brake master cylinder ? - The 1947 - Present Chevrolet & GMC Truck Message Board Network

menace121978 · 08-05-2010, 11:14 PM

hey guys!

will a '86 style master cylinder work on my '78? are the fitting the same size? i like the plastic reservoir alot better than the cast iron looking style. i'm about to order one but i just wanted to make sure.

i do know the brake boosters are the same... thanks!

Keith Seymore · 08-06-2010, 07:51 AM

Check and make sure they are plumbed the same; that is, I seem to recall my cast iron m/c the front reservoir went to the front brakes (and the rear to the rear); whereas on the plastic one the front reservoir was smaller, for the rear brakes and the rear portion was for the fronts.

(I hope that makes sense).

Otherwise than that swap the fittings should both be English flare (not ISO), the rear of the m/c should fit the booster, so as long as the fittings are on the outboard side of both you should be good to go.

K

karl · 08-16-2010, 07:09 PM

Im pretty sure the 81 and 86 are the same. 81 was the first year of that style. Another advantage is most of them have aluminum housings that dont need to be painted and wont rust. Im going that route also. Tired of rusty iron in my brake fluid, ect.

08-05-2010, 11:14 PM	#1
menace121978 Registered User Join Date: Jan 2009 Location: orangevale, ca Posts: 3,626	brake master cylinder ? hey guys! will a '86 style master cylinder work on my '78? are the fitting the same size? i like the plastic reservoir alot better than the cast iron looking style. i'm about to order one but i just wanted to make sure. i do know the brake boosters are the same... thanks! __________________ "Dennis the Menace" 1978 Silverado (2wd, 1/2 ton, short bed)complete nut & bolt frame off restomod LQ9/4L80E MY LS SWAP/FRAME OFF BUILD BOOK 2006 TBSS way too much to list

08-06-2010, 07:51 AM	#2
Keith Seymore Registered User Join Date: May 2009 Location: Motor City Posts: 9,167	Re: brake master cylinder ? Check and make sure they are plumbed the same; that is, I seem to recall my cast iron m/c the front reservoir went to the front brakes (and the rear to the rear); whereas on the plastic one the front reservoir was smaller, for the rear brakes and the rear portion was for the fronts. (I hope that makes sense). Otherwise than that swap the fittings should both be English flare (not ISO), the rear of the m/c should fit the booster, so as long as the fittings are on the outboard side of both you should be good to go. K __________________ Chevrolet Flint Assembly 1979-1986 GM Full Size Truck Engineering 1986 - 2019 Intro from an Old Assembly Guy: http://67-72chevytrucks.com/vboard/s...d.php?t=342926 My Pontiac story: http://forums.maxperformanceinc.com/...d.php?t=560524 Chevelle intro: http://www.superchevy.com/features/s...hevy-chevelle/

08-16-2010, 07:09 PM	#3
karl Registered User Join Date: Dec 2004 Location: grand terrace , caifornia Posts: 338	Re: brake master cylinder ? Im pretty sure the 81 and 86 are the same. 81 was the first year of that style. Another advantage is most of them have aluminum housings that dont need to be painted and wont rust. Im going that route also. Tired of rusty iron in my brake fluid, ect.



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