The 1947 - Present Chevrolet & GMC Truck Message Board Network







Register or Log In To remove these advertisements.

Go Back   The 1947 - Present Chevrolet & GMC Truck Message Board Network > General Truck Forums > Suspension

Web 67-72chevytrucks.com


Reply
 
Thread Tools Display Modes
Old 02-07-2015, 02:34 PM   #1
Shon
Registered User
 
Join Date: Sep 2005
Location: sc
Posts: 1,203
Camaro rear disc brake conversion

OK, I am fed up. I have the Camaro Rear disc brake brackets with the LT1 calipers and Impala rotors.
Truck is original 71 with Disc/Drum set up.
I can not get both sides to bleed. The driver side will spit out a nice stream of fluid but holding the brake pedal down it doesn't clamp enough to keep the rotor from turning. The other side just dribbles out.

What do I need? I am guessing I need a different combination valve (prop valve as some call them). Do I need a different Master Cylinder? Was hoping I could get this to work with what I have but I am doubting that now....

I have this set up currently:
http://www.piratejack.net/index.php?...emart&Itemid=6
__________________
71 Cheyenne C10 LWB cam'd 6.0/T56 Swap
Shon is offline   Reply With Quote
Old 02-07-2015, 08:50 PM   #2
RodnRudy
Senior Member
 
RodnRudy's Avatar
 
Join Date: Oct 2014
Location: New Palestine In
Posts: 930
Re: Camaro rear disc brake conversion

You need a disc/disc master cylinder and proportioning valve to make your set up work.
RodnRudy is offline   Reply With Quote
Old 02-08-2015, 09:22 PM   #3
Shon
Registered User
 
Join Date: Sep 2005
Location: sc
Posts: 1,203
Re: Camaro rear disc brake conversion

any recommendations on part numbers?
__________________
71 Cheyenne C10 LWB cam'd 6.0/T56 Swap
Shon is offline   Reply With Quote
Old 02-08-2015, 11:40 PM   #4
SierraMtns
Registered User
 
SierraMtns's Avatar
 
Join Date: Jun 2014
Location: Shingle Springs, CA
Posts: 869
Re: Camaro rear disc brake conversion

Can you post a picture to see what you are working with?

What size bore is your master? You might need a new one. I am running a 1" bore with disc/drum. I hear that some guys run a 7/8" bore with disc/disc. I know if you call Wilwood they will tell you need a 15/16" with disc/disc.

Did you run new lines? 3/16 or stock 1/4"?

http://www.piratejack.net/index.php?...emart&Itemid=6

http://www.piratejack.net/index.php?...emart&Itemid=6
SierraMtns is offline   Reply With Quote
Old 02-08-2015, 11:40 PM   #5
Joe Pass
Senior Member

 
Joe Pass's Avatar
 
Join Date: Aug 2013
Location: Windsor, California
Posts: 1,042
Re: Camaro rear disc brake conversion

That master cylinder has no residual valves in it. If it's like my disc setup I had to use the residual safety valves (2lb) front and rear because the pressure bled off after a bit. You should also have a proportioning valve at the rear supply line to allow more pressure to the front calipers for braking balance
Not saying that's all your issues, but it is a start. In most applications, the disc/drum M/C has built in residual valves for specific cars/trucks. The style that you have doesn't and will need to add them. That M/C should have both reservoirs the same size and should work
Name:  rear disc conversion 001.JPG
Views: 349
Size:  32.4 KB

Name:  rear disc conversion 005.JPG
Views: 348
Size:  33.4 KB

Name:  rear disc conversion 007.JPG
Views: 355
Size:  33.1 KB
Joe Pass is offline   Reply With Quote
Old 02-09-2015, 10:17 AM   #6
RodnRudy
Senior Member
 
RodnRudy's Avatar
 
Join Date: Oct 2014
Location: New Palestine In
Posts: 930
Re: Camaro rear disc brake conversion

Contact Pirate Jacks and tell them you are running disc/disc and they will be able to sell you the correct master and prop valve.
If your master cylinder is higher than your disc calipers you shouldn't have to run the two lb residual valves. The fluid shouldn't bleed back into the MC cause it's higher than the calipers.
RodnRudy is offline   Reply With Quote
Old 02-14-2015, 04:31 PM   #7
Shon
Registered User
 
Join Date: Sep 2005
Location: sc
Posts: 1,203
Re: Camaro rear disc brake conversion

got new MC and Combo valve from Pirate Jack. Same problem. The driver side spits out a stream of fluid but the pass side doesn't. Guess now I will replace that caliper and see if that is the issue.
__________________
71 Cheyenne C10 LWB cam'd 6.0/T56 Swap
Shon is offline   Reply With Quote
Old 02-14-2015, 05:33 PM   #8
Nochance
Registered User
 
Join Date: Sep 2014
Location: Houston, Texas
Posts: 27
Re: Camaro rear disc brake conversion

Think about how this system is plumbed. You have 1 steel brake line running from the front to the rear crossmember where it ties into a rubber hose that splits it for each side. So if you have pressure on one side you have to have pressure on the other side too, unless you have a restriction in the lines after the split or you just have air in the system. I would try and bleed the system again first and make sure you're only bleeding one wheel at a time or you will get the same result you are getting now. Pump up pedel open one bleeder and close, pump up pedal and open another bleeder, and repeat until pedal is firm.
Nochance is offline   Reply With Quote
Old 02-15-2015, 11:09 AM   #9
bbcmudtruck
Registered User
 
Join Date: Nov 2012
Location: ravenwood, mo
Posts: 709
Re: Camaro rear disc brake conversion

Just an idea here, but have you tried a vacuum pump bleeder? I got one from the parts store called "Mighty Vac" or something very close to that. Its an amazing tool and a must have in my garage. I've used that dang thing countless times. It contains all of the fluid and works great for a guy that doesn't always have an extra person on hand to help out. You can bleed the brakes all by yourself with this thing.
bbcmudtruck is offline   Reply With Quote
Old 02-15-2015, 11:27 AM   #10
Shon
Registered User
 
Join Date: Sep 2005
Location: sc
Posts: 1,203
Re: Camaro rear disc brake conversion

Well, I got my oldest son out there and pumped and pumped and got the new fluid flowing out the rear calipers and they work now. But will say the front is nasty and really should be replaced. So. Probably will end up redoing all the brake lines this year.
__________________
71 Cheyenne C10 LWB cam'd 6.0/T56 Swap
Shon is offline   Reply With Quote
Old 02-16-2015, 02:54 AM   #11
Andy4639
Old member
 
Andy4639's Avatar
 
Join Date: Jan 2002
Location: Liberty, & Garden City S.C. , U.S.
Posts: 19,936
Wink Re: Camaro rear disc brake conversion

Quote:
Originally Posted by Shon View Post
Well, I got my oldest son out there and pumped and pumped and got the new fluid flowing out the rear calipers and they work now. But will say the front is nasty and really should be replaced. So. Probably will end up redoing all the brake lines this year.
Shon,
Ant adding rear disc brakes fun! I feel for you. I had my daughter helping me and it was a pain. I ended up jacking the truck up in the back as high as I could get it safely and finally bleed them.I'm still not really sure if they are set right though. I really thought the truck would stop on a dime after this mod but it's about the same as it was!
__________________
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.
Andy4639 is offline   Reply With Quote
Reply

Bookmarks

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 08:44 AM.


Powered by vBulletin® Version 3.8.11
Copyright ©2000 - 2024, vBulletin Solutions Inc.
Copyright 1997-2022 67-72chevytrucks.com