Residual check valves - 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 03-04-2010, 08:49 PM
Registered User
 
Join Date: Oct 2007
Location: North Florida
Posts: 10
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
Residual check valves

Read a tech article on using 10psi RCV's on rear disk system when using Caddy E-brake calipers. The 10psi valve is supposed to give less pedal travel. Has anyone ever tried this?

    Advertisement
Reply With Quote Quick reply to this message
Sponsored Links
Advertisement
 
  #2 (permalink)  
Old 03-04-2010, 09:13 PM
65ELCMO's Avatar
Registered User
 
Last photo:
Join Date: Dec 2009
Location: Tucson,AZ
Posts: 189
Wiki Edits: 0

Thanks: 2
Thanked 3 Times in 3 Posts
Quote:
Originally Posted by Migman
Read a tech article on using 10psi RCV's on rear disk system when using Caddy E-brake calipers. The 10psi valve is supposed to give less pedal travel. Has anyone ever tried this?
disc uses a 2 lb check valve. 10 lb is for drum brakes
Reply With Quote Quick reply to this message
  #3 (permalink)  
Old 03-04-2010, 10:42 PM
cobalt327's Avatar
WFO
 
Last wiki edit: Intake manifold
Last journal entry: 1980 Malibu Wagon
Last photo:
Join Date: Mar 2009
Location: Atlanta
Age: 60
Posts: 5,037
Wiki Edits: 1616

Thanks: 128
Thanked 598 Times in 547 Posts
Quote:
Originally Posted by Migman
Read a tech article on using 10psi RCV's on rear disk system when using Caddy E-brake calipers. The 10psi valve is supposed to give less pedal travel. Has anyone ever tried this?
If your master cylinder is mounted below the calipers, you need a residual pressure valve. They are not needed if your master is on the firewall.

But the above 2 pound spec is correct- if it is needed.

Now, you mention these calipers specifically- there could be a reason for it w/them that is out of the ordinary.
Reply With Quote Quick reply to this message
  #4 (permalink)  
Old 03-04-2010, 11:14 PM
Registered User
 
Join Date: Oct 2007
Location: North Florida
Posts: 10
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
I am referring to the use of 10psi RCV on the Caddy calipers specifically. They are noted for causing a long pedal travel especially if the parking brake is not used frequently to keep the piston ratcheted out. They are also know to be very difficult to bleed.
Reply With Quote Quick reply to this message
  #5 (permalink)  
Old 03-05-2010, 09:34 AM
Frisco's Avatar
Glad To Be Here
 
Last photo:
Join Date: Nov 2002
Location: Canton, North Carolina
Age: 73
Posts: 2,244
Wiki Edits: 0

Thanks: 0
Thanked 8 Times in 8 Posts
Quote:
Originally Posted by Migman
I am referring to the use of 10psi RCV on the Caddy calipers specifically. They are noted for causing a long pedal travel especially if the parking brake is not used frequently to keep the piston ratcheted out. They are also know to be very difficult to bleed.
They are no more difficult to bleed than any other disc brake calipers.

They do have to be adjusted correctly to work well and that procedure is more time consuming. Once done though it will work well. The parking brake is built into the caliper and is cam operated. The use of the parking brake is what keeps the rear calipers properly adjusted.

The 10 psi residual valve is because of the longer travel of the pistons in these calipers and is to keep the calipers from retracting too far when the brake pedal has been released. These calipers retract approximately .050 with no residual valve in place as compared to front calipers that retract approximately .005. For under the floor mounted master cylinder you should also run a 2 psi residual valve for the front lines. You should also run an aftermarket adjustable regulator in the rear lines to enable you to balance the front to rear braking. The front brakes should be applied slightly before the rear. This is to prevent swapping ends if you have to use hard braking.

If manual brakes, use a 7/8"-1" bore master and a pedal ratio of 6-7:1.

If power brakes, use a 1 1/8" bore master and a pedal ratio of 4:1.

Don't waste your time with one of the small (too small) 7" single diaphragm boosters. They do not give enough boost to work well. If you must use one of the small diameter booster, then I suggest to get at least the dual diaphragm version.

