proportioning valve issue/mystery - Page 4 - Hot Rod Forum : Hotrodders Bulletin Board
Hotrodders.com -- Hot Rod Forum



Register FAQ Search Today's Posts Unanswered Posts Auto Escrow Insurance Auto Loans Advertise
Hot Rod Forum : Hotrodders Bulletin Board > Tech Help> Suspension - Brakes - Steering
User Name
Password
lost password?   |   register now

Reply
 
LinkBack Thread Tools
  #46 (permalink)  
Old 04-14-2019, 04:55 PM
johnsongrass1's Avatar
Race it, Don't rice it!
 
Join Date: Jul 2002
Location: Columbia, Mo
Age: 43
Posts: 7,031
Wiki Edits: 0

Thanks: 107
Thanked 736 Times in 604 Posts
Sorta following this thread but I'm starting to wonder if you have either the wrong pedal ratio, a very small bore MC, too much clearance on the pads/rotors shoes/drums, or the calipers are flexing or something along all those lines. Perhaps a combo of all of those.

    Advertisement
Reply With Quote Quick reply to this message
Sponsored Links
Advertisement
 
  #47 (permalink)  
Old 04-15-2019, 12:14 AM
Registered User
 
Join Date: May 2010
Location: san francisco CA
Posts: 194
Wiki Edits: 0

Thanks: 30
Thanked 0 Times in 0 Posts
Quote:
Originally Posted by johnsongrass1 View Post
Sorta following this thread but I'm starting to wonder if you have either the wrong pedal ratio, a very small bore MC, too much clearance on the pads/rotors shoes/drums, or the calipers are flexing or something along all those lines. Perhaps a combo of all of those.

tell me if im wrong but pedal ration wont decrease/ increase brake fluid pressure ?

about the master cylinder i have a 1 inch bore , i tried a 1-1/8 and it was wosre
with 1-1/8 yes hard pedal but almost nothing at the calipers

i adjusted the rrear drum pretty closed to the drum ( they drag) just to make sure . and basicly only the rear is working

calipers flexing? everything is new
and i did a pressure with caliper out of there braket. i could not install the pressure gages while there are mounted. just to say pressure its pretty low out of there braket wich i think avoid the flexing

also the front pads drag a little , i dont think there is clearance issue


everything is news . rotor , pads , line , hoses etc...
Reply With Quote Quick reply to this message
  #48 (permalink)  
Old 04-15-2019, 08:02 AM
55 Tony's Avatar
Registered User
 
Join Date: Nov 2018
Location: Cocke County, TN
Posts: 1,103
Wiki Edits: 0

Thanks: 134
Thanked 191 Times in 170 Posts
As for pedal ratio, yes and no. If your ratio is high, the pedal will be easier to press BUT it will not move as much fluid. If your ratio is low, the pedal will be harder but the same amount of movement will move more fluid. So if you press on the pedal with the SAME amount of pressure, the high ratio will give you more pressure than the low ratio, but it may not move enough fluid.

It is a kind of balancing act you have to learn when customizing brakes.



As far a calipers flexing, to tell you the truth I sometimes wonder if mine flex a little more than they should. That is something that doesn't matter if it's new. What matters is who made the calipers and how strong did they make them.
__________________
Young enough to learn ... too old to remember.
Reply With Quote Quick reply to this message
 
  #49 (permalink)  
Old 04-20-2019, 06:46 PM
Registered User
 
Join Date: May 2010
Location: san francisco CA
Posts: 194
Wiki Edits: 0

Thanks: 30
Thanked 0 Times in 0 Posts
well today i did few experiment again
i had 4:1 pedal ratio
i drilled a hole and went to 3:1
yes engine off pedal get harder
but engine 'on' nothing changed still pedal going down and no much breaks..
all break come from the rear i got almost nothing at the front

i even swap master cylinder one more time just " in case " to a 1 1/8

its even worse...front grab nothing

I did the test with the rear plugged at the master cylinder.. only kept had the front line hooked up at the mastrer cylinder
Reply With Quote Quick reply to this message
  #50 (permalink)  
Old 04-20-2019, 06:50 PM
55 Tony's Avatar
Registered User
 
