HOME FORUM RULES CONTACT
     
   
   

Go Back   CLASS RACER FORUM > Class Racer Forums > Stock and Super Stock Tech


Reply
 
Thread Tools Display Modes
Old 08-23-2015, 09:45 AM   #1
impstocker
Member
 
impstocker's Avatar
 
Join Date: Dec 2008
Location: Wingdale, NY
Posts: 302
Likes: 27
Liked 54 Times in 16 Posts
Default Brake line size

With my 1965 Impala I/SA 396/325 build, I ran 3/16 brake line to the back brakes which are drums. Up front I have disc plus have a Adjustable proportional for the line going to the back. It seems the car originally had 3/16 line to the back because the T fitting in back is for a 3/16 line.

Would I need a 1/4 line instead?

Thanks for any help

Will Lamprecht
impstocker is offline   Reply With Quote
Old 08-23-2015, 09:48 AM   #2
Eman
Member
 
Join Date: May 2014
Location: E TN
Posts: 435
Likes: 14
Liked 100 Times in 57 Posts
Default Re: Brake line size

3/16 should work fine, I used it on my Camaro. The adj proportioning valve might work better on the frt section to stop the frt.s from locking. You just have to experiment and see how your car works.
Eman is offline   Reply With Quote
Old 08-24-2015, 12:19 AM   #3
FireSale
VIP Member
 
FireSale's Avatar
 
Join Date: Feb 2014
Location: Lakewood Washington
Posts: 1,407
Likes: 29
Liked 236 Times in 127 Posts
Default Re: Brake line size

Prop valve goes in the line to the back brakes. It regulates pressure back there and keeps the rear from locking up before the front. Locking the rear first can spin the car. Because of weight transfer to the front of the car during braking, the front set must carry most of the stopping power for stability. Stunt drivers spin cars by pulling the emergency brake which locks the rear brakes only. The car nose dives and the rear tires break free.

Dale
__________________
Dale Shearon
68 Mustang 6394
FireSale is offline   Reply With Quote
Old 08-24-2015, 08:21 AM   #4
Eman
Member
 
Join Date: May 2014
Location: E TN
Posts: 435
Likes: 14
Liked 100 Times in 57 Posts
Default Re: Brake line size

Street cars and stunt cars are slightly different than dedicated drag cars. Locking the backs is bad and every car reacts differently especially after brake systems have been modified. Drag cars have skinny tires with high pressure and a small contact patch in the frt with large sticky low pressure tires on the back. That changes how the braking reacts along with the changes in weight bias and suspension modifications.
Try it the way you have it and adjust from there.
Eman is offline   Reply With Quote
Old 08-25-2015, 12:16 AM   #5
Todd Hoven
VIP Member
 
Join Date: Jul 2007
Posts: 1,329
Likes: 876
Liked 720 Times in 151 Posts
Default Re: Brake line size

should have a residual valve in the back with drum brakes, and the adjustable proportional valve in the front.
3/16 should be fine.

The front tires will lock before the back because the amount of rubber contact on the track. It takes more brake force to lock the rear tires up because of this, the only time the front adjustable valve is used is on hard stops, this just restricts flow to the front calipers on a hard brake condition.

The residual valve in the rear line helps the rear brakes apply the same time as the front so you have even braking.

Before I installed brakes on my firebird, I called and talked to different manufactures. Strange and Mark Williams directed me to using the components above in the same manner.

Willwood, Aerospace told me to use the valve in the back and no residual valve. They were wrong

I can hold my car to 4000 on the starting line and kill almost 10 mph at the cones without tire smoke in complete control. I'm using Strange lightweight front brakes and rear 9" drums. The car runs 10.60's at 123. weighs 3550.
__________________
Todd Hoven 1035 Stock
Todd Hoven is offline   Reply With Quote
Old 08-25-2015, 09:36 AM   #6
69Cobra
Senior Member
 
Join Date: Aug 2007
Location: California, Ky
Posts: 667
Likes: 27
Liked 1 Time in 1 Post
Default Re: Brake line size

Very good info Todd. What changes if you have 4 wheel disc?
__________________
Kris Rachford
69 Cobra 428CJ 4 Speed
C/S 3032
69Cobra is offline   Reply With Quote
Old 08-25-2015, 12:07 PM   #7
Todd Hoven
VIP Member
 
Join Date: Jul 2007
Posts: 1,329
Likes: 876
Liked 720 Times in 151 Posts
Default Re: Brake line size

Take out the residual valve in rear line. I would call to confirm that along with what to do with the adjustable valve in the front. I'm sure it stays
__________________
Todd Hoven 1035 Stock
Todd Hoven is offline   Reply With Quote
Old 08-25-2015, 12:27 PM   #8
FireSale
VIP Member
 
FireSale's Avatar
 
Join Date: Feb 2014
Location: Lakewood Washington
Posts: 1,407
Likes: 29
Liked 236 Times in 127 Posts
Default Re: Brake line size

I have the adjustable valve in the back line of a disk/disk installation, but it's a Sportsman street car. Stops fine.

Dale
__________________
Dale Shearon
68 Mustang 6394
FireSale is offline   Reply With Quote
Old 08-25-2015, 11:05 PM   #9
Run to Rund
Senior Member
 
Join Date: Sep 2007
Posts: 574
Likes: 6
Liked 44 Times in 22 Posts
Default Re: Brake line size

My '66 A body with 115" wheelbase came with a 1/4" line to the rear. That size is working fine for me.
Run to Rund is offline   Reply With Quote
Old 08-26-2015, 08:26 AM   #10
117X
Junior Member
 
Join Date: Apr 2014
Posts: 40
Likes: 0
Liked 1 Time in 1 Post
Default Re: Brake line size

My G Body has 1/4" to the front and 3/16" to the rear. It has Aerospace disks on all four corners and stops decent. When I first purchased the car the residual valve, which was located in the factory proportioning valve, was still there. It caused severe drag on the rear brakes. Since removing it the brakes release better but not as well as I'd like. When the car sits I do need to pump the brakes up a bit because there is no residual valve. Another oddity I noticed is, if I want to coast down the lanes and let the brake off gently it doesn't want to move. If I apply firm pressure and quickly let off the brake pedal it rolls right away. Has anyone ever noticed that with their system?


Todd, that is impressive you can hold at 4000; I can barely hold 3000. By the way, thanks again for you help at Cecil!
117X is offline   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 -4. The time now is 04:52 AM.


Powered by vBulletin® Version 3.8.11
Copyright ©2000 - 2024, vBulletin Solutions Inc.
Copyright © Class Racer.com. All Rights Reserved. Designated trademarks and brands are the property of their respective owners.