Previous Thread
Next Thread
Print Thread
Page 1 of 2 1 2
tricks to reduce drag on stock a-body discs? #220050
02/10/09 12:42 PM
02/10/09 12:42 PM
Joined: Apr 2007
Posts: 807
Toronto, Canada
D
dirtybee Offline OP
super stock
dirtybee  Offline OP
super stock
D

Joined: Apr 2007
Posts: 807
Toronto, Canada
i posted on Q&A also, just wondering if there are any tips or tricks people may want to share on how to get my front discs to spin more freely? they have quite a bit of resistance. manual a-body discs on a '70 b-body street/strip car. i'm lookin' to scrub off some ET for free 'cause i'm broke and bored

Re: tricks to reduce drag on stock a-body discs? [Re: dirtybee] #220051
02/10/09 01:10 PM
02/10/09 01:10 PM
Joined: Jun 2008
Posts: 2,828
usa
L
lewtot184 Offline
master
lewtot184  Offline
master
L

Joined: Jun 2008
Posts: 2,828
usa
i'm going thru some a-body front discs on a b-body issues. i don't have an answer to your problem but i do have some observations. when i switched from a 1.03 bore master cylinder to a 15/16 bore master cylinder the calipers would lock up. switched back to the 1.03 and the calipers are free. neither master cylinder has residual valves. the pistons in the calipers are very tight; i think too tight. i think the 15/16 bore master cylinder is applying more pressure moving the piston out of the caliper further. because the pistons are so tight they just can't release. i'm trying to find some rebuild kits (o-rings-dust shield) to see if i have the wrong o-rings. i hope yours stops better than mine, 'cause mine ain't worth two dead flies!

Re: tricks to reduce drag on stock a-body discs? [Re: dirtybee] #220052
02/10/09 01:34 PM
02/10/09 01:34 PM
Joined: Aug 2003
Posts: 32,278
Bend,OR USA
C
Cab_Burge Offline
I Win
Cab_Burge  Offline
I Win
C

Joined: Aug 2003
Posts: 32,278
Bend,OR USA
If your using the stock B body master cylinder and it was for drum brakes for both front and rear then you need to remove the residual valve from the line that the front brakes are hook up to, which is normally the rear line and reservoir If it is the stock drum brake master cyliner remove the brake line and get a small # 6 or #8 sheet metal screw around one inch long and thread it into the brass insert inside that port, once it is theaded in two or three turns pry it out. The residual valve is behind the brass retainer, it looks like a rubber flapper valve with a small spring in it, remove it and reinstall the retainer and hook the brake line back up, make sure and tighten it real tight so the seal on the retainer will reseal in the master cylinder and on the brake line, bleed the brakes and let us know if that was the main problem or not


Mr.Cab Racing and winning with Mopars since 1964. (Old F--t, Huh)
Re: tricks to reduce drag on stock a-body discs? [Re: Cab_Burge] #220053
02/10/09 02:31 PM
02/10/09 02:31 PM
Joined: Apr 2007
Posts: 807
Toronto, Canada
D
dirtybee Offline OP
super stock
dirtybee  Offline OP
super stock
D

Joined: Apr 2007
Posts: 807
Toronto, Canada
when i did the swap about 5 years ago i got knuckles from a yard and everything else was '74 manual disc duster parts store stuff, master, calipers, pads, and rotors ,bearings, seals, and a repro front brake line kit.

Re: tricks to reduce drag on stock a-body discs? [Re: dirtybee] #220054
02/10/09 02:38 PM
02/10/09 02:38 PM
Joined: Apr 2007
Posts: 3,746
Riverside, California
L
Lil Demon Offline
master
Lil Demon  Offline
master
L

Joined: Apr 2007
Posts: 3,746
Riverside, California
Buy Aerospace brakes.

Re: tricks to reduce drag on stock a-body discs? [Re: Lil Demon] #220055
02/10/09 02:41 PM
02/10/09 02:41 PM
Joined: Nov 2004
Posts: 6,890
North Alabama
M
Monte_Smith Offline
master
Monte_Smith  Offline
master
M

Joined: Nov 2004
Posts: 6,890
North Alabama
On a strip only car, an old trick is to leave the spindle nuts a little loose. The added runout, helps keep the pads pushed back. Would not do that on a car that sees lots of street duty though.

