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Hard Brake Pedal #1441489 05/24/13 06:47 PM 05/24/13 06:47 PM
Joined: Nov 2011 Posts: 29 Ohio J JT01 OP member
JT01 OP member J Joined: Nov 2011 Posts: 29 Ohio	I have a 69 Charger and installed a new SBBC brake system its disc on front drums on rear everything is brand new from front to rear including the lines my pedal is very hard to push and only moves just a little bit. I checked the vacuum and it has 16 inches of vacuum Ive put 2 new boosters on it with the same issue.Whats going on here with this thanks for any help.

Re: Hard Brake Pedal [Re: JT01] #1441490 05/24/13 07:39 PM 05/24/13 07:39 PM
Joined: Jul 2007 Posts: 1,682 Philadelphia R radar top fuel
radar top fuel R Joined: Jul 2007 Posts: 1,682 Philadelphia	How much vacuum is the booster seeing? Is the m/c bore too big?

Re: Hard Brake Pedal [Re: JT01] #1441491 05/24/13 10:16 PM 05/24/13 10:16 PM
Joined: Nov 2003 Posts: 36,041 Lincoln Nebraska R RapidRobert Circle Track
RapidRobert Circle Track R Joined: Nov 2003 Posts: 36,041 Lincoln Nebraska	I'd check how much clearance you have between the rounded nub on the end of the pushrod coming out of the booster & the bottom of the M/C rear piston (thimble). Want ~.060" or a bit less. Might crack a corner bleeder (either side) on the front then on the rear (seperately) & see if you get a full stroke. Might work the pedal & have a helper see how the front calipers are acting & might take off the rear drums & same deal but just a moderate amt of pedal travel when the rear drums are off so he dont pop the rear wheel cyl pistons out live every 24 hour block of time like it's your last day on earth

Re: Hard Brake Pedal [Re: JT01] #1441492 05/25/13 01:57 AM 05/25/13 01:57 AM
Joined: Jan 2003 Posts: 8,016 Polson, MT DoctorDiff master
DoctorDiff master Joined: Jan 2003 Posts: 8,016 Polson, MT	This is a common problem with SSBC brakes. You probably need a 15/16" bore master cylinder. Contact info

Re: Hard Brake Pedal [Re: DoctorDiff] #1441493 05/25/13 02:03 AM 05/25/13 02:03 AM
Joined: Sep 2005 Posts: 1,551 baldwinsville new york A a493demon pro stock
a493demon pro stock A Joined: Sep 2005 Posts: 1,551 baldwinsville new york	if you take off the master cyl. from the booster the rod should be adjustable , the rod might be adj. out too far try turning it in and see if that helps.

Re: Hard Brake Pedal [Re: a493demon] #1441494 05/25/13 10:07 AM 05/25/13 10:07 AM
Joined: Nov 2011 Posts: 29 Ohio J JT01 OP member
JT01 OP member J Joined: Nov 2011 Posts: 29 Ohio	Quote: if you take off the master cyl. from the booster the rod should be adjustable , the rod might be adj. out too far try turning it in and see if that helps. Allready did that never changed anything

Re: Hard Brake Pedal [Re: JT01] #1441495 05/25/13 12:20 PM 05/25/13 12:20 PM
Joined: Jan 2003 Posts: 8,016 Polson, MT DoctorDiff master
DoctorDiff master Joined: Jan 2003 Posts: 8,016 Polson, MT	What master cylinder are you running? Contact info

Re: Hard Brake Pedal [Re: DoctorDiff] #1441496 05/25/13 12:38 PM 05/25/13 12:38 PM
Joined: Nov 2011 Posts: 29 Ohio J JT01 OP member
JT01 OP member J Joined: Nov 2011 Posts: 29 Ohio	The one that came with the ssbc kit. Should I get a different one.

Re: Hard Brake Pedal [Re: JT01] #1441497 05/25/13 12:54 PM 05/25/13 12:54 PM
Joined: Jan 2003 Posts: 8,016 Polson, MT DoctorDiff master
DoctorDiff master Joined: Jan 2003 Posts: 8,016 Polson, MT	I don't think SSBC provides the correct master cylinder with their brake kits. Measure the bore size to confirm. You need a 15/16" master for a '73-'75 A-body power disc brake application. Contact info

Re: Hard Brake Pedal [Re: DoctorDiff] #1441498 05/25/13 08:02 PM 05/25/13 08:02 PM
Joined: Nov 2011 Posts: 29 Ohio J JT01 OP member
JT01 OP member J Joined: Nov 2011 Posts: 29 Ohio	Quote: I don't think SSBC provides the correct master cylinder with their brake kits. Measure the bore size to confirm. You need a 15/16" master for a '73-'75 A-body power disc brake application. [/quote. Where can I get one of these master cylinders and is it a 2 bolt application

