What master cylinder do I have? - The 1947 - Present Chevrolet & GMC Truck Message Board Network

grubsster · 09-24-2020, 02:56 PM

Looking for some help. My master cylinder went out this past weekend. I had bought a kit when I added disc brakes and need to replace the master but don't know what to buy.

**The Rocknrod** · 09-24-2020, 05:33 PM

4 wheel disc or front disc?
1” bore or a 1-1/8” bore master cylinder?
Where the rod from the booster goes into the master cylinder is it deep or shallow?

grubsster · 09-24-2020, 06:49 PM

Sorry, front disk, rear drum. I'm unsure of the bore size. I didn't check before I installed it a few years back. Just hoping someone recognizes the housing. I may be wrong but, I think I could use either bore size even if it's 1" I can go to 1 1/8.

**The Rocknrod** · 09-24-2020, 06:56 PM

The housing is basic you can get them anywhere. POL, CCP, Speedway, Summit. However if you have a deep or shallow pin/rod out of the booster and change it...
Also if you change the bore it will be a change in brake response. You can removed it pretty easy and check before you buy it twice - Like my wife accuses me of doing.

grubsster · 09-24-2020, 07:18 PM

Thanks. I was thinking of just buying one for a 72 C10 with disk brakes unless somebody has a better suggestion. My wife thinks I do the buy twice thing as well...

60apache · 09-24-2020, 09:27 PM

pretty sure its the same as an older corvette

**Captainfab** · 09-24-2020, 10:06 PM

That is typical of a '77-'82 Corvette which is what all of the aftermarket suppliers of the booster and master kits use. But could also be the '68-'76 Corvette with the deep bore in the back of the piston. You really should pull it off and see what the bore is in the back of the piston.

grubsster · 09-24-2020, 10:42 PM

Thanks everyone, I'll pull it off. Knowing that it is the same as a corvette one I'll know where to start.

**The Rocknrod** · 09-25-2020, 07:47 AM

You dont have to remove the brake lines. Just remove the two bolts that attach it to the booster, pull it toward the front of the truck slowly and take a look and the depth, then measure the bore. Put it back. I've done it.

**jayoldschool** · 09-25-2020, 02:31 PM

But... if it's Corvette, it's for four wheel discs.

**The Rocknrod** · 09-25-2020, 04:03 PM

Maybe if he has a disc/drum proportioning valve it will help.

**Captainfab** · 09-25-2020, 10:03 PM

Everyone that sells those booster and master conversion kits, supply a Corvette master for both disc/drum and disc/disc brake systems.

Quote:

Originally Posted by jayoldschool

But... if it's Corvette, it's for four wheel discs.

09-24-2020, 02:56 PM	#1
grubsster Registered User Join Date: Sep 2011 Location: N.C. Posts: 133	What master cylinder do I have? Looking for some help. My master cylinder went out this past weekend. I had bought a kit when I added disc brakes and need to replace the master but don't know what to buy. Attached Images

09-24-2020, 05:33 PM	#2
The Rocknrod Moderator Join Date: Aug 2011 Location: China Spring, TX Posts: 7,280	Re: What master cylinder do I have? 4 wheel disc or front disc? 1” bore or a 1-1/8” bore master cylinder? Where the rod from the booster goes into the master cylinder is it deep or shallow? __________________ Master Chief, US Navy, Retired 1964 C10 Step-side Short Bed - In Progress 2009 2500HD Duramax LTZ 1948 GMC Panel 1956 Big Window Stepside 1953 5 Window Chevy Stepside 1932 Coupe New Seat Foam for Bench Seats? Last edited by The Rocknrod; 09-24-2020 at 05:38 PM.

09-24-2020, 06:49 PM	#3
grubsster Registered User Join Date: Sep 2011 Location: N.C. Posts: 133	Re: What master cylinder do I have? Sorry, front disk, rear drum. I'm unsure of the bore size. I didn't check before I installed it a few years back. Just hoping someone recognizes the housing. I may be wrong but, I think I could use either bore size even if it's 1" I can go to 1 1/8.

