MASTER CYLINDER

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jazak5

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ORDERED A RAYBESTOS MASTER CYLINDER # MC36221
THIS ONE HAS THE CENTER BOLT HOLDING DOWN THE GASKET AND COVER
THE ONE ON THE CAR IS THE WIRE BAIL HOLD DOWN TYPE ARE THEY COMPATIBLE ???
MY CAR IS A 69 BARRACUDA 340 10 INCH DRUM FRONT/10 INCH DRUM REAR ( NON POWER ASSIST)
 
I think the bolted down type was an earlier design. Not sure what year they changed to the bail, but I believe they should be compatible...
 
If you have both master cylinders in hand, refresh my memory. The reservoir with wire clamp has a vent cut through center web so front and rear circuits can share a pre determined amount of fluid.
The reservoir with bolt in its center web does not have this feature ? I forget.
In any case, master cylinder bore size is a lot more important than reservoir/cap design. What differences are hiding there, I have no clue.
 
both are spec for 1 inch bore,thanks about the vent I'll look
 
I think the wire retainers came on board in 1970.Or with the KH brakes.
I think the screw-tops are drum/drum only?With equal sized reservoirs.
I'm kindof guessing.
As long as the bore and reservoir size works for you, I wouldn't worry about the cap style.
I prefer the capseals with bellows; no venting required.
Brake fluid loves moisture. It will suck it out of the air like a tree sucks it out of the ground.But the brake system hates water.
 
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Your MC should have equal sized MC reservoirs. And the body of the MC will be fairly short. I never thought that there was any difference in the MC vs. hold down mechanism, unless it was the original manufacturer's style.
 
the reservoirs are equal//I was worrying about the fluid volume(visually it's tough to compare oval vs' square without CC'ing them) and what is correct for my car
 
the reservoirs are equal//I was worrying about the fluid volume(visually it's tough to compare oval vs' square without CC'ing them) and what is correct for my car
Not to worry... the drum/drum systems use the smallest reservoirs.
 
Again my memory is a hit and miss. Drum drum brakes have residual pressure valve or hold off valve ?, just inside the line port(s) of master cylinders heading a system that has dispersion block only / no proportioning valve downstream.
You could just take for granted the aftermarket got it right and it will work fine.
If the master cylinder produces pressure you can stop. Stopping distance, pedal travel, operator effort, are the real issues. With luck it'll brake better than ever.
 
Again my memory is a hit and miss. Drum drum brakes have residual pressure valve or hold off valve ?, just inside the line port(s) of master cylinders heading a system that has dispersion block only / no proportioning valve downstream.
You could just take for granted the aftermarket got it right and it will work fine.
If the master cylinder produces pressure you can stop. Stopping distance, pedal travel, operator effort, are the real issues. With luck it'll brake better than ever.
Paragraph one has unusual terminology, but seems, essentially, correct.
Paragraph two, however,makes too many assumptions to be totally true.
A), the pressure has to end up in the wheel cylinders. B) the pressure has to activate the shoes, C) the shoes have to rub against the drums , and D)The drums have to shed the heat so generated.
Just swapping M/Cs by itself will produce no change in the system unless the old M/C had problems that the new M/C solves.
 
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well duh, I think all the bulbs were working before the power was turned off . lets pay the bill and get it on before we replace all the bulbs. There is a better analogy. I just rolled outa bed here.
 
Check the size of the fittings on the MC, the early bolt down style have a different fitting for the rear port on the MC. I have a 69 Cuda with kh disc non powered and it has the bolt down style. I always question when I see the bail style on a 69 or earlier A body.
 
tried rock auto parts 3x"s kept getting the same wrong mc even after sending photo's of the wrong part when their photo was the one I needed !!!! The guys at my local NAPA saved the day and got the correct one !!!!

