Brake Question

[Jim Yergin]

Jim, have you thought of using an Explorer master cylinder,

since you are using an Explorer rear setup?

Robert,

Thanks for the suggestion but I don't think that will work. The Explorer uses a power assist to create the necessary pressue and the master cylinder bore is over 1". I don't have power assist so that is why I went to a smaller bore master cylinder.

Jim Yergin

[DJ194950]

Jim are you using something like this to determine brake pedal ratio?

[Jim Yergin]

Yes. I am trying to decrease the "Y" distance in the right hand diagram.

Jim Yergin

[Robert Horne]

Robert,

Thanks for the suggestion but I don't think that will work. The Explorer uses a power assist to create the necessary pressue and the master cylinder bore is over 1". I don't have power assist so that is why I went to a smaller bore master cylinder.

Jim Yergin

I am using a master cylinder from a 94 Bronco, with the bore over 1 inch, I believe 1 and 1/8.

I am not using the power assist. Working great the past couple of years.

It takes no more to foot pressure to use the 1 and 1/8 MC, than it did with the small bore MC,

I was using several years...

[Jim Yergin]

Robert,

Do you have Explorer rear disc brakes?

Jim Yergin

[Robert Horne]

Robert,

Do you have Explorer rear disc brakes?

Jim Yergin

No, I have Ford Ranger drum type.

I know it is like comparing apples and oranges with these brake modes.

I believe needed brake stop power comes down to the gross weight of the vehicle,

more than if using drum or disc, power assist or not, size of MC, etc.

I have experimented with several type setups on my Plymouth, and it still

takes about the same amount of foot pressure.

My old Chevy Van, 4200 lbs, non power assist, takes just a little more foot

pressure than all the setups I have used on my 3000 lb Plymouth.

With my Van, I prefer this setup in wet or snowing conditions over all the

modern all disc, power assist, anti locking, modern setups available.

[Don Coatney]

Jim are you using something like this to determine brake pedal ratio?

Great explanation of pedal ratio. I have saved this to my files. Thanks for posting!

[Jim Yergin]

On to plan "B". I changed the pedal ratio to what I calculate to be 6.5 to 1. Did not improve the brake performance. In fact it was worse. It appears that it now requires a longer throw. I have decided to take ECI's advice and install Explorer drum brakes on the rear. Went to the salvage yard today and got drum brake backing plates to install the drum brakes. Will let you know the results. Now that I have the car running very well I really want it to stop just as well.

Jim Yergin

[Dave72dt]

I would expect it to have more travel.  That's geometry.  It also means if you had some way to measure  the pressure you applied to the pedal and a brake line pressure gauge installed, it would take less effort on the pedal to achieve the same line pressure.

Edited May 26, 2014 by Dave72dt

[Don Coatney]

I would expect it to have more travel.  That's geometry.  It also means if you had some way to measure  the pressure you applied to the pedal and a brake line pressure gauge installed, it would take less effort on the pedal to achieve the same line pressure.

I agree. More pedal travel is the cost of less foot pressure.

[Andydodge]

Jim, I have been running 4 wheel disc brakes on my 1940 Dodge since about 1976/77..........and it stops fine..........what I have is as follows and whilst these are obviously from Australian only cars the basic design, premise should be similar.........on the front 1940-56 style independent front end I have 1974 Leyland P76 11" vented disc brakes made by PBR in Oz, these are approx. 1" thick and use a Ford/Mopar bolt pattern.......the rear brakes are Oz 1990 Ford Falcon non vented 11" discs attached to the 1990 Falcon rear axle........so I have vented and non vented discs.........the master cylinder is a standard 1974 Leyland P76 Dual Circuit master cylinder made by PBR, this master cylinder when used on the standard Leyland was in a Disc/Drum brake system however I made inquiries when I built the car and found that by removing the rear brake proportioning valve this master cylinder would work fine as it was the same one used by Oz Ford in 1976 when they used a 4wheel disc setup on the Falcon GT's.........in fact I have used the Leyland master cylinder AND power brake booster..........the car has pendant hanging pedals with the pedal assembly a 1963 Chev Impala pedal assembly modified by lengthening the pedal 2" to allow for the difference in floor to dash height between the 1940 Dodge and 1963 Chev.........this car stops on a dime.......if anything the pedal maybe a little too soft but after nearly 40 yrs I'm used to it................I would suggest you get in touch with a brake specialist company and give them all the particulars............there is a place here in Oz called Hoppers Stoppers, they are on the net and may be able to give some unbias advice via email...........I don't have any pics of the rear end and the front end pics are not really any use but I do have some of the engine bay showing the master cylinder/booster.............I find it astounding that you have been recommended to go back to a drum brake.........wish I could offer any other assistance.............good luck & regards, Andy Douglas         

[Jim Yergin]

Today I finished the installation of the 1994 Explorer 10" drums on my rear axle in lieu of the disc brakes. The brakes on my car now work better than ever. It has gone from being a terror to drive to now being a pleasure.

I reinstalled the 1" bore master cylinder and replaced the 2lb residual valve in the rear with a 10 lb. Had to modify the lower shock plate under the leaf springs to allow the backing plates to fit.

Jim Yergin

Edited June 15, 2014 by Jim Yergin

[Don Coatney]

Glad to hear all is better.

[Conroe Powdercoating]

thats awesome to hear you are happy driving it. I am going through that now, I love the car, hate the brakes. so now its up on stands and I am doing an explorer drum rear and making disc brackets and using explorer disc . I love driving my car, I just want it safe to drive.