Help with brakes

[dart6]

Hi there, i'm looking for opinions about a 68 Superbee clone i recently bought. It has front discs with FMJ calipers and drums at the rear with 7/8in wheel cylinders. The manual m/cyl was 1 1/8 which gave a hard pedal and the braking was pretty woeful. I've replaced the manual m/cyl with a 1in one. i blew all the lines clear and the pedal travel increased a ton but the car is still hard to pull up. Extremely hard to lock up. Front and rear brakes appear to be newish.

 

[GTX JOHN]

We run 7/8 master cylinders on all our cars and it helped a
bunch in petal effort over 1 1/8.

 

[dart6]

We run 7/8 master cylinders and it helped a
bunch over 1 1/8.

With 1in the pedal is just off the floor

 

[493 Mike]

With 1in the pedal is just off the floor

That is too close! Is all the air out?
Mike

 

[lewtot184]

Try bleeding the system.it may take a few times to really get the air out. Check all connections to make sure they're snug. Make sure the distribution block isn't full of junk. I have an a- body disc, 11"drums in back , 1" master cylinder on my 65 dodge and the pedal is firm. It's not a perfect system but safe. The 11" drums with a power assit on my 69 r/ t are far superior.

 

[icetech]

Hi there, i'm looking for opinions about a 68 Superbee clone i recently bought. It has front discs with FMJ calipers and drums at the rear with 7/8in wheel cylinders. The manual m/cyl was 1 1/8 which gave a hard pedal and the braking was pretty woeful. I've replaced the manual m/cyl with a 1in one. i blew all the lines clear and the pedal travel increased a ton but the car is still hard to pull up. Extremely hard to lock up. Front and rear brakes appear to be newish.

I was running the 1.03" MC and the car didn't want to stop.. basically it would slow down gradually.. i just switched to the 15/16" alum MC and it's a massive difference... kinda wish it was 7/8 for even better pressure, have only had a couple of test drives but it's a huge difference over the 1"

P.S. my setup is manual slider disc/calipers in front and 10" drums rear..

Mopar Aluminum Master Cylinder Kit

Package includes new, aluminum master cylinder with large rectangular reservoir, billet aluminum 4 hole or 4 stud adapter and push rod retaining ring.

www.doctordiff.com

 

[Ron H]

Elementary question, but was new the MC bled?

 

[WileE]

When all else fails ...

 

[HALIFAXHOPS]

Back to basics is the brake pushrod adjusted properly?

 

[4mulas]

Something is not right with the master or the bleeding of it

 

[4mulas]

Back to basics is the brake pushrod adjusted properly?

There is no real adjustment on a manual pushrod. It’s either in the master or not.

 

[RemCharger]

There is no real adjustment on a manual pushrod. It’s either in the master or not.

True, but if it's too short, then time for an adjustable one. Or some type of " adjustment" to the original.

 

[BigFlo]

When I put manual discs in the front (10” drums in rear), I also used the 15/16” master cylinder from Dr Diff. Before my rear drums were adjusted properly, my pedal was low and soft. I would make sure the rears are adjusted properly first and all air is bled out of the lines. You didn’t mention a proportioning valve. If you have one, is it adjusted properly?
After adjusting these things in my system, I have very good pedal feel and stopping power - and I don’t have to stand on the pedal.

 

[dart6]

Hey thanks a lot of good responses here. I'll go through and rebleed it.
It has a proporting valve. How do you know when it is adjusted right?
The pushrod is adjustable

 

[RemCharger]

It should be adjusted so the rear brakes don't lock up.

 

[GTX JOHN]

There are adjustable pushrods available.

OR the stock one could be extended with a sleeve around it to
preserve the integrity and strength of it,

 

[BigFlo]

Prop valve adjustment process from Wilwood. Make sure those drum shoes are also adjusted correctly

 

[1STMP]

You might also check to see
if the new master has
residual check valves
installed. (2lb front, 10lb
rear). You may have
inadvertantly aquired a
master for a 4 disc system.

 

[OneWheelPeel]

You might also check to see
if the new master has
residual check valves
installed. (2lb front, 10lb
rear). You may have
inadvertantly aquired a
master for a 4 disc system.

What would that look like?

 

[1STMP]

What would that look like?

Where the brake lines run
into the master, there will
be a brass fitting similar to
a carburator jet. If they're not
there, then the master you
have is for a 4 disc system
unless the residual check
valves are installed
somewhere inline of each
front or rear circuit. You
can purchase the inline
types from Summit if your
system is void of any.

Edited to wish you a Happy
New Year!