Hi guys, after having some problems with my Master Cylinder, booster and so... I decide to upgrade my brakes system, but I need some clarification.

My original truck configuration (F150, 1986) is using a 1" Iron master cylinder, a pressure differential valve and it has built in an Anti Panic valve, Rear wheel cylinder 7/8" and standard light duty front calipers, no proportional valve is installed nor bleeder pin (I'm in Venezuela, our trucks usually has some minor differences with those made in USA)

Recently the rear wheel cylinders where replaced to 15/16" and also a set of "almost new" front calipers coming from a Bronco 1995. Now I found also a "almost new" 1 1/8" aluminum master cylinder, coming from a F350-1994 and a proportional valve from a F150-1993.

I want install this M/C and proportional valve but my questions are:

1º Should I remove the Differential Pressure Valve and install standard distribution blocks?
2º Should I leave the Differential Pressure Valve BUT remove the Anti Panic Valve?
3º Should I leave all systems as is and just install the Master Cylinder with its own proportional valve? any interference between valves??
4º Installing this 1 1/8" M/C will give too much breaking power?

My trucks weights about 4.700 lbs and sometimes is used to pull a fishing boat&trailer about 1.100lb + 200 lb stuff. Beside that, it is mainly a highway used truck, no load.

I apologize for this long post, but I want be as clear as possible. Any help will be appreciated.

 

No ideas guys???

 

your brakes are a crucial parts to your vehicle..any deprivation in braking power means youre in a danger of losing control..see youre truck pulling a fishing boat and trailer with a heavy weight..you should upgrade your braking system and other parts of your vehicle with a newly one with the help of professional mechanics that will give you the finest brake assistance.

 

Yes your are right, but since I'm located in Venezuela, there is not too much people good knowledge about brakes, so that's why I ask you guys...

Any more ideas???

 

> 1º Should I remove the Differential Pressure Valve and install standard distribution blocks?

No, if you lose a brake circuit it shuts it off and gives you at least some braking power from the other circuit.

> 2º Should I leave the Differential Pressure Valve BUT remove the Anti Panic Valve?

Leave the ABS system too, especially if pulling a trailer. It will help prevent both the truck and trailer locking their drum brakes up at the same time. Especially when braking while going down a slippery/rainy incline.

> 3º Should I leave all systems as is and just install the Master Cylinder with its own proportional valve? any interference between valves??

Just install the F-350 master cyl (booster combo if you have it).

> 4º Installing this 1 1/8" M/C will give too much breaking power?

No.

 

Thanks for the input. Some clarification...

There is no ABS installed on that truck (Jet ) What we know here as Anti-Panic valve is some sort of pressure accumulator installed for the rear brakes, it accumulates pressure for 1 second or so if you kick brakes, this reduce the initial wheel blocking a lot...

It was used before the proportional valve was factory stock item.

 

javi2001,

Increasing the size of the M/C will DECREASE your brake line pressure for a given pedal pressure & boost. Going from 1" to 1-1/8" will decrease your braking power by 21%, assuming no changes in the wheel cylinders. Increasing wheel cylinder diameter does increase breaking, so your rear cylinder modification partially compensates for the increased M/C diameter.

If you did not change the front cylinder diameters, then you are more likely to lock up the rear & go sideways. I think the purpose of your "anti-panic" valve is to help delay locking up the rear wheels, so I think you should keep it.

The bottom line for you (& all of us pickup people) is that a pickup sometimes has no load in the back and sometimes has a lot. This makes it tough to engineer the braking system properly. I recommend that no matter what you do you do some testing under conditions where you can't get into too much trouble. Do panic stops (building up from low speeds) and see what locks up first. (It may help to have an external observer.)

In my opinion, too much brake in the rear will get you into more trouble than too little. Some ballast in the bed might help you avoid the extreme problem of going sideways when unloaded. I like the idea of a piece of steel plate that does not take up any of your bed space. Use a couple of bolts to hold it in place and take it out when you need full capacity. (It will also give you a better ride & handling with little loss in mpg & acceleration.)

 

Hey that was the kind of input I was looking for... Thanks a lot.

Well, you are right, I did lost some breaking power in the front & compensated to rears by cylinder change. It right now is giving a lot of breaking power in the rears it was exactly what i was looking for since my truck is not used for load so often BUT I'm towing a boat of about 2.000 lbs almost 2-3 times per month in trips about 300 miles.

Now I'm working to install the RABS system to fix the rear wheels locking problem when not loaded, it is a very simple upgrade.

Thanks again...