Manual brakes are scary

[AC64]

I have discs in front & drums in the rear. I don’t think I could lock them up on sheet ice with both feet on the brake pedal. The sensation while braking is like a power brake car with the engine off. The pedal is up with no spongeness, but just doesn’t stop. What is the best master cylinder to use if you are unable to use a brake booster?

 

[Bighouse]

Factory parts? If so find out what car had non power disc/drums if any did and go from there.

 

[Beekeeper]

Sounds like the bore in the master cylinder may be too big

 

[65hemi]

I had a similar issue. Switched to 15/16” mc and braking was way better.

 

[diesel_lv]

I've got 15/16" master on my disc/drum on '67 4dr Coronet n it stops on a dime. If I stomp, it'll 4 wheel lock easily.

 

[hunt2elk]

I use a 15/16" master on all 3 of my manual disc/drum cars as well. They all stop a lot better than you are describing.

 

[Outsider]

Sounds like what the previous posters said about mismatched master cyl, or the rotors are glazed.

 

[MoparLeo]

What kind of mystery car is it and are the brakes original or a conversion ? Details always help.

 

[AC64]

Sounds like the bore in the master cylinder may be too big

You know what——that’s what I was thinking, as the pedal travel is maybe an inch & feels like you are pushing on a brick. Anybody have a part #?

 

[AC64]

I've got 15/16" master on my disc/drum on '67 4dr Coronet n it stops on a dime. If I stomp, it'll 4 wheel lock easily.

Are your master cyl reservoirs different sizes—-smaller in front & larger in back?

 

[AC64]

What kind of mystery car is it and are the brakes original or a conversion ? Details always help.

It’s a 64 max wedge car with disc conversion in front & drum rears

 

[hunt2elk]

@srw-409. You will have to explain the big red "X" for a simple statement I made that is indeed a fact.

 

[Beekeeper]

Are your master cyl reservoirs different sizes—-smaller in front & larger in back?

The disc/drum master does indeed have a larger reservoir in the rear for the fronts. And the common one used is for a 74 or so A body disk/drum with 15/16” bore.

 

[MoparLeo]

Aftermarket conversion ?Brand/type. How complete ? calipers, prop valve, master, brake size front/rear? Trying to get more details on what you have to help with diagnosis. More info, better help.

 

[AC64]

@srw-409. You will have to explain the big red "X" for a simple statement I made that is indeed a fact.

Very sorry—-I’m on my iPad & it seems I’m all thumbs

 

[kiwigtx]

@srw-409. You will have to explain the big red "X" for a simple statement I made that is indeed a fact.

More than likely a bad case of 'Fat fingers' - the guy has been here 13 years, and has made 65 posts in that time.....not really what you'd call a solid contributor.

 

[AC64]

Aftermarket conversion ?Brand/type. How complete ? calipers, prop valve, master, brake size front/rear? Trying to get more details on what you have to help with diagnosis. More info, better help.

Thanks Leo—just really digging into it now. Master appears to be a two circuit drum/drum, as both reservoirs are the same size. Has a thumb screw type prop valve. I am pulling wheels tomorrow to verify type & brand of hardware

 

[71charger_fan]

I have front discs off of a Volare and a Dr. Diff rear disc conversion. I'm using a RAYBESTOS MC36412 and am very happy with the braking performance. I love the feel of manual brakes.

 

[Cranky]

I've had lots of cars with manual brakes including a manual 4 wheel drums on a 10.60 car that stopped just fine while and aftermarket 4 wheel disc 9.90 car stopped like crap. Sounds like you have the wrong MC and what does it do when you change the bias with the adjustable Pvalve?

 

[AC64]

I've had lots of cars with manual brakes including a manual 4 wheel drums on a 10.60 car that stopped just fine while and aftermarket 4 wheel disc 9.90 car stopped like crap. Sounds like you have the wrong MC and what does it do when you change the bias with the adjustable Pvalve?

Thanks cranky—-had a 12.00 Belvedere in the 60’s that I never had a problem stopping. I believe it’s got a drum /drum MC on a disc / drum system. I don’t want to adjust on the prop valve for fear of making it worse before I pull the wheels and verify hardware.