Join Date: Nov 2018
Location: Cocke County, TN
Posts: 1,103
Wiki Edits: 0

Thanks: 134
Thanked 191 Times in 170 Posts
I think I asked before, can you show us pictures of the master cylinder and proportioning valve? Also pictures of the calipers showing the hose and bleeder.
__________________
Young enough to learn ... too old to remember.
Reply With Quote Quick reply to this message
  #51 (permalink)  
Old 04-20-2019, 10:54 PM
Registered User
 
Join Date: May 2010
Location: san francisco CA
Posts: 194
Wiki Edits: 0

Thanks: 30
Thanked 0 Times in 0 Posts
Here you can see last test with only the front line hooked up
Attached Thumbnails
Click image for larger version

Name:	20190420_191339_1555818815648.jpg
Views:	42
Size:	72.6 KB
ID:	442535   Click image for larger version

Name:	20190420_191749_1555818833484.jpg
Views:	38
Size:	60.1 KB
ID:	442537   Click image for larger version

Name:	20190420_191813_1555818845699.jpg
Views:	39
Size:	42.9 KB
ID:	442539  
Reply With Quote Quick reply to this message
  #52 (permalink)  
Old 04-21-2019, 07:52 AM
55 Tony's Avatar
Registered User
 
Join Date: Nov 2018
Location: Cocke County, TN
Posts: 1,103
Wiki Edits: 0

Thanks: 134
Thanked 191 Times in 170 Posts
Can you possibly put shop air pressure into the calipers? No, that low pressure won't stop the car, but it should be a decent amount of resistance when trying to spin the wheel.
Before I get yelled at, yes this could introduce a small amount of moisture into the system, but with all the bleeding going on, you can always bleed a little more.
__________________
Young enough to learn ... too old to remember.
Reply With Quote Quick reply to this message
  #53 (permalink)  
Old 04-21-2019, 11:56 PM
Registered User
 
Join Date: May 2010
Location: san francisco CA
Posts: 194
Wiki Edits: 0

Thanks: 30
Thanked 0 Times in 0 Posts
with the car on jacks
and someone pressings on the breaks engine off , the front wheels stops


i also look for any flex from the caliper engine on. and nothing
should metric caliper move a little or no?
Reply With Quote Quick reply to this message
  #54 (permalink)  
Old 04-22-2019, 07:29 AM
rip-tide's Avatar
Magazines have “ISSUES”
 

Last journal entry: Looks good
Join Date: Mar 2017
Location: Woodstock, GA
Posts: 911
Wiki Edits: 0

Thanks: 16
Thanked 313 Times in 227 Posts
Is that a single piston caliper, who's brake kit are you using? Would like to view the parts, my un-expert opinion at the moment is telling me they are not up to the j O B.

The only flex and it is not a flex, it is simply a caliper centering itself, too the rotor and for the most part, only happens after pads are swapped.

If you have a link to the source of the parts used please provide... Think that could be helpful to all.


Pep
Reply With Quote Quick reply to this message
The Following User Says Thank You to rip-tide For This Useful Post:
Vincentnova (04-23-2019)
  #55 (permalink)  
Old 04-22-2019, 07:56 AM
55 Tony's Avatar
Registered User
 
Join Date: Nov 2018
Location: Cocke County, TN
Posts: 1,103
Wiki Edits: 0

Thanks: 134
Thanked 191 Times in 170 Posts
Rip, I think the calipers do actually flex *open* a bit normally. With over 1000 psi x the square inches of surface area of the caliper cylinder, that's a lot of pressure. But forget that for now because ...

I caught something I don't recall reading before. Back in post #45, he said they are POWER brakes. That changes everything! It didn't even click when I saw the picture of the master cylinder with the booster behind it. Gawd I feel foolish going this long without asking that.


Some people change the pedal ratio lower to get less travel in the pedal with power brakes. But I don't think his booster is working so that would result in a very hard pedal with less braking then he has now.

