I'm about to loose my mind

348tripower · April 13, 2018, 03:53:04 PM

I have been working on the wagon trying to get it all done for cruising this summer. I am back to the lousy brakes I have.
Last year before Kalamazoo I added residual pressure valves to the system, per Franks advice, even tho it has a firewall mounted master cylinder and changed the maser cylinder to a 1 1/8 bore with a combination valve set up for disc/ disc brakes. I even changed out the Eldorado calipers to a non parking brake caliper thinking I couldn't get the air out of them. Still lousy brakes.
So I thought lets go back to the Eldorado stuff which have smaller pistons and see if there are any changes now. My thinking was that there was more fluid that had to be moved with the larger pistons so the smaller ones may help and I have the parking brake system all set up and want to use it. So I made the move and still have lousy brakes.
I can lock the fronts up on gravel but on pavement it won't happen.
The front calipers are NAPA SE4622/23 S10 units 1 1/8 CPP master cylinder and a 8 inch dual diaphram universal booster.
Any ideas?
Thanks,
Don
PS I think I know everything there is to know about setting up Eldorado Calipers

348tripower · April 13, 2018, 04:19:34 PM

And since my head hurts so bad from trying to figure this thing out can anybody confirm what I just found? I think I just discovered that a 2013 Dodge Challenger has a vacuum pump to operate the brake booster. I am hooked to a hose but I really never checked it for vacuum. :oops: And I really never noticed any brake pedal difference with the engine running.
Also I wonder if I have to add a pump what to use?

kb426 · April 13, 2018, 05:44:51 PM

One thing I want to mention, I saw this video earlier in the week. This guy put a torpedo level across the top of the master cylinder and raised the rear of the vehicle until it was level. When he stepped on the pedal, bubbles came out of the front side of the cylinder. He says that air bubbles get caught on the rear side of the piston cup and you can't remove them without the cylinder being level. I haven't run into that before probably because I was lucky. My thought about your booster is even if it doesn't have enough vacuum, the pedal should still be real solid. An 1 1/8 master is large enough that I wouldn't expect to lock up much without a booster. From what I read, the leg force is based upon 100lbs of foot pressure for an average human. On the Pro-touring website under the disc brake topic, there is a 12 page explanation about disc brake operation with more info than I have ever seen in one place. Some of the formulas were provided by engineers. I read that a week ago when I was looking for answers to my setup on the 72 F100. If you want a link, I'll provide one. There was a brake calculator spreadsheet that someone had done that was available for a free download. I looked it over and it allows you to put in lots of info and see where you are at in braking force.

348tripower · April 14, 2018, 06:14:59 AM

Quote from: "kb426"One thing I want to mention, I saw this video earlier in the week. This guy put a torpedo level across the top of the master cylinder and raised the rear of the vehicle until it was level. When he stepped on the pedal, bubbles came out of the front side of the cylinder. He says that air bubbles get caught on the rear side of the piston cup and you can't remove them without the cylinder being level. I haven't run into that before probably because I was lucky. My thought about your booster is even if it doesn't have enough vacuum, the pedal should still be real solid. An 1 1/8 master is large enough that I wouldn't expect to lock up much without a booster. From what I read, the leg force is based upon 100lbs of foot pressure for an average human. On the Pro-touring website under the disc brake topic, there is a 12 page explanation about disc brake operation with more info than I have ever seen in one place. Some of the formulas were provided by engineers. I read that a week ago when I was looking for answers to my setup on the 72 F100. If you want a link, I'll provide one. There was a brake calculator spreadsheet that someone had done that was available for a free download. I looked it over and it allows you to put in lots of info and see where you are at in braking force.

I have a hard peddle but I don't think I have any assist. I am going to check the vacuum I have out of the hose I am hooked too. It does have vacuum but I don't know if it has 18 inch pounds required for the 8 inch booster. I found out that I hooked to that hose because it was a recommended booster vacuum source on one of the conversion sites.
I would like that link too please!

kb426 · April 14, 2018, 08:28:10 AM

This is the long brake thread: http://www.pro-touring.com/threads/104584-Brake-sizing-and-selection-tutorial-featuring-Ron-Sutton-and-Tobin-of-KORE3
I will attempt to send you the excel calculator in a pm.
Have you checked the check valve on the booster to see if it works properly? Is the vacuum connection on the intake manifold run into the open plenum or is there a chance that it is ported? Would it make sense to connect a hand vacuum pump up to the booster and see if it will hold a vacuum? Just thinking out loud.

UGLY OLDS · April 14, 2018, 11:05:52 AM

Don...Just a thought ...Do you have a place along the frame rail for a vacuum "reserve tank" ?? I used these both in my Olds & in my Kidd's Dodge ... Both were made from race header collector extension pipes with the ends welded closed ....( Approx 3 1/2" X 14" ), Then a pipe fitting with a hose nipple was added ...They are connected to the manifold on both cars with a one-way check valve & the cars vacuum line is "T'ed" in after the check valve ...... I use then due to both cars still having vacuum wipers ... The wipers on both cars work well regardless of the amount of throttle opening ...
The Olds works so well that the wipers will continue to run approx 2 minutes after the engine is shut off .... :?

