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My experience - Scarebird Front Disc Brake Conversion

bobfake

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Hi all,

I thought I'd share my experience installing the Scarebird (US Car Tool) front disc brake conversion on my '68 Super Bee. I did this over the past weekend and I've included pictures below.

To start - my experience was really good. I did run into a few things that I will mention here and I had a conversation with John Pasemann who owns US Car Tool/Scarebird to let him know.

I did this conversion by myself, with the exception of bleeding the brakes where I had my wife help me. Otherwise...just me.

I met these guys at the Chrysler Carlisle show a few weeks ago and the thing I really liked was that with the exception of their engineered caliper brackets, everything else was off the shelf. I was able to use my existing drum brake spindles and everything clears my 14" road wheels!!! I was concerned that the 11.75" rotors would cause a clearance problem (they didn't). I also opted to buy their "monster calipers" which are the same as the ones on the parts list, but they are modified to have a 2.75" piston instead of the smaller stock piston. All in, I think I'm just over $600.

Here's the parts list...as you can see, everything is available at your local parts store:

Scarebird Brake Parts List.png


The instructions are not complicated, but there were a few areas where they were a bit unclear. I mentioned these to John and he's going to have them updated to be more clear. Those areas are:

1) The 4 holes in the caliper brackets to mount the bracket to the spindle were just a bit too small. I enlarged them by a couple of thousandths to get my existing bolts to fit. No compromise of the bracket's integrity.
2) There are bearing spacers that slide onto the spindle and the inner bearing rides on. The picture was not very clear as to their orientation.
3) Regarding the bearing spacers, they state that if they are "too loose" on the spindle to add some Loctite. But what does "too loose" mean in this context? Mine fit snugly, so I didn't worry about it.
4) When talking about the "residual pressure valve", they reference the "upper left picture", but it is actually the picture on the right on the previous page.
5) The dust caps are a bit looser than I think they should be, but they are on so far.

With another set of hands, I probably could have gotten this completed in a day. The car stops tremendously and with no pulling to either side. What a joy to drive!!! All in all, I highly recommend looking at the Scarebird option if you want disc brakes on the front of your B body.

My 11"x3" drum assemblies with pads are available for sale if anyone is looking for them.


Scarebird Disc Brake Conversion (2).JPEG
Scarebird Disc Brake Conversion (3).JPEG
Scarebird Disc Brake Conversion (5).JPEG
Scarebird Disc Brake Conversion (8).JPEG
Scarebird Disc Brake Conversion (9).JPEG
Scarebird Disc Brake Conversion (10).JPEG


Scarebird Disc Brake Conversion (4).JPEG


Scarebird Disc Brake Conversion (6).JPEG


Scarebird Disc Brake Conversion (7).JPEG
 
I like the idea of scarebird as you mentioned using off the shelf parts. Is it a drum master cylinder or a disc master cylinder?
 
I like the idea of scarebird as you mentioned using off the shelf parts. Is it a drum master cylinder or a disc master cylinder?
I believe it’s a drum master cylinder. Dual reservoir. USCT/Scarebird stated the factory master cylinder works. Only concern I would have is if the car has a single reservoir master cylinder, then you have to be really careful to make sure it doesn’t run dry as the pistons expand as the pads wear.

Mine looks like this:

IMG_5831.jpeg
 
So it uses a transmission front pump seal as a wheel seal?
Yes…strangely. But it works. One would think a seal for a 77 Cordoba rotor would be the right part but…

Here are all of the part numbers needed for my conversion. All from Rock Auto except the brackets and calipers/pads which I got from USCT/Scarebird:

IMG_5833.jpeg
 
I used a scarebird kit on my 69 Cuda about 8 years ago and it worked great. For a while the company was having a hard time keeping stock, as I tried to order a kit for another car a while back and they did not have the parts. But yes a decent price and it works good.
 
I believe it’s a drum master cylinder. Dual reservoir. USCT/Scarebird stated the factory master cylinder works. Only concern I would have is if the car has a single reservoir master cylinder, then you have to be really careful to make sure it doesn’t run dry as the pistons expand as the pads wear.

Mine looks like this:

View attachment 1897137
This is a drum front and rear master cylinder.
Part of the problem is that they potentially don't have a large enough reservoir for the disc brakes as they wear.
But most of our classics don't get driven enough to get close to that point.
I don't like a single pot master cylinder on anything you plan to drive, a single point of failure and you have no brakes.
 
Another feature of a drum master cylinder is that they have a residual valve in each circuit, that retains a small amount of pressure that keeps the cups from collapsing in the wheel cylinders. The disc brake master cylinder omits this residual valve in the front brake circuit, allowing the fluid pressure to fall back to zero. This allows the caliper piston to fully retract by the design of the piston seal, disengaging the brake pads from the rotors.
By using a drum brake master cylinder with front disc brakes, a small amount of pressure (about 3 lbs.) is retained in the front circuit, causing the pads to be constantly applied against the rotor, causing a drag. The front brakes will eventually heat up and seize. When I first converted my 1964 Polara to disc brakes, about 40 years ago, I did not understand this dynamatic, and used a drum brake master cylinder. On my first test drive with my new improved braking system, I had to be towed home, because my front brakes seized up. Just saying.
 
Can the residual valve be pulled from the drum master? I seem to remember it lives right under the line fitting.
EDIT: Nevermind, scarebird instructions mention this:
"Check the master cylinder before installing it to verify it does not have a residual pressurevalve as shown in the upper left picture. A simple poke with an unbent paper clip will show ifyou have this valve. If it does it must be removed."

Also how far dd you make it before they seized up? Just wondering if its evident after a run around the block or if it takes longer, and if someone falls to this after X miles, could they crack the line at the MC to relieve the pressure and limp home?
 
Last edited:
Sorry - I should have mentioned that. I am using the dual reservoir manual master cylinder. Works great. A lot less pedal pressure required than with the drums.
You mention "dual reservoir" twice but every 1968 and later car had those anyway.
It is great that this has worked out for you.
 
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