hi all, I have a 70 challenger 340 with power disc brakes. Is the correct master cylinder the one with the flush piston and holding tab or the one with the protruding piston and no tab. Problem is there is a new master installed and it leaks from the back and down the front of the booster. Not sure what's going on or how to fix it. Thanks
Need help with master cylinder!
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Chryco Psycho
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The master needs to be rebuilt properly or replaced .
Xcudame
Well-Known Member
The original part number for the 70 master cylinder with power disc brakes is 2944453 casting number 2239171.
And yes, the current master cylinder need rebuilt or replaced with the above part number.
And yes, the current master cylinder need rebuilt or replaced with the above part number.
Steve340
Well-Known Member
I have two cars with the double diaphragm "Hemi" style booster and they have the protruding piston.
I think if you have the pancake Midland Ross booster it has the flush piston.
It was a few years ago - Pretty sure this is correct.
You need to make sure the booster pushrod clearance is right in any case.
Is the master lid leaking?
If not as Chryco said a new cylinder.
I think if you have the pancake Midland Ross booster it has the flush piston.
It was a few years ago - Pretty sure this is correct.
You need to make sure the booster pushrod clearance is right in any case.
Is the master lid leaking?
If not as Chryco said a new cylinder.
moparleo
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Remove the master and check. If the fluid has gotten into the booster you need to add that to your parts list of rebuild or replace.
I have the flush mount piston with the tear drop holding tab. I beleive it is incorrect and need the one with the protruding piston. This is what I need help with, which is the correct master for my car ? Thanks
Xcudame
Well-Known Member
Your correct master cylinder should look something like this. Don't mind the dust and grime, it's got over 100,000 miles on it!
moparleo
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You have a drum brake Master Cylinder.
The part that you are calling a spacer is acting as a spacer/washer to take up the space of the M/C piston retaing clip. Without it the master Cylinder would not evenly tighten up to the booster.
Always buy new when you can. Not all rebuilts are trustworthy.
Click on this link for one option.
1966-1974 Mopar Bendix Master Cylinder, 1.125 Inch Bore
The part that you are calling a spacer is acting as a spacer/washer to take up the space of the M/C piston retaing clip. Without it the master Cylinder would not evenly tighten up to the booster.
Always buy new when you can. Not all rebuilts are trustworthy.
Click on this link for one option.
1966-1974 Mopar Bendix Master Cylinder, 1.125 Inch Bore
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Should I remove that spacer and mount the correct master to the booster without it. I believe the correct master has the slightly protruding plunger
Xcudame
Well-Known Member
Yes, remove the spacer and turn in the plunger poking out of the vacuum booster in the same thickness. If the plunger engages the new master cylinder too much, it will mess it up!
Xcudame
Well-Known Member
OK, I did some digging for you (isn't retirement nice?). First is a link talking about 70 Disc Brake master cylinders. Looks like Raybestos MC36283 would work per the link.
The 1970 Hamtramck Registry "T/A Brake Tips"
Second, looks like Rockauto has the Raybestos master cylinder MC36283 for $59.79 plus shipping.
1970 DODGE CHALLENGER 5.6L 340cid V8 Master Cylinder | RockAuto
The 1970 Hamtramck Registry "T/A Brake Tips"
Second, looks like Rockauto has the Raybestos master cylinder MC36283 for $59.79 plus shipping.
1970 DODGE CHALLENGER 5.6L 340cid V8 Master Cylinder | RockAuto
340challconvert
Well-Known Member
Here is a pic of my original pb booster (early Oct. 70 340 Challenger w Disc brakes) face of yours is a little different then mine and my original correct master cylinder (2229171) for disc brakes (thermometer front) with the stop on the plunger. There is a inexpensive tool to correctly set the plunger depth coming from the booster
When I look up the masters for my car they all show the plunger sticking out slightly not the ones with the tab so this is where I'm confused the pic I posted shows the one I have been seeing listed for my car.. crazy
And the one with the tab thats flush is on my car but it was replaced so it may be wrong. Also has a spacer for the tab. I have a pic posted for that . I don't want to get the wrong one.driving me nuts lol
Steve340
Well-Known Member
It is kind of likely you have a drum brake power booster - I do not know if they are different.
In any case if the master bolts up properly it will work.
I would buy the one the one with the protruding piston.
You might still need the spacer - but see how it fits without it.
Buy the tool posted by 340challconvert - it takes all the guesswork out of setting the booster pushrod clearance.
Take care not to lose the booster reaction pad. It is a hard rubber pad between the booster diaphragm and the pushrod.
In any case if the master bolts up properly it will work.
I would buy the one the one with the protruding piston.
You might still need the spacer - but see how it fits without it.
Buy the tool posted by 340challconvert - it takes all the guesswork out of setting the booster pushrod clearance.
Take care not to lose the booster reaction pad. It is a hard rubber pad between the booster diaphragm and the pushrod.
do you know where I can get that tool ?
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