Weird brake problem - Hot Rod Forum : Hotrodders Bulletin Board
Hotrodders.com -- Hot Rod Forum



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

Reply
 
LinkBack Thread Tools
  #1 (permalink)  
Old 03-15-2008, 07:18 AM
Rob Keller's Avatar
AKA:"SLOWRIDE66"take it easy!
 
Last wiki edit: How to post pictures on a forum
Last journal entry: 85 Suburban
Last photo:
Join Date: May 2004
Location: Central Florida U.S.A.
Age: 48
Posts: 4,297
Wiki Edits: 38

Thanks: 0
Thanked 1 Time in 1 Post
Question Weird brake problem

Like you would expect any less from me?. . .

Any way
1988 Chevy 3+3 1 Ton Dualie with Hydro boost.

This has been going on for months I have to use a syringe to so a "fluid transfer" from the rear portion of the master to the front . the front goes down & the rear over flows.

At 1st it was about once a week now its like every 100 miles

I have checked the whole system for leaks & stuff its all about a year old minus the rear flex line & steel lines.

This I just don't get

Any Help???

    Advertisement
__________________
"SlowRide66"

"Illegitimis non carborundum"
Don't let the bastards grind you down!

Crankshaft Coalition Master List of Hotrodding Forums
Reply With Quote Quick reply to this message
Sponsored Links
Advertisement
 
  #2 (permalink)  
Old 03-15-2008, 07:28 AM
New Member
 
Join Date: Nov 2003
Posts: 29
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
Ok.. interesting problem! I take it that the TOTAL amount of fluid is staying the same.. i.e. you don't have to add any or take any out.. just move it from one to the other, rite?

That being the case- it must be migrating from one circuit to the other. The only points of commonality that i can thing of are the master cyl itself, and the hydraulic switch that turns on the idiot light if you have a failure in one circuit (sometimes referred to as a 'proportioning valve'. That is - unless you have other common points in your system (either stock or added).

I believe that normally the ports to the reseviors are open on 'pedal up' - i.e. there is no pressure in either circuit when your foot is off. I can't see why fluid should be forced from one circuit to another under those conditions. If one port were still being covered, increased engine compartment heat could build up pressure in one circuit, and somehow force it over to the other. A leak in the the switch/proport valve might permit migration too. particularly if one resevior is higher than the other. Is it going from high to low.. i.e. is the resevior losing fluid higher than the one gaining it? Could be a leak in the master cylinder between circuits too i guess. Have you checked to see if both circuits are working 100%? Sometimes it's hard to tell...

Good Luck..

Rabbit
Reply With Quote Quick reply to this message
  #3 (permalink)  
Old 03-15-2008, 07:38 AM
F&J F&J is offline
Registered User
 

Last journal entry: 32 Ford cabriolet conversion/windshield
Last photo:
Join Date: Mar 2007
Location: Connecticut
Age: 62
Posts: 1,571
Wiki Edits: 0

Thanks: 0
Thanked 1 Time in 1 Post
What he said




If I had to roll the dice, I'd change the master first. Just seems more likely?


P-valves from GM were pretty pricey as I recall some years back? I don't know if they are avail in aftermarket.
Reply With Quote Quick reply to this message
  #4 (permalink)  
Old 03-15-2008, 08:19 AM
powerrodsmike's Avatar
Hotrodders.com Moderator
 
Last wiki edit: Make a fiberglass fan shroud
Last journal entry: Next.. ..Bagging the king B (barge)
Last photo:
Join Date: Jan 2005
Location: gilroy, california
Age: 53
Posts: 4,108
Wiki Edits: 161

Thanks: 0
Thanked 3 Times in 3 Posts
I saw a problem like that once on a car with a Midland Ross type remote booster installed in one side of the system. (installed in front line only...early factory plumbed TCI setup on a 34 coupe )


Under certain conditions, the cup seals of a master cylinder will let fluid past them on the return stroke. Because of a difference in flow back to the master, the front cylinder would pull fluid from the rear chamber on the return stroke, pumping the rear dry and overflowing the front after a while. (It could have been the other way around on that car, it was a few years ago, but you get the idea.)

As long as there are no restrictions in your lines, such as an uncentered combination valve or a restrictive prop valve or possibly a bypassing cup seal in your MC, you should see no fluid swapping.

I'd say get your combination valve and rear load sensing prop valve rebuilt or replaced. (I know of a couple of places that do that service) Replace the mc too.


Or just drill a hole in the wall of the master cylinder between the reservoirs...It doesn't have to be low in the reservoirs, a 3/16" hole about 1/2" down should do it. That will let the fluid levels equalize when one level gets too high.


Later, mikey
__________________
my signature lines...not really directed at anyone in particular..

BE different....ACT normal.

No one is completely useless..They can always be used as a bad example
Reply With Quote Quick reply to this message
  #5 (permalink)  
Old 03-15-2008, 09:37 AM
Registered User
 
Last photo:
Join Date: Jul 2007
Location: norcal
Age: 58
Posts: 762
Wiki Edits: 0

Thanks: 1
Thanked 2 Times in 2 Posts
hi rob, i'll answer your PM later. rain can be a bummer at the drags.

upon reading this thread i thought "why not just drill a hole in the master between the 2 reservoirs if everything is working properly??" but i thought that was too goofy of an answer to post--then low and behold i read down and mikey comes up with the same solution--go figure...

OH, by the way rob, we have the NHRA summernationals at my local dragstrip (sears point-now infinion raceway) it happens in july and we don't get rain in july!!! i go every year, i have an in for free tix and it's a great show...

EDIT: of course drilling a hole in the master would entail taking it off the truck, draining it, cleaning out the shavings from drilling, reinstalling it, bleeding it--oh crap, why not just replace it???

by the way--i have done 100s of masters and i have NEVER seen that problem--you come up with some interesting stuff...

