going to feel much different or stop any better during a one time panic stop than it will with your rear drums.

If you are after the look, or know that how you want to drive the car will require better repeatability in the braking system, then you want the disc brakes back there and there's really no reason to try a set on first before going with the setup you ultimately want. If you're committed to disc brakes for the reasons above, save the time and money on your test setup and go straight to the setup you want. You'll be money and time ahead.

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Old 02-15-2024, 01:04 PM
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Joe, if you are in the Jacksonville Fl area, I would be more than glad to swap brakes and I go back to drum rear brakes on my 78 TA. I pulled all the parts from a 1980 bird and installed on my rear diff. They work ok but brake pedal feel was better when I had drums.

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Old 02-15-2024, 01:36 PM
joes455 joes455 is offline
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Thanks Jason,what kit would you recommend?I like the in rotor E brake.On a side not ,the drums always have runout.I also have a adjustable pressure control valve going to the back.Thanks Doc,but I'm keeping all the original drum brake besides don't want to deal with oem E brake .

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Old 02-15-2024, 01:44 PM
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If you're not planning on doing anything different with your OEM front setup, I'd recommend one of Wilwood's 11" rear disc packages. They will have a drum in hat ebrake setup like you are wanting. I don't know if scarebird is still selling parts or not, but he also has a ford explorer package that uses a drum in hat ebrake system as well.

If you're planning on a complete brake package upgrade, while still utilizing your 15" rally ii's, WilWood claims they can get their 12" rotors with a forged narrow superlight 6 piston caliper in the front and their dynapro 4 piston caliper in the rear, inside a 15" wheel. You can go to wilwood's site and get wheel fitment templates of their various offerings. You'd want to measure the wheels first.

Even if their "kit" doesn't come in the necessary flange offset you need in the back, they have spacers for the backing plates that you can purchase at minimal cost to change things as necessary to get the flange offset and caliper centering accurate. I did that on my rear kit where I needed a 2.75" flange offset verse a more standard 2.81" offset.

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  #6  
Old 02-15-2024, 03:28 PM
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Quote:
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I...I don't know if Scarebird is still selling parts or not, but he also has a ford explorer package that uses a drum in hat ebrake system as well....
No, I am retired. I did however sell the rights to USCT and they could build the rear setup. This has nothing to do with the Ford Explorer but uses Citation front calipers (2-1/4" piston) and S10 rear 2WD rotors.

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Old 02-15-2024, 03:39 PM
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Quote:
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No, I am retired. I did however sell the rights to USCT and they could build the rear setup. This has nothing to do with the Ford Explorer but uses Citation front calipers (2-1/4" piston) and S10 rear 2WD rotors.
Thanks for the clarification. I'm sure this will be helpful for people looking.

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Old 02-15-2024, 04:42 PM
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Thanks Jason,my axle offset came in at 2.70 with axles pushed in against different cross shaft.I guess it should be measured with c clip against clutch pack.Wiwood had the kit I need pn 140-14400.

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Old 02-15-2024, 07:08 PM
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Who makes a caliper that will fit the oem back plate with out the E brake?

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Old 02-15-2024, 07:41 PM
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Will a D52 front caliper work? Looks really similar.

  #11  
Old 02-15-2024, 08:30 PM
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Thanks Doc ,in my notes I show a D52,but have no idea what model and make car to order from

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Old 02-16-2024, 07:08 AM
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That will be the factory front disc caliper for your car.

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Old 02-16-2024, 07:23 AM
Red80TA Red80TA is offline
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Americans don't use park brakes anyway.

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Old 02-16-2024, 08:22 AM
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Quote:
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That will be the factory front disc caliper for your car.
Not necessarily:

D52 is a pad designation for GM pads used from 1969 to the early 90's. Calipers that used this pads had at least a dozen different hose configurations and widths (for 1" and 1-1/4" thick rotors) along with SAE and Metric banjo bolts (or the hose went straight in, ala Cadillac Eldos).

Almost all used the 2-15/16" piston.

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Old 02-16-2024, 12:36 PM
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If I go to the auto zone what application should I give ? Also what rotor?My intention is to see if I will like disc brakes with the cheapest caliper .I believe that the reason these disc brakes have bad reviews is partly due to the stock brake lines size and going to a next size up 5/16 makes a bid difference

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Old 02-16-2024, 01:14 PM
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Are you fabricating mounting brackets yourself? I don't know if I've ever seen anything off the shelf with the 7.06" mount spacing necessary to run the big caliper with the d52 pads.

This is the type of kit you typically see. This uses non-ebrake metric calipers on a 5.48" mount spacing. The most common complaint I see about these rear kits is a soft pedal and it's almost always because getting the ebrake provision calibrated properly is insufferable. Using a non ebrake metric caliper in the rear takes that out of the equation.

https://www.speedwaymotors.com/GM-10...RoC2CcQAvD_BwE

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  #17  
Old 02-16-2024, 03:24 PM
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Thanks for hanging in there with me Jason,caliper will be from a 82 malibu,now I just need rotors.Any suggestions?

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Old 02-16-2024, 04:39 PM
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79-81 TA rear disc plates take a "metric" size D154 caliper like on late 80s Monte Carlos but had a ratchet e brake in the piston that often locked up. If you do not need an E brake D154 calipers can work fine with the 11" TA rotor C tek part #121.6025. Those calipers are used in a LOT of the after market rear brake kits.
I have the full TA with ratchet calipers on both my TAs silicon fluid is the trick to helping not lock up.

My IA/Camaro has a 12 bolt with the backing plates and D154 calipers and flex hoses to them. On all cars the front lines are T'd and rear has an adjustable prop valve in it. It is manual MC Mopar roughtly 15/16 with Wilwood Dynalite kit on the front.

Power booster, MC and pedal ratio all affect pedal feel. TA 4WD used a dual diaphragm booster that needs an even lower ratio pedal than regular power brakes .
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Last edited by Skip Fix; 02-16-2024 at 04:48 PM.
  #19  
Old 02-16-2024, 04:47 PM
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Over on NastyZ28 there is a list of parts for an S10 rear disc setup.
And if you want a blingy D154 caliper Wilwood makes a dual piston one!

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1978 Trans Am original owner 10.99 @ 124 pump gas 455 E heads, NO Bird ever!
1981 Black SE Trans Am stockish 6X 400ci, turbo 301 on a stand
1965 GTO 4 barrel 3 speed project
2004 GTO Pulse Red stock motor computer tune 13.43@103.4
1964 Impala SS 409/470ci 600 HP stroker project
1979 Camaro IAII Edelbrock head 500" 695 HP 10.33@132 3595lbs
  #20  
Old 02-16-2024, 04:59 PM
joes455 joes455 is offline
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Thanks Skip,what is a ratchet e brake?

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