B body 4 wheel disc brakes
#2645848
04/16/19 09:56 PM
04/16/19 09:56 PM
|
Joined: Mar 2009
Posts: 1,058 bigfork mn
dragram440
OP
super stock
|
OP
super stock
Joined: Mar 2009
Posts: 1,058
bigfork mn
|
Working on my charger again trying to get the brakes to work better and looking for suggestions. I have converted the front from drum to early 80' diplomat front disc. The rear i used gm metric calipers and jeep rotors i believe. I have a universal master from summit with 7/8 bore. And a adjustable prop. Valve on the rears ne t to the master. I just cant seem to get a decent pedal, always low and kinda spongee. The cars runs almost 130 mph in the 1/4 and is kinda hard to slow down. Just trying to figure out which way to go. Thanks for any advice.
67' charger 499 RB
10.57 at 127
|
|
|
Re: B body 4 wheel disc brakes
[Re: dragram440]
#2645851
04/16/19 10:01 PM
04/16/19 10:01 PM
|
Joined: Mar 2009
Posts: 2,470 Sydney,Australia
tex013
top fuel
|
top fuel
Joined: Mar 2009
Posts: 2,470
Sydney,Australia
|
I guess you may be needing a larger bore master cylinder . Probably 15/16 or 1
Tex
New best ET 10.259@129.65 . New best MPH 130.32 Finally fitted a solid cam, stepped it up a bit more 3690lbs through the mufflers New World block 3780lbs 10.278@130.80 . Wowser 10.253@130.24 footbraking from 1500rpm Power by Tex's Automotive
|
|
|
Re: B body 4 wheel disc brakes
[Re: tex013]
#2645853
04/16/19 10:04 PM
04/16/19 10:04 PM
|
Joined: Mar 2009
Posts: 1,058 bigfork mn
dragram440
OP
super stock
|
OP
super stock
Joined: Mar 2009
Posts: 1,058
bigfork mn
|
I should have said i have tried a larger bore master but that was off a 94 ram so i wasnt sure if the power master what the problem was so i switched to the small bore master with not a lot of change.
67' charger 499 RB
10.57 at 127
|
|
|
Re: B body 4 wheel disc brakes
[Re: dragram440]
#2645854
04/16/19 10:05 PM
04/16/19 10:05 PM
|
Joined: Mar 2009
Posts: 1,058 bigfork mn
dragram440
OP
super stock
|
OP
super stock
Joined: Mar 2009
Posts: 1,058
bigfork mn
|
I keep thinking it is the master. Any suggestions on what work good with a setup like this?
Last edited by dragram440; 04/16/19 10:10 PM.
67' charger 499 RB
10.57 at 127
|
|
|
Re: B body 4 wheel disc brakes
[Re: dragram440]
#2645879
04/16/19 11:01 PM
04/16/19 11:01 PM
|
Joined: Jul 2004
Posts: 1,145 Arizona, USA
gsmopar
super stock
|
super stock
Joined: Jul 2004
Posts: 1,145
Arizona, USA
|
I keep thinking it is the master. Any suggestions on what work good with a setup like this? Contact Dr. Diff. I ran a similar set up with his master and it worked great and was inexpensive. https://www.doctordiff.com/
|
|
|
Re: B body 4 wheel disc brakes
[Re: dragram440]
#2645893
04/17/19 12:03 AM
04/17/19 12:03 AM
|
Joined: Jun 2003
Posts: 52,972 Romeo MI
MR_P_BODY
Master
|
Master
Joined: Jun 2003
Posts: 52,972
Romeo MI
|
First thing is open up the prop valve all the way then bleed the brakes again.. after bleeding try them again and see if the rears lock up.. if they do adjust the prop.. a prop valve just slows down the fluid so maybe you had your to tight and it was slow putting on the rears.. prop valves should be open to bleed
|
|
|
Re: B body 4 wheel disc brakes
[Re: MR_P_BODY]
#2647170
04/20/19 10:27 AM
04/20/19 10:27 AM
|
Joined: Nov 2003
Posts: 36,041 Lincoln Nebraska
RapidRobert
Circle Track
|
Circle Track
Joined: Nov 2003
Posts: 36,041
Lincoln Nebraska
|
As said confirm that the air is out of there then you will know if there is a proportioning problem (or not). I grab a helper & have him pump the pedal vigorously several times then on the next down stroke (with perfect timing) I open the bleeder which this helps get the agitated air out of there & in some cases the caliper needs to be pulled & tilted just right (in your hand/still connected) for the air to rise to the top. It like the air vent in the Egyptian pyramids, the air vent exit (bleeders) dont need to be exactly at 12 0'clock but where the passage meets the bore needs to be at or close to 12 0'clock. Put a block under the pedal so the cups dont go past their normal wear area & it helps him control the pedal movement better.
