Moparts
Front or Rear Caliper Mount??
Posted By: 440PURSUIT
Front or Rear Caliper Mount?? - 12/27/12 07:37 PM
65 Coronet with A body Spindle with 11 Rotor, Slider Calipers.
I have them rear mounted.
Will front mount improve braking?
I dont have a sway bar on this car but would consider install. Will it be a problem?
Thanks
Posted By: AndyF
Re: Front or Rear Caliper Mount?? - 12/27/12 07:43 PM
No change in braking performance but the hose routing is easier with the calipers mounted to the front. Rear hung calipers are more difficult to plumb since there isn't very much room for the hose.
Posted By: 440PURSUIT
Re: Front or Rear Caliper Mount?? - 12/27/12 08:27 PM
Just drove the 65 Coronet. Lackluster braking. I had a locking up condition due to pushrod adjustment at first. Pads must be glazed.
Lock up fixed.
I posted yesterday about pads. I ordered the last set of Bendix Titanium Metallic II's from Rock.
Car has 1 1/8 Manual Master sourced from E-Burg, 69 Coronet Drum Distribution block, 74 up 11 Inch Sliders with organic pads, Rear Line Prop Valve and 10*2 rear shoes.
Posted By: skicker
Re: Front or Rear Caliper Mount?? - 12/27/12 08:50 PM
Your front brake package is done similar to mine...I think the lackluster part begins with the distibution block for drum brakes.
Posted By: AndyF
Re: Front or Rear Caliper Mount?? - 12/27/12 09:32 PM
Brake effort will be high with the large diameter master cylinder. So you'll need to stand on the pedal to get the car to stop. If you want a lower pedal effort and don't mind more pedal travel then swap to a smaller bore size in the master cylinder.
The drum distribution block with a rear mounted prop valve should work just fine. That is a standard way to go when retrofitting an older car. My '65 is set up the same way.
Only thing you should double check is your caliper mounting. If you rear mounted a set of front mounted calipers then you might have installed them upside down. People do that all the time and then they can't figure out why the brakes don't work very well. The bleeder needs to be at the very top of the caliper so that air can escape.
Posted By: RapidRobert
Re: Front or Rear Caliper Mount?? - 12/27/12 09:54 PM
Quote:
Will front mount improve braking?
As said no, If you're going together ideally you'd want the calipers on the opposite side (front or rear) of the spindle as the hard line/hose mounting tab is so in other words the hose has to go horizontally behind/past the spindle to go from the caliper to reach the tab. If you are already up & running as is sounds like you are then if you have the right hose that does not bind/rub/kink from lock to lock or up/down in the suspensions' travel you're set. On my 65 Dart I mistakenly put the calipers on the rear & I needed to bend the front section of those particular hoses that is a hard line to get it all to clear. EDIT '74 A discs
Posted By: 440PURSUIT
Re: Front or Rear Caliper Mount?? - 12/27/12 10:35 PM
Car is up and running. I used the bigget bore cylinder for disc drum. This is the 10-1860 1981 D150 cylinder.
The bleeders are pointing up. Been there, done that! LOL
I will try the pad swap and if no success, try the longer stroke, smaller bore, MD. Recommendations?
Thanks
Posted By: BigBlockMopar
Re: Front or Rear Caliper Mount?? - 12/27/12 11:46 PM
If you have a feeling the brakes just don't grab hard enough, you should go to a smaller diameter MC.
(Why did you choose the largest?)
I think you'll end up with a 15/16" or 1-1/32" MC in the end.
Was/is this a manual or power braked car?
Posted By: JDMopar
Re: Front or Rear Caliper Mount?? - 12/28/12 03:12 AM
I did pretty much the same swap on a 64 Belvedere wagon. I used A-body spindles with the calipers front mounted, A-body proportioning valve,11.75 rotors with pin type caliper adapters and calipers and hoses from a 70 Roadrunner.I used a NEW master cylinder for a 70 Roadrunner with power disc brakes. I cut 2 small notches in the bottom of my k frame, and used a sway bar from a 70 Roadrunner...and also the lower control arms from a 70 Roadrunner. Can you tell I had a 70 Roadrunner parts car?
My wagon was a factory power drum brake car, is why I went with the power master cylinder, and the Roadrunner master cyl bolted right up. That behemouth would stop on a dime and give you nine cents change after the swap! Good luck.
Posted By: Cab_Burge
Re: Front or Rear Caliper Mount?? - 12/28/12 03:36 AM
Did you verify that the new master cylinder had the residual pressure valve removed for the front disc brakes? If not, do that
Posted By: 440PURSUIT
Re: Front or Rear Caliper Mount?? - 12/28/12 03:43 AM
Manual brake conversion....
