Rear disc brakes - The 1947 - Present Chevrolet & GMC Truck Message Board Network

Andy4639 · 12-05-2014, 02:29 AM

? on my rear disc brakes i installed on my 71. I can stop the truck Ok but it just seems to not have the stopping power I thought it would after the swap! Is there anyway to check the brakes and see if they are working correctly.
I can jack it up and have my daughter inside and I spin the wheel and she can stop it but I havent tried it in gear just me spinning it by hand.
I can't get it to slid even trying while driving it.
The e brake will hold it on a hill so it's adjusted right I think.
Any suggestions guys.

andrewmp6 · 12-05-2014, 03:25 AM

Did you change the master cylinder and proportioning valve?

panhandler62 · 12-05-2014, 08:14 AM

The comment above is on point.

Also; you should note that rear discs are not going to make an appreciable difference in stopping power. They have a lot going for them but in a pickup the majority of the stopping load is on the front breaks (as much as 80% in some cases.)

SCOTI · 12-05-2014, 09:41 AM

Quote:

Originally Posted by panhandler62

The comment above is on point.

Also; you should note that rear discs are not going to make an appreciable difference in stopping power. They have a lot going for them but in a pickup the majority of the stopping load is on the front breaks (as much as 80% in some cases.)

The difference will be under hard repeat braking or under extremely wet conditions where drum brakes fade quickly vs discs.

Andy4639 · 12-06-2014, 03:24 AM

Yes guy's everything was swapped out. New booster, master cyclinder, proportioning valve, and stainless lines and hoses all for disc brakes. Everything was done and as stated it seems to stop fine when normal driving it just doesn't seem any better than the drums though. I was really hoping it would stop better are faster I should say.

andrewmp6 · 12-06-2014, 04:12 AM

The rear kit is what 11 inch rotors and single piston caliper?It will be some better then drums but like said the front brakes do more stopping then the rears.

SCOTI · 12-06-2014, 04:33 AM

Front brakes = 70% of brake effort regardless of what the rear brakes are.

72MARIO · 12-06-2014, 11:13 AM

Did you brake in the pads correctly ?

Andy4639 · 12-06-2014, 09:06 PM

Quote:

Originally Posted by 72MARIO

Did you brake in the pads correctly ?

I did as they (CPP) recommended.

dwcsr · 12-06-2014, 09:12 PM

Id get a pressure gage kit and test the line pressure at each caliper
http://www.speedwaymotors.com/SSBC-A...Kit,50352.html

it will save you time and money. look for 1000 to 1200 PSI

Andy4639 · 12-07-2014, 03:28 AM

Thanks,
I will check into the pressure gauge. A friend has a shop he may have one I can use.

bbcmudtruck · 12-20-2014, 10:50 AM

Its been said already, I'll just chime in to add to it. Most of your stopping power comes from the front. If you want to stop faster, try some bigger rotors with some larger calipers up front. Rear discs, in my opinion, are pleasing to the eye, but not much use on a pickup. I'm planning on a rear disc setup for my truck as well. However my goal is for the front and rear brakes to look killer behind the wheels.

Jahloha · 01-03-2015, 08:38 PM

Which proportioning valve did you go with? Saw in another thread you did rear discs, but required a pv swap. Planning my disc build and hoping for your feedback, thanks!

Andy4639 · 04-15-2015, 01:12 PM

I got the Disc/Disc valve from CPP also when I ordered the kit.

12-05-2014, 02:29 AM	#1
Andy4639 Old member Join Date: Jan 2002 Location: Liberty, & Garden City S.C. , U.S. Posts: 19,945	Rear disc brakes ? on my rear disc brakes i installed on my 71. I can stop the truck Ok but it just seems to not have the stopping power I thought it would after the swap! Is there anyway to check the brakes and see if they are working correctly. I can jack it up and have my daughter inside and I spin the wheel and she can stop it but I havent tried it in gear just me spinning it by hand. I can't get it to slid even trying while driving it. The e brake will hold it on a hill so it's adjusted right I think. Any suggestions guys. __________________ 1971 LWB Custom, 6.0LS & 4L80E, Speedhut.com GPS speedometer & gauges with A/C. 20" Boss 338's Grey wheels 4 wheel disc brakes. My Driver Seeing the USA in a 71 Upstate SC GM Truck Club 2013,14 and 2016 Hot Rod Pour Tour http://upstategmtrucks.com/ Get out and drive the truck this summer and have some fun! It sucks not being able to hear! LWB trucks rule, if you don't think so measure your SWB! After talking to tech support at Air Lift I have found out that the kit I need is 60811. Per the measurements I gave them. Ride height of truck inside spring and inside diameter of springs.

12-05-2014, 03:25 AM	#2
andrewmp6 Registered User Join Date: Jan 2009 Location: Louisville,Ky Posts: 5,811	Re: Rear disc brakes Did you change the master cylinder and proportioning valve?

12-05-2014, 08:14 AM	#3
panhandler62 Java Mechanic Join Date: Jun 2005 Location: Martinsburg, WV Posts: 6,763	Re: Rear disc brakes The comment above is on point. Also; you should note that rear discs are not going to make an appreciable difference in stopping power. They have a lot going for them but in a pickup the majority of the stopping load is on the front breaks (as much as 80% in some cases.) __________________ Keith 11 Lincoln MKT -- Momma's wagon 13 G37xS -- middle age crazy car 68 C20 Fleetside -- RIP Decorating the whole town up at a cost of $27 ....