live every 24 hour block of time like it's your last day on earth
|
|
|
Re: B body 4 wheel disc brakes
[Re: MR_P_BODY]
#2647320
04/20/19 05:10 PM
04/20/19 05:10 PM
|
Joined: Dec 2004
Posts: 10,558 Rittman Ohio
fourgearsavoy
I Live Here
|
I Live Here
Joined: Dec 2004
Posts: 10,558
Rittman Ohio
|
I have been using a pressure bleeder for the last couple years and it works great. I have always used the "pump and hold" method but since I got the pressure bleeder I don't need to bug anybody to help me bleed the brakes. One other thing to look at is the rear caliper mounts. The caliper needs to be pressurized before you tack the bracket to the housing. Attach a dial indicator to the bracket and see if it moves when brake is applied. Gus
Last edited by fourgearsavoy; 04/20/19 05:14 PM.
64 Plymouth Savoy 493 Indy EZ's by Nick at Compu-Flow 5-Speed Richmond faceplate Liberty box Dana 60
|
|
|
Re: B body 4 wheel disc brakes
[Re: MR_P_BODY]
#2647356
04/20/19 07:33 PM
04/20/19 07:33 PM
|
Joined: Jan 2008
Posts: 2,363 Cotati, CA
Dave Hall
top fuel
|
top fuel
Joined: Jan 2008
Posts: 2,363
Cotati, CA
|
130 mph? Is this a drag race only car? What does it matter brakes are brakes.. it a matter of hyd pressure FWIW, my drag car has the MC plumbed opposite of what I did with my street car. The street car has 4 wheel discs. On factory setups, the pedal feel is set by adjusting the REAR brakes. Not so in a drag car. Front runners don't stop nearly as well as slicks. Why would you put the brake bias to the front on a DRAG ONLY car? My street car , rear calipers have a bracket for the e-brake and when I first put them on, I didn't have the cable setup. Pedal feel was night and day after I installed the e-brake cable setup. Don't know about the OP's brakes. I would imagine his calipers are divorced from the e-brake.
|
|
|
Re: B body 4 wheel disc brakes
[Re: dragram440]
#2647374
04/20/19 08:10 PM
04/20/19 08:10 PM
|
Joined: Mar 2007
Posts: 3,287 West Coast, USA
jbc426
master
|
master
Joined: Mar 2007
Posts: 3,287
West Coast, USA
|
Russell makes spring loaded bleeder valves that they describe as a one man brake bleeder. They are nice when it comes to stopping air from creeping back through the valves while bleeding. When used with a Mitty power bleeder, they work very well.
One of the problems with the factory style bleeder, is that air can seep past the threads while the valves are open for bleeding. I wrap several layers of Teflon tape on the bleeder threads to counter that air intrusion. It seems to be effective, as well.
A proportioning valve is a band-aid for improperly matched front and rear brakes. Caliper bore size, number of caliper bores and correct matching of front and rear caliper bores, plus the correct master cylinder sizing is critical to get the brakes properly biased. The clamping force of the front and rear calipers should be properly matched so they provide the proper level of front to rear bias without the need for a pressure reducing or proportioning valve to try and fix a mis-matched set of calipers.
Another brake system item that many are unfamiliar with is a hydraulic pressure shock reducer that cuts down the pressure spike of the fluid to the rear brakes and dramatically reduces rear wheel lock-up when the brake pedal is applied suddenly at speed. It doesn't reduce the line pressure, rather it just dampens the initial shock wave during high speed, spirited brake applications. It's well known on the racing circuit, but seldom mentioned hear.
1970 Plymouth 'Cuda #'s 440-6(block in storage)currently 493" 6 pack, Shaker, 5 speed Passon, 4.10's 1968 Plymouth Barracuda Convertible 408 Magnum EFI with 4 speed automatic overdrive, 3800 stall lock-up converter and 4.30's (closest thing to an automatic 5 speed going)
|
|
|
Re: B body 4 wheel disc brakes
[Re: Bill MeLater]
#2648849
04/25/19 12:58 PM
04/25/19 12:58 PM
|
Joined: Mar 2009
Posts: 1,058 bigfork mn
dragram440
OP
super stock
|
OP
super stock
Joined: Mar 2009
Posts: 1,058
bigfork mn
|
Sorry it has been so long since I got back to this thread. As far as air goes I think I have got all the air out of it. I had originally pressure bleed all the system and I went though last night and manually bleed all four corners and did get a couple small bubbles out of one of the fronts. I did talk to Dr Diff and he said the smaller bore master will give me a longer throw on the pedal but more pressure, The bigger bore master will give me less travel on the pedal but not as much pressure. As of now I have the small bore master on it which would make sense why I have a lower pedal. Maybe it is a 4000 lb car and has manual brakes so they just dont stop it good. I was maybe going to try a better pad to see if it would give me a little more power. Any recomendations on a good pad that has lots of stopping power? Thanks again for the info.
67' charger 499 RB
10.57 at 127
|
|
|
|
|