Last edited by techron; 03-15-2008 at 09:45 AM.
Reply With Quote Quick reply to this message
  #6 (permalink)  
Old 03-15-2008, 11:26 AM
Rob Keller's Avatar
AKA:"SLOWRIDE66"take it easy!
 
Last wiki edit: How to post pictures on a forum
Last journal entry: 85 Suburban
Last photo:
Join Date: May 2004
Location: Central Florida U.S.A.
Age: 48
Posts: 4,297
Wiki Edits: 38

Thanks: 0
Thanked 1 Time in 1 Post
Oh Yea lucky me

Why couldn't i be interesting in some other area .

like .... like ....

Because I am too busy chasing my tail with chit like this .

LOL

Mikey
GM's Dual Mode Hight Sensing Proportioning Valve

It's by passed think this could have a issue.



I also thought about drilling a hole in between them, But it would have to be on a angle.

Then I thought about cutting the wall with my cut off Wheel making a slot.
I think I can do this on the truck with some cap plugs & a Shop Vac .


T Hoose

Yea it dose not seem to use any fluid unless the rear gets over filled & I pop the cap to have it spill all over.

I think I let it go dry & now it has a bit of air but it still will shut off if you forget to take it out of gear @ a traffic light.
{my other truck it a automatic }

Its a Bone stock System I need to replace a pressure line on the power steering side .all the outer rubber has fallen off & it weeps a bit bit that should not effect it any.



Thanks for all the great replies



R
__________________
"SlowRide66"

"Illegitimis non carborundum"
Don't let the bastards grind you down!

Crankshaft Coalition Master List of Hotrodding Forums
Reply With Quote Quick reply to this message
  #7 (permalink)  
Old 03-15-2008, 11:46 AM
Member
 
Last photo:
Join Date: Jun 2007
Location: murfreesboro tn.
Posts: 731
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
Weird brake problem

glad you asked this question , been a long problem for me
i drilled in place using magnets to catch all .
have you totally flushed the fluid .
i found out that fluid breaks down over the years
i had a neighbor who put power steering fluid in his .
he thought trans went out .
that fluid gets hot and expands and applies the brakes .
i towed it back wards , felt drag , swapped ends and still no go pulling home .
thought brakes were locking ,loosened the lines and got sprayed with fluid ,
pulled like should be afterward.
Reply With Quote Quick reply to this message
  #8 (permalink)  
Old 03-15-2008, 10:34 PM
Registered User
 
Last wiki edit: How to title a hot rod Last photo:
Join Date: Feb 2007
Location: West Virginia
Age: 25
Posts: 3,389
Wiki Edits: 8

Thanks: 14
Thanked 1 Time in 1 Post
Quote:
Originally Posted by powerrodsmike

Or just drill a hole in the wall of the master cylinder between the reservoirs...It doesn't have to be low in the reservoirs, a 3/16" hole about 1/2" down should do it. That will let the fluid levels equalize when one level gets too high.


Later, mikey

Exactally what I was thinking


Shane
Reply With Quote Quick reply to this message
  #9 (permalink)  
Old 03-16-2008, 09:11 AM
Rob Keller's Avatar
AKA:"SLOWRIDE66"take it easy!
 
Last wiki edit: How to post pictures on a forum
Last journal entry: 85 Suburban
Last photo:
Join Date: May 2004
Location: Central Florida U.S.A.
Age: 48
Posts: 4,297
Wiki Edits: 38

Thanks: 0
Thanked 1 Time in 1 Post
Quote:
Originally Posted by Chevrolet4x4s
Exactally what I was thinking


Shane

Z~actly What I did.





R
__________________
"SlowRide66"

"Illegitimis non carborundum"
Don't let the bastards grind you down!

Crankshaft Coalition Master List of Hotrodding Forums
Reply With Quote Quick reply to this message
  #10 (permalink)  
Old 03-18-2008, 05:12 PM
New Member
 
Join Date: Nov 2003
Posts: 29
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
Weird brake problem

Burnt Olds>
I don't think that there should be any pressure at all in the lines with the pedal up. If there is, i'd suspect that the master piston is not being fully released - thereby blocking the port to the master cylinder reservior. THis would cause pressure to build up in the lines under the right circumstances. With the port open, no pressure could be developed. I had this prob once with a MGB - the front pads would drag - and heat up so much the front wheels were effectively locked. I had to bleed fluid to drive off.. (this is in the middle of a busy commuter road in rush hour naturally!! Investigation revealed that the pedal linkage was not rully returning to 'pedal up'. An added return spriing cured the problem. No power assist naturally on an MGB (dragging your feet would almost work). Cheers

Rab
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:
If you do not want to register, fill this field only and the name will be used as user name for your post.
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:

Log-in

Human Verification

In order to verify that you are a human and not a spam bot, please enter the answer into the following box below based on the instructions contained in the graphic.




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
master cylinder interchange runn141 Suspension - Brakes - Steering 7 05-03-2009 05:15 AM
Hotrodders Knowledge Cluster: Disc Brake Conversions Jon Suspension - Brakes - Steering 0 08-29-2003 03:34 PM
Brake Lock-up Problem landroid Suspension - Brakes - Steering 5 04-02-2003 06:28 PM
Major Brake Problem... HELP ME! 98rocket Suspension - Brakes - Steering 8 03-17-2003 05:22 PM
Brake problem NEED HELP 74huggerorange Suspension - Brakes - Steering 7 02-27-2003 06:46 PM


All times are GMT -6. The time now is 10:34 PM.


Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2014, vBulletin Solutions, Inc.
Search Engine Optimization by vBSEO 3.6.0 PL2
Copyright Hotrodders.com 1999 - 2012. All Rights Reserved.