So Nova, what size vacuum booster do you have and how much vacuum do you have? Where is the vacuum hose hooked up? And are you using a power master cylinder? Show a pic of the back end of one of the others you tried. It should have a very shallow hole in the center of the piston. Deep hole is for manual brakes.
__________________
Young enough to learn ... too old to remember.
Reply With Quote Quick reply to this message
  #56 (permalink)  
Old 04-22-2019, 10:03 AM
rip-tide's Avatar
Magazines have “ISSUES”
 

Last journal entry: Looks good
Join Date: Mar 2017
Location: Woodstock, GA
Posts: 911
Wiki Edits: 0

Thanks: 16
Thanked 313 Times in 227 Posts
That's a 7in booster, (small) usually for under the floor installs. Easy to troubleshoot a bad booster, apply the brake with the motor off.

Holding, start the engine the peddle will move closer to the floor if good, and NOT hit the floor. Stops about 2 inches or so..above the floor board...

Tony is on it, especially if the pedal in all the way on the floor...


If it is going to the floor here is something to look into:
There is a defined adjustment for the MC to booster actuator pin hight or length, and a tool for setting it.


Here is a picture and the instruction for usage .... mine it the 20 dollar version they sold before CNC came along LOL


Pep
Attached Thumbnails
Click image for larger version

Name:	Booster.jpg
Views:	22
Size:	19.2 KB
ID:	442567   Click image for larger version

Name:	TOOL.jpg
Views:	21
Size:	77.6 KB
ID:	442571  
Attached Files
File Type: pdf MPB-F200-50.pdf (187.4 KB, 7 views)

Last edited by rip-tide; 04-22-2019 at 10:16 AM.
Reply With Quote Quick reply to this message
The Following User Says Thank You to rip-tide For This Useful Post:
Vincentnova (04-23-2019)
  #57 (permalink)  
Old 04-22-2019, 01:12 PM
Bob37pont's Avatar
Curmudgeon at Large
 
Join Date: Jan 2018
Location: Astatula, FL
Posts: 275
Wiki Edits: 0

Thanks: 177
Thanked 50 Times in 42 Posts
Quote:
Originally Posted by rip-tide View Post
That's a 7in booster, (small) usually for under the floor installs. Easy to troubleshoot a bad booster, apply the brake with the motor off.

Holding, start the engine the peddle will move closer to the floor if good, and NOT hit the floor. Stops about 2 inches or so..above the floor board...

Tony is on it, especially if the pedal in all the way on the floor...


If it is going to the floor here is something to look into:
There is a defined adjustment for the MC to booster actuator pin hight or length, and a tool for setting it.


Here is a picture and the instruction for usage .... mine it the 20 dollar version they sold before CNC came along LOL


Pep
Man that would have saved me a lot of trial & error!
At least mine is on the firewall, and the cowl support rod allowed me to hang the MC with a bungie cord when I separated it from the booster!
Reply With Quote Quick reply to this message
  #58 (permalink)  
Old 04-22-2019, 01:51 PM
ericnova72's Avatar
More for Less Racer
 
Join Date: Jan 2007
Location: S.W. Lower Michigan
Age: 52
Posts: 17,602
Wiki Edits: 0

Thanks: 270
Thanked 3,183 Times in 2,671 Posts
This is just a shot in the dark...but I know many of the GM master cylinders from the late 60's up through the late 70's the front fluid cavity feeds the REAR brakes, and the rear fluid cavity feeds the FRONT brakes.

My be something to check as to why you get rear brakes with plenty of fluid but no real amount of pressure or fluid volume to the front brakes.
Reply With Quote Quick reply to this message
  #59 (permalink)  
Old 04-23-2019, 02:50 AM
Registered User
 
Join Date: May 2010
Location: san francisco CA
Posts: 194
Wiki Edits: 0

Thanks: 30
Thanked 0 Times in 0 Posts
Quote:
Originally Posted by rip-tide View Post
Is that a single piston caliper, who's brake kit are you using? Would like to view the parts, my un-expert opinion at the moment is telling me they are not up to the j O B.