Re: Hard Brake Pedal [Re: JT01] #1441499 05/25/13 08:21 PM 05/25/13 08:21 PM
Joined: Nov 2003 Posts: 36,041 Lincoln Nebraska R RapidRobert Circle Track
RapidRobert Circle Track R Joined: Nov 2003 Posts: 36,041 Lincoln Nebraska	An 89 Dakota 15/16" M/C would be a 2 bolt app. The 73-75 A body 15/16" app would not live every 24 hour block of time like it's your last day on earth

Re: Hard Brake Pedal [Re: JT01] #1441500 05/25/13 08:30 PM 05/25/13 08:30 PM
Joined: Jan 2003 Posts: 25,871 Rio Linda, CA John_Kunkel Too Many Posts
John_Kunkel Too Many Posts Joined: Jan 2003 Posts: 25,871 Rio Linda, CA	Be sure the booster pushrod isn't preventing the rear piston in the MC from fully returning. If the pushrod is adjusted out too far the rear piston won't allow the fluid to return to the reservoir and you'll get a hard pedal. The INTERNET, the MISinformation superhighway

Re: Hard Brake Pedal [Re: John_Kunkel] #1441501 05/25/13 08:58 PM 05/25/13 08:58 PM
Joined: Nov 2011 Posts: 29 Ohio J JT01 OP member
JT01 OP member J Joined: Nov 2011 Posts: 29 Ohio	Quote: Be sure the booster pushrod isn't preventing the rear piston in the MC from fully returning. If the pushrod is adjusted out too far the rear piston won't allow the fluid to return to the reservoir and you'll get a hard pedal. We adjusted the pushrod all the way in and it still has a hard pedal

Re: Hard Brake Pedal [Re: RapidRobert] #1441502 05/25/13 09:06 PM 05/25/13 09:06 PM
Joined: Nov 2011 Posts: 29 Ohio J JT01 OP member
JT01 OP member J Joined: Nov 2011 Posts: 29 Ohio	Quote: An 89 Dakota 15/16" M/C would be a 2 bolt app. The 73-75 A body 15/16" app would not Would this M/C have the lines going in on the drivers side

Re: Hard Brake Pedal [Re: JT01] #1441503 05/25/13 09:08 PM 05/25/13 09:08 PM
Joined: Nov 2003 Posts: 36,041 Lincoln Nebraska R RapidRobert Circle Track
RapidRobert Circle Track R Joined: Nov 2003 Posts: 36,041 Lincoln Nebraska	I would think so but I'm not sure. I'd have your parts house pull it off the shelf & let you know live every 24 hour block of time like it's your last day on earth

Re: Hard Brake Pedal [Re: RapidRobert] #1441504 05/25/13 11:52 PM 05/25/13 11:52 PM
Joined: Nov 2011 Posts: 29 Ohio J JT01 OP member
JT01 OP member J Joined: Nov 2011 Posts: 29 Ohio	would this work http://www.ebay.com/itm/380584877050?ssPageName=STRK:MEWAX:IT&_trksid=p3984.m1438.l2649

Re: Hard Brake Pedal [Re: JT01] #1441505 05/26/13 12:37 PM 05/26/13 12:37 PM
Joined: Nov 2011 Posts: 29 Ohio J JT01 OP member
JT01 OP member J Joined: Nov 2011 Posts: 29 Ohio	I also found this one and could buy a adapter plate to make it work. Let me know guys if any of the se I listed will work thanks. http://www.jegs.com/i/Right+Stuff/965/DBMC15/10002/-1

Re: Hard Brake Pedal [Re: JT01] #1441506 05/26/13 02:57 PM 05/26/13 02:57 PM
Joined: Jan 2003 Posts: 25,871 Rio Linda, CA John_Kunkel Too Many Posts
John_Kunkel Too Many Posts Joined: Jan 2003 Posts: 25,871 Rio Linda, CA	Quote: Quote: Be sure the booster pushrod isn't preventing the rear piston in the MC from fully returning. If the pushrod is adjusted out too far the rear piston won't allow the fluid to return to the reservoir and you'll get a hard pedal. We adjusted the pushrod all the way in and it still has a hard pedal You still need to make sure the rear piston is returning. With the lid off the MC, have somebody gently depress the brake peddle and look for a burble of fluid on the fluid surface in rear reservoir....if no burble the piston isn't fully returning. The INTERNET, the MISinformation superhighway

Re: Hard Brake Pedal [Re: JT01] #1441507 05/26/13 03:49 PM 05/26/13 03:49 PM
Joined: Jan 2003 Posts: 8,016 Polson, MT DoctorDiff master
DoctorDiff master Joined: Jan 2003 Posts: 8,016 Polson, MT	Loosen the master cylinder mounting nuts. If the unit springs forward, the input rod must be shortened. I can provide a new, aluminum 15/16" bore master with billet adapter for $100, or a new, 4-bolt iron version for $75. Contact info

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