Just a thought .....

Bob...

kb426 · April 14, 2018, 11:21:10 AM

Don, I only see the vacuum pump listed for the 3.6 v6. The 5.7 has a power booster spec as 9.56" single. That's 71.78" sq area. A double 8" is 100.53" . That should be more than enough. I noticed the RT master is 1 1/16 bore.

348tripower · April 14, 2018, 05:22:06 PM

Thanks for all the replies. I'm going to go to a smaller bore master cylinder and see what happens. I have checked for vacuum and I do have 18 inches.
Originally I didn't have the rear Eldorado calipers adjusted properly now I do. I do know the booster is working. I went thru the test this morning and it drops when I start the car. The check valve is fineIt just has no pressure to the calipers. I can drive away with the pedal pressed. So I'll know more later in the week.

kb426 · April 14, 2018, 05:45:00 PM

Don, you're not a beginner. From what you have described, something is happening that isn't within the range of normal. Would putting a pressure gauge in the front brakeline be a good test?

Crosley.In.AZ · April 14, 2018, 11:23:00 PM

Talking about similar deal tonight with a friend. He had Eldo parking brake style disc calipers on the rear of his 52 Buick with 9 inch differential.

He changed calipers to non parking brake style , was better. Then he learned to tilt the Eldo calipers up so the bleeder was at the very top. Re-installed the Eldo calipers. And got the calipers to adjust up finally, bleed out some air.

He added a Chevelle booster bracket to his booster on the firewall. That tilted the booster & master cyl up. Changed his brake arm to booster ratio. He had to drill a new hole in the peddle arm. Shorter throw on the peddle, brakes work great now.

348tripower · April 15, 2018, 09:26:30 AM

Thanks KB and Crosley,

I just got done checking and I have a 5:1 pedal ratio and that should be fine.
It looks to me that with out the engine running I can only move the push rod about 1/2 inch. That should relate to the 1 1/8 bore master. Larger master, less travel, harder pedal. according to what we have learned a 15/16 to 1 inch master cylinder should fix the problem. In my searches I have found that C4 Corvettes had 7/8 and 15/16 master cylinders depending on pedal ratio. S10 Chevrolets were .944 to 1 inch

348tripower · April 19, 2018, 07:09:15 AM

So here is a update to my problem. I changed my master cylinder out for the third time yesterday after proving out that the booster is working. I changed to a 1 inch bore from a 1/18 bore. All the sites that deal with brakes tell me that in a disc/disc set up I need a 8 inch booster and a 1 1/8 master cylinder. My booster is 7 inches because of limited space. With the 1 inch master I still have no lock up of the brakes and the pedal is on the floor. With the 1 1/8 master I can't push any harder to get lock up even tho I have plenty of pedal.

I clamped off the rear line and bingo! I can lock up the front brakes. So it looks like I need to go to a drum brake set up on the rear to ever get this thing to stop properly. Seems as stated the 7 inch booster is too small for the disc/disc set up.
So there we have it. :oops:
I call the car the C note special because every time I get a hold of the door handle it cost at least a hundred bucks

416Ford · April 19, 2018, 07:51:18 AM

Quote from: "348tripower"I call the car the C note special because every time I get a hold of the door handle it cost at least a hundred bucks

Glad to hear your making some progress and I like the name.

Charlie Chops 1940 · April 20, 2018, 09:42:02 AM

Don....the C-note Special it is. I got a couple of those.

Chasing brake problems with more perfectly good parts isn't a lot of fun, is it? I just try to go back to real basic setups and not listen too hard to all the current business experts. Seems like most of their expertise is in selling the parts,and not in making them work. Then throw in badly made parts disguised as real parts and one gets questions ones own sanity.

You're on the right path now I think. I've done a few scratch 4 wheel disc cars and the parking brake issues along with incompatible parts seems to make for questionable value.

BFS57 · April 21, 2018, 11:04:40 AM

Quote from: "Charlie Chops 1940"Don....the C-note Special it is. I got a couple of those.

Chasing brake problems with more perfectly good parts isn't a lot of fun, is it? I just try to go back to real basic setups and not listen too hard to all the current business experts. Seems like most of their expertise is in selling the parts,and not in making them work. Then throw in badly made parts disguised as real parts and one gets questions ones own sanity.

You're on the right path now I think. I've done a few scratch 4 wheel disc cars and the parking brake issues along with incompatible parts seems to make for questionable value.

Hello;
WOW! Im right now, in my driveway, updating my 57 chevy to all disc. Only difference is I purchased "everything" from one place and most of this kit (so to speak) is Wilwood!
I have the duel booster, duel master 1 1/8" bore, combination valve, wildwood duel piston calipers, with eleven inch Disc Front and back, the Caddy calipers out back with the emergency brakes, (instructions say to use the emergency brake a couple times to adjust these to the disc) all new SS brake lines!!! Oh! I have the booster brackets that are short (about 1.5 inches from the firewall) and mounts booster "straight"
So far everything looks good, now working on the rear end parts, Everything looks fantastic, I sincerely hope that it all works.
As far residual valves go, Im thinking that on a firewall system they are not needed, My knowledge (reading articles) is that these are for under car mounted booster/master combos!

Bruce