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Dave the Wave
07-25-2020, 05:28 AM
ok, my `57, disc brake conversion up front, factory brakes in the rear. all new pads, rotors, lining and drums. even before i put the new stuff in/on, why can`t i lock up the brakes? thanx.

BamaNomad
07-25-2020, 06:16 AM
Perhaps your tires are MUCH larger than tires typically being used with those brake systems. When you 'Lock Up' your brakes, generally you know it when your tires break friction with the surface. If there's much more friction/stiction from the tires/road than the brakes it will be difficult to lock up the brakes (maybe try it on a wet slippery surface).. :)

Are you able to STOP when you need to and quickly enough? That's the real key...

markm
07-25-2020, 06:56 AM
55&56 Here with Camaro/Chevelle Style disk up front and 57 Olds 11 0r 77 Cutlass 11 drums on rear no issues. I used second gen Camaro second gen Camaro prop valves.

Dave the Wave
07-25-2020, 09:23 AM
factory is 11 inch, right? thanx for the replies!

markm
07-25-2020, 09:29 AM
Correct, I thought 55-57 was 10.0 but its been so long since I had stock brakes. Rock Auto says 11.00 for 55-57. I had 9.5 rear when I had a 66 Chevelle 12 bolt.

Dave the Wave
07-26-2020, 02:51 AM
and yea, i guess i can stop fast enough. just thought it could be better.

BamaNomad
07-26-2020, 04:16 AM
and yea, i guess i can stop fast enough. just thought it could be better.

Dave, if you aren't SURE about your braking, then let a car buddy friend drive your car and give you HIS assessment... :) DO you have HUGE tires and std brakes (even if they be disks?)...?

Dave the Wave
07-26-2020, 05:45 AM
255/60x15 on rear 205`s on front. thanx

55 Rescue Dog
07-26-2020, 07:04 AM
When you say you can't lock up the brakes, which would be a good thing, what master cylinder size, how much pedal travel, and how hard you are pushing? Brake pad compound can make a difference, along with many other things. I'm setting up my car for manual brakes, but I have to custom make the brake pedal mount, and I'm worried about pedal flex because I will need a lot of pedal force, even using a 7:1 Wilwood race pedal.
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Dave the Wave
07-26-2020, 08:15 AM
all stock chevy, and i`m really pushing on the pedal. and, rear drums, after driving around town get super hot, can hold my fingers on them, but not for long. so i guess there are adjusted as far as i can go? e-brake cable has play, loose.

55 Rescue Dog
07-26-2020, 10:09 AM
At a minimum you need a dual master cylinder setup with a proportioning valve, and a couple other things with a disc/drum system. Takes different pressures, and fluid volume. The fronts might not be doing much with a single master cylinder.

Chevy Chase
07-26-2020, 12:26 PM
Sounds like you need to install an adjustable proportioning valve to set the rear brake pressure. I remember installing one on my 55 Chevy after installing a Dana 60 rearend back in the 80's.11128Summit part # G3905.

Rick_L
07-26-2020, 02:18 PM
A lot of assumptions being made here.

What master cylinder do you have and what is the bore size? It should be 1" or smaller. Some brake conversions supply a 1-1/8" bore, but that should only be used with a booster.

What calipers do you have?

A proportioning valve is only going to help if the rear brakes lock up - which they should first.

Big tires and wheels only matter to this question if they are HUGE - like the tires on a lifted truck, etc.

Dave the Wave
07-27-2020, 02:11 PM
i dont know the answer to most of these questions. all gm stuff, including a dual cyl., proportioning valve.

55 Rescue Dog
07-27-2020, 04:06 PM
Sorry I can't help you much without much more detail, and pictures. I'm trying to figure out why I can't get the brakes to lock up on my 02 Camry beater, which probably had crappy brakes when new. Everyone needs good brakes. You might need to find a local professional, which could be infinitely cheaper than what could happen.

enigma57
07-27-2020, 08:03 PM
Have you considered adding a power brake booster? Several different types available. Makes a lot of difference and all OEM disc brake applications use them. For a reason.