Posted By: 440PURSUIT
Re: Front or Rear Caliper Mount?? - 12/28/12 03:48 AM
Would the 81 mc not be valved properly for disc/drum?
Posted By: Cab_Burge
Re: Front or Rear Caliper Mount?? - 12/28/12 03:51 AM
I've heard some weird storys about some of the later model Mopar M.C. Pull the little brass plug out of the port feeding your front brakes and see if that little rascal is in there or not
Posted By: Stanton
Re: Front or Rear Caliper Mount?? - 12/28/12 04:24 AM
Quote:
I used the bigget bore cylinder for disc drum.
This is a case where bigger is definitely NOT better. As Andy said, the larger bore increases pedal effort. You're using a 1.125" bore, swap to a 1.03" and it will take much less effort on your part.
Posted By: 440PURSUIT
Re: Front or Rear Caliper Mount?? - 12/28/12 04:27 AM
Run a screw in it and pry? Ideas
Posted By: 440PURSUIT
Re: Front or Rear Caliper Mount?? - 12/28/12 04:39 AM
Pads have shipped. Will try those. Prob get an Advance smaller bore also.
Posted By: RapidRobert
Re: Front or Rear Caliper Mount?? - 12/28/12 05:04 AM
stick a drill bit deep into the brass cone seat & if it has a RPV you'll feel its' springiness as it is only a piece of neoprene on a spring.
Posted By: 440PURSUIT
Re: Front or Rear Caliper Mount?? - 12/28/12 05:11 AM
Anyone havebthe application ofbthe smaller bore (alleged) disc/drum master? Thanks
Posted By: mopowers
Re: Front or Rear Caliper Mount?? - 12/28/12 03:59 PM
Quote:
Anyone havebthe application ofbthe smaller bore (alleged) disc/drum master? Thanks
I just bought one at the parts store yesterday. The application I used was a 74 Dart. The power disk/drum master had a 15/16" bore (actually 31/32"- I guess they may hone them when they reman them???) The manual disc/drum master cylinder had a larger bore. So, I got the power master. And yes, it had the recess for the retainer.
This is the one I got:
http://www.oreillyauto.com/site/c/detail...2&ppt=C0066
Posted By: 440PURSUIT
Re: Front or Rear Caliper Mount?? - 12/30/12 02:27 PM
Did a bot more research...Will check my Caliper Piston size. I assume they may be the smaller 74 Dart Calipers.
I see 78 Diplomat is about .10" larger.
Any one know the application of the smaller Rear wheel cylinder?
C
Posted By: 70Cuda383
Re: Front or Rear Caliper Mount?? - 12/30/12 02:36 PM
Quote:
Did a bot more research...Will check my Caliper Piston size. I assume they may be the smaller 74 Dart Calipers.
I see 78 Diplomat is about .10" larger.
Any one know the application of the smaller Rear wheel cylinder?
C
you're doing it wrong... (on the rear cylinders)
when increasing brake pressures/clamping loads for better braking, you want BIGGER caliper pistons/wheel cylinders, and SMALLER master cylinders.
Posted By: 5spdcuda
Re: Front or Rear Caliper Mount?? - 12/30/12 02:36 PM
Mid '70's pick up trucks generally used a 7/8 in. wheel cylinder instead of the more common 15/16 in. one found on cars. That's how I ordered mine.
Posted By: TheRamMan
Re: Front or Rear Caliper Mount?? - 12/30/12 03:29 PM
the 15/16 disc master is the best( 1707) 4 bolt there is....super rare now due to wonderful expert advice and articles...no 2 bolt conversion,no master blocks..no adjustable brake rods..that are never long enough for good thread engagement..esp on e body
and it is era correct, AND LOOKS RIGHT
Posted By: 440PURSUIT
Re: Front or Rear Caliper Mount?? - 12/30/12 06:12 PM
70 Cuda- I had 15/16 on rear. I found I had the 74 Dart 2.6" Piston Caplier on front.
I am swapping to the smaller MC now and ordered 2.75 Dippy Calipers.
Looking forward to the improvement.
Will swap pads when Calipers arrive. $23 for a loaded pair. Wholesaler closeout from ROCK. Wonder what pads are included?????
C-
Posted By: AndyF
Re: Front or Rear Caliper Mount?? - 12/30/12 07:37 PM
You'll see a 12% increase in brake force by going with the 2.75 inch caliper. That might be enough to fix the issue right there. If not, swap to a smaller bore size
MC and test it again. Stepping up to the larger 11.75 inch rotors would also be a good way to increase front brake force.
