Master cylinder help in Hawaii

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steveh

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Hi all,

Just moved from Tampa to Hawaii. Got the dart off the ship today only to find that I had little to no pedal. Limped it home bled it...but its leaking from the MC cover and I'm loosing pressure. Brakes are a mixed bag o parts. It had a ssbc (power) front disk conversion on drum spindles several years back, but I just swapped everything out to LBP spindles and single piston calibers kept the SSBC booster and MC. So I have the following questions:

1)what MC will work best with my set up?
2) any one got a quick list of part#s

I really want to get it right the first time cause shipping to HI will be more expensive that the MC itself. Don't want to do returns from HI

Thx in advance
Steve
 
Hey brother... Give me a PM. I have a mc sitting on my shelf... May work for you? It was from a 67 or 68? 4 bolt pattern. Again new. Couldn't use it for my situation. No guarantee I can help but I will try!
 
A leaky cover will not make your brakes not work. (Well unless it it sloshes so bad it empties the cyclinder)
Are you sure it the cover, and not seepage from somewhere else?

Sounds like a piston seal leak to me, since you had to bleed it.
 
Finally got internet up and running again so from the top.

Pauly V100: Thanks for the welcome...been on the island for about two wks now and loving it

Dfnsmns34: Thanks for the offer to assist...unfortunately I've got this ssbc aftermarket disc swap kit that uses a two bolt instead of the four bolt...I'll PM you later

383Duster: Yeah OReilly's could order in an OEM MC but I've got this aftermarket SSBC power brake kit that uses a two bolt MC

TrailBeast: I hear ya...I have some pedal, Not loosing a lot of fluid, just enough to cover the exterior of the MC and drip down on to the manifold and inner fender.

I'm gonna try to call the SSBC tech line to see if they can give me an aftermarket part # that is readily available even in HI
 
I don't know for sure, but I suspect that 2-bolt MC's are pretty interchangeable. I have one from a 99 Breeze on my Dart but on the Breeze booster. That booster has an adjustable rod tip on the MC side, so easy to tweak. See if yours does. You could take your MC to a parts store, with some vernier calipers and compare dimensions to some off-the-shelf Mopar ones. Don't go past 1990's or you get to "bubble flare" ports. The piston diameter is critical as far as the pedal travel vs effort trade-off. I understand the Mopar Performance MC's is just a standard 80's truck part with a big price markup (see FABO posts). SSBC is probably similar.
 
Bill pretty much hit the nail on the head. Grab a MC from a late 80's Chrysler car,and your good to go.
Most get one from a Dakota as mentioned.The resivours (sp ?) Are made of plastic,and there are 2 different styles.One is slanted and the other is flat or level. Avoid the slanted one.
 
Thanks to all...I plugged the outlet going to the front and had a stiff pedal. Hooked it up and it was soft and went to the floor...so now I'm thinkin it must be one of two things

1) bad single piston caliper from NAPA

2) when I changed out the (SSBC KH like 4 piston caliper) for a late model single piston caliper without changing the master I dont have enough pressure because the bore is different????

Dont know where to go from here and welcome thoughts and advice

thx
Steve
 
So I guess the real question I am asking is...

If I swap to 73 and up single piston caliper (which I did) do I need to change to a different MC to build up enough pressure to activate the single piston caliper???

It's not like I have no brakes at all...as long as is pump it a bit, the pedal will stiffen up enough to stop the car fairly well but it is far from what it should be.

Thx in advance
Steve
 
This may sound silly...but did you bleed the breaks after hooking them back up?
 
Mike,

Bled and Bled and Bled...same soft pedal. OBTW, you cant insult my mechanical skills, cause I have little.

While troubleshooting today I plugged the MC and had a stiff pedal. Hooked the line up goin to the front brakes and smoosh. It builds up pressure with pumping...so I "think" the MC is good.

Tools havent arrived yet so tomorrow,I'm gonna by a set of vice grips and clamp the hoses one at a time to see if one of the calipers is bad. Again, I "think" thats the next step...

Just cant help but think that maybe the bore on the SSBC MC which was designed for KH 4piston calipers aint pushin enough fluid to make the single piston calipers function properly.

Open to Ideas here
thx
Steve
 
What MC did you end up going with ?
Did you bench bleed it ?
My thoughts:There is still air in the system.
 
steveh said:
Mike,
It builds up pressure with pumping...so I "think" the MC is good.

Just cant help but think that maybe the bore on the SSBC MC which was designed for KH 4piston calipers aint pushin enough fluid to make the single piston calipers function properly.
Click to expand...

MC's do not have a check valve, so pumping the pedal does not inherently increase the pressure. Air in the system would not be overcome by multiple pumps, so I doubt you have air. When pumping does help is when there is a leak in the MC piston seal, so it can't hold pressure. I had that with a recently installed MC (single pot). Pulled the piston out and found the seal had been cut by a sharp edge in the bore left after the rebuilders honed the bore and didn't file the ports smooth.

I doubt the single piston caliper has more piston area than 2 pistons of the KH 4-piston caliper. You could measure them and calculate. The piston area determines the final force on the pads, for a given pedal effort. What determines the volume required is both the piston area (rel. to MC area) and the free travel in the pads. Calipers have very little travel since they don't have a retract spring and rely on the twisting of the square O-ring seal to pull the pads back. I doubt the MC's used with K-H and with later calipers varied much in bore diameter. Usually the difference is between manual and power MC's.
 
i gotta agree, i really doubt theres much pedal difference between the two calipers you're using.
 
Well...based on bill's comments, perhaps I should stop all the fuss and save everyone's time and just slap on a 2 bolt system from a diplomat as suggested earlier and go from there. I'll let you know how it turns out.


appreciate the assist
 
So why even try to help if your not going to answer a couple simple questions ?

And Bill, doubt it all you want. Steve already questioned his mechanical skill.
If he did not bench bleed the MC properly and bleed the brake system properly,there will be air in the system. Period. No ifs ands or buts about it. We're not splitting an Atom here.
 
Johnny Dart said:
If he did not bench bleed the MC properly and bleed the brake system properly,there will be air in the system.
Click to expand...
True, but I am not sure how pumping the pedal multiple times would help if there was air in the system. It might help if the air was around the MC piston in some strange way like moving the bubbles around. For sure he should bleed the MC first, then the brake lines, whether he keeps his existing MC or gets another one.
 
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