...

Go Back   Lateral-g Forums > Technical Discussions > Brakes
User Name
Password



Reply
 
Thread Tools Display Modes
  #21  
Old 10-17-2017, 07:12 PM
67rsssls's Avatar
67rsssls 67rsssls is offline
Member
 
Join Date: Oct 2007
Location: Atoka, TN
Posts: 40
Thanks: 0
Thanked 0 Times in 0 Posts
Default

Hey Mark,

Does the factory use something similar to fill the hydraulic clutch system?

Thanks,

Steve
__________________
Steve
Reply With Quote
  #22  
Old 10-18-2017, 02:25 PM
preston preston is offline
Senior Member
 
Join Date: Nov 2005
Posts: 637
Thanks: 0
Thanked 22 Times in 14 Posts
Default

Looks good and could uncover small leaks, but I've never had an issue getting a rock hard brake pedal just using one of those cheap pressure bleeders. I felt like I found God the first time I used one instead of pumping the pedal. But I don't have an ABS module either.
Reply With Quote
  #23  
Old 10-23-2017, 11:30 AM
TheJDMan's Avatar
TheJDMan TheJDMan is offline
Senior Member
 
Join Date: Jan 2011
Location: Northern Virginia
Posts: 689
Thanks: 5
Thanked 25 Times in 13 Posts
Default

I visited the Corvette assembly line in Bowing Green a while back and one of the items I specifically tried to see was how they bleed brakes on the line. I was not able to figure out exactly where they did this much less how they did it. But it was clearly a very quick procedure. This is great information to know that a GM system can hold that pressure and vacuum. Now if Wilwood can tell me if their MCs will handle this kind of pressure and vacuum I should be set with my C6 Z06 calipers. Thanks for this info Mark!
__________________
Steve Hayes
"Dust Off"
68 Camaro
Speed has never killed anyone. Suddenly becoming stationary, that's what gets you!
"Jeremy Clarkson"
Reply With Quote
  #24  
Old 10-23-2017, 07:17 PM
Hydratech®'s Avatar
Hydratech® Hydratech® is offline
Supporting Manufacturer

HydratechBraking.com

 
Join Date: Jul 2004
Location: Music City
Posts: 421
Thanks: 3
Thanked 66 Times in 30 Posts
Thumbs up A little baffled...

Hi Mark, great to see you post this, though I will say that it has me baffled as to how the brake system you have videoed holds that amount of vacuum. All of the directional cup seals in the system are designed to balloon out under pressure (MC, caliper piston seals). I'm very surprised to see that you have managed to draw that amount of vacuum and have it hold. Apparently the GM OEM cup seals are tight enough within their respective bores to also allow this strong of a vacuum to also be applied and held with the components you are using. I can see where square cut caliper piston seals may hold a vacuum, but the cup seals in the MC? Hmmm... Remember how everybody always talked about a ten pound residual valve in the rear brake circuit on drum brake equipped cars to prevent the cup seals from allowing air to get drawn in? My personal testing has shown that rear drums work just fine without the residual pressure... I am now curious as to how aftermarket MC's and caliper pistons may react to having a vacuum drawn on the system.

Ford has circulated a PS system bleeding procedure over the year that uses vacuum to assist in drawing air out of the PS system over the years too. I have tried this a few times on various different year / make / models with both empty and filled systems with zero success - will not hold a vacuum. On a running, happy and healthy PS system, my occasional previous testing with vacuum applied (while the engine is running) has actually "pissed off" the power steering system by drawing air in. I'm suspecting the front PS pump shaft seals (as they really aren't designed to hold any particular pressure), but haven't been able to prove it. Interesting that a high pressure hydraulic system is designed to hold pressure, but in my POWER STEERING (not brake) testing, vacuum has always worked out to be a "pie in my face", so I no longer fool with it.

Interesting...
__________________
There IS a difference - Thank you for choosing Hydratech!

Paul M. Clark <-- the Ukrainian - Slava Ukraini !
Founder / Master Engineer
Hydratech Braking Systems ®
www.hydratechbraking.com
Reply With Quote
  #25  
Old 10-24-2017, 07:40 AM
dontlifttoshift's Avatar
dontlifttoshift dontlifttoshift is online now
Senior Member
 
Join Date: Oct 2012
Location: Beach Park. IL
Posts: 928
Thanks: 10
Thanked 168 Times in 100 Posts
Default

I use vacuum to bleed power steering and hydraulic clutch systems all the time. Not 30" of vacuum but enough to suck the air out successfully. It is the Ford recommended procedure for clutch bleeding.

My testing with drum brakes and no residual valve ended with an okay pedal and adequate operation but the pedal height was always changing. I don't have the problem when the valve is in place.

I have had enough early vette masters apart to question how they could ever hold vacuum. There must be something in the late model master cylinders to accommodate that. Next time I have a complete new system, I will apply vaccum and see if it holds.
__________________
Donny

Support your local hot rod shop!
Reply With Quote
  #26  
Old 05-11-2019, 08:43 AM
jlwdvm jlwdvm is offline
Senior Member
 
Join Date: Aug 2010
Posts: 343
Thanks: 0
Thanked 17 Times in 8 Posts
Default

I'm confused as to why the vacuum port and fluid port communicate with each other above the master.
Reply With Quote
Reply

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 04:46 PM.


Powered by vBulletin® Version 3.8.11
Copyright ©2000 - 2024, vBulletin Solutions Inc.
Copyright Lateral-g.net