Brake fluid on firewall

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Futzy1

Futzy1

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Ok so I bought my 73 dart 4 door a week ago. Good bones, but needs some love. Anyways, when I first drove her, the brake pedal was a little spongy, but nothing too major. When I checked the master, the fluid looked like it may never have been changed. after I bled the system the brakes got worse, and are now non existent. I've now bled it twice, and never saw any obvious leaks, and stopped getting bubbles in the bleed, but then while working on some wiring under the dash I noticed a bit of brake fluid on the cabin side of the firewall under the brake pushrod.
So at this point I'm pretty sure it's my master cylinder, but I thought I'd check in and see if anyone had anything else I should check.
 
Also, one person I talked to said I needed to replace the pushrod. any thoughts???
 
Cool. thanks guys. I ordered one the second I thought it might be the problem just to get the ball rolling on the shipping. now it's back to the wiring problems. . . .
 
The instructions included wont detail how to remove and reinstall the push rod. A factory service manual has that.
You'll probably need a new body gasket between master cylinder and firewall. That never comes with so... Order a reproduction from somewhere like DMT or find a piece of sheet foam packing material and cut to fit. In some cases the foot print of the MC casting doesn't quite or completely cover the hole in the firewall. Cut you body gasket oversize.
Wouldn't life be grand if everything needed was included?
They could atleast use a piece of this foam material for packaging the master cylinder.
 
I just checked the manual. The instruction for removing the pushrod in the MC removal section is "remove the push rod." lol

Screenshot_20161116-050720.png
 
OK so the factory service manual wasn't much help. How I do it... Small block of wood (2x4), drill a hole through the middle then cut it in half through the hole. Put it back together with a couple of drywall screws capturing the push rod. Block holds the piston/spool in so the master cylinder doesn't come completely apart when the rod is pulled. I have used the brake pedal as my puller ( block positioned between master cylinder and firewall ). Beware... You could damage the brake lamp switch this way. Disconnecting the 2 fluid lines was the last step.
I'm sure others have their methods too.
 
I've been looking around the forum ever since I checked the manual. One thing it looked like a lot of people recommended was to leave the MC installed, remove the brake switch, and pull on the pedal. at this point I'm just hoping the new MC Comes with the pushrod grommet. My impatience always seems to get the best of me. The new MC will be in tomorrow, and I really don't want to have to wait to install it. lol
 
All that "holds" the pushrod in is basically a rubber ring. There is no magic to getting the pushrod out, although they can get stuck in there due to the rubber ring drying out from old age.
 
The little finger on the backside, holds the guts in, is sheet metal/weak. A good yank on the rod can pull the guts right through it. More brake fluid spills. That's why I use/suggest the block.
 
Futzy1 said:
...I'm just hoping the new MC Comes with the pushrod grommet...
Click to expand...

I'm pretty sure it won't. You can find an o-ring that is "close enough" at almost any hardware store. Sorry I don't know the size. But it really depends on the I.D. of the hole in the piston anyways, as they are not all the same.
 
Well, harbor freight 382 piece of ring assortment for 8 bucks, here I come. lol
 
I always used a part of a vacuum line or fuel hose cut just slightly smaller than the ring that comes out, if there's enough left of it to measure.

if it just splits when it comes out, you can reuse it.
 
69_340_GTS said:
I'm pretty sure it won't. You can find an o-ring that is "close enough" at almost any hardware store. Sorry I don't know the size. But it really depends on the I.D. of the hole in the piston anyways, as they are not all the same.
Click to expand...

So funny enough, it looks like it came with the ring. what it did not come with however, was a freaking bench bleed kit. lol. hey, it's here, my car will stop again, and all is right with the world
 
Aaaaaannnnnndddddd the nuts are seized. . . off to get a splitter
 
Annnnnnddddddd. . . .the splitter won't fit between the MC and the firewall. this is the stuff of nightmares. lol
 
If you unbolt the MC, which you must do anyway, the tubes usually allow you to pull it away from the firewall.

I have seen an early A w/ manual MC that wasn't rusted on the firewall below.
 
I reluctantly took my torch to the bolts. I was worried about the cluster of electronics right next to the MC, but I took my time and wrapped everything in a couple layers of tinfoil. A bit of fire and ice later, everything came off gangbusters. Got the new one on, and hey, now my car stops again. now it's back to trying to wrap my head around adding an aftermarket ac.
 
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