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

HotRod929 · 09-12-2002, 02:01 PM

What kind do I have? I saw some on ebay for our trucks but they said that they would not work with Bendex and Delco. What does that mean and do I have one of those. Ill include a pic. Thanks

HotRod

RodC · 09-12-2002, 02:15 PM

Why look on ebay for a MC? I bought mine at Advance Auto $12.00 no paypal, no shipping they even had it in stock.

HotRod929 · 09-12-2002, 02:29 PM

True but I would still like to know what I have. THanks

HotRod

RodC · 09-12-2002, 02:36 PM

That looks like the one for the 3/4 ton since you have the 20 it is probably the orig.

The Delco and bendix ones you are looking at are probably for the 1/2 ton. I went throught the same questions when I replaced my booster. I don't know if there are different models for the 3/4 ton?

wlee · 09-12-2002, 02:38 PM

Looks like a stock 3/4 ton drum brake M/C to me . . . should be available at most parts stores. I would agree with RodC - get one locally - much less hassle if you have a problem, and you don't have to pay shipping.

Suicide-D · 09-12-2002, 02:57 PM

definately purchase locally... I sold a booster and master cylinder last night for a 72 1/2 ton. Took me 30 minutes and 3 different books to find the right one and I had the old one laying on the counter in front of me. There a quite a few different series of brakes on these trucks. And the difference with the Delco and Bendix lies in the booster dimensions.

Southpa · 09-12-2002, 02:59 PM

I just got rid of two of those styles of master cylinders. One was for a drum brake system (equal sized wells) and the other was for a disc system (front well bigger). Both leaked out the cap but still worked fine. I will never buy the single clip style m/c again. I will also NEVER buy a remanufactured m/c again. Thats probably why they both leaked out the cap, part of the re-man process should be planing down the top surface. It sucks to buy one and then find lots of big dents and nicks around the rim. Spend the extra money for a NEW m/c with the double hold-down clips.

Stout72 · 09-12-2002, 03:56 PM

If what you have is original equipment, call a couple of your local autoparts stores and ask if they have a m/c for your year and model. Take yours with you to the store and match it up to be sure. Shouldn't be too hard to find a new one. Don't fuss with ebay, used, or rebuilding. New ones are cheap enough, between $12 and $65 depending on where it's made. And you'll get a warranty. Personally, I'd buy the Bendix (I did a couple of months ago) Came with good, understandable installation instructions. Should have come with bleeding tubes, too, but someone musta lifted 'em from the box before I got it.

Follow the bench bleeding instructions to the letter. Can't stress enough how important it is to get the sucker properly bench bled first. Take your time and have patience, it takes a little while to assure you get all of the air out. Good luck.

Iron-Butt · 10-29-2002, 09:11 PM

Does any one know what the booster fits. I have the same booster. Two trips to the auto parts stores and no luck finding it. if you know which one I can use to replace it with another one let me know.
Thanks,
David

nate68 · 10-30-2002, 03:46 AM

the booster is a 3/4 ton booster but it will fit a 1/2 ton and prolly a 1 ton. i gotta buy a new one tomorrow mine's goin out. i checked online they're like 100 bucks, dammit

trukman1 · 10-30-2002, 11:49 AM

HR, I think your wanting to know the TYPE (Manufacturer), not just where to get another one. I can't help on the type but I do have some advice. I had the same setup on my truck and when I went for a replacement I found out there are 3 different pistons in the master cylinders...1) 1 1/4" deep recess, 2) 1 3/8" deep recess and 3) 1/4" shallow recess. I have the double diaphram booster like yours (the thick style as opposed to the thinner, single diaphram version) and mine took the shallow version. I was able to purchase a '77 Corvette unit at Autozone that fit since I went to an aftermarket proportioning valve with flush outlets on the side. In your photo it appears the proportioning valve is in-line with the master cylinder. If you purchase a stock unit you may have trouble finding a M/C that has the outlets flush like yours appears to be. The 'vette unit has flush outlets and the shallow piston. Check that piston on your unit before trying to install or purchase another. I had a lot of advice from friends that really educated me to the many variations that can be encountered. Hope this helps.