My car was built near the end of the model year and most likely on a Friday it's a '70 mc and I know that it hasn't been changed
 
Yeah, I don't order much from Rock Auto ...... it's just another parts warehousing operation that has no way to correct the parts mistakes that sneak into the parts books over the years. At least, with NAPA, you can get the part and hold it in your hand and say yea or nay.
 
Hate to hijack this thread, but. Master cylinders Nader has a 1" bore. 66 Dart, wilwood a in the front, new master cylinder, best brake 10-1628 off a 78 Aspen. Wilwood prop valve. Can't get anymore than 1/2" of pedal? Bench bled the MC. Now because the way the prop valve sits on the MC studs, I'm assuming I have it plumbed wrong? Firewall side (large reservoir) for the front?? If that's the case, I'm backwards. Will keep me from getting pedal? Obviously I'll change it, but I'm wondering if there are other issues?
Thanks

image.jpeg
 
Hate to hijack this thread, but. Master cylinders Nader has a 1" bore. 66 Dart, wilwood a in the front, new master cylinder, best brake 10-1628 off a 78 Aspen. Wilwood prop valve. Can't get anymore than 1/2" of pedal? Bench bled the MC. Now because the way the prop valve sits on the MC studs, I'm assuming I have it plumbed wrong? Firewall side (large reservoir) for the front?? If that's the case, I'm backwards. Will keep me from getting pedal? Obviously I'll change it, but I'm wondering if there are other issues?
Thanks

View attachment 1714948859

image.jpeg
 
If the lines under the valve are also reversed, then you will still be proportioning the rear brakes. You would just need to top up the little reservoir more often.
But if the lines underneath are such that you are proportioning the front brakes, well that would be bad.And because the calipers are more or less instant on, yes I can imagine a very short pedal travel. To understand why, you have to understand how the M/C works inside. Get the top plumbing reversed, and make sure the plumbing underneath matches it;that is to say that the big reservoir actually operates the front brakes unproportioned. Then it should work normally, try not to limit the rear fluid excessively, rather try to run as much pressure back there,as possible, short of premature lock up.
Those short lines look like copper on my screen, having a reddish hue.I hope they are not copper. They need to be steel, and double flared.A M/C can generate in excess of 2000psi; I have no idea what it takes to burst a copper pipe of that size, but I sure wouldn't want to find out.
On the rear, what's back there; drums or discs
 
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They are drums on the back. They have a copper hue, they are brake lines, 3/16" EZ bend. NiCopp I believe it's called. And yes, the front is still the front and the rear is still the rear, just coming out of the wrong reservoir I guess. Should have researched it more, assumed (bad,I know) that the ports would be lined up to the prop valve ports?
 
I have no experience with that valve so I don't know which end is which. But if I was to guess, then the knob end would be for the rear. The end for the front would normally have two outlets, for left and right fronts

I went to the Willwood site and saw that the valve is clearly marked, and yours is definitely reversed.And that will for sure limit the pedal travel. Get it right and bleed it and things should be back to normal.
 
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I have no experience with that valve so I don't know which end is which. But if I was to guess, then the knob end would be for the rear. The end for the front would normally have two outlets, for left and right fronts

I went to the Willwood site and saw that the valve is clearly marked, and yours is definitely reversed.And that will for sure limit the pedal travel. Get it right and bleed it and things should be back to normal.
Thank you AJ. I appreciate the input
 
same

Again my memory is a hit and miss. Drum drum brakes have residual pressure valve or hold off valve ?, just inside the line port(s) of master cylinders heading a system that has dispersion block only / no proportioning valve downstream.
You could just take for granted the aftermarket got it right and it will work fine.
If the master cylinder produces pressure you can stop. Stopping distance, pedal travel, operator effort, are the real issues. With luck it'll brake better than ever.[/QUOTEsame
 
OK, I'm at my wits end. Changed the master cylinder, Wilwood says 1" bore is perfect. Threw out the line lock! Threw out the distribution block, assured everything is plumbed correctly! Still, no pedal!!!! No leaks. Wilwood proportioning valve set dead in the middle. Bleed em out, no air.
I was told, pull the calipers and push the pistons all the way back in. Anyone have any idea why I cant get these to bleed out properly?? And yes, I bench bled the master.
1966 Dodge dart convertible. 318, 904, master cylinder is out of a 1978 Dodge Aspen. Re manufactured master from Cardone. Best brakes 10-1628.
HELP!!!!!!!
 