The only flex and it is not a flex, it is simply a caliper centering itself, too the rotor and for the most part, only happens after pads are swapped.

If you have a link to the source of the parts used please provide... Think that could be helpful to all.


Pep


at first i got a kit from a seller on ebay for 1959 to 1964 impala
complet front kit with line etc .
its easy to find , cheapest complet kit on ebay
it came with a 1 inch mc ,the booster ,prpotioning valve and lines
caliper a the gm metric 2 and half inch piston
same one that you can get from a the auto parts store .

then i also tried a 1-1/8 master cylinder
and i also have a master from jeggs an other 1 inch that i also tried
with same results
Reply With Quote Quick reply to this message
  #60 (permalink)  
Old 04-23-2019, 02:55 AM
Registered User
 
Join Date: May 2010
Location: san francisco CA
Posts: 194
Wiki Edits: 0

Thanks: 30
Thanked 0 Times in 0 Posts
Quote:
Originally Posted by 55 Tony View Post
Rip, I think the calipers do actually flex *open* a bit normally. With over 1000 psi x the square inches of surface area of the caliper cylinder, that's a lot of pressure. But forget that for now because ...

I caught something I don't recall reading before. Back in post #45, he said they are POWER brakes. That changes everything! It didn't even click when I saw the picture of the master cylinder with the booster behind it. Gawd I feel foolish going this long without asking that.


Some people change the pedal ratio lower to get less travel in the pedal with power brakes. But I don't think his booster is working so that would result in a very hard pedal with less braking then he has now.

So Nova, what size vacuum booster do you have and how much vacuum do you have? Where is the vacuum hose hooked up? And are you using a power master cylinder? Show a pic of the back end of one of the others you tried. It should have a very shallow hole in the center of the piston. Deep hole is for manual brakes.

i have an hard pedal when engine is off
before i had a spongy pedal even engine off
i moved from 4:1 to 3:1 pedal ratio , and now engine i get an harder pedal
but engine on still the same..pedal go low and front calipers almost grab nothing


vacum hose is connected at the intake (engine is a lq4 )
yes i use power master cylinder
and yes shallow hole behind master cylinder ( im aware about that )
Reply With Quote Quick reply to this message

Recent Suspension - Brakes - Steering posts with photos

Quick Reply
Message:
Options

Register Now

In order to be able to post messages on the Hot Rod Forum : Hotrodders Bulletin Board forums, you must first register.
Please enter your desired user name (usually not your first and last name), your email address and other required details in the form below.
User Name:
Password
Please enter a password for your user account. Note that passwords are case-sensitive.
Password:
Confirm Password:
Email Address
Please enter a valid email address for yourself.
Email Address:
Insurance
Please select your insurance company (Optional)

Log-in



Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
 
Thread Tools

Posting Rules
You may post new threads
You may 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
Trackbacks are On
Pingbacks are On
Refbacks are On


Similar Threads
Thread Thread Starter Forum Replies Last Post
pin on proportioning valve andybird Suspension - Brakes - Steering 10 04-17-2003 10:48 AM
When is a proportioning valve needed? jpd37 Suspension - Brakes - Steering 2 03-25-2003 10:42 AM
master cylinder and proportioning valve? curtisstarlight Suspension - Brakes - Steering 3 03-18-2003 10:12 AM
S-10 Proportioning Valve TurboS10 Suspension - Brakes - Steering 5 01-03-2003 11:42 AM
adjusting proportioning valve stoke46 Suspension - Brakes - Steering 2 05-06-2002 09:14 PM


All times are GMT -6. The time now is 12:36 PM.


Powered by vBulletin® Version 3.8.8
Copyright ©2000 - 2019, vBulletin Solutions, Inc.
Search Engine Optimization by vBSEO 3.6.0 PL2
vBulletin Security provided by vBSecurity v2.2.2 (Pro) - vBulletin Mods & Addons Copyright © 2019 DragonByte Technologies Ltd.
Copyright Hotrodders.com 1999 - 2012. All Rights Reserved.