Those of you running FORD dual piston front calieprs and gm rear calipers.... what mc

Erik

Erik

Well-Known Member
Joined
Oct 20, 2005
Location
Wilmington, NC
i have a set of dual piston calipers up front and a set of front gm 1 ton in the rear....

i searched and found that the e350 Master Cylinder is not good for 4 wheel discs so i ordered a 78 grand marquis...

it'll be here tomorrow



who is running THIS setup? what are your thoughts on it?

i'm confused about what to do with my stock properotioning valve since it's meant for rear drums.... should i change it out as well??

thanks

-Erik
 
i read about that and the grand marquis. i went with the G.M. only b/c of price and the thread on here i found mentioned more about it than the vette one..... figured there was a reason but i could have been wrong....
 
I used a Chevy 1-ton MC. Out of old 1-ton trucks, vans, and basically anything chevy I think.

I have Ford dual piston's on the front (D60), and Ford dual piston's on the rear (off of the front of an E250 van). Granted my truck is probably not very heavy, but it will lock up the back tires pretty easily even going 50mph down the road. I have a Wilwood proportioning valve, because I didn't want to leave the factory POS on there, I wanted something adjustable.

The chevy MC was easy to make fit my Toyota booster, just made a plate to adapt it over. I could have bought the kit for $100, I spent $20...
 
i saw that one but if i ran it i would have my stock proportioning valve with it's two inlets and three outlets then i'd have this one coming off the rear outlet and then feedign the rear brakes...

though more expensive, the $110 unit seemed like a better choice to help keep the clutter down and keep everything as one single unit.

idealy i want an oem unit that will work from autozone or advance but i don't think i'm going to find that.... hence the reason i am interested in this route...

-Erik
 
if i do the cheap wilwood it only have 1 in and 1 out though..... that would be fine to put inline to the rear but i'd still have the stock prop. valve feeding the front.

should i even upgrade my master? or is this massive 1 1/8" bore MC goingt o take away any feedback i might have fromt he brake pedal?

i don't like full hydro b/c of it's lack of steering feedback.... if my brakes lose their feedback b/c of a huge master cylinder i'll be hating it pretty bad.....
 
Oh

While you're at it, find some 90/10 Copper Nickel Tubing to use for brakeline. Extremely corroison resistant, and easy to work with.
 
I don't see that you really need a prop. valve for the front brakes. I have a prop. valve beside my seat for the rear axle, that is all you should ever need to adjust.

With the large chevy MC on my truck, it almost feels soft, but there are no leaks, I have bled it, and it stops GREAT, so I am not sure if it is "soft" or just different from the MC/brakes I had before.
 
running grand marquis and it will stand me on my nose. Never had an offroad vehicle with that good of brakes.
 
hummm

a prop valve beside seat for the rear brakes would be cool....

sqrl$$, what prop valve are you running? how does the pedal feel? any feedback?

i drove a yj with the same brakes as mine but with a 1 1/16" bore master cylinder and the pedal felt really soft and had no feedback, but it would lock up the brakes without blinking....

-erik
 
I didnt change anything with the system except the m/c. Still using stock proportioning valve (91 YJ). I don't feel alot of push back against the pedal if that is what you mean by feedback. Pedal is smooth and easy to be very precise. I am running a 78 f250 D44 w/dual piston front calipers and a 78 f250 D60 rear with Chevy calipers in the rear and 38's. On the street you can lock them up if you really stand on them. In the trails you can ease over anything with very little pedal effort.
 
hummm

and you don't have any problems with the rear having more stopping power than the front?

we are both running the same calipers so your input is greatly aprpeciated.

-Erik <--- picked up the marquis MC yesterday
 
Nothing that I have noticed. It doesn't seem to slide the rears that I have noticed. I think the only thing I had to do was to use a conversion bushing because the fitting on the marquis m/c and the jeep brake line were different sizes. Picked it up at autozone.
 
ok i just put it in....

the pedal feels harder than i want it, but i'd rather have it really hard/firm than have it soft and overly sensitive like i have felt on other people's setups.

the tapped holes in it are the same sizes as my stock holes were for the lines leading to my proportioning valve/combination valve but they were in opposite locations.... i merely bent the lines/crossed the lines and tightened them up.

i also adjusted the rod slightly.... i threaded it in about 6 turns so the pedal wouldn't grab so high... i was afraid the brakes were hanging without adjusting it......


it stops great, but it feels like mechanical brakes because the pedal is so firm. the rears still do seem to lock up sooner than the fronts, but it's not nearly as bad. next time it rains i'll report back to let everyone know how it goes... before it would bring the ass end around..... we'll see.....

i left my stock 89 prop valve unmodified. i was going to pull the oring but it sounds like all that will do is put more fluid to the rear and i already have enough/more than enough so i left it alone.

-Erik
 
ignore the wiring mess.

i'm still not done with my 4.0 / aw4 swap so i haven't clened the wiring up yet.

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i'm thinking that the reason the pedal is so hard is b/c didn't the marquis have hydro boost? if so, i'm gonna need more vacuum to get the pedal feel the way i "want" it

on the street i'm happy with the way it is..... i don't think i'd like it on the trails though... it would suck having to put a lot of my weight on the brake pedal to keep from moving..... i'd rather have it sensitive in that sort of situation... maybe an electric vacuum pump... hummm




ps- in gravel the fronts locked up first... on pavement the rears lock up first.
 
it should be viewable shortly

http://www.youtube.com/watch?v=U8GMNGyvyEw

looks like i need a proprotioning / combination valve and MAYBE a vacuum pump since i don't have hydro boost.


I know i'm being anal about it but i want my brakes to feel like they did when the jeep was stock. I know it's possible.... it's just a matter of figuring out how.....
 
Hahah, great video. That looks like the kind of stuff I like to do.

Ive got dual piston fords in the front and single piston GM's in the rear on my jeep. Stock '00 TJ master cylinder, with a Wilwood adjustable proportioning valve beside the seat, turn just about all the way out (I think thats around 50%) reduction. I can lock up the brakes pretty much whenever I want to, even w/38's. Ive got it to where the front and rear lock up at pretty much the same time, though the rear locks sooner if Im starting into a turn. Ive been pretty pleased with the feel and responsiveness of this setup. Ive been running the rear w/valve for about 5 years, and added the front dual pistons about 3 years ago. No leaks or other problems, just take the time to set up it right and make sure you have plenty of room for driveshafts and such.
 
I don't understand, my pedal feels great, not hard at all and it is very responsive. I don't have to apply hardly any pressure in the trails and it stays on any kind of rockpile I want. I didnt' switch my lines like you did, don't know if that makes a difference or not. I just hooked them straight up just like they unhooked from the old m/c.
 
ok to hook them straigh up the way they unhooked would mean that you cut the fittings off the lines and put the big fitting on the opposite line...... i might try that.

i wish i had a boost/vacuum gauge to hook up temporarily to see if that had anything to do with my pedal feel....

perhaps my brake booster is bad?
 
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