The Stovebolt Site Forums The Shop Area General Truck Talk Another Master Cylinder Question

After reading olblu49's post about upgrading to a dual master cylinder on his AD, I have given some serious thought to upgrade my TF ('56 3100) to the dual system. I plan on keeping the drum brakes (all new) on the truck. I saw where Brothers had an adaptor bracket for around $100, and the dual cylinder for also around $100. Would like to hear from others that have done this upgrade on a TF, and their thoughts and recomendations.

Can't speak for the TF but I've installed a dual on my AD...the mounting bracket will be required. As I've mentioned before, once you start disturbing your original stuff (lines/fittings) you're going to find that it is less complicated to get a coil of 3/16 line, and upgrade the whole system. The master can be picked up at most any parts house for around $50-60. I've never had any problems with rebuilts....possibly the $100. unit from Brothers, is new unit.

You might want to carry your bracket in to make sure that the master holes will line up. Would venture to guess that a 70's Chevy manual master would work. Be sure to get the necessary fittings/reducers for the master.

There is a lot of good brake info at:

http://www.ECIhotrodbrakes.com
http://www.mpbrakes.com
http://www.classicperform.com

Hope this helps.

I'm thinking of the same upgrade on my '56. I'll probably buy the bracket from one of the specialty vendors but I'm sure I can get a better deal on the MC at my flaps.

Fla54Chevy3100s guess that a '70s truck MC would work is a good guess. But does anyone know for sure? I'm assuming since the stock one is 1⅛" bore, the replacement should be the same bore.

But the stock one pushed 4 slaves with the 1⅛" bore. The dual will be pushing 2 and 2. Does this mean it should be smaller bore?

After doing some research I decided on the '73-78 Chevy truck, non-boosted, MC. I just ordered it from Rock Auto as well as wheel cylinders and hoses. It was a bunch cheaper than ordering from the usual truck specialty vendors.

The best price I found on the bracket was from CPP.

I'll get new brake lines locally. The master parts book lists the lengths needed and I'll bend them myself. Of course I may have to adjust those lengths to compensate for the different MC.

I'm doing the brakes in conjunction with installing a '59 GMC rear end with 3.07 gears.

Hey Cletis,

I think Rock Auto is one of the best kept secrets on the internet. I've used their site on a daily basis to pinpoint and compare parts for different years....it's almost like having your own Hollander (sp) manual.

I've ordered their merchandise, and as you pointed out, it's a bunch cheaper, they carry quality parts and their customer service is good. It's too bad more folks aren't aware of it. It's another useful tool in our box for old trucks!! www.RockAuto.com

Dave

I read ths article from Brothers Truck the other night and it made it sound as easy as just using the existing lines and some extensions. Not so. I looked under my truck today and found the line going forward only goes to the left front brake. The line going aft splits and goes to the right front and both rear. I'm going to re-plumb mine so that both fronts work off one half of the dual MC.

Been lookin', I know this has been discussed numerous times but I just taint found the right answer. What year or years master cylinder is typically used for the dual conversion? Any one know the casting numbers or part numbers, i.e., Chevy, Napa, AutoZone, etc., etc. that you should watch for?
I like to rebuild my own parts and would like to get one off a junker or swap meet table.
I'm assuming that the later dual MC are 3/16" lines, any suggestions for adapting them to 1/4" lines like my 1950, 3604 Huck brakes use??
I can’t remember ever seeing inverted flare get biggers, and really hate to think of going 3/16” SAE to a 1/4” MPT union then 1/4” MPT back to 1/4” SAE. That’s gonna be six extra brass fittings with eight extra places to leak.
I’m sure the hot rod forums have covered this ad nausea but I don’t frequent any of them as I have been one of those purist’s up till now.
Denny Graham
Sandwich, IL

Hey, Cletis,

I saw (somewhere) a diagram that plumbed only one of the front wheel cylinders from one of the MC reservoirs. I couldn't figure that out.

In your case, it means if the three wheels go out, your truck will pull to the left. I always thought pulling to the right, while not good, was still better as far as on-coming traffic is concerned.

Hey Denny....go to www.RockAuto.com, click start, Chevrolet, 1975, C10, brakes, scroll down to master cylinder, scroll down to the manual and you have a description and picture of the master cylinders. Suggest you check out the links I posted above to answer your questions about "brakes" of all different kinds. The big difference in master cylinders is the mounting flange hole spread (GM-FoMoCo), the bore size, and outlet configuration, manual/power, drum/drum,disc/drum, or disc/disc. I've found that if you match your application with weight of your vehicle, manual or power and type of brakes, you're going to be in the ball park. Take this info and head for your local parts house.

One of the above mentioned links even tells you specifically which GM master they are selling you by year and application. I don't see any value in ordering when you can get it locally with a lifetime warranty. Hope this helps.

Dave

Thanks to everyone who responded to my question about the MC upgrade. Looking to complete mine as soon as some "decent" weather gets back to VA--cold as the deckins' here now. I got some real good information to go forward with this project. Will let you know how it turns out.