I have posted info on these calipers and the proper adjustment for them on this site before. If you are unable to find that info with the SEARCH function, I can attach the info here.
Reply With Quote Quick reply to this message
  #6 (permalink)  
Old 03-05-2010, 09:53 PM
Registered User
 
Join Date: Oct 2007
Location: North Florida
Posts: 10
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
Thanks Frisco. I needed to hear from the voice of experience re 10psi RCVs. I was concerned about dragging brakes. You're right re bleeding as long as they aren't clocked differently then stock position with bleeder screw at the top. Most of the DB conversion kits allow a variety position's making it a good idea to bleed them unmounted with the bleed screw at the top.
Reply With Quote Quick reply to this message
  #7 (permalink)  
Old 03-06-2010, 08:57 AM
Rickracer's Avatar
ASE Master Tech, Fabricator
 
Last wiki edit: Taurus 2-speed fan control wiring diagram Last photo:
Join Date: Jan 2010
Location: Kissimmee, Florida
Age: 55
Posts: 937
Wiki Edits: 8

Thanks: 0
Thanked 3 Times in 3 Posts
Quote:
Originally Posted by Frisco
....They do have to be adjusted correctly to work well and that procedure is more time consuming. Once done though it will work well...
...Until the pads wear, then they will need adjusting again...

Quote:
Originally Posted by Frisco
...The front brakes should be applied slightly before the rear. This is to prevent swapping ends if you have to use hard braking....
I believe you have this backwards, the rear brakes should apply before the front brakes, but with less pressure.

Quote:
Originally Posted by Frisco
...I have posted info on these calipers and the proper adjustment for them on this site before. ...
I would NOT recommend using this system at all because of the adjustment problems. I worked for GM during this time, and personally worked on several cars that had redesigned parts installed numerous times with no real improvements. GM went to a divorced E-brake system on the Vettes a long time ago, and on everything else recently, for a reason. If you're doing a rear disc swap, it's normally for better brakes, why switch to a system that was a PITA when it was new, and never really got any better. I used a rear disc brake system from a 2000 Blazer on my S10, along with the front system from a 98 up F body, and I tell people "if you're not strapped in, I CAN make you kiss the windshield",
Reply With Quote Quick reply to this message
  #8 (permalink)  
Old 03-06-2010, 09:10 AM
Frisco's Avatar
Glad To Be Here
 
Last photo:
Join Date: Nov 2002
Location: Canton, North Carolina
Age: 73
Posts: 2,244
Wiki Edits: 0

Thanks: 0
Thanked 8 Times in 8 Posts
Quote:
Originally Posted by Rickracer
...Until the pads wear, then they will need adjusting again...
There is a built in ratchet mechanism that will keep the pads adjusted correctly. HOWEVER, that only works when the parking brake is engaged/dis-engaged. That is why the factory states that the parking brake should be used when parking.


Quote:
Originally Posted by Rickracer
...I believe you have this backwards, the rear brakes should apply before the front brakes, but with less pressure.
Not backwards at all. Most vehicles have 60% (+) of the stopping performed by the front brakes. If the rear brakes are applied first, they will lock up and lose traction because of the weight transfer.


Quote:
Originally Posted by Rickracer
...I would NOT recommend using this system at all because of the adjustment problems.
I ran this system on my '30 Ford coupe. As you stated, it is/was a PITA to get to work correctly. I even had to modify the mechanical advantage of the parking brake to get it to apply enough force to get the parking brake to hold. I would NOT recommend this setup either based on my personal experience. However, for those seeking advise or opinions with this system I will offer what I have found.
Reply With Quote Quick reply to this message
  #9 (permalink)  
Old 03-06-2010, 09:24 AM
Rickracer's Avatar
ASE Master Tech, Fabricator
 
Last wiki edit: Taurus 2-speed fan control wiring diagram Last photo:
Join Date: Jan 2010
Location: Kissimmee, Florida
Age: 55
Posts: 937
Wiki Edits: 8

Thanks: 0
Thanked 3 Times in 3 Posts
Quote:
Originally Posted by Frisco
There is a built in ratchet mechanism that will keep the pads adjusted correctly. HOWEVER, that only works when the parking brake is engaged/dis-engaged. That is why the factory states that the parking brake should be used when parking.
Even if the parking brake is used, it doesn't really work like it's supposed to. As I said, (in less detail), I fought with one of these systems for the better part of a year on an (83?) Camaro while working for a Chevy dealer, and tangled with a couple of Caddies during the same time period. The Camaro owner was VERY picky, and every time his pedal dropped a bit, it was back in the shop. I had those calipers apart so many times, I could do it blindfolded, all under warranty pay, which, if you ever worked for a dealer, you'd know, really SUCKS.



