Put my new master cylinder in!!! But got a Question - The 1947 - Present Chevrolet & GMC Truck Message Board Network

HotRod929 · 09-21-2002, 02:37 AM

I put my new master cylinder in my truck tonight. I bled the master cylinder when it was on the truck then connected the break lines. Tested the breaks and they worked fine. I did not bleed the breaks at each break drum. I drove the truck for like 2 hours tonight and worked the breaks really hard and they worked perfectly. My truck stops on a dime now. What my question is is that do I still need to bleed the breaks? Please let me know. Thanks

HotRod

Slammed67 · 09-21-2002, 02:48 AM

I don't think you'd HAVE to bleed them, but if it were me, I would, just to make sure there is no air in the lines. Just me $0.02.

68CST327 · 09-21-2002, 02:52 AM

Same as above. I would just to be sure. Who knows, maybe your brakes will be even better after you bleed them individually.

HotRod929 · 09-21-2002, 02:57 AM

Ok so maybe I should...Whats the order of the wheels that I should bleed? Which ones should I bleed first? Thanks

HotRod

jostrans68 · 09-21-2002, 03:51 AM

Iwould bleed two reasons make sure there is no air 2 get the old fluid out. My .02 Jack

Southpa · 09-21-2002, 04:38 AM

Any time you open the hydraulic system it should be purged of air. You could be just riding on well-balanced front brakes.

Burlinator · 09-21-2002, 06:08 AM

start at the wheel farthest away from the master(right rear) then work your way around and do the LF last

nitor · 09-21-2002, 10:23 AM

You should always bleed the brakes after breaking the lines. Burlinator has it right, start with the farthest and work your way to the Master cylinder, RR, LR, RF, LF.

71402BB · 09-21-2002, 10:31 AM

Yes, Burlinator has it right! You also might want to think about bleeding out the old break fluid! You never know just how old the "old" break fluid is in there and when that stuff starts to get old it will gum up your wheel cyclinders! Whice also means your brakes will start acting very strange, if that was to happen!

tom hand · 09-21-2002, 12:40 PM

I have worked as a mechanic for more years than I want to admit. When I worked in a forklift shop it was nothing to change out 6 or 7 master cylinders in one day. I have never had to bleed the brakes for changing one. Air wants to rise up in fluid, and what little air that is in the lines will burp up thru the master cylinder. If you leave the top off you can see it. If your pedal is rock hard I would not worry about it, unless you want to get the old fluid out.

09-21-2002, 02:37 AM	#1
HotRod929 Registered User Join Date: Mar 2002 Location: Bondurant, IA but in Worcester, MA for school Posts: 767	Put my new master cylinder in!!! But got a Question I put my new master cylinder in my truck tonight. I bled the master cylinder when it was on the truck then connected the break lines. Tested the breaks and they worked fine. I did not bleed the breaks at each break drum. I drove the truck for like 2 hours tonight and worked the breaks really hard and they worked perfectly. My truck stops on a dime now. What my question is is that do I still need to bleed the breaks? Please let me know. 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/

09-21-2002, 02:48 AM	#2
Slammed67 Progress = 0% Join Date: Nov 2001 Location: Kansas City, MO Posts: 2,108	I don't think you'd HAVE to bleed them, but if it were me, I would, just to make sure there is no air in the lines. Just me $0.02. __________________ Jason - '67 GMC swb \| '57 Bel-Air 4dr hardtop \| '56 210 4dr Wagon \| 2000 GMC Sierra

09-21-2002, 02:57 AM	#4
HotRod929 Registered User Join Date: Mar 2002 Location: Bondurant, IA but in Worcester, MA for school Posts: 767	Ok so maybe I should...Whats the order of the wheels that I should bleed? Which ones should I bleed first? 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/

09-21-2002, 03:51 AM	#5
jostrans68 Jostrans68 Join Date: Mar 2001 Location: Bloomington indiana Posts: 1,182	Iwould bleed two reasons make sure there is no air 2 get the old fluid out. My .02 Jack __________________ [CGTW Member former 67-72 now with a 96 silverado

09-21-2002, 04:38 AM	#6
Southpa Registered User Join Date: May 2000 Location: Victoria, BC, Canada Posts: 2,410	Any time you open the hydraulic system it should be purged of air. You could be just riding on well-balanced front brakes. __________________ 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.

09-21-2002, 02:52 AM	#3
68CST327 Registered User Join Date: Aug 2002 Location: USA Posts: 443	Same as above. I would just to be sure. Who knows, maybe your brakes will be even better after you bleed them individually.

09-21-2002, 06:08 AM	#7
Burlinator Just Another Crazy Canuck Join Date: Dec 2000 Location: Richmond,British Columbia Canada Posts: 1,228	start at the wheel farthest away from the master(right rear) then work your way around and do the LF last __________________ 1985 454/465/205, 38.5x11-16BOGGERS soon to be installed: 14bDETROIT,Edelbrock Performer cam,intake and valve springs,Comp roller tips,MSD HEI

09-21-2002, 10:23 AM	#8
nitor Too many projects Join Date: Aug 2002 Location: Morrow, OH Posts: 344	You should always bleed the brakes after breaking the lines. Burlinator has it right, start with the farthest and work your way to the Master cylinder, RR, LR, RF, LF.

09-21-2002, 10:31 AM	#9
71402BB now thats a true COON DOG Join Date: Nov 2000 Location: Franconia, NH Posts: 1,977	Yes, Burlinator has it right! You also might want to think about bleeding out the old break fluid! You never know just how old the "old" break fluid is in there and when that stuff starts to get old it will gum up your wheel cyclinders! Whice also means your brakes will start acting very strange, if that was to happen! __________________ current project 67 402BB stout th350 3.08's with a locker. Plan on tubs 18.5's out back! (thanks Burnsman!) 71 SWB Stepside, was a 250, now is a 402 Big Block with 4 speed and 3.73's ( was crushed by a tree, bed sold, motor pulled) was my first truck!... oh well... 72 LWB 4x4 350 4-speed 3.08's posi wearing army olive drab green (SOLD!) 68 BURB 50TH LOOKALIKE work in progress, soon to have 250-I6 with a 3-speed on the tree 4.11's and posi ( currently sitting in back yard tarped awaiting time, $$$, and lots of love!) 67 1 TON- work truck 396 sm 420 4-speed, flat bed 4.57 gears "big red" (my first landscape truck, very rusty and crusty! but still gets the job done when needed!)

09-21-2002, 12:40 PM	#10
tom hand CCRider Join Date: Feb 2000 Location: Olive Branch,MS,USA Posts: 2,232	I have worked as a mechanic for more years than I want to admit. When I worked in a forklift shop it was nothing to change out 6 or 7 master cylinders in one day. I have never had to bleed the brakes for changing one. Air wants to rise up in fluid, and what little air that is in the lines will burp up thru the master cylinder. If you leave the top off you can see it. If your pedal is rock hard I would not worry about it, unless you want to get the old fluid out. __________________ 72 GMC Sierra SWB almost finished---- 84 Softail Olive Branch MS



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