I had a thread a while back citing all my troubles trying to convert my power brakes to manual brakes but the thread got stale and there was really to much information to cipher through in order to ask questions appropriately. So I am starting a new thread. Here is what Ive got.... 53 Chevy Truck 3100, slammed to the ground 74 Camaro front calipers 79 Camaro rear drums 7/8s wheel cylinders I believe 88 S10 assembly and prop valve Originally power brakes from another s10 assembly, but I went crawling and got a manual assembly. First I tried using a 72-79 Camaro Manual master cylinder 1 inch bore, but I could not get it bled down, so I assume it was a bad refurbished unit, but during installation I found out that I would have to fabricate a pushrod holder because the bore is to small to hold a pushrod.. Now I am read several forums about people using 69 vette manual masters so I am going to give this a shot. My question is which port should I run the front brakes out of and why? I know I will now need to get a residual valve for the rear drums, but I am ok with that. Any other suggestions on this setup I would appreciate. Thanks! Pictures of master... Front says 1/2 and back (firewall) says 9/16 thread. Inside, looks like the front reservoir is a tad bigger.
That particular master shouldn't be different fron to rear. Corvettes at time were four wheel disc, so front and rear should be the same. Add a residual valve for the rear and you should be good to go. I wouldn't run it through the s10 combination valve with the residual though.
Why are you making this so difficult? Just get yourself a stock 74 Camaro drum/disc manual master and be done. The residual valve will be in that master. The Brass combination valve is just a manifold and not necessary at all. They are almost always guaranteed to cause you trouble. I would then mount a 55 and later truck manual brake light switch, not hyd. in line. It really is just that easy. The Wizzard
Like a dog chasing his tail. Unless you KNOW what bore sizes you are dealing with you will continue to have problems.
The 74 master does not have a deep hole to hold the pushrod. They used cup retainers that I don't have and cannot not find one to buy.
The bore size for both the camaro and the corvette manual master are a 1 inch bore... I know this, but I don't know what port the front brakes should go, primary or secondary.
The bore size of the front calipers and rear wheel cylinders should be a non issue in this. The part numbers on the camaro for power or manual are the same. Same wheel cylinders and same caliper size. I know some have said there are wheel cylinders specific for manual brakes, but I guess in the camaros case it is the same.
"First I tried using a 72-79 Camaro Manual master cylinder 1 inch bore, but I could not get it bled down" Are you ABSOLUTELY POSITIVE you bench bled the master correctly and are bleeding the brakes correctly? Based on the results from your "engine runs rich" post, I can't help but wonder if you are overlooking something very simple here. Are you also positive the brakes are plumbed correctly?
I did find in the last go around that I have it plumbed wrong, I have the primary (small reservoir) plumbed to the front brakes and the secondary (large reservoir) to the rear drums. But after swamping those two out I was still having a pedal that didnt get stiff until the floor. Your right though I seemed to look over the simplest things and make it so much harder on myself.
chevy has a manual disk front and drum rear master used on pickups used right up into the 80's, no screwing around with extra RPV's, just T the front line, make sure you have a return spring on the pedal under the dash, the right freeplay on the pushrod, adjust the rear brakes up tight before bleeding, i followed your engine start up trouble as well.
Yeah, kinda made an ass out of myself on the build process. Ill never live that choke line down. But shit, young and dumb and learning. Thats my excuse atleast. lol.
I just looked up that master cylinder... How would that master be plumbed in? It looks like the back (firewall side) is the larger sized reservoir? That to the front brakes?
the large reservoir is for the disk brakes, and here is why, each pad is about 1/2" thick new, there are 4 pads, so from the time the pads are new till their worn out the pistons will move 1" per side for a total of 2" travel, so if the pistons are 2.25" DIA then you need about 8 cubic inches of fluid in the reservoir so it will not go dry before the pads wear out.
The larger chamber ALWAYS goes to the fronts. The pictured master looks like a manual cylinder, but you are better off getting a power assisted master, as the push rod bore is most/always deeper, alowing a safer/easier install on a custom system. At least have the parts guy pull both for comparison.
Thanks for that info. That is exactly what I am going to do. Ill let you know how it turns out tomorrow.
On the master shown it will have the valve for the rear in the line port. It should be the forward (not the bolt flange) end (small chamber). To check this take a piece of .035 welding wire or a very small drill bit blunt end in and poke it gently in the brass hole. The check valve will stop the wire about 1/8" in. The Disc brake port will let the wire go in quite a ways further, like an inch or more. That's why you don't need an inline residual valve, it's already there. The Wizzard
I dunno I am using a Willwood manual master. It was no more expensive than a big heavy corvette unit. I don't know where you got your master mounted but if your disc brakes are above the master you will still need a residual valve to keep the fliud from returning to the master.
P&B; I've heard this story for years. I have found it to not be true on several cars. The only time I have seen it happen is when the car has a leaking wheel cyl to let air in so it can gravity feed back to the master. In the case of my 51 and my F-100 it has never happened, once it does I will check for leaks above the master first. Think water in the straw and your thumb on the end. That's how it was explained to me, found it to be true. The Wizzard
You are probably correct, I had a lot of cars with under floor masters stock that didn't have a problem. But I have seen it more with the disc craze than any other that you need to put something in there.
mgtstumpy. What year do you think I would need then? I am about to order a 77 Chevy C10.. Comes with a pushrod, but I have an adjustable one anyway, and it looks like it has a deep cup.
If your '51 and F-100 brake systems are stock, the master cylinders already have a stock internal residual or check valve.
I built the braking system in my 46 Chevy from scratch, maybe my system will help you because it worked PERFECT, had great peddle, and stopped HARD. 77 Ford pickup manual disc/drum master cylinder. Mustang II front calipers (I know they are different than yours but it shouldn't make a difference.) S10 rear drums Residual pressure valves on front and rear because master was under the floor. Speedway adjustable proportioning valve in the rear line. I ended up with the proportioning valve almost wide open without the rear brakes locking, it had kick ass peddle and stopped quick. Scot
I never did see if your S10 prop valve is a combo valve that's designed to block off one side of the system if there's a loss of pressure. Given it's a factory part it probably is. Those do go bad sometimes. When they're tripped to one side or the other, you will never get a hard pedal out of them.
If it is resetable there should be a rubber bulb on one end of it and you can push the piston back over. However, with that being said, I have never seen a factory proportioning valve used in a non stock application that has worked as intended. They are designed for a specific weight vehicle with a specific front/rear weight bias. A Speedway valve is anywhere from 32.00 up to 100.00 for a fancy one with brake light switch, get an adjustable one and it will work as intended. Scot
That's because this is a Power Assisted M/C. Power Assisted M/C are shallow, manual M/C are deep. Sorry, but incorrect and the oposite is true, I'll explain, The power assited units help hold the pushrod in place as it goes throgh the diaphram unit. The manual M/C do not have any way to hold the P/R in place, EXCEPT for the deep well machined/made into the actual plunger. DO NOT use a Power M/C with Manual brake set-up as the push rod could easily fall out and then you have no brakes what so ever, TR
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