12-06-2014, 03:24 AM	#5
Andy4639 Old member Join Date: Jan 2002 Location: Liberty, & Garden City S.C. , U.S. Posts: 19,945	Re: Rear disc brakes Yes guy's everything was swapped out. New booster, master cyclinder, proportioning valve, and stainless lines and hoses all for disc brakes. Everything was done and as stated it seems to stop fine when normal driving it just doesn't seem any better than the drums though. I was really hoping it would stop better are faster I should say. __________________ 1971 LWB Custom, 6.0LS & 4L80E, Speedhut.com GPS speedometer & gauges with A/C. 20" Boss 338's Grey wheels 4 wheel disc brakes. My Driver Seeing the USA in a 71 Upstate SC GM Truck Club 2013,14 and 2016 Hot Rod Pour Tour http://upstategmtrucks.com/ Get out and drive the truck this summer and have some fun! It sucks not being able to hear! LWB trucks rule, if you don't think so measure your SWB! After talking to tech support at Air Lift I have found out that the kit I need is 60811. Per the measurements I gave them. Ride height of truck inside spring and inside diameter of springs.

12-06-2014, 04:12 AM	#6
andrewmp6 Registered User Join Date: Jan 2009 Location: Louisville,Ky Posts: 5,811	Re: Rear disc brakes The rear kit is what 11 inch rotors and single piston caliper?It will be some better then drums but like said the front brakes do more stopping then the rears.

12-06-2014, 04:33 AM	#7
SCOTI Registered User Join Date: Apr 2001 Location: DALLAS,TX Posts: 22,066	Re: Rear disc brakes Front brakes = 70% of brake effort regardless of what the rear brakes are. __________________ 67SWB-B.B.RetroRod 64SWB-Recycle 89CCDually-Driver/Tow Truck 99CCSWB Driver All Fleetsides @rattlecankustoms in IG Building a small, high rpm engine with the perfect bore, stroke and rod ratio is very impressive. It's like a highly skilled Morrocan sword fighter with a Damascus Steel Scimitar..... *Cubic inches is like Indiana Jones with a cheap pistol.*

12-06-2014, 11:13 AM	#8
72MARIO Registered User Join Date: Nov 2000 Location: Huntsville Ontario Canada Posts: 4,051	Re: Rear disc brakes Did you brake in the pads correctly ? __________________ 1968 Suburban numbers matching all original truck now equipped with 6.0/4L80 on Accuair http://67-72chevytrucks.com/vboard/s...d.php?t=625017 1967 C/20 6.0/4L80 Roofing Truck 1990 V2500 Suburban "Plow Truck" 2005 TAHOE DD

12-06-2014, 09:12 PM	#10
dwcsr Hollister Road Co. Join Date: Apr 2005 Location: Houston Posts: 6,131	Re: Rear disc brakes Id get a pressure gage kit and test the line pressure at each caliper http://www.speedwaymotors.com/SSBC-A...Kit,50352.html it will save you time and money. look for 1000 to 1200 PSI

12-07-2014, 03:28 AM	#11
Andy4639 Old member Join Date: Jan 2002 Location: Liberty, & Garden City S.C. , U.S. Posts: 19,945	Re: Rear disc brakes Thanks, I will check into the pressure gauge. A friend has a shop he may have one I can use. __________________ 1971 LWB Custom, 6.0LS & 4L80E, Speedhut.com GPS speedometer & gauges with A/C. 20" Boss 338's Grey wheels 4 wheel disc brakes. My Driver Seeing the USA in a 71 Upstate SC GM Truck Club 2013,14 and 2016 Hot Rod Pour Tour http://upstategmtrucks.com/ Get out and drive the truck this summer and have some fun! It sucks not being able to hear! LWB trucks rule, if you don't think so measure your SWB! After talking to tech support at Air Lift I have found out that the kit I need is 60811. Per the measurements I gave them. Ride height of truck inside spring and inside diameter of springs.

12-20-2014, 10:50 AM	#12
bbcmudtruck Registered User Join Date: Nov 2012 Location: ravenwood, mo Posts: 709	Re: Rear disc brakes Its been said already, I'll just chime in to add to it. Most of your stopping power comes from the front. If you want to stop faster, try some bigger rotors with some larger calipers up front. Rear discs, in my opinion, are pleasing to the eye, but not much use on a pickup. I'm planning on a rear disc setup for my truck as well. However my goal is for the front and rear brakes to *look* killer behind the wheels.

01-03-2015, 08:38 PM	#13
Jahloha Registered User Join Date: Oct 2013 Location: Anaheim, CA Posts: 526	Re: Rear disc brakes Which proportioning valve did you go with? Saw in another thread you did rear discs, but required a pv swap. Planning my disc build and hoping for your feedback, thanks! __________________ -JASON My grandpa, Gramps, won a 1970 C20 in 1969 for $1. I'm on a mission to restore it before he passes. My 1970 C20 Build Thread

04-15-2015, 01:12 PM	#14
Andy4639 Old member Join Date: Jan 2002 Location: Liberty, & Garden City S.C. , U.S. Posts: 19,945	Re: Rear disc brakes I got the Disc/Disc valve from CPP also when I ordered the kit. __________________ 1971 LWB Custom, 6.0LS & 4L80E, Speedhut.com GPS speedometer & gauges with A/C. 20" Boss 338's Grey wheels 4 wheel disc brakes. My Driver Seeing the USA in a 71 Upstate SC GM Truck Club 2013,14 and 2016 Hot Rod Pour Tour http://upstategmtrucks.com/ Get out and drive the truck this summer and have some fun! It sucks not being able to hear! LWB trucks rule, if you don't think so measure your SWB! After talking to tech support at Air Lift I have found out that the kit I need is 60811. Per the measurements I gave them. Ride height of truck inside spring and inside diameter of springs.



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