Brake Help! - The 1947 - Present Chevrolet & GMC Truck Message Board Network

1BadSS · 11-24-2006, 05:12 PM

I've been messing with the c10 all day today, so far I've put two new wheel cylinders in the truck and still cannot get the brakes to bleed out starting in the rear. The bleeders are dripping fluid out but the pedal isnt getting any harder at all.

I've even tried the one man / speed bleeders and they arent worth a crap.

Any idea's guys?

PanelDeland · 11-24-2006, 05:23 PM

What was the reason for changing wheel cylinders?Was the pedal spongy or did you have leaks? Give some more details for better diagnostic help.You are bleeding them one at a time right?there should be fairly solid streams of fluid coming out rather than dribbles.

1BadSS · 11-24-2006, 05:28 PM

Quote:

Originally Posted by PanelDeland

What was the reason for changing wheel cylinders?Was the pedal spongy or did you have leaks? Give some more details for better diagnostic help.You are bleeding them one at a time right?there should be fairly solid streams of fluid coming out rather than dribbles.

The PO did the 5lug front disc and 5lug rear swap on the truck when he had it, broke the rear bleeders off and gave up on the truck. The truck itself, has never had rear brakes as long as i've owned it. So I went out and put two new wheel cylinders into it today.

The pedal has some hesitation but then goes to the floor. The fluid isnt spraying out like it should, also cant get these speed bleeders to work either.

1BadSS · 11-24-2006, 05:35 PM

Also if it helps, the rear pot was dry when I got to it.

Robert1970C20rstbukt · 11-24-2006, 05:50 PM

Sounds like the rubber brake hose collapsed and isn't letting the fluid flow through.

1BadSS · 11-24-2006, 06:01 PM

Quote:

Originally Posted by Robert1970C20rstbukt

Sounds like the rubber brake hose collapsed and isn't letting the fluid flow through.

There are no rubber hoses on the rear circuit of these trucks, is there?

Sweet72 · 11-24-2006, 06:32 PM

Yes there is a rubber hose going from the T fitting on your rear axle to the hard line on the frame. Also this could be the proportioning valve stuck and porting all pressure to the front brakes only. Remove a line from the rear wheel cylinder and see if fluid flows freely (with a helper of course) when the pedal is pressed.

PanelDeland · 11-24-2006, 09:01 PM

I spent about $5.00 on a one man bleeder kit.Mrs.P ain't much of a helper and if she lets off a couple times before I'm ready we don't get along for a couple days.It's basically a cup with a lid that has a hose attachment and a vent.By putting fluid in it and slipping the hose over the bleeder,you can pump the brakes by yourself,then close the bleeder.Make sure you don't let the MC run dry.Also the hose may be collapsed internally and need replacement even if it looks good.Remember it's probably 35 or 40 years old.

1BadSS · 11-24-2006, 09:06 PM

Quote:

Originally Posted by PanelDeland

I spent about $5.00 on a one man bleeder kit.Mrs.P ain't much of a helper and if she lets off a couple times before I'm ready we don't get along for a couple days.It's basically a cup with a lid that has a hose attachment and a vent.By putting fluid in it and slipping the hose over the bleeder,you can pump the brakes by yourself,then close the bleeder.Make sure you don't let the MC run dry.Also the hose may be collapsed internally and need replacement even if it looks good.Remember it's probably 35 or 40 years old.

Thanks panel, but all of the hoses are brand new, mc is brand new, wheel cyl's are brand new, calipers are brand new.

Just not getting fluid. Like I mentioned earlier, the Rear pot in the MC was bone dry before I tried to get it going, could this be causing any problems?

**truckdude239** · 11-25-2006, 12:02 AM

prop vavle sounds like its closed i dont know the exact way of opening but once you get it open let the brake gravty bleed frist (open bleeders till fuild comes out the shut them and bleed like normal

low'n slow · 11-25-2006, 12:13 AM

If the MC is new or was dry, did you bench bleed it before installation?

jhow66 · 11-25-2006, 01:12 AM

Read this to see if it will help--
http://www.classicperform.com/TechBo...t.htm#testprop

1BadSS · 11-25-2006, 01:36 AM

Should just sell this truck and buy a ford, 67-72's have been nothing but trouble for me. My 65 has never given me any of these problems while doing brake work.

1BadSS · 11-25-2006, 01:37 AM

Quote:

Originally Posted by low'n slow

If the MC is new or was dry, did you bench bleed it before installation?

It was supposedly new, was dry when I got to it in the rear pot. Is it possible that this is the cause of the rear brake issues? I mean I have absolutely no pedal in the truck period, no brakes what so ever.

dwaite72lnghrn · 11-25-2006, 08:46 AM

If the bleeders were broken off for a long time and the old MC was dry I would say your brake lines are rusted closed on the rear circuit. Problem with brake lines and air and a little fluid is it pulls moisture and rusts. looks like you need new brake lines.

