The 1947 - Present Chevrolet & GMC Truck Message Board Network







Register or Log In To remove these advertisements.

Go Back   The 1947 - Present Chevrolet & GMC Truck Message Board Network > 47 - Current classic GM Trucks > The 1967 - 1972 Chevrolet & GMC Pickups Message Board

Web 67-72chevytrucks.com


Reply
 
Thread Tools Display Modes
Old 07-21-2013, 07:25 PM   #1
missionstreettattoo
Registered User
 
missionstreettattoo's Avatar
 
Join Date: Apr 2013
Location: sapulpa oklahoma
Posts: 76
1968 c10 brake proportioning valve

is it possible that this is the reason i cannot get any pedal to my brakes? i have bled three brake fluid bottles through and it still goes to the floor. i got a master cylinder bleeding kit and di that. still to the floor. the shoes are adjusted out properly. the proportioning valve is the only thing left.
missionstreettattoo is offline   Reply With Quote
Old 07-21-2013, 07:31 PM   #2
missionstreettattoo
Registered User
 
missionstreettattoo's Avatar
 
Join Date: Apr 2013
Location: sapulpa oklahoma
Posts: 76
Re: 1968 c10 brake proportioning valve

why does my truck with drum brakes even have what is called a disc brake proportioning valve? and can i just bypass this?
missionstreettattoo is offline   Reply With Quote
Old 07-21-2013, 08:47 PM   #3
lolife99
Old Trucks and a BelAir
 
lolife99's Avatar
 
Join Date: Nov 2002
Location: Mid-MO
Posts: 19,520
Re: 1968 c10 brake proportioning valve

Quote:
Originally Posted by missionstreettattoo View Post
why does my truck with drum brakes even have what is called a disc brake proportioning valve? and can i just bypass this?
They don't.
Drum brake trucks just have a distribution block.
__________________
Keith
lolife99 is offline   Reply With Quote
Old 07-21-2013, 09:44 PM   #4
missionstreettattoo
Registered User
 
missionstreettattoo's Avatar
 
Join Date: Apr 2013
Location: sapulpa oklahoma
Posts: 76
Re: 1968 c10 brake proportioning valve

this is what is below my master cylinder. I have drum brakes all the way around. i can bypass this right?
Attached Images
 
missionstreettattoo is offline   Reply With Quote
Old 07-22-2013, 10:20 AM   #5
missionstreettattoo
Registered User
 
missionstreettattoo's Avatar
 
Join Date: Apr 2013
Location: sapulpa oklahoma
Posts: 76
Re: 1968 c10 brake proportioning valve

so is this something i can remove and connect brake lines directly to the master cylinder? any thoughts? this is my last place to look in finding why i cannot get anything but a saft pedal. straight to the floor. no matter what i have done.
missionstreettattoo is offline   Reply With Quote
Old 07-22-2013, 10:38 AM   #6
lolife99
Old Trucks and a BelAir
 
lolife99's Avatar
 
Join Date: Nov 2002
Location: Mid-MO
Posts: 19,520
Re: 1968 c10 brake proportioning valve

You can remove it,... but you will lose your brake light switch.
You may have a bad M/C.
I would bench bleed it and try again.
__________________
Keith
lolife99 is offline   Reply With Quote
Old 07-22-2013, 10:59 AM   #7
Ridgeclimber
Registered User
 
Join Date: Jul 2012
Location: Maple Ridge. B.C.
Posts: 142
Re: 1968 c10 brake proportioning valve

Is your master cylinder new? It's hard to tell from the picture. If the master cylinder is used, maybe the cup seals in the master cylinder could be leaking by causing the pedal to go down. If the master cylinder is new. Start by bench bleeding it, slowly. Don't pump it hard and fast. If there is air in it you could break up the air and air rate the fluid. Then instal the cylinder and start by bleeding the right rear wheel first. Then left rear, then right front then left front. Again pump the pedal slowly and don't turn the air and fluid into foam. Good luck.
Posted via Mobile Device
Ridgeclimber is offline   Reply With Quote
Old 07-22-2013, 11:08 AM   #8
Mister-B
Account Suspended
 
Join Date: Oct 2012
Location: Salt Lake City, Utah
Posts: 3,338
Re: 1968 c10 brake proportioning valve

Get a new master cylinder for $17, and bench bleed it. Your current one has probably gone bad
Posted via Mobile Device
Mister-B is offline   Reply With Quote
Old 07-22-2013, 12:06 PM   #9
cdowns
Senior Member
 
cdowns's Avatar
 
Join Date: Jan 2003
Location: daytonabeach
Posts: 21,551
Re: 1968 c10 brake proportioning valve

i have found buying and reading a factory service manual for a particular vehicle can help you know what you have and how to fix it
__________________
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
cdowns is offline   Reply With Quote
Old 07-22-2013, 12:39 PM   #10
Steve Cole
Registered User
 
Join Date: May 2012
Location: Faith,NC
Posts: 549
Re: 1968 c10 brake proportioning valve

I have never seen bleeder screws ON the master cylinder before! WOW! Are they tight when your pumping? You did put the cap back on, right? Sounds dumb but it could happen. Do you EVER get a tight pedal? or is it always soft?

