Let's play...identify this Master Cylinder

[Jason72Bronco]

Thanks to all of the contributions on my previous thread regarding brake issues after a front disk conversion. Based on those, I decided to replace the master cylinder. Easy enough, right?

Well, as you can see from the pics, I do not have a stock Bronco MC or vacuum boost (I don't think any stock MC's lines came out the non-engine side). Now, I recall the previous owner bragging about how he had installed a "custom" booster and MC setup that did not require cutting the fender well. I vaguely remember him mentioning a Pontiac, but I really have no idea where this setup is from. You can see from the pics the part number on the side of the MC, but it is hard to make out, even after I rubbed some chalk on it. I googled the heck out of it, and no luck. I can find no part numbers or ID on the boost unit. (One good thing is he actually did install a proportioning valve, which will be good for my disk setup.)

So, anybody that may help me figure this out....thanks!

 

[Apogee]

First, I would measure the spread on the stud spacing, GM = 3.40" and Ford = 3.25". Then I would measure the bore size of the master cylinder so you know where you're starting and can adjust if desired. Shallow or deep pushrod hole depth? Now you should have the information you need to choose a master cylinder regardless of what you currently have.

 

[broncoman1972]

Here's my guess. 76-80 Skyhawk, Monza, Starfire and Sunbird. I searched "master cylinder 2823938" Yoyopart had no pick but had some crossover numbers. It showed Bendix 11737. Rock auto had this: http://www.rockauto.com/catalog/moreinfo.php?pk=1371856

It doesn't show applications, but back to yoyopart (which oddly shows a different picture so I'm not 100% on this) and they show the above vehicles.

That's my best guess after a quick search. Good luck!

 

[Jason72Bronco]

Thanks Broncoman! I was reading that "9" as a "3".

 

[Apogee]

Good guess, but all of the 7/8" bore, manual disc/drum Monza units I've ever seen had the race track oval outlet port bosses, not round like yours. That said, if I'm wrong and that is what it is, then a 7/8" bore MC would definitely fall on the undersized side of things if you're going to run power disc/drum brakes.

Are those support brackets from the inner fender to the MC mounting studs?

 

[broncoman1972]

That said, if I'm wrong and that is what it is, then a 7/8" bore MC would definitely fall on the undersized side of things if you're going to run power disc/drum brakes.

I agree.