09-24-2020, 06:56 PM	#4
The Rocknrod Moderator Join Date: Aug 2011 Location: China Spring, TX Posts: 7,280	Re: What master cylinder do I have? The housing is basic you can get them anywhere. POL, CCP, Speedway, Summit. However if you have a deep or shallow pin/rod out of the booster and change it... Also if you change the bore it will be a change in brake response. You can removed it pretty easy and check before you buy it twice - Like my wife accuses me of doing. __________________ Master Chief, US Navy, Retired 1964 C10 Step-side Short Bed - In Progress 2009 2500HD Duramax LTZ 1948 GMC Panel 1956 Big Window Stepside 1953 5 Window Chevy Stepside 1932 Coupe New Seat Foam for Bench Seats?

09-24-2020, 07:18 PM	#5
grubsster Registered User Join Date: Sep 2011 Location: N.C. Posts: 133	Re: What master cylinder do I have? Thanks. I was thinking of just buying one for a 72 C10 with disk brakes unless somebody has a better suggestion. My wife thinks I do the buy twice thing as well...

09-24-2020, 09:27 PM	#6
60apache Registered User Join Date: Mar 2010 Location: brandon, ms Posts: 384	Re: What master cylinder do I have? pretty sure its the same as an older corvette

09-24-2020, 10:06 PM	#7
Captainfab 60-66 Nut Join Date: Mar 2007 Location: Coeur d'Alene, Idaho Posts: 23,246	Re: What master cylinder do I have? That is typical of a '77-'82 Corvette which is what all of the aftermarket suppliers of the booster and master kits use. But could also be the '68-'76 Corvette with the deep bore in the back of the piston. You really should pull it off and see what the bore is in the back of the piston. __________________ Power Steering Box Adapter Plates For Sale HERE Power Brake Booster Adapter Brackets For Sale '63-'66 HERE and '67-'72 HERE and '60-'62 HERE and "60-'62 with clutch HERE Rear Disc Brake Brackets For Sale. Impala SS calipers HERE Camaro Calipers HERE D52 Calipers HERE 6 Lug HERE Hydroboost Mounting Plates HERE

09-24-2020, 10:42 PM	#8
grubsster Registered User Join Date: Sep 2011 Location: N.C. Posts: 133	Re: What master cylinder do I have? Thanks everyone, I'll pull it off. Knowing that it is the same as a corvette one I'll know where to start.

09-25-2020, 07:47 AM	#9
The Rocknrod Moderator Join Date: Aug 2011 Location: China Spring, TX Posts: 7,280	Re: What master cylinder do I have? You dont have to remove the brake lines. Just remove the two bolts that attach it to the booster, pull it toward the front of the truck slowly and take a look and the depth, then measure the bore. Put it back. I've done it. __________________ Master Chief, US Navy, Retired 1964 C10 Step-side Short Bed - In Progress 2009 2500HD Duramax LTZ 1948 GMC Panel 1956 Big Window Stepside 1953 5 Window Chevy Stepside 1932 Coupe New Seat Foam for Bench Seats?

09-25-2020, 02:31 PM	#10
jayoldschool Moderator Join Date: Dec 2012 Location: ON, Canada Posts: 2,151	Re: What master cylinder do I have? But... if it's Corvette, it's for four wheel discs.

09-25-2020, 04:03 PM	#11
The Rocknrod Moderator Join Date: Aug 2011 Location: China Spring, TX Posts: 7,280	Re: What master cylinder do I have? Maybe if he has a disc/drum proportioning valve it will help. __________________ Master Chief, US Navy, Retired 1964 C10 Step-side Short Bed - In Progress 2009 2500HD Duramax LTZ 1948 GMC Panel 1956 Big Window Stepside 1953 5 Window Chevy Stepside 1932 Coupe New Seat Foam for Bench Seats?



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