Richard H. · 11-25-2006, 10:31 AM

You are in a world of unknowns, you really need to start at the MC.
You can bench bleed it on the truck. Problem is the fittings to do this
usually come with a new or rebuilt MC. Two plastic fittings that fit into
the front and back line fittings with plastic clear hose that pumps it
right back into the MC. This can take up to a half hour to get ALL the
air out of the MC pistons.
While bleeding the system you never let the mc run out! I just did all
the brakes on my C 10 and it took over a quart of fluid to do it right.
Do not re-use any fluid.
HTH Richard

1BadSS · 11-25-2006, 11:58 AM

Quote:

Originally Posted by dwaite72lnghrn

If the bleeders were broken off for a long time and the old MC was dry I would say your brake lines are rusted closed on the rear circuit. Problem with brake lines and air and a little fluid is it pulls moisture and rusts. looks like you need new brake lines.

The thing is, the right rear Wheel cyl was plum dry, while the left rear was full of fluid and the line was filled with fluid too, but the pot was dry.

IIRC, when I filled the rear pot, pumped it a couple of times and removed the rear lines, they both let out about a cup or so full of fluid while changing out the wheel cylinders, now they dont seem to want to bleed out.

cdowns · 11-25-2006, 12:46 PM

i memory serves me right theres a knob on the front of the combination valve that theres a tool to hold it in the out position so you can bleed the brakes/ i always pulled it out and wedged a piece of wire to keep it open// if you've got a service manual the proper procedure is covered in there

ratrod67 · 11-25-2006, 01:11 PM

I'd pull the brake line loose from the prop valve and the rubber hose and blow air through it. Then move to the rubber hose and then through the axle lines. If all are clear I would say the master or the prop valve is bad. Is it possible the rear pot on the master was dry and the piston or seals are bad in that side? You just need to eliminate 1 part at a time. I'd start with the easiest. The lines.

GMCMAX · 11-25-2006, 01:20 PM

I would start from scratch at the m/c and work back. Check for fluid at all the fittings along the way and see where it's not getting to, but it sounds like the prop vakve switched, probably after you filled the m/c and pumped, the cupfull could have been the line draining from the prop to the rear.

jhow66 · 11-25-2006, 01:21 PM

You cannot bleed the rear until you push "in" on the needle on the front of prop. valve. Use a small C-clamp and do this .

1BadSS · 11-25-2006, 03:03 PM

Finally got them to bleed out.

Was pushing on the pedal and loading it with the rear one man bleeder cracked and all I heard was 'SPIIIIIIIIIT' and it shot fluid clear across the rear to the other drum, and then bled out the other side and it finally did the same. Finally got both the rear and the front bled out.

powell72 · 11-25-2006, 03:34 PM

Quote:

Originally Posted by 1BadSS

Should just sell this truck and buy a ford, 67-72's have been nothing but trouble for me.

See, now don't you feel bad for saying that?

1BadSS · 11-25-2006, 03:46 PM

Quote:

Originally Posted by powell72

See, now don't you feel bad for saying that?

Not really, my 65 has never given me these troubles when it came to brakes or anything.

11-24-2006, 05:12 PM	#1
1BadSS NOT REALLY BANNED! Join Date: Jul 2004 Location: Shawnee, KS Posts: 1,072	Brake Help! I've been messing with the c10 all day today, so far I've put two new wheel cylinders in the truck and still cannot get the brakes to bleed out starting in the rear. The bleeders are dripping fluid out but the pedal isnt getting any harder at all. I've even tried the one man / speed bleeders and they arent worth a crap. Any idea's guys? __________________ 1987 Mustang Coupe - 2.7 Stroker, 78mm turbo, Stainless header, 3" Exh, FMIC, 160lb/hr Injectors, MS3, twin walbro 255's, 34psi. Eating V8's daily. 04 Pontiac GTO 04 Ford Mustang GT 68 C20 LWB stripper truck 73 K5 Cheyenne 76 C20 Sierra Crew SRW 88 K20 Suburban I'm not hammering on metal just to hammer, i'm creating a piece of art.

11-24-2006, 05:23 PM	#2
PanelDeland I am a Referee of life. Join Date: Jun 2000 Location: Greensboro N.C. Posts: 13,993	Re: Brake Help! What was the reason for changing wheel cylinders?Was the pedal spongy or did you have leaks? Give some more details for better diagnostic help.You are bleeding them one at a time right?there should be fairly solid streams of fluid coming out rather than dribbles. __________________ 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"

11-24-2006, 05:35 PM	#4
1BadSS NOT REALLY BANNED! Join Date: Jul 2004 Location: Shawnee, KS Posts: 1,072	Re: Brake Help! Also if it helps, the rear pot was dry when I got to it. __________________ 1987 Mustang Coupe - 2.7 Stroker, 78mm turbo, Stainless header, 3" Exh, FMIC, 160lb/hr Injectors, MS3, twin walbro 255's, 34psi. Eating V8's daily. 04 Pontiac GTO 04 Ford Mustang GT 68 C20 LWB stripper truck 73 K5 Cheyenne 76 C20 Sierra Crew SRW 88 K20 Suburban I'm not hammering on metal just to hammer, i'm creating a piece of art.

