Cascade Crew

Twilightoptics

Chevette. I ditched the stock prop valve, installed a line lock on the front brake side and adjustable prop valve on the rear line. Bought a remaned Master Cylinder. Manual Brakes from the factory. MC rod fits around the pedal without pre-loading.

Problem is I've bleed the system to death. The car wont stop until you've pumped the brakes 3-4 times or hit the very end of the pedal. After pumping it acts ALMOST normal. Driving around the block the pedel will slowely lose it's firmness the less it's used.

What's the culprit here? Thanks guys.

PS I found one SMALL weap on one of the rubber lines but it still seems like there is another problem?

rjmcgee · The Hammer Joined: 08 Jan 2004 Posts: 2328

Are the rear drums adjusted up good, like your not trying to move the shoes a long ways? Can you adjust the Prop valve and close off the rear brakes to see if the fronts only work normal?

Twilightoptics · Posted: Sun May 25, 2008 10:21 am Post subject:

Fronts seem to be where the lack of braking is from.

rjmcgee · The Hammer Joined: 08 Jan 2004 Posts: 2328

Hmmm, time to install a parachute on the Chevette.

Seriously though, if there are no leaks then it would seem like something is pushing the piston back into the caliper as you drive. Shrug

Dewey316 · Posted: Sun May 25, 2008 10:36 am Post subject:

Mayve the remanned master is bad ? Have they ever worked right at all, with that master?

chevymad · Posted: Sun May 25, 2008 12:48 pm Post subject:

Rod might be right. On disc brake setups theres usually a valve that holds about 10psi on the discs to keep them from retracting all the way. Sometimes its in the master, sometimes the proportioning valve. You've got a mismatched system right? Chevette master and camaro/s10 brakes?

I'd see if either a camaro or s10 master would bolt on. I think you can also get the residual pressure valves. Actually here's a link..

http://ecihotrodbrakes.com/discbrake_kit_components.html

Al Hasse · Posted: Sun May 25, 2008 1:44 pm Post subject:

If I can get the 4th gen master cylinder I have to work properly (maybe a shorter pushrod in booster), you can try my old one if it bolts up.

Twilightoptics · Posted: Sun May 25, 2008 6:27 pm Post subject:

I can make either one fit. Did S10/Camaro ever come with a manual master? I've never had a master off our cars with the booster. Is the rod longer for booster style master or is it all the same?

I didn't think about residual valves. I knew you had to use them on setups with the master as a low point.

I'll have to pop the hood on the maro and take a look and measure the bolt studs.

The Maro/S10 style has the valve in the master then?

Quasi-Traction · Posted: Sun May 25, 2008 6:48 pm Post subject:

Here's the Napa PN for a Manual master for an S-10.

http://www.napaonline.com/MasterPages/NOLMaster.aspx?PageId=470&LineCode=SS&PartNumber=4739570&Description=Brake+Master+Cylinder+-+New

chevymad · Posted: Sun May 25, 2008 7:24 pm Post subject:

I'm actually not sure where the residual valve is in our systems. It's either in the proportioning valve or master. Beings that several of the crew have replaced the proportioning valve with the aftermarket one, I'm assuming its in the master.

Twilightoptics · Posted: Sun May 25, 2008 7:25 pm Post subject:

Can't seem to find a manual one of the Maro/Birds.

I do see manuals for the S10 as per Chris.

The Chevette master has a built in rod. I wonder if it will be able to detatch. The S-10 ones are just a dimple for a rod.

chevymad · Posted: Sun May 25, 2008 7:27 pm Post subject:

Could probably steal the rod off an s10 at one of the yards too. Or even make something.

Twilightoptics · Posted: Sun May 25, 2008 7:28 pm Post subject:

S-10 one has to be it. The Maro one mounts at an angle while the S-10 and Chevette are pretty much straight out. So the Maro one would be too steep.

Guess I'll go see if the yard is open tomorrow. Since I need a panhard bolt too. I'll measure the Chevette studs and go check the yard. IIRC the Master studs for the Chevette come off the pedal assembly.

chevymad · Posted: Sun May 25, 2008 7:28 pm Post subject:

One more thing, it may not be just the residual valve. The chevette master just might not be able to move enough fluid for the larger brakes you are using. You've got larger pistons in front, and large brake cylinders as well.

Twilightoptics · Posted: Sun May 25, 2008 7:30 pm Post subject:

I was wonder about that as well. Though the piston on the stock caliper was virtually the same size.

I think the S-10 setup seems to be the way to go. Now how to fund it.

Looks like a 79 Maro has a Manual Brake setup. Has the metal cap. Might be better than the S-10 setup. I need the Double Invert flares. No Bubble flares!

Quasi-Traction · Posted: Sun May 25, 2008 11:25 pm Post subject:

If you wanna hit the yard tomorrow paul, I'll go with you.

I need a water pump pulley.