scarebird disk brake conversion on 1964 880

[Markus]

I found that the calipers were too tight in the Scarebird brackets so I relieved them so they could move. But even after that the fronts would still bind up.
But now I think I have narrowed it down to the adjustment rod in the booster that pushes on the master cylinder. I have made several adjustments and its either no brake bind and hard to stop or the front brakes hang up a little and it stops great. Tomorrow I'm going to work on it a little more.

 

[traintech55]

I found that the calipers were too tight in the Scarebird brackets so I relieved them so they could move. But even after that the fronts would still bind up.
But now I think I have narrowed it down to the adjustment rod in the booster that pushes on the master cylinder. I have made several adjustments and its either no brake bind and hard to stop or the front brakes hang up a little and it stops great. Tomorrow I'm going to work on it a little more.

This seems to be a common problem lately. Another member went through the same thing with his conversion. I think he had to send his back to the rebuilder. Good luck.

 

[saylor]

markus - make sure your lines are in the correct spots on the MC front/rear circuits.

was there already a prop valve on the car? maybe follow the brake line from MC downwards about a foot - was there some kind of brass block there already?

when stabbing the MC to booster, you want the pushrod to hold the MC about 1/8" out from flush. like you cannot by hand set the MC flush because of the pushrod. if you stab the MC on and it hits the mount plate/firewall, make the pushrod longer with the adjusto tip on the end of the rod. then use lock nuts and tighten that sucker down.

if you added an aftermarket prop valve of any sort - set it to neutral or wide open so it is not in play right now, like make sure it is balance 50/50 and not reducing any pressure to either front or rear - we want it not doing anything yet.

try not to die -

- saylor

 

[jake]

I had to do multiple adjustments with my pushrod, half a turn is a ton. I drove around with a 1/2 speed wrench and would pop my master and adjust on the side of the road. Once i honed it in, she stops on a dime and does not drag one bit.

 

[Markus]

Saylor - Thanks for the heads up on centering of the combo/prop valve! That's exactly what it was, back brakes weren't even engaging because of being off center. Now I just need to rebleed after I borrow the tool that keeps it centered while bleeding. It would have been nice if CCP would send directions and maybe this tool to make sure guys do this everytime, it sure would alleviate a lot of problems.
Jake- I totally agree! I was only turning rod in or out a 1/6th of a turn at a time. Now that I'm on the right track, I will be dialing it in.

 

[saylor]

holy **** I may earn a hat someday. well kick *** man. bleed that sukka! careful on the bleeders don't strip them.

go find an empty mall parking lot or office parking lot or lowes or somewhere so we don't kill anyone. go about 20 mph and lock em up. adjust prop valve as needed. do that about 50 times before you get out on the road for real. you want the fronts/discs doing most of the stopping work, but if you lock em up into a skid condition, the rears will lock and slide you out. adjust to the forward a bit more. with that adjuster you may be able to get pretty accurate on the pressure application front/rear.

also go in reverse and brake many times.

once you have the line pressures set and balanced nice, and the brakes will bake in a bit and start to get a seat from you going forwards/backwards all over the parking lot, you are gonna be aight.

try not to die -

- saylor

 

[Markus]

Got the combination/prop valve centered, but still no difference. Front brakes still hang up, turn back the pushrod LITERALLY 1/6th of a turn and the brakes barely slow you down, turn it back a 1/6th of a turn and the damn thing locks the front brakes up! I'm about done with this and going back to drum brakes.

 

[Slantsix]

How much pedal travel you have?
Is that kit designed to be used with manual brake pedal and linkage? Because most Mopars has more pedal ratio with manual linkage than with boosted. I doubt its brake pedal or linkage, but trying to think outside of the box.

 

[Markus]

I had power drum on it previously. I appreciate it tho!

 

[xander18]

Hey guys,

To anyone who did a Scarebird swap (preferably on a <64), what dual diaphragm booster did you use? Looks like there are a few part numbers off of Imperials in the late 60s. But RockAuto lists some as single diaphragm that sure look like duals and I'm not sure if some will have a fitment issue on my 64 Newport.