I'm attempting to install a Speedway 47-59 Chevy PU Basic Kit on my straight axle Nova with Olds/Pontiac rear end. I figured out the front calipers and finally got the master cylinder hung. On to the plumbing. The fronts are Speedway 47-59 PU kit calipers. Plumbing away from the master cylinder, what order to I place the residual valve (using a 2PSI) to the line lock (and then on to the T junction)? The rear brakes are 1964 Olds Super 88 drums. Plumbing away from the master cylinder, what order to I place the proportioning valve to the residual valve (using a 10PSI)? I bought the kit, master cylinder, and residual valves sort of under blind faith that the Speedway technician/salesperson would guide me. If you guys have any additional advice on getting the system going, I would greatly appreciate it.
I'd put the line lock on the caliper side of the residual valve. 2 lb in front is correct. If you are using an inline adjustable proportioning valve I am not sure but need to find out as I have one for my 48 that I plan to install.
this kit? https://static.speedwaymotors.com/pdf/910-31916.pdf They also have 8 pages of brake tech info. https://www.speedwaymotors.com/the-toolbox/brakes-tech~34-1-2 Probably wouldn't hurt to skim through them. Aside from that, I'd plumb the residual valves along the ch***is after the drop from the firewall with easy access. The line lock is normally placed close to the MC. On the rear, have you confirmed you need the proportioning valve? When mixing and matching parts along with the bigs and littles which are normal on a car with line lock, an adjustable one is normally chosen since you are not a stock set up. I'd keep it handy to adjust and service, and if the choices are before or after the residual, I'd go before. If this is going on track, check to see if there are rules about the flywheel area or other placement before bending up the lines.
RodstRace hit exactly on what I am thinking on my 48 with the adjustable proportioning valve for the rear brakes rather than one of those contraptions that sticks on the side of the master cylinder. In my case it is because with disk brakes on the front personal experience says that the rear brakes like to lock up and cause the truck to do things that I just flat do not want it to do including have the *** end p*** the front end when I am on the brakes. That is partially because it is a pickup with a bad front rear weight bias empty though. Being able to dial in the pressure to the rear brakes lets you stop straight just about every time and if you plan to race it that means a lot as you need all the help you can get with those jacked up too high in the air g***er abortions. You would be a lot better off just using 90/10 shocks on the stock suspension and not running a front sway bar as far as going fast and having it handle goes.
Normally the little check valve behind the seat for the line for the drum brake side is enough with those . I don't have an image of them in the master cylinder but they are in the rebuild kits along with a spring and a new br*** seat and screws to pull the br*** seats out of the master cylinder. Those springs have enough pressure for a firewall mounted system but my experience with a 68 C 10 master cylinder on my 48 says they don't have enough tension for an under the floor system and will bleed off after the rig sits for a week or so. Let it sit for three weeks and you have to bleed the brakes. I'm thinking that that the inline residual valves got real notice well after I put the dual master cylinder on my 48 in the 90's. I never had trouble with it until I got a box with wheels daily driver and let it sit for days on end.
As mentioned residual valves with a high mounted master is wasting money and time. Just unnecessary. I start with the master, and plumb to the proportioning valve and then back to the rear brakes. Then up front from master to line lock, to driver's side front wheel. T at the driver's side, and then across to the p***enger side whatever route is cleanest. I think you should also check lock to lock turning first as it appears your hoses to the front calipers might have an interference issue and need to be relocated before you plumb them in. Unless it's just the picture angles making them look that way?
I think I can answer all of your questions and make the system far less complicated for you.. If your interested in the info , please call or text me.. Email works as well.. No offense to Ryan , but the HAMB PM system ( at least for me ) is a bit of a pita.. Dave lewis 831-262-7294 Leftturndave@aol.com
You could very well need a 10 psi residual valve in the rear line when using a firewall mounted "repop Corvette style" master with rear drum brakes. Without it many wheel cylinders will **** air on release and the pedal will go soft in time. Easier to install one now than find out later you should have. It happens.
When the brakes are released the pressure on the wheel cylinder cups drops faster than the pistons retract creating a low pressure area, letting the cups relax and air sneak in. Some wheel cylinders had cup expanders in the past; but don't think they do anymore.
Both of my cars use firewall mounted masters and both are disc/drum setups. One uses a Subaru master, and one uses the same Corvette master. Neither have residual valves. The older one has been working almost 12 years, and the newer build almost 5 years. If ****ing air was a possibility wouldn't all the car makers have used residual valves when they built disc/drum setups with firewall mounted master cylinders? If they didn't think they were needed, I sure wont add them to mine. If air could somehow "sneak in" then when you hit the pedal fluid would sneak out too!
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