11-24-2006, 05:50 PM	#5
Robert1970C20rstbukt Registered User Join Date: Jun 2004 Location: Beeville, Texas Posts: 1,943	Re: Brake Help! Sounds like the rubber brake hose collapsed and isn't letting the fluid flow through. __________________ RJD 1984 Chevrolet C30 welding truck 454/SM465 1977 GMC C15 pickup 350/TH350 1970 Chevrolet C20 pickup 350/TH400 1970 Chevrolet K20 Suburban 454/TH350 1969 GMC 8500 478M V6/5 spd winch truck

11-24-2006, 06:32 PM	#7
Sweet72 Registered User Join Date: Nov 2003 Location: Alexandria, VA Posts: 1,534	Re: Brake Help! Yes there is a rubber hose going from the T fitting on your rear axle to the hard line on the frame. Also this could be the proportioning valve stuck and porting all pressure to the front brakes only. Remove a line from the rear wheel cylinder and see if fluid flows freely (with a helper of course) when the pedal is pressed. __________________ '72 GMC SWB C1500 Custom, frame-off in progress. 383 SBC, 9:1CR, Comp Cams XE262H, Scat internal balanced crank, Eagle SIR 6" rods, Keith Black dish pistons, Dart Iron Eagle 72/180 heads, Weiand Stealth intake, Stewart stage I water pump, Holley 4bbl vac sec, TH350 with B&M Shift Improver Kit. 12 bolt positraction.

11-24-2006, 09:01 PM	#8
PanelDeland I am a Referee of life. Join Date: Jun 2000 Location: Greensboro N.C. Posts: 13,993	Re: Brake Help! I spent about $5.00 on a one man bleeder kit.Mrs.P ain't much of a helper and if she lets off a couple times before I'm ready we don't get along for a couple days.It's basically a cup with a lid that has a hose attachment and a vent.By putting fluid in it and slipping the hose over the bleeder,you can pump the brakes by yourself,then close the bleeder.Make sure you don't let the MC run dry.Also the hose may be collapsed internally and need replacement even if it looks good.Remember it's probably 35 or 40 years old. __________________ 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"

11-25-2006, 12:02 AM	#10
truckdude239 Senior Member Join Date: Sep 2005 Location: Lewisville, Nc Posts: 10,233	Re: Brake Help! prop vavle sounds like its closed i dont know the exact way of opening but once you get it open let the brake gravty bleed frist (open bleeders till fuild comes out the shut them and bleed like normal __________________ David fuller Ase Certified Mechanic Click here to help support our board!! 1971 Chevy c-10 under going a 4.8l LSx swap Build Thread http://67-72chevytrucks.com/vboard/s...d.php?t=421305 2007 Honda Accord my daily 145kmiles 2002 Honda Accord 4 door With 330k(sisters car) 2005 toyota Avalon 228k( brothers car) 2002 Sububran 5.3 245k 2000 Tahoe 5.3l 378 General manager for Marco's Carwash & lube

11-25-2006, 12:13 AM	#11
low'n slow Too Dumb To Know Better Join Date: Nov 2005 Location: Texas Posts: 882	Re: Brake Help! If the MC is new or was dry, did you bench bleed it before installation?

11-25-2006, 01:12 AM	#12
jhow66 Registered User Join Date: Jun 2002 Location: Knoxville Tenn. Posts: 3,058	Re: Brake Help! Read this to see if it will help-- http://www.classicperform.com/TechBo...t.htm#testprop __________________ 56 Chevy Bel-Air 2dr. HT (purchased new) 71 Chevy Cheyenne SWB PU (502HO) 65 GMC short bed step--work in progress and my gofer

11-25-2006, 01:36 AM	#13
1BadSS NOT REALLY BANNED! Join Date: Jul 2004 Location: Shawnee, KS Posts: 1,072	Re: Brake Help! Should just sell this truck and buy a ford, 67-72's have been nothing but trouble for me. My 65 has never given me any of these problems while doing brake work. __________________ 1987 Mustang Coupe - 2.7 Stroker, 78mm turbo, Stainless header, 3" Exh, FMIC, 160lb/hr Injectors, MS3, twin walbro 255's, 34psi. Eating V8's daily. 04 Pontiac GTO 04 Ford Mustang GT 68 C20 LWB stripper truck 73 K5 Cheyenne 76 C20 Sierra Crew SRW 88 K20 Suburban I'm not hammering on metal just to hammer, i'm creating a piece of art.