Monte

Re: tricks to reduce drag on stock a-body discs? [Re: Cab_Burge] #220056
02/10/09 02:41 PM
02/10/09 02:41 PM
Joined: Nov 2006
Posts: 396
California, USA
P
Phil Saran Offline
enthusiast
Phil Saran  Offline
enthusiast
P

Joined: Nov 2006
Posts: 396
California, USA
Cab, what about on 73-76 A-body disc brakes?
I've got the later 2 bolt M/C and my fronts
are tight too.

I've also heard of racers adding springs between
the brake pads to help eliminate drag on the
rotors?

opinions?


Phil Saran Parker, Colorado
Re: tricks to reduce drag on stock a-body discs? [Re: Lil Demon] #220057
02/10/09 02:48 PM
02/10/09 02:48 PM
Joined: Apr 2007
Posts: 807
Toronto, Canada
D
dirtybee Offline OP
super stock
dirtybee  Offline OP
super stock
D

Joined: Apr 2007
Posts: 807
Toronto, Canada
if it was a race only car i would ( if i wasn't out of a job right now) but i heard that it takes a few pumps on the pedal till they stop the car( which is probably why they have ZERO resistance ) and this is basically my daily driver when there isn't 2 frikkin' feet of snow on the ground . seriously though aerospace look like a really nice setup

Re: tricks to reduce drag on stock a-body discs? [Re: lewtot184] #220058
02/10/09 02:55 PM
02/10/09 02:55 PM
Joined: Apr 2007
Posts: 807
Toronto, Canada
D
dirtybee Offline OP
super stock
dirtybee  Offline OP
super stock
D

Joined: Apr 2007
Posts: 807
Toronto, Canada
i wonder if some emery cloth on the outer side of the piston would help it release better? or maybe it would just create a leak . sorry, it's winter and i am bored, AND broke

Re: tricks to reduce drag on stock a-body discs? [Re: dirtybee] #220059
02/10/09 03:09 PM
02/10/09 03:09 PM
Joined: Apr 2007
Posts: 3,746
Riverside, California
L
Lil Demon Offline
master
Lil Demon  Offline
master
L

Joined: Apr 2007
Posts: 3,746
Riverside, California
Quote:

if it was a race only car i would ( if i wasn't out of a job right now) but i heard that it takes a few pumps on the pedal till they stop the car( which is probably why they have ZERO resistance ) and this is basically my daily driver when there isn't 2 frikkin' feet of snow on the ground . seriously though aerospace look like a really nice setup




You heard wrong on the pumps to stop the car. The first pump is softer as it is setting the piston but will stop the car just fine. I can nose dive my Demon at the stripe running 144 mph. The second pump brings the pressure to max (1100psi) and is very firm.

BTW - Aerospace makes a street kit as well that has no resistance.

Sorry about the job and the snow.

Re: tricks to reduce drag on stock a-body discs? [Re: dirtybee] #220060
02/10/09 03:10 PM
02/10/09 03:10 PM
Joined: Jul 2003
Posts: 2,637
Western Michigan
68Fastback Offline
master
68Fastback  Offline
master

Joined: Jul 2003
Posts: 2,637
Western Michigan
Here is something from the Tech Archives

http://www.moparts.org/Tech/Archive/brake/13.html

Re: tricks to reduce drag on stock a-body discs? [Re: 68Fastback] #220061
02/10/09 04:13 PM
02/10/09 04:13 PM
Joined: Apr 2007
Posts: 807
Toronto, Canada
D
dirtybee Offline OP
super stock
dirtybee  Offline OP
super stock
D

Joined: Apr 2007
Posts: 807
Toronto, Canada
demon, is there a link for aerospace just to see the street kit, even if i don't buy now. 68fastback thanks for that link, interesting, i was thinking about a spring to separate the pads and all around informative bit of info. thx very much guys for informing me

Re: tricks to reduce drag on stock a-body discs? [Re: dirtybee] #220062
02/10/09 04:34 PM
02/10/09 04:34 PM
Joined: May 2008
Posts: 1,084
1940 North Victory Boulevard ...
@
@#$%&*! Offline
New user name, Same old jerk!
@#$%&*!  Offline
New user name, Same old jerk!
@

Joined: May 2008
Posts: 1,084
1940 North Victory Boulevard ...
The piston shouldn't touch the bore, it's surrounded by fluid and just slides in the seal.

"i wonder if some emery cloth on the outer side of the piston would help it release better?"