Last edited by Steve Cole; 07-22-2013 at 12:40 PM. Reason: typo
Steve Cole is offline   Reply With Quote
Old 07-22-2013, 01:42 PM   #11
Ridgeclimber
Registered User
 
Join Date: Jul 2012
Location: Maple Ridge. B.C.
Posts: 142
Re: 1968 c10 brake proportioning valve

Is the pedal just low towards the floor or is it spongy. That is two different problems. If the pedal is low could be brake shoes out of adjustment or be shoes not seated into the drums. If the pedal is hard then creaps to the floor it could be the master cylinder leaking internally. If the pedal is just spongy then it could be air in the system. Just another thing to consider.
Posted via Mobile Device
Ridgeclimber is offline   Reply With Quote
Old 07-22-2013, 04:07 PM   #12
missionstreettattoo
Registered User
 
missionstreettattoo's Avatar
 
Join Date: Apr 2013
Location: sapulpa oklahoma
Posts: 76
Re: 1968 c10 brake proportioning valve

if it sits any time at all, the pedal goes straight to the floor, after a few pumps, there is pedal again. the master cylinder was bought new at oreillys a year ago and installed then. only in the last month have i gotten all the lines and things replaced and hooked up.
missionstreettattoo is offline   Reply With Quote
Old 07-22-2013, 04:07 PM   #13
missionstreettattoo
Registered User
 
missionstreettattoo's Avatar
 
Join Date: Apr 2013
Location: sapulpa oklahoma
Posts: 76
Re: 1968 c10 brake proportioning valve

so the bleeder valves on the mc are strange?
missionstreettattoo is offline   Reply With Quote
Old 07-22-2013, 04:12 PM   #14
Mister-B
Account Suspended
 
Join Date: Oct 2012
Location: Salt Lake City, Utah
Posts: 3,338
Re: 1968 c10 brake proportioning valve

Quote:
Originally Posted by missionstreettattoo View Post
if it sits any time at all, the pedal goes straight to the floor, after a few pumps, there is pedal again. the master cylinder was bought new at oreillys a year ago and installed then. only in the last month have i gotten all the lines and things replaced and hooked up.
Have you bench bled the master cylinder yet? If not, you need to stop what you're doing and go do that. What's happened with your brakes since a year ago when you bought the MC? Did you get a leak, have a cylinder go bad, etc? If so, this could have allowed your pedal to travel further then it should. Mix that with all the to the floor pumping you've done, and you probably have a shot MC now. If you want to save some time and aggravation, I'd recommend you buy a new $17 MC, bench bleed it, install it (keep the block below the MC in tact), bleed all the brakes at the cylinders, and then tell is how it went. See, some of us have gone through something similar to this not too long ago, wink wink.
Posted via Mobile Device
Mister-B is offline   Reply With Quote
Old 07-22-2013, 04:38 PM   #15
missionstreettattoo
Registered User
 
missionstreettattoo's Avatar
 
Join Date: Apr 2013
Location: sapulpa oklahoma
Posts: 76
Re: 1968 c10 brake proportioning valve

well the truck never ran. it was parked the whole year ive had it,but i guess my next step will be a different master cylinder, just do it and see what happens.
missionstreettattoo is offline   Reply With Quote
Old 07-22-2013, 04:42 PM   #16
Mister-B
Account Suspended
 
Join Date: Oct 2012
Location: Salt Lake City, Utah
Posts: 3,338
Re: 1968 c10 brake proportioning valve

Quote:
Originally Posted by missionstreettattoo View Post
well the truck never ran. it was parked the whole year ive had it,but i guess my next step will be a different master cylinder, just do it and see what happens.
And don't install the new MC without bench bleeding it first, or you'll have issues still
Posted via Mobile Device
Mister-B is offline   Reply With Quote
Reply

Bookmarks

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump


All times are GMT -5. The time now is 01:32 AM.


Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2014, vBulletin Solutions, Inc.
Copyright 1997-2013 67-72chevytrucks.com