11-25-2006, 08:46 AM	#15
dwaite72lnghrn Registered User Join Date: Jun 2002 Location: central pa Posts: 1,525	Re: Brake Help! If the bleeders were broken off for a long time and the old MC was dry I would say your brake lines are rusted closed on the rear circuit. Problem with brake lines and air and a little fluid is it pulls moisture and rusts. looks like you need new brake lines. __________________ 72 longhorn c30 502BB/th400/fact air/4.11rear/ custom camper 72 bug(the better half's) under reconstruction 2009 HHR aqua blue 71 GMC k20 350/sm465 2009 Chevy hd3500 6.6 Victory Red crew cab dually Dave & Jeanne

11-25-2006, 10:31 AM	#16
Richard H. Spanked once Join Date: Oct 2006 Location: Intheshop, Indiana Posts: 969	Re: Brake Help! You are in a world of unknowns, you really need to start at the MC. You can bench bleed it on the truck. Problem is the fittings to do this usually come with a new or rebuilt MC. Two plastic fittings that fit into the front and back line fittings with plastic clear hose that pumps it right back into the MC. This can take up to a half hour to get ALL the air out of the MC pistons. While bleeding the system you never let the mc run out! I just did all the brakes on my C 10 and it took over a quart of fluid to do it right. Do not re-use any fluid. HTH Richard

11-25-2006, 12:46 PM	#18
cdowns Senior Member Join Date: Jan 2003 Location: daytonabeach Posts: 22,956	Re: Brake Help! i memory serves me right theres a knob on the front of the combination valve that theres a tool to hold it in the out position so you can bleed the brakes/ i always pulled it out and wedged a piece of wire to keep it open// if you've got a service manual the proper procedure is covered in there __________________ 71c-10 350/2004r/4:11 lowered3/4 longbed/dead by hurricane MEANING OF DEATH::::: SOMEBODY ELSE GETS YOUR STUFF DONT BELIEVE EVERYTHING YOU THINK TAKE MY ADVISE;I DON'T USE IT ANYWAY

11-25-2006, 01:11 PM	#19
ratrod67 Registered User Join Date: Sep 2002 Location: DFW Texas Posts: 2,270	Re: Brake Help! I'd pull the brake line loose from the prop valve and the rubber hose and blow air through it. Then move to the rubber hose and then through the axle lines. If all are clear I would say the master or the prop valve is bad. Is it possible the rear pot on the master was dry and the piston or seals are bad in that side? You just need to eliminate 1 part at a time. I'd start with the easiest. The lines.

11-25-2006, 01:20 PM	#20
GMCMAX Active Member Join Date: Jan 2006 Location: Lower Mid-East Ca. Posts: 326	Re: Brake Help! I would start from scratch at the m/c and work back. Check for fluid at all the fittings along the way and see where it's not getting to, but it sounds like the prop vakve switched, probably after you filled the m/c and pumped, the cupfull could have been the line draining from the prop to the rear. __________________ Never try to teach a pig to sing; it wastes your time and annoys the pig! Gets More Chicks My lugnuts require more torque than your honda makes! 68 GMC, 4X4 conversion w/73 k20 running gear and springs, 350 4spd, 4.10's, D44 powerlok front, 14BFF govlock rear, 33" tires, lifted 4".



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11-25-2006, 01:21 PM	#21
jhow66 Registered User Join Date: Jun 2002 Location: Knoxville Tenn. Posts: 3,058	Re: Brake Help! You cannot bleed the rear until you push "in" on the needle on the front of prop. valve. Use a small C-clamp and do this . __________________ 56 Chevy Bel-Air 2dr. HT (purchased new) 71 Chevy Cheyenne SWB PU (502HO) 65 GMC short bed step--work in progress and my gofer

11-25-2006, 03:03 PM	#22
1BadSS NOT REALLY BANNED! Join Date: Jul 2004 Location: Shawnee, KS Posts: 1,072	Re: Brake Help! Finally got them to bleed out. Was pushing on the pedal and loading it with the rear one man bleeder cracked and all I heard was 'SPIIIIIIIIIT' and it shot fluid clear across the rear to the other drum, and then bled out the other side and it finally did the same. Finally got both the rear and the front bled out. __________________ 1987 Mustang Coupe - 2.7 Stroker, 78mm turbo, Stainless header, 3" Exh, FMIC, 160lb/hr Injectors, MS3, twin walbro 255's, 34psi. Eating V8's daily. 04 Pontiac GTO 04 Ford Mustang GT 68 C20 LWB stripper truck 73 K5 Cheyenne 76 C20 Sierra Crew SRW 88 K20 Suburban I'm not hammering on metal just to hammer, i'm creating a piece of art.

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