'72 C10 Brake failure - The 1947 - Present Chevrolet & GMC Truck Message Board Network

Techx · 07-21-2011, 02:40 PM

I've read and checked several threads, but I am at a lost. I replaced the master cylinder, extended my brake push rod and now I don't have brakes at all. I bench bled the master cylinder and I bled each individual brake, using an entire bottle of fluid. Can anyone give me an idea on how I could still have air in the line?

**Classic Heartbeat** · 07-21-2011, 02:53 PM

Did the mastercylinder ever run too low while bleeding? Also, Did you tighten the bleeders befor the brake peddel was relieced? WES

Techx · 07-21-2011, 03:53 PM

The master cylinder always had plenty of fluid and I tightened the bleeders while the brake was fully pressed.

Sammy · 07-21-2011, 04:12 PM

These trucks are hard to bleed. Unless your master cylinder is bad, which isn't very likely, you have air in the lines somewhere. Some folks have taken two days of bleeding to get the all air out. Start over again with someone knowledgeable to do the brake pedal for you. In your case one bottle wasn't enough.

Techx · 07-21-2011, 04:15 PM

Thanks I'll just keep on keepin on.

**Classic Heartbeat** · 07-21-2011, 04:46 PM

Also use this order to bleed them with... 1st, Right Rear. 2nd, Left Rear, 3rd, Right Front. 4th Left Front. WES

fastwillie 696969 · 07-21-2011, 04:56 PM

some post the video bleeding brakes by yourself with bottle and hose

‪How To Bleed Air Out Of Your Car's Brake...

camrycurt · 07-21-2011, 04:59 PM

Another thought...I recently replaced the master cylinder in my 1970 C10 with drums all the way around and gravity bled each brake line and didn't have any problems. You might consider trying the gravity method. If I can have success with it, it's pretty foolproof.

It also took me a while to bench bleed the MC, as you probably found out. Each time I thought I was getting close I'd get another bubble and so I'd keep going. I kept tapping and pushing and eventually things tightened up real firm so I knew it was good.

Just my $0.02.

Lee H · 07-21-2011, 05:44 PM

Why did you extend the push rod?
Posted via Mobile Device

PanelDeland · 07-21-2011, 06:48 PM

Lee H has a good point.How much did you extend the pushrod? Too much will not release enough for fluid to drop into the cyl.This may not be your problem if you got good flow thru the lines but it's worth mentioning.

Techx · 07-22-2011, 04:16 AM

Well it is 3 in the morning and still no luck. I shortened the rod back up and tried gravity bleeding. Every so often I would close the valves back up and pump the brakes and start the gravity bleed over. I'm on my 3rd bottle of brake fluid now.
Posted via Mobile Device
Posted via Mobile Device

fastwillie 696969 · 07-22-2011, 06:07 AM

try this get a jar add new brake fluid 1/3 of the jar would be good ,get your hose and connect it to the bleeder valve ,with M/C filled and capped ,crack open bleeder now watch the jar while pumping the brakes watch the jar and see if you can see any air bubbles keep going until the fluid level goes up in the jar ,close the bleeder and check the M/C level top off if needed. then connect the hose on the other side repeat operation ,i assume that the M/C is bleed and no leaks ,hoses and connections are good ,if it doesnt flush the air out ,then a power bleeder might need to be used ,they hook up to the M/C good luck by the way just for snot, what DOT number are you using on brake fluid

Techx · 07-22-2011, 07:28 AM

Dot3
Posted via Mobile Device

Techx · 07-27-2011, 10:54 PM

I finally got all the air out. I have never worked on a vehicle with manual brakes and didn't realize that it would take so long getting the air out. I also talked to my helper and I believe he was not closing the bleeders while I pumped my brakes. That would be another reason that it took so long to get all the air out.

**MusicMan70** · 07-27-2011, 11:12 PM

Great to hear you figured it out....what a relief, BrakeOn!

71swb4x4 · 07-27-2011, 11:28 PM

Next time if you can, have your helper do the pumping and you run the bleeders so you know it's done right.