09-12-2002, 02:01 PM	#1
HotRod929 Registered User Join Date: Mar 2002 Location: Bondurant, IA but in Worcester, MA for school Posts: 767	What kind of master cylinder do I have???? What kind do I have? I saw some on ebay for our trucks but they said that they would not work with Bendex and Delco. What does that mean and do I have one of those. Ill include a pic. Thanks HotRod Attached Images __________________ 1970 Chevy C-20 350 V-8 Turbo 350 w/ shift kit Dana 60 w/ 4.10 gears AND Powr-Loc POSI New Additions: Summit Headers 135amp alternator Proform HEI Edelbrock 1406 600cfm carb Sunpro Tach Powr-Loc POSI Edelbrock Performer RPM Intake MSD 6A Ignition Box AIM: HotRod929 Visit My Site: http://1970chevy.netfirms.com/

09-12-2002, 02:15 PM	#2
RodC Registered User Join Date: Nov 2001 Location: Fairmont WV Posts: 304	Why look on ebay for a MC? I bought mine at Advance Auto $12.00 no paypal, no shipping they even had it in stock. __________________ Rod Childers '71 C10 Stepside

09-12-2002, 02:29 PM	#3
HotRod929 Registered User Join Date: Mar 2002 Location: Bondurant, IA but in Worcester, MA for school Posts: 767	True but I would still like to know what I have. THanks HotRod __________________ 1970 Chevy C-20 350 V-8 Turbo 350 w/ shift kit Dana 60 w/ 4.10 gears AND Powr-Loc POSI New Additions: Summit Headers 135amp alternator Proform HEI Edelbrock 1406 600cfm carb Sunpro Tach Powr-Loc POSI Edelbrock Performer RPM Intake MSD 6A Ignition Box AIM: HotRod929 Visit My Site: http://1970chevy.netfirms.com/

09-12-2002, 02:36 PM	#4
RodC Registered User Join Date: Nov 2001 Location: Fairmont WV Posts: 304	That looks like the one for the 3/4 ton since you have the 20 it is probably the orig. The Delco and bendix ones you are looking at are probably for the 1/2 ton. I went throught the same questions when I replaced my booster. I don't know if there are different models for the 3/4 ton? __________________ Rod Childers '71 C10 Stepside

09-12-2002, 02:38 PM	#5
wlee Just an Old Mr Goodwrench Join Date: Feb 2002 Location: Green Ridge, MO USA Posts: 259	Looks like a stock 3/4 ton drum brake M/C to me . . . should be available at most parts stores. I would agree with RodC - get one locally - much less hassle if you have a problem, and you don't have to pay shipping. __________________ 1969 CST 20 Longhorn 1970 CST 20 Fleetside 1991 Jaguar Sovereign 1992 Mazda Miata

09-12-2002, 02:57 PM	#6
Suicide-D Registered User Join Date: Jan 2001 Location: Katy, TX...but the love of my life resides in Dublin,OH. Posts: 1,408	definately purchase locally... I sold a booster and master cylinder last night for a 72 1/2 ton. Took me 30 minutes and 3 different books to find the right one and I had the old one laying on the counter in front of me. There a quite a few different series of brakes on these trucks. And the difference with the Delco and Bendix lies in the booster dimensions.