:) Just an idea,

Harry

BamaNomad
07-28-2020, 04:38 AM
If the OP is having an issue with not being able to apply enough pedal pressure to generate stopping force, then I agree he should consider that, but to correct a statement Harry made in the prior post...

No, not "all OEM disc brake applications use them. For a reason." as Harry posted.

There were (and possibly still are) several factory OEM disk brake installations which used Manual brakes. The mid-late '60's 4-wheel disk brakes on Corvettes supplied both manual and power disk brake options (The manual versions used smaller diameter MC than did the PB option). I recall in the '69-70 time frame when I first began looking at NEW cars (Chrysler and Chevrolet), Chevelles... Roadrunners... Darts.. etc all provided for disk brake installations (front only) with a manual MC. I considered those at the time because the Power option was higher priced than the manual disk option and I had NO money! :)

I'm building my '57 Nomad currently using the big disk brake parts from a '96 Corvette and utilizing a manual MC from a '67-69 Corvette. Before I decided to go this way, I talked to several owners of trifives who were using a manual MC with disk brakes and were happy with them, although a couple did say that their wives didn't like the pedal pressure required.

markm
07-28-2020, 06:33 AM
My 72 Cheyanne Super came with A/C & PS, but did NOT have power brakes. It stopped much better than the 64 Custom it replaces.

Robert Haas
07-28-2020, 09:28 AM
Ratio?

I am currently building my 55 using Wilwood manual MC and their 12" big brake kit with 4 piston calipers. Wilwood said I need at least a 6 to 1 pedal ratio . 1114411145

Rick_L
07-28-2020, 09:44 AM
The stock pedal ratio is 6:1, so no mods needed there. Just use Wilwood's recommendation for master cylinder bore size based on the calipers you've selected. You probably need 7/8" or 15/16" with those, but don't take my word for it.

Old Buzzard
07-28-2020, 10:51 AM
"You probably need 7/8" or 15/16" with those, but don't take my word for it."

Rick, exactly what the Wilwood tech told me, when I asked about non power m/c size.
OP, put a brake pressure gauge on it. You'll find out really quick, if the system is working correctly.

enigma57
07-28-2020, 11:08 PM
I stand corrected, Bama. If there were OEM manual disc brakes available on American cars, I was not aware of them.

When I ordered my new 1969 Nova SS396, it came with front disc and rear drum brakes. Had to order the SS model to get the L78 engine and the Nova SS cars that year came with front disc brakes and 12-bolt rearends as standard. Only power disc brakes were available. There were no manual disc brakes available for those cars. I asked when ordering.

That said...... Just because I've never seen an OEM disc brake setup without a power brake booster....... Doesn't mean there were none.

My apologies,

Harry

BamaNomad
07-29-2020, 05:06 AM
We all know a little bit of different knowledge, Harry... that's how/why we're able to help one another here in the forum!~ :)

WOW... that '69 Nova SS you ordered with the L78 engine... HAD to be very fast! Did you use all your vietnam combat pay on that one? :)
I'd LOVE that car right now... :) (and I don't even like big blocks!)... :)

Chevy Chase
07-29-2020, 11:25 AM
A lot of assumptions being made here.

What master cylinder do you have and what is the bore size? It should be 1" or smaller. Some brake conversions supply a 1-1/8" bore, but that should only be used with a booster.

What calipers do you have?

A proportioning valve is only going to help if the rear brakes lock up - which they should first.

Big tires and wheels only matter to this question if they are HUGE - like the tires on a lifted truck, etc.

My 57 Chev sta wgn has manual frt disc brakes, rear drums and dual master cyl with side mounted proportioning valve. The car stops as it should. I think Rick brought up an excellent point regarding the correct master cylinder. However, I disagree with his statement about "the rear brakes lock up - which they should first." I disagree because the front brakes do most of the braking.

Yes, I did install an adjustable proportioning valve to prevent the rear brakes from locking up first in a panic stop.