07-21-2011, 02:40 PM	#1
Techx Registered User Join Date: Jul 2011 Location: Pea Ridge, AR Posts: 20	'72 C10 Brake failure I've read and checked several threads, but I am at a lost. I replaced the master cylinder, extended my brake push rod and now I don't have brakes at all. I bench bled the master cylinder and I bled each individual brake, using an entire bottle of fluid. Can anyone give me an idea on how I could still have air in the line?

07-21-2011, 02:53 PM	#2
Classic Heartbeat Project Junkie! Fishing Poor!! Join Date: Dec 1999 Location: Olympia,Wa. 98512 Posts: 10,770	Re: '72 C10 Brake failure Did the mastercylinder ever run too low while bleeding? Also, Did you tighten the bleeders befor the brake peddel was relieced? WES __________________ On-line catolog Classic Heartbeat Pickup Parts WEHEPP@comcast.net Call us Toll Free (888) 338-2502 Like Us on Facebook No appointment necessary. 72 BB Chevy Custom Deluxe / Custom Camper 67 I-6 (Soon to be 5.7 LS1) Panel 68 BB Chevy Short Bed 72 6.0 LQ9 Short Bed Chevy 4X4 Olympia's fastest growing truck parts supplier. Olympia's home for Wayward Chevys

07-21-2011, 03:53 PM	#3
Techx Registered User Join Date: Jul 2011 Location: Pea Ridge, AR Posts: 20	Re: '72 C10 Brake failure The master cylinder always had plenty of fluid and I tightened the bleeders while the brake was fully pressed.

07-21-2011, 04:12 PM	#4
Sammy Registered User Join Date: Apr 2000 Location: Bonne Terre, Mo Posts: 3,005	Re: '72 C10 Brake failure These trucks are hard to bleed. Unless your master cylinder is bad, which isn't very likely, you have air in the lines somewhere. Some folks have taken two days of bleeding to get the all air out. Start over again with someone knowledgeable to do the brake pedal for you. In your case one bottle wasn't enough. __________________ '69 Chevy Long Fleet & '71 GMC Short Step & Project "ODD BALL" "You can wash a pig, soak it in most expensive perfume. In the end it is still just a pig." ODD BALL build thread http://67-72chevytrucks.com/vboard/s...d.php?t=478629"

07-21-2011, 04:15 PM	#5
Techx Registered User Join Date: Jul 2011 Location: Pea Ridge, AR Posts: 20	Re: '72 C10 Brake failure Thanks I'll just keep on keepin on.

07-21-2011, 04:46 PM	#6
Classic Heartbeat Project Junkie! Fishing Poor!! Join Date: Dec 1999 Location: Olympia,Wa. 98512 Posts: 10,770	Re: '72 C10 Brake failure Also use this order to bleed them with... 1st, Right Rear. 2nd, Left Rear, 3rd, Right Front. 4th Left Front. WES __________________ On-line catolog Classic Heartbeat Pickup Parts WEHEPP@comcast.net Call us Toll Free (888) 338-2502 Like Us on Facebook No appointment necessary. 72 BB Chevy Custom Deluxe / Custom Camper 67 I-6 (Soon to be 5.7 LS1) Panel 68 BB Chevy Short Bed 72 6.0 LQ9 Short Bed Chevy 4X4 Olympia's fastest growing truck parts supplier. Olympia's home for Wayward Chevys

07-21-2011, 04:59 PM	#8
camrycurt Registered User Join Date: Jul 2010 Location: Leesburg, VA Posts: 420	Re: '72 C10 Brake failure Another thought...I recently replaced the master cylinder in my 1970 C10 with drums all the way around and gravity bled each brake line and didn't have any problems. You might consider trying the gravity method. If I can have success with it, it's pretty foolproof. It also took me a while to bench bleed the MC, as you probably found out. Each time I thought I was getting close I'd get another bubble and so I'd keep going. I kept tapping and pushing and eventually things tightened up real firm so I knew it was good. Just my $0.02. __________________ Curt 1970 C/10, 250 L6 with Rochester BV carb, SM465 4 speed, 3.73 open rear