09-12-2002, 02:59 PM	#7
Southpa Registered User Join Date: May 2000 Location: Victoria, BC, Canada Posts: 2,410	I just got rid of two of those styles of master cylinders. One was for a drum brake system (equal sized wells) and the other was for a disc system (front well bigger). Both leaked out the cap but still worked fine. I will never buy the single clip style m/c again. I will also NEVER buy a remanufactured m/c again. Thats probably why they both leaked out the cap, part of the re-man process should be planing down the top surface. It sucks to buy one and then find lots of big dents and nicks around the rim. Spend the extra money for a NEW m/c with the double hold-down clips. __________________ 1970 GMC 1500 Custom Original 350/TH350 Victoria, BC, Canada You can wish in one hand and crap in the other. See which one gets filled first.

09-12-2002, 03:56 PM	#8
Stout72 Not my good side. Join Date: Mar 2002 Location: Fairfield, California Posts: 222	If what you have is original equipment, call a couple of your local autoparts stores and ask if they have a m/c for your year and model. Take yours with you to the store and match it up to be sure. Shouldn't be too hard to find a new one. Don't fuss with ebay, used, or rebuilding. New ones are cheap enough, between $12 and $65 depending on where it's made. And you'll get a warranty. Personally, I'd buy the Bendix (I did a couple of months ago) Came with good, understandable installation instructions. Should have come with bleeding tubes, too, but someone musta lifted 'em from the box before I got it. Follow the bench bleeding instructions to the letter. Can't stress enough how important it is to get the sucker properly bench bled first. Take your time and have patience, it takes a little while to assure you get all of the air out. Good luck. __________________ 72 Chevy K20 Custom Camper, 350/350, 4" lift, dual shock suspension front & rear. Daily driver and a work in progress. 00 Suburban LT 90 Camaro RS 79 Yamaha XS1100 Special (Ol' Reliable)

10-29-2002, 09:11 PM	#9
Iron-Butt 454 club Join Date: Oct 2002 Location: Oklahoma Posts: 1,348	Does any one know what the booster fits. I have the same booster. Two trips to the auto parts stores and no luck finding it. if you know which one I can use to replace it with another one let me know. Thanks, David __________________ David 1965 Chevrolet c-10 454 automatic Custom bbw swb. 1965 Chevrolet C-10 swb (Sold) 1963 Chevrolet C-10 6 Cyl automatic with dual exhaust, pb, ps and 17's. R.I.P "I will miss you. 1967 Chevrolet C-10 6 Cyl Custom lwb 1939 Chevrolet Coupe, 350 v8 automatic. 1935 Chevrolet 2 Dr Standard in the works. 2015 Harley Davidson Street Glide. 2023 Chevrolet Stingray Z51 Convertible. I never want to grow up.

10-30-2002, 03:46 AM	#10
nate68 Registered User Join Date: Jan 2000 Location: ca Posts: 1,110	the booster is a 3/4 ton booster but it will fit a 1/2 ton and prolly a 1 ton. i gotta buy a new one tomorrow mine's goin out. i checked online they're like 100 bucks, dammit __________________ 68 short step, 406/700r4, 9" w/discs.

10-30-2002, 11:49 AM	#11
trukman1 Registered User Join Date: Apr 2001 Location: Beavercreek, Ohio 45431 Posts: 737	M/C Type HR, I think your wanting to know the TYPE (Manufacturer), not just where to get another one. I can't help on the type but I do have some advice. I had the same setup on my truck and when I went for a replacement I found out there are 3 different pistons in the master cylinders...1) 1 1/4" deep recess, 2) 1 3/8" deep recess and 3) 1/4" shallow recess. I have the double diaphram booster like yours (the thick style as opposed to the thinner, single diaphram version) and mine took the shallow version. I was able to purchase a '77 Corvette unit at Autozone that fit since I went to an aftermarket proportioning valve with flush outlets on the side. In your photo it appears the proportioning valve is in-line with the master cylinder. If you purchase a stock unit you may have trouble finding a M/C that has the outlets flush like yours appears to be. The 'vette unit has flush outlets and the shallow piston. Check that piston on your unit before trying to install or purchase another. I had a lot of advice from friends that really educated me to the many variations that can be encountered. Hope this helps.

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