power to manual brakes

Bryan · Post by **Bryan** » Mon Jul 18, 16 2:57 pm

If converting a car from power to manual brakes, due you have to change the brake lines or do you use the existing?

i may answer my own question here, i suppose it depends on what size connections the master cylinder has?

or do you order a manual master cylinder using your existing size?

Sorry for going around the houses.

Pete · Post by **Pete** » Mon Jul 18, 16 3:04 pm

I am not convinced that you need to change the M/C unless you are also going from Drum to disc (and even then you can remove the residual valve from the M/C).

IF you can bend the pipes back and mount the M/C, it may be worth just trying the original one first. You may find the pedal pressure is not acceptable but that is personal choice.

Push Rod may be an issue - I have just bought an adjustable one as I have changed Master Cylinders on the Challenger.

Bryan · Post by **Bryan** » Mon Jul 18, 16 3:25 pm

I already have discs on the front.

Have i got this right... remove the servo part and remount the existing M/C and order a new pushrod?

Pete · Post by **Pete** » Mon Jul 18, 16 3:30 pm

I don't know.
It's one of those situations where you just have to try it to see how it works out.
The push rod that is attached to the brake pedal may work just fine, but I doubt it....You will probably need an adapter plate - I did as I was going from 4 bolt M/C to a Bananarama! 2 bolt one.

mopar_mark · Post by **mopar_mark** » Mon Jul 18, 16 6:04 pm

Manual Brake pedals typically have a higher ratio, than a non manual brake pedal.

Manual Pedal: 5 or 6:1
Servo pedal: 4 or 5:1
These are not actual ratios, more of a guideline, but wont be far wrong

Ratio is determined by;
Distance from the fulcrum point to Pedal centre
Distance from the fulcrum point to the centreline of the master cylinder

Do the manual conversion 1st & try it out.... strong legs, big boots all help & pedal pressure may feel OK

Mick70RR · Post by **Mick70RR** » Mon Jul 18, 16 6:29 pm

Power brake cars use a bell crank behind the firewall to reduce the pressure to the master cylinder. Because of the bell crank the master cylinder is mounted lower on the firewall. I'd guess it would be quite a bit more work than you may think.

Blue · Post by **Blue** » Mon Jul 18, 16 9:08 pm

First of all Bryan, are we talking Mopar here? I known you've been working on a Ford.....

Bryan · Post by **Bryan** » Mon Jul 18, 16 9:36 pm

Hi Blue, its on my Ford but i was assuming the principle would be the same.

Blue · Post by **Blue** » Tue Jul 19, 16 6:35 am

Thought this might be the case. I can only talk Mopar, it's all I have any experience of, but as you say some of it will be similar. I normally order up a new manual M/C to suit the new set up as the bore size is usually different, you will need the correct pushrod for it as well and whatever Ford uses to stop it falling out of the M/C, Mopar use a flat round grommet. Strip off the servo and bellcrank assy. back to the pedal. New M/C and pushrod should be a striaght bolt in to the original position. Brake pipes can normally be bent to line up and connections are the same size.