Re: tricks to reduce drag on stock a-body discs? [Re: dirtybee] #220063
02/10/09 04:53 PM
02/10/09 04:53 PM
Joined: Apr 2007
Posts: 3,746
Riverside, California
L
Lil Demon Offline
master
Lil Demon  Offline
master
L

Joined: Apr 2007
Posts: 3,746
Riverside, California

Re: tricks to reduce drag on stock a-body discs? [Re: dirtybee] #220064
02/10/09 04:57 PM
02/10/09 04:57 PM
Joined: Jan 2003
Posts: 73,560
U.S.S.A.
J
JohnRR Offline
I Win
JohnRR  Offline
I Win
J

Joined: Jan 2003
Posts: 73,560
U.S.S.A.
Quote:

demon, is there a link for aerospace just to see the street kit, even if i don't buy now. 68fastback thanks for that link, interesting, i was thinking about a spring to separate the pads and all around informative bit of info. thx very much guys for informing me




do you have PIN type calipers ??? I think you'll need those to do the spring trick if I am reading the link above correctly , you'll need a pretty hefty spring to get a sliding caliper to move .

Re: tricks to reduce drag on stock a-body discs? [Re: JohnRR] #220065
02/10/09 05:16 PM
02/10/09 05:16 PM
Joined: Jan 2003
Posts: 9,980
Ansonia, CT
C
CJK440 Offline
master
CJK440  Offline
master
C

Joined: Jan 2003
Posts: 9,980
Ansonia, CT
What keeps the coil spring on the pin from pushing the piston too far back??

I'm sorta thinking that you could get that scary feeling that you get when you forget to pump the pedal on the daily driver after a pad swap but at 120mph.....


Just enjoying the drive...... Back to basics with a little boost thrown in.
Re: tricks to reduce drag on stock a-body discs? [Re: CJK440] #220066
02/10/09 05:48 PM
02/10/09 05:48 PM
Joined: Jan 2003
Posts: 73,560
U.S.S.A.
J
JohnRR Offline
I Win
JohnRR  Offline
I Win
J

Joined: Jan 2003
Posts: 73,560
U.S.S.A.
Quote:

What keeps the coil spring on the pin from pushing the piston too far back??






No idea , the links above says to do it , I think you could play with spring tension ??? BUT you need to be careful of coil bind as the pads wear ???

Last edited by Johnahah; 02/10/09 05:49 PM.
Re: tricks to reduce drag on stock a-body discs? [Re: JohnRR] #220067
02/10/09 07:20 PM
02/10/09 07:20 PM
Joined: Jan 2004
Posts: 13,211
Mt. Vernon, Ohio
dartman366 Offline
I Live Here
dartman366  Offline
I Live Here

Joined: Jan 2004
Posts: 13,211
Mt. Vernon, Ohio
If the caliper's are hanging up any they will drag, I fixed mine a few years ago by putting new caliper's on it,,,,and yes Monte's Idea work's, but the ultimate answer is Aerospace.


Light travels faster than the speed of sound,,,this is why some people seem bright untill you hear them speak.
Re: tricks to reduce drag on stock a-body discs? [Re: dirtybee] #220068
02/10/09 07:52 PM
02/10/09 07:52 PM
Joined: Nov 2005
Posts: 659
New Hampshire, USA
O
oldiron Offline
mopar
oldiron  Offline
mopar
O

Joined: Nov 2005
Posts: 659
New Hampshire, USA
When I think of it, I turn the wheel back and forth a quarter turn, but its a stick car. It does work though


66 Belvedere Vert, 4 Speed/Jerico, slowly, very slowly, getting faster - NA LD Wedge
New New Best: 10.56 @129
68 B'cuda 4 gear Jerico - Another New Best of 9.86 & Trying to slow up
https://www.youtube.com/watch?v=T4jDLKwd9Gs
Re: tricks to reduce drag on stock a-body discs? [Re: oldiron] #220069
02/11/09 03:47 PM
02/11/09 03:47 PM
Joined: Jan 2003
Posts: 2,931
P
Paul_Fancsali Offline
master
Paul_Fancsali  Offline
master
P

Joined: Jan 2003
Posts: 2,931
My 4 piston disc brakes feel like unadjusted drums bet you have a piston or hanging up

Page 1 of 2 1 2

Advertisement
Forum Statistics
Forums32
Topics193,833
Posts2,261,969
Members25,802
Most Online1,424
Jun 20th, 2018
Moparts Newest Topics
Looking for Machine Shop
by Erik. 03/21/19 03:28 PM
66 Hemi Satellite 4 speed
by lilcuda. 03/21/19 03:28 PM
RIP Justin Carter ......
by kidmopar. 03/21/19 03:14 PM
B5 Blue Paint Code ?
by JFChallenger440. 03/21/19 03:05 PM

Powered by UBB.threads™ PHP Forum Software 7.7.1