Opinions on manual brakes

pottsie, generally for the front brakes you use the well closest to the plunger end of the M/C. Corvettes have been 4 wheel disc brakes from the mid 60's and have equal or very close to equal wells front and rear, TR

 

GM did away with manual brakes a lot earlier than ford did, thats why i ran the ford truck master cylinder. Like traditions racing said, dont run a power M/C setup with your manual brakes, bad shit can happen.

Brakes aren't that complicated if you just use the right basic components. You need a reasonable MANUAL DISC/DRUM master cylinder, an adjustable proportioning valve, and residual pressure valves because you are mounting under the floor.


Thats it.

Don't over think it.


Scot

 

I had a combo valve on my '55 Chevy (manual disc/drum) that caused me fits when it came to brake bleeding. It would allow me to bleed the fronts, but I could barely get anything out of the rears (fluid or air). Turns out the internal plunger would move forward, blocking off the rear ports. To keep the plunger depressed while I bled the rear brakes, I made an "L" shaped bracket that bolted to the side of the valve, then I removed the bracket and bled the fronts.

 

Cool...

Any truth in the statement above about not needing a prop valve? I am now going to try using a 77 c10 manual master.

Also, for clarification my master is mounted on the firewall using 88s10 brackets. And that master im using does have a residual valve in the rear circut.

 

Thanks for chiming in TR i get the feeling you know more then just motors....

I really aapreciate that you explain things to me instead of just telling me that wont work.

 

My 51 Ford is a Nova front with Disc and my Truck is Chevell with disc. Both have drum brakes in the rear. Both are master under floor, no brass valve and just stock valve in master cyl. Never had an issue. You now have enough information to be totally confused again. With your master mounted on the firewall I'm not sure why the bleed back issue even came into the conversation.
The Wizzard

 

Sorry, your "explaination" is totally wrong. Just where did you learn about brakes in general? Your logic (?) is exactally bass-ackwards.

 

Well, yes, as someone else said it should have that rubber bulb on it which in theory resets it. It also should have an electrical terminal on it - just hook a test light from it to a hot + source, if it lights, it's tripped.

My 1989 R/G/V/P service manual told you that to reset it, you had to open the lines at the master to balance the pressure. It also had a bleeding method done with the engine running, and long slow strokes of the pedal to try to avoid tripping it. I found it to be like getting to the center of a Tootsie pop - you never get there without biting, and you never get more than 3 pumps without tripping the damn thing.

Now since then I had a '95 van and to bleed those, which in my case has a prop valve and an ABS unit, you used a GM special tool that screwed on and held that button down. But the one with the iron body has no provision to attach the tool.

Bottom line for me was the only way to bleed and get a good hard pedal was to pressure bleed the system, every time, as that would push the fluid through without tripping the valve. You can backyard-engineer one if you have to.


The S10 unit is probably close to right, but were I you I'd consider an adjustable one. In theory if you have Camaro calipers and Camaro wheel cylinders, then a Camaro master cylinder will do the job - but you might need a Camaro prop valve, and the big thing is you probably need the pushrod, or at least one that is the same length and moves the same distance when you hit the pedal.

I don't think you've said for certain, but what are you using for a pedal unit? An S10? I see they're on the firewall. I junked the Trans-Am I had, so I can't tell you what the throw is on one.

Also, when you go for a master, look it up on Rock Auto and see what the interchange is. Sometimes a lot of cars/trucks use the same one.

 

Your rear cylinders are 15/16, the 79 MC was 1 1/8" For the manual config. But if you see below I found the same mix of parts with the correct 1" MC.

Your fronts are 2 15/16ths and a 1" Bendix MC Wagner part number F80293. In 75-73 the same combo was available as what you have piecedd together. Use this MC. There are literally DOZENS of combinations possible so I used my Wagner and in your case my Carquest version of the brake spec bible.

 

Thanks tman. I used a 1 inch bore master out of a 77 C10. I got a lot more break pedal now then before. I still feel like there might be a little air in the line so I am going to keep bleeding. I might end up going to 1 1/16 or 1 1/8 if I cant get the pedal where its stiff in the upper 3/4. Right now it gets hard half way down. But since I cant drive the truck yet I dont know if its enough break yet, like I said, if it isnt I will be going with a larger bore MC.

Thanks again TMAN!

 

your pedal being low usely means the rear brakes are not adjusted up enough, if your pedal gets hard 1/2 way down then call that good enough till your driving it a little and the rear shoes get a better seat.

 

Work on a good bleed. Air can be frustrating. One good thing I learned from my old boss at teh hotrod shop is how many folks mess up this one simple item. That is why I keep my brake bibles handy!

 

Rear brakes are adjusted out to where I cant even turn the drum. I planned on adjusting them back out a turn or two to keep the shoes from burning up. I am fairly certain that its air in the lines somewhere. Just gotta keep bleeding.

 

I have had good results using speed bleeders on my car.nice when no one is around to help.

 

I'm reading this thread and learning right along with you, pottsie.....

Wayne

 

do you have a pedal return spring up under the dash and how much free play do you have?

 

If you are having trouble bleeding the system and feel like there is air still in it ... check for leaks. I found a bad flare on a car I once owned. It didn't "piss" everywhere (to the point of being an obvious leak) but was just enough of a leak that a tiny amount of fluid would come out and a small amount of air would get sucked back in. Just because a fitting is tight (or new) doesn't mean it is leak free if the flare isn't decent.

 

Ive always been told that, with all else being equal, you will have a firmer pedal with a 1" bore M/C than you will with a larger bore.
Have you checked the amount of brake pedal free play you have? You need a little (I usually shoot for 1/8" between the brake rod and the bottom of the M/C cup). The more excessive the freeplay, the further your pedal will go down before it hardens up.
On the subject of leaks, check for fluid seeping past the caliper/wheel cylinder pistons and at the back of the M/C...I hope some of this helps...

 

Good advice, I've seen many a caliper with a bad o-ring right out of the box, sometimes the remanufacturers (is that a word?) pinch them during reassembly. I just use like a little dental pick and lift the caliper boot slightly. If there is any fluid at all in there, its bad.

 

well hows the brakes working now?

 

Brakes are progressively better. I am fighting a leaky fitting on the master right now. But prior to findin gthat leak the pedal seemed firm up top. I wont know for sure until its on the ground rolling ill update everyone in a month or two when that happens.

Thanks again for all the help and advice!