Robert Haas
07-29-2020, 01:01 PM
If one axle brakes lock up before the other, you prefer it to be the rear brake that lock first, since it tends to maintain steering and vehicle direction better.
Golly, I have been driving 50 years and that sure as heck ain't how I feel. I have had full on emergency lock ups in my life, (more then I can count in the multi million miles I have driven) and I tell you right now, if the back end locks up it is going to be the front end in very short order.

BamaNomad
07-29-2020, 01:52 PM
Robert: You are right. I deleted my post... I can't explain what I was thinking on that post... :)

markm
07-29-2020, 02:01 PM
I remember my Olds Starfire with the hand held e brake, great for doing Mannix turns.

Chevy Chase
07-29-2020, 03:45 PM
Robert: You are right. I deleted my post... I can't explain what I was thinking on that post... :)

Hey BamaNomad , We all have a brain fart once in a while :>)

Rick_L
07-29-2020, 04:27 PM
However, I disagree with his statement about "the rear brakes lock up - which they should first."

I wasn't very clear here. What I meant is that if the rear brakes lock up first without a proportioning valve, that is the main sign that you need one. If they won't lock up at all, then your attention should be elsewhere.

If the car's disc conversion uses the typical GM parts, the master cylinder bore should be 1", and the front calipers should be the bigger Chevelle type with 7" between the anchor bolts - not the Malibu/S10 calipers that are 5.5" between the anchor bolts.

markm
07-29-2020, 05:02 PM
My 55 had this issue, the guy who started my 55 used a crappy Speedway disk kit with Metric calipers. I switched to Chevelle stuff and improved it

enigma57
07-29-2020, 09:49 PM
Yes, I recall hearing of the disc brake kits that used the 'metric' calipers not stopping as well as they should, Mark. Apparently, the full sized GM car calipers have a great deal better clamping force and when substituted for the 'metric' calipers, stop a lot better.

Happy Motoring,

Harry

enigma57
07-30-2020, 12:50 AM
We all know a little bit of different knowledge, Harry... that's how/why we're able to help one another here in the forum!~ :-)

WOW... that '69 Nova SS you ordered with the L78 engine... HAD to be very fast! Did you use all your vietnam combat pay on that one? :-)
I'd LOVE that car right now... :-) (and I don't even like big blocks!)... :-)


Gary, I was WIA 8 May of '67 and mustered out of the Corps against my wishes Friday 13th, Oct., 1967. During those years, my folks were having a pretty rough time and one of the reasons I left for the service straight out of high school was so they would have one less mouth to feed. When I was in the Corps, I sent my paycheck such as it was to my folks back home except for $20 per month to live on.

The first new car I bought Stateside was a '68 Camaro. I saved the money for the car over a 6 month period from my civilian pay. It was just too sexy looking to pass up, but it was a 'stripper' with a 250 6-banger and 3-speed column shift and a bench seat. Yes, a Camaro with a bench seat. No power, no A/C. When I bought it, I was newly married and son #1 was on the way. The salesman at the time tried to point us toward a new Nova as a family car, pointing out more rear seat and trunk space as well as identical mechanicals.

Well, by the following year, we were ready for a new car to replace the Camaro. We lived simply and I worked so many hours driving a moving van for Bekins and humping furniture up and down stairs at the time that I had saved up a small nest egg and went down to the local Chevy dealer with good intentions of ordering a new '69 Nova to suit my quickly growing family.

Of course, when I looked over the options sheet, I lost my head and before long, had special ordered the L78 engine, an optional 400 Turbo transmission (4-speed was standard with this engine) and because the engine was only available in the SS package, the front disc brakes and 12-bolt rear were a part of the package.

Like the Camaro, I spec'd Rally Green paint, black interiour, a column shift and front bench seat and tinted glass. Only appearance item I added was bright trim around the side windows.

No power anything except for the power disc brakes and no A/C. Wheels were 7" wide plain steel rims painted body colour with the small hubcaps. Tires were redline wide ovals. This is a car like mine......

http://www.hongliyangzhi.com/manufacturers/chevrolet/chevrolet-nova/1969-chevrolet-nova-ss-396/1969-chevrolet-nova-ss-396-5.jpg

https://www.theelectricgarage.com/auctions/68/img_4575.jpg

In hind sight, I should have spec'd power steering and A/C. I ordered it with a highway gear (3.07 gearset in rear).

