Master Cylinder push rod question

[dan juhasz]

So the 69 A12 that I purchased was originally drum/drum. The previous owner installed a common front disc brake kit but continued to use the drum/drum master. I ordered a master from online tube that was listed as manual or power brake application. My concern is the piston does not have the machined groove to lock in the push rod. I called pirate Jack and asked about their master cylinder and he said it would also not have that groove. Is there a factory appearing master cylinder for manual disc brakes that has a groove to lock in the rod?

 

[R413]

I bought one from NAPA for a 1973 Dart with manual disc brake. It had the groove and pedal feel is just right.

But this was 30 years ago. Don't know what they sell for that now.

 

[gtx6970]

I bought one from NAPA for a 1973 Dart with manual disc brake. It had the groove and pedal feel is just right.

But this was 30 years ago. Don't know what they sell for that now.

Yep. Put one on this . Worked like a charm.

 

[dan juhasz]

Yep. Put one on this . Worked like a charm.

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That display picture for the master doesn't even show the bolt holes to hold the boot over the pushrod. Do you remember doing your install? Did it have the provision for the retainer and push rod boot? Did your push rod snap into place and stay locked in?

 

[gtx6970]

That display picture for the master doesn't even show the bolt holes to hold the boot over the pushrod. Do you remember doing your install? Did it have the provision for the retainer and push rod boot? Did your push rod snap into place and stay locked in?

No boot or provision for the boot on the back side. But yes the internal piston has the groove for the retainer to snap into

 

[gtx6970]

By application the one I linked above is for Power disc brakes,

This one is listed for manual disc brakes. BUT it has the larger piston / bore size. Which is not ideal for manual disc brake converted car. At least so I am told.
I went with the smaller bore size on the car . And had no complaints

But neither one have the provision for the boot on the back side

 

[Bird 426]

This is in my Dart. Has the groove for locking the pushrod . You can use a piece of vacuum hose to lock the pushrod in if your old one is bad.

 

[dan juhasz]

This is in my Dart. Has the groove for locking the pushrod . You can use a piece of vacuum hose to lock the pushrod in if your old one is bad.

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I saw that part number on Rock Auto I will order it. Thanks

 

[dan juhasz]

This is in my Dart. Has the groove for locking the pushrod . You can use a piece of vacuum hose to lock the pushrod in if your old one is bad.

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Does that unit have a snap ring at the back of the piston ?

 

[Bird 426]

Yes. 15/16" bore, I think. Manual.

 

[dadsbee]

You can use a piece of vacuum hose to lock the pushrod in if your old one is bad.

You can...but for 3 bucks from Dr Diff you can make sure it stays there with the correct rubber.

Mopar Manual Brake Push-Rod Retainer, Bushing, Clip Rubber Grommet