Scarebird brake issues

[my5thmopar]

I've already talked with another member here that has a similar experience with his scarebird front disks. The brakes stop the truck good now but, I really don't like the pedal feel. I'm not looking for a fix to my brakes in this thread...... I'm just trying to find out if others have had similar experiences. I would also like to know your scarebird setup. When I changed to front disks, I immediately noticed a lower pedal and kind of soft. The manual drums all around would stop the truck quickly with a high hard pedal. I changed when I put the 440 in and I'm trying to modernize the truck. My setup started with manual front disk and rear drums. That wasn't great pedal and went to power with a 9 inch booster. That didn't help either so, I added rear disks. My pedal moves too much for my liking. Block off either front or rear and the pedal is high and hard. Put both together and the pedal will move a few inches. My theory is the pedal ratio is off and there isn't enough fluid volume. Anyone else with scarebird issues working good or bad? Craig

[PwrWgnDrvr]

Small diameter master has to travel a lot further to move enough fluid to fill all 4 caliper cylinders. But PSI is higher so pedal force (feel) is lighter.

[my5thmopar]

Small diameter master has to travel a lot further to move enough fluid to fill all 4 caliper cylinders. But PSI is higher so pedal force (feel) is lighter.

Agree. I’m using a 80s Dodge truck 1 1/8 MC now and it helped. I may try
A larger one or even one of the step MC but they say it is hard to bleed. Craig

[BigBlockTrucks]

I used scarebird on my 60 d 100. It has crown Vic rear axle with rear disc and a master cylinder with booster from a 93 camaro. I also used an adjustable proportioning valve. As I recall I redrilled a new hole in the brake pedal about an inch lower which gave more travel to the piston. The pedal is high with a firm feel. I am happy with it.

[my5thmopar]

I used scarebird on my 60 d 100. It has crown Vic rear axle with rear disc and a master cylinder with booster from a 93 camaro. I also used an adjustable proportioning valve. As I recall I redrilled a new hole in the brake pedal about an inch lower which gave more travel to the piston. The pedal is high with a firm feel. I am happy with it.

Isn't that mc 1 inch bore? Are you saying that you had an issue with the position or travel of the pedal or both? I'm trying to visualize how that effects the setup. Craig

PS I think you’re saying you drilled pedal to get the ratio closer to 4:1 which would help the pedal travel. I’m going to try that for my fix. Thanks

[PwrWgnDrvr]

A master cannot have more travel than the max it is designed/cast for.

[BigBlockTrucks]

I used scarebird on my 60 d 100. It has crown Vic rear axle with rear disc and a master cylinder with booster from a 93 camaro. I also used an adjustable proportioning valve. As I recall I redrilled a new hole in the brake pedal about an inch lower which gave more travel to the piston. The pedal is high with a firm feel. I am happy with it.

Isn't that mc 1 inch bore? Are you saying that you had an issue with the position or travel of the pedal or both? I'm trying to visualize how that effects the setup. Craig

PS I think you’re saying you drilled pedal to get the ratio closer to 4:1 which would help the pedal travel. I’m going to try that for my fix. Thanks

I believe it is a 1 inch bore. I redrilled for alignment reasons. I don’t know the bore of the original as there wasn’t anything when I started.

I did all of this ten plus years ago. It still works as well as ever. I was always curious how well it would work with weight in the truck.

[JLeather]

We've already spoken about this, but I'll throw my $.02 in on the thread for posterity. I've gone back and forth on my scarebird m/c and prop valve setup. I started with a 1 1/8" m/c and a GM PV2 prop valve. Truck stopped well, but pedal was way too soft. Probably 4"+ of travel. I changed to an 80's C20 1 1/4" m/c; pedal feel was great but the truck required too much effort to stop. I suspect this was actually due to the fact that I later discovered my loaded AC Delco front calipers apparently came without any grease on the slider pins and were stuck. I went back to a 1 1/8" for a while but recently seem to have settled on a good working combo. I'm now running a 1 1/4" m/c from a 70's F250 (I had to slot the holes slightly) and a wilwood adjustable prop valve. I think on a non-power scarebird install a 1 1/8" would be good, but for a power install I've only been happy with the pedal feel on the 1 1/4".

[BigBlockTrucks]

We've already spoken about this, but I'll throw my $.02 in on the thread for posterity. I've gone back and forth on my scarebird m/c and prop valve setup. I started with a 1 1/8" m/c and a GM PV2 prop valve. Truck stopped well, but pedal was way too soft. Probably 4"+ of travel. I changed to an 80's C20 1 1/4" m/c; pedal feel was great but the truck required too much effort to stop. I suspect this was actually due to the fact that I later discovered my loaded AC Delco front calipers apparently came without any grease on the slider pins and were stuck. I went back to a 1 1/8" for a while but recently seem to have settled on a good working combo. I'm now running a 1 1/4" m/c from a 70's F250 (I had to slot the holes slightly) and a wilwood adjustable prop valve. I think on a non-power scarebird install a 1 1/8" would be good, but for a power install I've only been happy with the pedal feel on the 1 1/4".

Out of curiosity,how much does your truck weigh. I have never weighed a sweptline but my 1960 mentioned above weighs under 3500. As said it stops well with a 1 inch master. Are you still running drums in the back?

Not discounting others ideas ,just getting the info on the site and learning at the same time.

[JLeather]

Not sure what mine weighs. If you redrilled your pedal pivot an inch lower, however, you would have reduced your mechanical leverage on your pedal which would offset the increased hydraulic leverage of the smaller m/c bore. Or are you saying you left your pedal pivot alone and redrilled the m/c pushrod mount hole an inch lower?

[BigBlockTrucks]

Not sure what mine weighs. If you redrilled your pedal pivot an inch lower, however, you would have reduced your mechanical leverage on your pedal which would redrilled offset the increased hydraulic leverage of the smaller m/c bore. Or are you saying you left your pedal pivot alone and redrilled the m/c pushrod mount hole an inch lower?

I was concerned when I redrilled the pedal about the leverage but I did anyway to make the booster work. I have extra pedals and figured it was worth a try.

What I redrilled was the arm of the pedal. I didn’t change the pivot.

With the help of the vacuum booster I figured it takes less effort to do the job.

[my5thmopar]

I put a late 80s gm master for a 1 ton truck on today. Like @JLeather It's an 1 1/4. This was the one hydro-boost guys use and it mates with the MC. I gained about 1-1/2 inch pedal height. I haven't panic stopped since it's raining here from Ida. I'm pretty happy with the pedal feel. I need to bleed the brakes again. I'm not sure if I'm going to drill the pedal. I suspect that the pedal will be higher but, the effort might become too much even with the power booster. I'll repot back with my findings. Craig