Yes, it was fast. But honestly, a professionally built and prepped small block car could match it wheel for wheel from a standing start until the Nova reached 90 MPH and that was when the L78 engine started pulling like a freight train. That was because of the big solid lifter cam and the large port rectangular port heads, I suspect. Same cam and heads as the 425 and 435 HP 427 'Vette. With a bit less cam and a set of oval port heads fitted with the larger valves, I believe the car would have run better 0 - 90 MPH with the 3.07 highway gears.

I liked the Nova, but there was one thing I could not stand about the car. That was the hokey chrome things on the hood. Looked like stylized finned valve covers and the sun would hit them and blind you. 2nd day I had the car, I covered the rear surfaces with masking tape. 3rd day, I picked up the hood, popped the retainers off the darned things wrapped them in towels. Put them in the trunk and never saw them again. :-)

Here is a photo of a Nova SS with the offending hood ornaments that I removed from mine (not my car and I did not have a black vinyl top as this one does)......

http://topclassiccarsforsale.com/uploads/photoalbum/1969-chevy-nova-ss-396-ci-numbers-match-m-21-docs-ex-cond-video-1.jpg

Happy Motoring,

Harry

BamaNomad
07-30-2020, 05:23 AM
The 3.07 gear was hurting you Harry! :)

During my time at Keesler AFB the fastest thing on the street in the southern Mississippi area was a '69 Nova SS driven by one of the guys who worked in Paul Vanderley's Speed Shop. L78 wtih Torquer intake manifold and huge Holley, with big rear end gears (4.10 or better), big tube hooker headers! He had a standing bet with anyone who would put up $100 on a drag race. I don't think he ever lost! The L78 engine was among Chevy's strongest big blocks!

markm
07-30-2020, 07:23 AM
I run the L78 cam in my 65 Impala 396 325 hp and love it.

enigma57
07-30-2020, 01:16 PM
You are right, Gary. The huge intake ports and big solid lifter cam were not well suited to the 3.07 highway gear at all. Learned that the hard way. I did not buy the car to drag race and once I figured out what it would and wouldn't do...... Limited getting down hard on it to rolling starts and from highway speeds when passing. Then all was good.

I might add that the original L78 intake and 780 Holley 4bbl carb were stolen whilst my car was en route from up North and priour to my receiving it from the Chevy dealer here in Texas. Those parts were on back order in Jan. of 1969, so I worked a deal with the dealer and he had his parts and service guys substitute the intake and tri-power carbs for a '67 435 HP 427 'Vette. I had to sign my mechanical warranty away, but that was no biggie.

Whether that added to the issues with getting the car moving from a standing start, I cannot really say. One thing I can tell you though...... When both the 500 cfm secondary carbs kicked in...... You better either feather the throttle or be moving fast enough before you get down on it because things begin happening in a hurry when you drop the hammer on 1,355 cfm all at once.

Best regards,

Harry

markm
07-30-2020, 01:22 PM
Really surprised the L-78 came with 3.07 gears I would have guessed 3.31/3.55/3.73.

BamaNomad
07-30-2020, 02:49 PM
I'm fairly certain an L78 would have had 3.73 gears std (at least with manual trans) maybe one stop below that for an auto (3.55 or ?); to get anything else it would have had to be special ordered.

markm
07-30-2020, 02:54 PM
In the SS Chevelle the 3.31 was very popular.