Quote:
Originally Posted by Frisco
...Most vehicles have 60% (+) of the stopping performed by the front brakes. If the rear brakes are applied first, they will lock up and lose traction because of the weight transfer.
Agreed on the percentage, even greater on FWD cars, but that's what the metering valve does, it applies pressure to the rear brakes first, and the proportioning valve keeps the pressure from exceeding rear traction. Weight transfer doesn't really happen in any significant way until the front brakes apply.

Quote:
Originally Posted by MPBRAKES
What does a proportioning valve do?
A proportioning valve is used in the rear to decrease the rate of pressure rise to the drums relative to the pedal force as weight is shifted to the front during braking. This prevents the rear from locking up under hard braking conditions.
What does a metering valve do?
A metering valve or "hold off valve" is used in the disc portion of a disc/drum system to hold off the application of the front discs slightly allowing the slower reacting rears to catch up. This provides rear stability on wet surfaces and reduces excessive pad wear.
The above info, and more, can be found here: http://www.mpbrakes.com/technical-su...nce-valves.cfm

Quote:
Originally Posted by Frisco
I ran this system on my '30 Ford coupe. As you stated, it is/was a PITA to get to work correctly. I even had to modify the mechanical advantage of the parking brake to get it to apply enough force to get the parking brake to hold. I would NOT recommend this setup either based on my personal experience. However, for those seeking advise or opinions with this system I will offer what I have found.
I am sure that info is appreciated, for somebody that's already stuck with one of these systems, your experience and knowledge will be quite handy,

Last edited by Rickracer; 03-06-2010 at 10:20 AM.
Reply With Quote Quick reply to this message
  #10 (permalink)  
Old 03-06-2010, 04:39 PM
cobalt327's Avatar
WFO
 
Last wiki edit: Intake manifold
Last journal entry: 1980 Malibu Wagon
Last photo:
Join Date: Mar 2009
Location: Atlanta
Age: 60
Posts: 5,037
Wiki Edits: 1616

Thanks: 128
Thanked 598 Times in 547 Posts
Actually, it appears GM has employed BOTH front-first AND rear-first schemes for brake application through the years.

Pre-combo valve brake systems could have a 'correction valve' that "was used to hold off pressure to the rear brakes so the front brakes would go on a split second before the rears." More @ http://www.inlinetube.com/Prop%20Valves/pro_valves.htm

Generally speaking, the combo valve's valving uses a rear-brakes-on-first scheme, the idea being there will be better vehicle stabilization.
Reply With Quote Quick reply to this message
  #11 (permalink)  
Old 03-07-2010, 07:36 AM
Rickracer's Avatar
ASE Master Tech, Fabricator
 
Last wiki edit: Taurus 2-speed fan control wiring diagram Last photo:
Join Date: Jan 2010
Location: Kissimmee, Florida
Age: 55
Posts: 937
Wiki Edits: 8

Thanks: 0
Thanked 3 Times in 3 Posts
Wow, thanks Cobalt, that's the first I've heard of that, and I stand corrected,
I still think rear just slightly first is a better idea for a disc/drum system, but I don't plan to run drum brakes anymore anyway,
Reply With Quote Quick reply to this message
  #12 (permalink)  
Old 03-07-2010, 08:17 PM
cobalt327's Avatar
WFO
 
Last wiki edit: Intake manifold
Last journal entry: 1980 Malibu Wagon
Last photo:
Join Date: Mar 2009
Location: Atlanta
Age: 60
Posts: 5,037
Wiki Edits: 1616

Thanks: 128
Thanked 598 Times in 547 Posts
Quote:
Originally Posted by Rickracer
I still think rear just slightly first is a better idea for a disc/drum system, but I don't plan to run drum brakes anymore anyway,
I agree. And drum brakes (especially fronts ) are getting to be fewer and farther between as time goes on.