The 1" bore may be perfect.And your Combination valve is the new distribution block.
Push-rod length? If the pushrod length is too short, then the pedal will have to travel some extra distance before it does anything hydraulic, and it may not push enough fluid out to affect any stopping action. It would be,in effect,be applying less than full pedal travel to the M/C pistons.
If the pushrod is too long, it is possible for the C-port to not be exposed enough to allow proper bleeding. Or if it is not exposed at all, then it will be impossible to pump fluid down the lines. The pushrod can be adjusted anywhere between too short and too long, but I don't like too-short cuz of the delay in engagement and the aforementioned long low pedal.
Since you had a hard pedal before the line swap, I would have to assume there is a pocket of air somewhere.
What method are you using to bleed; 2-man, gravity, or power?
Before you go crazy, answer this; Can you get a hydraulic resistance with 3 or 4 quick full travel stabs on the pedal and pressing down on the last?(remove the floormat.) If yes, that says the M/C is working, and you may have a mechanical issue. If no, then the problem is most likely hydraulic/air.

The method of pushing the pistons back is neat, and I have used it myself on occasion. There is a bit of science behind it tho. The idea is that forcing the piston back, will force trapped air somewhere upstream,to return to the M/C. The trick is to have the piston out quite far before you start, say 80% of it's travel. Then a long continuous push 'til it hits bottom. Of course,the compensating port will have to be open for this to work.And it is best to allow the system to rest for a period of time, to allow the air to migrate up through the C-valve. So I usually remove the calipers and pads, and install blocks or C-clamps, sized to allow about 80% piston travel. Be careful to not allow the pistons to pop out,or the reservoir to run dry. I do both sides. Then I remove most of the fluid from the reservoir. Then I force one piston back to the bottom,and clamp it there, and recheck the reservoir. I remove more fluid as I see fit.With small reservoirs, you might have to remove fluid more than once. Then I repeat on the other side. And finally top up the reservoir. Then I walk away for a few hours, perhaps overnight.
During the away-time, the air can continue to rise up into the M/C.
The next morning, I have a helper tickle the pedal, while I watch the compensating port for the emergence of the final remnants of air. Tickling the pedal is just that; very short gentle strokes. Just enough stroke to compress the air tiny bit. Then release the pedal to allow the air to pop up into the reservoir.As the air pops out, fluid will flow into the chamber, repeat as often as necessary, until no more air pops out.
For this to work, the C-port has to be the high point. If this is not possible, then the air will pile up at the other end of the piston chamber, and all the tickling in the world won't help. In this case I crack the fitting at the M/C and allow the air out there, while the helper maintains a bit of pedal pressure. As soon as she stops farting, I secure the fitting. Then it's time to put the calipers back on and retest. And then we move to the back,if so required.
Of course all this dinking around means the possibility of brake fluid going everywhere, so protect your paint.
 
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2 man. I have my mechanic from work bleeding while I pump em up. Ordered new rear wheel cylinders will try that on Wednesday. All the hardare, ie brake pedal, push rod etc are original to the car that had manual brakes. These are still manual. I have not checked the pedal ratio, may do that tonight, but since it is all stock to the car, I didn't feel it necessary. But now, maybe. Would there be a pocket of air in one of the pistons on the new wilwoods? Put new wilwoods on my 71 Dart a couple years ago, and had zero problems???
I'm confused.
By the way, all new lines from In line tube.
 
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