55 Rescue Dog
07-30-2020, 02:59 PM
Braking balance is a huge issue on old vehicles without ABS like we take for granted now. The only way to maximize braking on these old things is try to come up with a setup that works the best. You must try and do something to get the front/rear brake balance optimized, and test it with by trying to see what happens at lockup. If the fronts lock up too soon, you can't steer. If the rear locks up too soon, all hell breaks loose. More fun though sometimes.
I'm going for an adjustable setup, with different F/R master cylinders with a balance bar, prop valve, and 2 brake pressure gauges.

markm
07-30-2020, 03:09 PM
Harry

My first Camaro was 67 equipped with a 250 also 3 on tree.

enigma57
07-30-2020, 07:45 PM
They were more rare than the bucket seat models with console mounted shift lever, Mark. Maybe we should have kept our old 6-bamger 'stripper' Camaros as an investment? :)

FWIW...... I like the '67 Camaros best. They had vent windows and the side windows had more support than the '68 and '69 models. Also lacked the hokey side marker lights that first came out in '68.

Happy Motoring,

Harry

Rick_L
07-30-2020, 07:54 PM
Stop dreaming, the relative worth of a stripped down 6 cylinder Camaro isn't changing. And the vent window deal goes both ways.

markm
07-31-2020, 04:01 PM
Me too Harry, my first 67 was a little different than yours bucket seats with 250 with a Saginaw on the tree. Rick I always felt like 68 and 69 Camaros were parts cars for to keep 67s going, 69/68 have ugly grilles and side lights and no vent windows and 69 look like fat pigs with wimpy rear wheel openings.

55 Rescue Dog
07-31-2020, 04:14 PM
I was hoping for an interesting thread about non-power brakes. Oh well.

enigma57
07-31-2020, 06:44 PM
Well, we do digress here from time to time, Rescue Dog! But 3 pages out of 5 on topic ain't bad, all things considered. :)

Happy Motoring,

Harry

enigma57
07-31-2020, 07:46 PM
Mark, my eldest son had a '68-1/2 Firebird when he was just out of high school. At least that's what we called it after we figured out that it was a '68 Firebird from front bumper to firewall to top of A-pillar and had '68 doors...... But everything to the rear of that was a '69.

Thought it looked 'different', but couldn't quite figure out why. Then after it was tee-boned by an illegal alien..... We pulled the parts off that were still good...... And I realized that at some point, the '68 Firebird must have been rearended and someone had brazed the rear body shell of a '69 Firebird to the '68 from top of A-pillar and rear of front door opening...... Back.

They did a pretty good job of it. You'd never have known it had been wrecked before had you not seen the seams under the carpet where it had been brazed together with yellow brass rod. And as bad as it was hit when my son was driving...... The brazed seams held up just fine.

Best regards,

Harry

markm
08-01-2020, 05:32 PM
Back on topic that 67 Camaro with manual drum bralkes did not stop for shit, at least a Fire chicken with manual brakes got fined drums. Harry , your story reminds me of the Cambird. A buddy in high school wrecked his 67 green Firebird and put a 67 Camaro front clip on it. All the lines matched but it was ugly.

enigma57
08-01-2020, 08:21 PM
:) Mark, you got me to thinking. I believe many of us have either wanted a particular car or truck that has eluded us...... Or have considered the possibility of building our own one off 'phantom'...... A car or truck the factory never built but we would love to have one if they had.

Is there a particular car or truck that you would love to own but has eluded you so far? Or that was never made...... But you might seriously consider building for yourself? I do. Just wondering if you or anyone here does, as well.

Happy Motoring,

Harry

BamaNomad
08-02-2020, 06:29 AM
How about a 'real trifive'.... :)

11169

11170

11171

markm
08-02-2020, 08:47 AM
Bama that is kinda cool, as far as projects I will never get to a 55/56 1/2 ton PU and a 58 Impala top the list.

Old Buzzard
08-02-2020, 11:04 AM
Likely, most of the basement dwellers wouldn't know the difference.....

55 Rescue Dog
08-02-2020, 02:46 PM
That Try567 is a work of art. I wondered if it had manual brakes?

enigma57
08-02-2020, 10:56 PM
How about a 'real trifive'.... :)


:) I like it! Thanks, Gary! Kinda reminds me of the old Johnny Cash song......

https://www.youtube.com/watch?v=18cW_yHo3PY

Happy Motoring,

Harry

55Jim
08-03-2020, 08:23 PM
How about a 'real trifive'.... :)

11169

11170

11171

Yes it is :D