Good riddance, IMHO- as (w/a few exceptions) they are labor intensive to maintain/repair, heavy and prone to fade.
Reply With Quote Quick reply to this message
  #13 (permalink)  
Old 03-08-2010, 09:47 AM
bentwings's Avatar
bentwings
 
Last photo:
Join Date: May 2002
Location: St.Paul, Minn
Age: 72
Posts: 1,798
Wiki Edits: 0

Thanks: 0
Thanked 16 Times in 15 Posts
I use the Cad rear calipers with the e-brake. I had to switch them from side to side to get the bleeders in the right position and the brake levers in the right position for my cables as mounted them on top. This also required that I reverse the guts so the e-brake applied when I pulled on the handle. It was a bit of a mystery when I first installed them (no instructions with the kit) why they applied when I released the handle. The adjuster caused them to get totally messed up until I started taking things apart to find the problem. I also had to change the leverage so I had enough pull on them to hold the car against the motor at idle. In fact I finally had to get a 3000 converter to finish this off. Works great now. I have pictures but it would be very difficult to see what I did unless you knew these inside and out. I really don't but I just followed the mechanics of them and adapted to them. Hotrodder lingo for "made them work the way I wanted them to, rather than the way they were designed to work."

Actually I think the disc unit that mounts on the front of the 9 inch rear end would be better if you have room. I know that the integral drum brake is supposed to work great but I just didn't want that style. Hard headed I guess.
Reply With Quote Quick reply to this message
  #14 (permalink)  
Old 03-09-2010, 03:50 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
My understanding and experience with cars with or without metering valves showed me that a metering valve only holds pressure from the fronts until 50 or so psi is reached. This keeps the fronts from doing all the work at low speeds. If you drive a non metered disc/drum car on slippery or loose surfaces, you'll find the fronts apply first, and they will skid just a little on the loose stuff. In normal braking the timing is correct, where the drum brakes in the rear give slightly more stopping power at the beginning of a brake application, but are quickly outpowered by the disc fronts as the pressure rises.
If you ever looked at the graphs that show actual stopping power, drum brakes have the advantage over disc at the beginning of an application, but they build up heat so fast that they become ineffectual in a short time. That's why you find rear discs on most anything these days.

I have used a 10# rpv several times on the gm low drag FRONT calipers to band-aid a low pedal , which retract about .020-.030", and had no dragging issues...If that Caddy piston retracts .050", as Frisco states, then it's most likely the same seal design as the low drag front caliper, and a 10# rpv would work fine.

IIRC, most all those Cad calipers were intended to be used with a stepbore master cylinder, which would deliver the larger amount of fluid needed to activate the brakes. Many hotrodders use a smaller plain bore master cylinder, hence the need for an RPV as a band-aid for a low pedal.

I agree with all the above posters, the Cad caliper is a PITA, to adjust and maintain and I wouldn't build a new system using them..Explorer or S-10 or Corvette style internal parking brakes are the way to go. I have also used the pinion mounted ones, and they are not very good, IMO.

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
  #15 (permalink)  
Old 03-09-2010, 07:21 AM
Rickracer's Avatar
ASE Master Tech, Fabricator
 
Last wiki edit: Taurus 2-speed fan control wiring diagram Last photo:
Join Date: Jan 2010
Location: Kissimmee, Florida
Age: 55
Posts: 937
Wiki Edits: 8

Thanks: 0
Thanked 3 Times in 3 Posts
Quote:
Originally Posted by powerrodsmike
.Explorer or S-10 or Corvette style internal parking brakes are the way to go....
Don't forget the "LS" ('98 + up) Camaro brakes either. I thought about doing them on my S10, but it's so light in the rear compared to a Camaro, it would have thrown the "natural" braking balance off. They would be a GREAT option for a passenger car though.
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:

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
Problem setting up guts of ten bolt rwruther Transmission - Rearend 18 08-30-2007 11:07 PM
Valves GearHead69 Engine 3 10-13-2003 05:51 PM
Mixed up valves. meschnebly Engine 4 10-07-2003 08:55 AM
Cleaning valves babyface Engine 9 06-26-2003 04:49 PM
429 Exhaust Valves BigBlockBabe Engine 9 03-28-2003 04:24 AM


All times are GMT -6. The time now is 12:54 AM.


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.