07-21-2011, 05:44 PM	#9
Lee H Registered User Join Date: Jun 2010 Location: Upland Ca Posts: 4,139	Re: '72 C10 Brake failure Why did you extend the push rod? Posted via Mobile Device __________________ 1972 C10 SWB, Air, PS, PB, 350/350THM. Second owner. 1965 Corvette roadster, 44K miles, 327/365 SHP, 4 speed, side exhaust, knockoffs, teak, second owner (bought in 1970), Have ALL numbers matching components. My frame off restoration thread: http://67-72chevytrucks.com/vboard/s...d.php?t=556703

07-21-2011, 06:48 PM	#10
PanelDeland I am a Referee of life. Join Date: Jun 2000 Location: Greensboro N.C. Posts: 13,993	Re: '72 C10 Brake failure Lee H has a good point.How much did you extend the pushrod? Too much will not release enough for fluid to drop into the cyl.This may not be your problem if you got good flow thru the lines but it's worth mentioning. __________________ The 47-present Chevrolet and GMC Truck Message Board Network,it's owners,moderators,members,and associates of any type should not be held responsible for my opinion. You can't fix stupid,not even with duct tape. "My appearance is due to the fact that "GOD" does punish you for having too much fun!" Barrett-Jackson has perfected alchemy,they make rust into gold! "You can lead a horse to water but you can't saddle a duck" "Cleverly disguised as a 'Responsible Adult' "Sometimes your Knight in shining armor is just a retard in tinfoil"

07-22-2011, 04:16 AM	#11
Techx Registered User Join Date: Jul 2011 Location: Pea Ridge, AR Posts: 20	Re: '72 C10 Brake failure Well it is 3 in the morning and still no luck. I shortened the rod back up and tried gravity bleeding. Every so often I would close the valves back up and pump the brakes and start the gravity bleed over. I'm on my 3rd bottle of brake fluid now. Posted via Mobile Device Posted via Mobile Device

07-22-2011, 06:07 AM	#12
fastwillie 696969 ~Rest In Peace~ Join Date: May 2005 Location: CALIFORNIA NOR CAL Posts: 9,707	Re: '72 C10 Brake failure try this get a jar add new brake fluid 1/3 of the jar would be good ,get your hose and connect it to the bleeder valve ,with M/C filled and capped ,crack open bleeder now watch the jar while pumping the brakes watch the jar and see if you can see any air bubbles keep going until the fluid level goes up in the jar ,close the bleeder and check the M/C level top off if needed. then connect the hose on the other side repeat operation ,i assume that the M/C is bleed and no leaks ,hoses and connections are good ,if it doesnt flush the air out ,then a power bleeder might need to be used ,they hook up to the M/C good luck by the way just for snot, what DOT number are you using on brake fluid __________________ is it fast ? it has a lighting bolt donut? B___H please, I can remove 90% of your so called "beauty" with a kleenex

07-22-2011, 07:28 AM	#13
Techx Registered User Join Date: Jul 2011 Location: Pea Ridge, AR Posts: 20	Re: '72 C10 Brake failure Dot3 Posted via Mobile Device

07-27-2011, 10:54 PM	#14
Techx Registered User Join Date: Jul 2011 Location: Pea Ridge, AR Posts: 20	Re: '72 C10 Brake failure I finally got all the air out. I have never worked on a vehicle with manual brakes and didn't realize that it would take so long getting the air out. I also talked to my helper and I believe he was not closing the bleeders while I pumped my brakes. That would be another reason that it took so long to get all the air out.

07-27-2011, 11:12 PM	#15
MusicMan70 Senior Member Join Date: Feb 2011 Location: Corona, CA Posts: 1,820	Re: '72 C10 Brake failure Great to hear you figured it out....what a relief, BrakeOn! __________________ MusicMan70 1961 GMC Suburban

07-27-2011, 11:28 PM	#16
71swb4x4 Senior Member Join Date: Nov 2003 Location: Brookings, SD Posts: 10,497	Re: '72 C10 Brake failure Next time if you can, have your helper do the pumping and you run the bleeders so you know it's done right. __________________ Some people are like slinkies, they aren't good for anything, but you can't help but smile when you see one tumble down the stairs.



Register or Log In To remove these advertisements.

Register or Log In To remove these advertisements.