(I covered a lot of this topic in my B-body book.)
Posted By: 440PURSUIT
Re: Front or Rear Caliper Mount?? - 12/30/12 08:31 PM
Andy, thanks for insight.
Found the smaller MC at Advance last night and swapped in out. Loosened the rear shoes a bit while at it.
Went out and warmed up existing pads. Not much difference.
Tested prop valve and started to get bias with valve all the way out. I can notice the front begin to engage now as I get a bit of nose down went applying brakes at speed.
Once the brakes seemed as good as they'd get I did a few panic stops (15-20mph) and still get rear lock up.
Not as severe now, though.
Will wait for loaded Diplomat Calipers to arrive.
Any pad recommendation for those? May need to source a better pad.
Posted By: 440PURSUIT
Re: Front or Rear Caliper Mount?? - 01/03/13 02:03 AM
I read up on Feets brake math.
I have calculated the Pedal Ratio to be 4.8.
The 65 Coronet has a 12" long pedal and the pushrod bolt hole 2.5" down from pivot.
With the existing setup 15/16 MC and 2.6 Calipers, I am only generating 695 lbs of line pressure.
So....If I redrill a hole at 1.5" I will increase the pressure to 1157.
Is this recommended?
This is a 65 Coronet and I just read that 65 and back B bodies have different pedals. There is also a hole lower than the one I'm using at 1 7/8" lower.
Does any one know if this is a Power or Manual Brake Pedal?
The car was converted to a 4 speed before I got it. I am thinking a Power brake pedal was used.
Thoughts?
Posted By: feets
Re: Front or Rear Caliper Mount?? - 01/03/13 10:29 PM
Drilling the hole higher in the pedal will make the pedal feel softer with more travel.
Play around with master cylinder sizes and see if some odd size will work with your ratio.
Posted By: MoparMarq
Re: Front or Rear Caliper Mount?? - 01/03/13 11:47 PM
Quote:
Drilling the hole higher in the pedal will make the pedal feel softer with more travel.
Play around with master cylinder sizes and see if some odd size will work with your ratio.
Plus, redrilling another hole for a different pivot distance will place the pushrod at an up-angle (from the m/c, that is) which may create some issues with pushrod angularity and a thrust force on the lower half of the m/C bore. Don't know enough about pushrod lengths and so forth to know if this is something to be concerned about, but I'd sooner go with a smaller bore m/c and keep the correct pivot distance so the pushrod is still pushing somewhat straight down the bore rather than at an angle.
Posted By: 440PURSUIT
Re: Front or Rear Caliper Mount?? - 01/05/13 10:02 PM
Drilled the hole higher before I saw Feets' Post. Pedal sucks! DOH!
Found a prop valve in my stuff and will try to hold off rear brakes.
Will see how this goes...
Posted By: 440PURSUIT
Re: Front or Rear Caliper Mount?? - 01/06/13 12:05 AM
Swapped the Pushrod back to stock location. The pedal came back firm.
Went for a first ride with the prop/combo valve installed. This si the prop valve for a 70 the has 2 parts. I only used the lower part that is similar to drum brake distribution block.
Took the car for a test and found the prop/combo valve makes a difference. Backs don't lock regardless of existing "adjustable prop valve" position.
Actually, the fronts work better with the adjustable letting more fluid to rear since it cuts them off quicker.
I would consider that braking is now good. I will move to 7/8 rear wheel cylinders and hope for continued improvement.
Do you think that 2.75 Diplomat Calipers will help the cause???
Thanks
Posted By: RapidRobert
Re: Front or Rear Caliper Mount?? - 01/06/13 04:24 PM
Quote:
Do you think that 2.75 Diplomat Calipers will help the cause?
yes more front bias & 76 A body (only) calipers are also 2.75" & the hose mounting location may or may not be in a better location for your app (or may be the same) I'm not sure but I'd have the parts guy pull both of em so you can eyeball em both when you go in to make your purchase
Posted By: 440PURSUIT
Re: Front or Rear Caliper Mount?? - 01/06/13 06:51 PM
I installed the 2.75 later Diplomat calipers. The Hose Mount location comes in from the bottom. This seems better than the A Body 2.6's that feed from top.
We installed the calipers and new Ambulance Pads (Metallic). The car seems to brake fine, but won't put you through the windshield.
Coming down driveway I was able to lock up both front first.
All in all its safe now. I will still try some adjustment and the 7/8 rear wheel cylinders.