Brakes master cyl. swap - The 1947 - Present Chevrolet & GMC Truck Message Board Network

69halfton · 06-21-2009, 09:39 PM

well, summer holidays are here. with that means summer job, and with that means i have money again to do some much needed maintenance work on the ol' girl.

so i picked up a new master cyl. for my truck last week, and im going to be installing it tomorow. (how much do you normally pay for a master? i will have paid 43 bucks once i get the refund for the old one)

I remember somebody on here talking about "bench bleeding" the master before installation. what the heck is "bench bleeding"

i also heard that it its a must or else i would wreak the seals or something?

its all very foggy lol..

My plan was going to be install the new one, fill it with fresh fluid, and then open all the bleeders and let gravity do its work, slowly flushing the lines. as the bleeders begin to bleed clean fluid, ill close it so that the next one farther down the line will recieve its fluid.

do i need to "bench bleed"? or is the gravity thing going to sorta do that when its in the truck?

Longhorn Man · 06-21-2009, 10:02 PM

i hope that is a brand new master cylinder for that price. I've put reman'd ones on every truck I've had... 3/4 ton drum, 1/2 ton drum, one ton drum, 3/4 ton drum/disc... and never paid more than 25 bucks.

Did your master cylinder come with bench bleeding directions, or the caps needed for the job?
I googled how to bench bleed a master cylinder, and got this link for you.
http://www.misterfixit.com/brakbld1.htm

69halfton · 06-21-2009, 10:16 PM

thats a great help longhornman, thanks!

yes its a brandnew one. i havent really looked through anything yet, just checked to see if it looked the same

69halfton · 06-22-2009, 01:29 PM

so i made the swap, everything went very well but i have a problem.

i have gotten fluid to all the wheel cyl. except the left rear, or drivers side rear wheel.

they all gravity bled until clean, including the passengerside rear wheel.

I cant get even a drop of fluid out of the drivers rear, and i have no clue why this would happen. it was working before..

anybody have any ideas?

Longhorn Man · 06-22-2009, 04:13 PM

try pressure bleeding, could just be a piece of rust partially blocking the line or the T fitting.
Honestly, myself, if the pedal is firm, I'd say screw it. But I get flamed for that kind of talk.
Firm pedal = no air in the system.

06-21-2009, 09:39 PM	#1
69halfton Registered User Join Date: Apr 2007 Location: King City, Ontario, Canada Posts: 974	Brakes master cyl. swap well, summer holidays are here. with that means summer job, and with that means i have money again to do some much needed maintenance work on the ol' girl. so i picked up a new master cyl. for my truck last week, and im going to be installing it tomorow. (how much do you normally pay for a master? i will have paid 43 bucks once i get the refund for the old one) I remember somebody on here talking about "bench bleeding" the master before installation. what the heck is "bench bleeding" i also heard that it its a must or else i would wreak the seals or something? its all very foggy lol.. My plan was going to be install the new one, fill it with fresh fluid, and then open all the bleeders and let gravity do its work, slowly flushing the lines. as the bleeders begin to bleed clean fluid, ill close it so that the next one farther down the line will recieve its fluid. do i need to "bench bleed"? or is the gravity thing going to sorta do that when its in the truck? __________________ - Jason If you can turn, Youre not going fast enough. Favorite caption: first car to 200 mph in the 1/4 mile, no parachute, drum brakes all the way around.. ..back when men were men.

06-21-2009, 10:02 PM	#2
Longhorn Man its all about the +6 inches Join Date: Jan 2001 Location: Hilliard Ohio Posts: 2,693	Re: Brakes master cyl. swap i hope that is a brand new master cylinder for that price. I've put reman'd ones on every truck I've had... 3/4 ton drum, 1/2 ton drum, one ton drum, 3/4 ton drum/disc... and never paid more than 25 bucks. Did your master cylinder come with bench bleeding directions, or the caps needed for the job? I googled how to bench bleed a master cylinder, and got this link for you. http://www.misterfixit.com/brakbld1.htm Last edited by Longhorn Man; 06-21-2009 at 10:05 PM.

06-21-2009, 10:16 PM	#3
69halfton Registered User Join Date: Apr 2007 Location: King City, Ontario, Canada Posts: 974	Re: Brakes master cyl. swap thats a great help longhornman, thanks! yes its a brandnew one. i havent really looked through anything yet, just checked to see if it looked the same __________________ - Jason If you can turn, Youre not going fast enough. Favorite caption: first car to 200 mph in the 1/4 mile, no parachute, drum brakes all the way around.. ..back when men were men.

06-22-2009, 01:29 PM	#4
69halfton Registered User Join Date: Apr 2007 Location: King City, Ontario, Canada Posts: 974	Re: Brakes master cyl. swap so i made the swap, everything went very well but i have a problem. i have gotten fluid to all the wheel cyl. except the left rear, or drivers side rear wheel. they all gravity bled until clean, including the passengerside rear wheel. I cant get even a drop of fluid out of the drivers rear, and i have no clue why this would happen. it was working before.. anybody have any ideas? __________________ - Jason If you can turn, Youre not going fast enough. Favorite caption: first car to 200 mph in the 1/4 mile, no parachute, drum brakes all the way around.. ..back when men were men.

06-22-2009, 04:13 PM	#5
Longhorn Man its all about the +6 inches Join Date: Jan 2001 Location: Hilliard Ohio Posts: 2,693	Re: Brakes master cyl. swap try pressure bleeding, could just be a piece of rust partially blocking the line or the T fitting. Honestly, myself, if the pedal is firm, I'd say screw it. But I get flamed for that kind of talk. Firm pedal = no air in the system.



Register or Log In To remove these advertisements.

Register or Log In To remove these advertisements.