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I went round and round with the brakes on a 95 f350 at work last year it had a shitty pedal we changed everything and finally put a booster on it and it worked great

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Discussion starter · #942 ·
Warrantied the master and its good, could be better. But I can atleast lock up the rear brakes. I reused the nylon covered in braided lines from the eb that are a few yrs old and beat up in the front. I think if I replace those it might be better. Also did an alignment on it and got my thrust angle and toe good. Rear housing is fawked. I questioned if it was possiblly bent when it was in the bronco. Now I am sure of it. Guess I should of looked closer before welding all that expensive shit to it lol. Fawk it and run it lol.

I have my mustache tires on it right now for the alignment. Fawker sure is fun on the pavement :sonicjay:. Those stock tires and 5.38's sure rip up quick.
 
Discussion starter · #943 ·
Nope, still not good enough. In 4 lo I cannot hold the vehicle on obstacles. I am starting to ? my pedal ratio. That is tonights project to investigate.
 
Discussion starter · #944 · (Edited)
Anybody know what the pedal ratio of a 96 f250 is?





Okay to sum up the differences in attempt to get the brakes better.

I was very happy with the EB brakes. Difference's that I can come up with between the two.

EB
Master cylinder was 1.250 bore-best guess a 4 or 5:1 pedal ratio-and booster was 8.750 in dia.

Buggy
Master cylinder is 1.125-7:1 pedal-and booster is 7" in dia.

My pedal
http://www.summitracing.com/parts/wil-340-1290

I removed vacuum from my booster, while i did notice a difference in stopping power, it was pretty slight difference. Almost not noticeable.
 
Stoopid fix but works, put a 10 psi check valve in the lines right off the master Cylinder, so it keeps a low 10 psi to all 4 brakes (hasnt historically been a big deal for the ones ive installed) that way all the lines are pre filled with 10 psi, so ur pedal and booster only have to create a few more pounds of pressure and move lots less volume.

Usually do it to help 1 ton brake conversions on jeeps, when they still dont work 100% after a 1.25" ram master Cylinder.

Iono..but its a fairly cheap try?

sended frum dis stoopid fone.
 
What's the fluid capacity of your new vs old? Smaller master dia bore= more psi= better brakes provided you can move enough fluid to push the pistons as far as they need to go. How much vacuum do you draw at idle? Not positive how a booster works exactly but you had 4 or 5(ratio) x 60 sq in (minus bore) x your vac psi with the 8.75" booster vs 7(ratio) x 38.5 sq in (minus bore) x your vac psi now if that makes any sense to you.

Anything more than a 2 psi check valve is a bandaid anyway. My Durango mastered TJ has kung foo brakes without them.
 
Discussion starter · #947 ·
Resivors are the same size with the 1.250 and 1.125 masters. Honestly if they didn't say on them the size, you wouldn't be able to tell them apart. Both came on the same application. Difference is 2wd vs 4wd.

I would.imagine vacumn is standard amount as my motor isn't anything crazy.
 
Bore x stroke = fluid content. Smaller bore with same stroke moves less fluid. Resi doesn't matter as long as the bore doesn't suck air prior to movement.
 
Block the rears off so your only moving fluid to the front and see if you have enough pressure to hold with just the fronts. Should eliminate the fluid capacity question.
 
Discussion starter · #953 ·
I didn't try and drive it with rear blocked, but with the rear blocked the pedal travel and firmness really didn't change. Same with the front blocked.
 
Mine will stall out on low lock with just foot pressure( no booster) locked with a ball valve for my e-brake when I forget I set it. To not be able to lock the brakes up baffles me.
 
do you have any goofy bends in the lines? not that you missed the obvious stuff....but maybe a bubble is giving you hell?
 
I wouldn't waste any time tracking down the vacuum, that's an assisting system. The brakes will will still function the same without a booster but would require more physical input from the driver. You have an issue in the hydraulics, either an air bubble, a line expanding, a seal in the MC leaking, or a leak elsewhere.

NOT sent from an iPhone
 
How is the pedal? can you hit the floor with it? get better on the second pump? or is it hard and just not enough pressure. With the smaller mc and more pedal ratio you should have more pressure unless you don't have enough stroke (fluid vol.) The only way to fix that is back to a bigger bore or lessen your pedal ratio. A residual press vavle might help if it gets better on the second pump.
 
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