Filling & Bleeding New Brake Lines ??

[Rack Man]

I am about ready to fill & bleed my new power brake system for the first time....I am wondering whats the best and easiest way to do that ?...I have heard of "Gravity" filling the lines but not really sure how to do that....do I gravity feed them one at a time or open all bleeder screws at the same time?

Also, I did not bench bleed my MC so I need to do that while its installed....that should'nt be too much trouble....but do I need to include the Prop valve when I bench bleed it?...Also, what about brake fluid?....DOT5 or DOT3?.....

Btw, this is a complete new CPP booster/MC kit with all new SS hard lines


Any insight would be greatly appreciated!

[Alex Hayley]

Some people like gravity bleeding the MC while some insist on bench bleeding the MC first. To gravity bleed, assemble the entire system and fill the MC. Open all bleed screws and keep the MC filled while watching and fixing leaks. I found it useful to occasionally tap the bottom of the MC to release trapped air.

For bench bleeding the MC, I did not include the proportioning valve.

I would go with a high quality DOT4 fluid but since you have a completely new system(including brake cylinders and calipers right?) you could use DOT5.

[Rack Man]

Yes...I replaced everything including the wheel cylinders and calipers....I read somewhere that DOT5 is much harder to bleed...any truth to that?

[Longhorn Man]

don't use dot 5 in a street truck. It doesn't absorb water so you end up wiith sections of pure water in the lines in places.
I'm sure google will find you alll kinds of info.

[cdowns]

when bleeding these brakes the most commonly overlooked procedure is clamping the pin on the combination valve to keep it centered

[QKENUF4U]

Mity-vac.........

[Rack Man]

Originally Posted by cdowns

when bleeding these brakes the most commonly overlooked procedure is clamping the pin on the combination valve to keep it centered

Good tip...but what is a combination valve & where is it located?....or is it just another name for the prop valve?.....

[cdowns]

Originally Posted by Rack Man

Good tip...but what is a combination valve & where is it located?....or is it just another name for the prop valve?.....

proportiong valve is what people wrongly call a combination valve

[mclairmo]

A combination valve typically includes in one block a metering valve for the front discs, a proportioning valve for the rear brakes and possibly a residual valve for the rear drums. You can purchase all of these valves separately and plumb them individually if you want. The CPP kit should include a combination valve. I used DOT 5 before and it gives you a mushy pedal and leaks very easily. Only good for a show car where you don't want it to eat painted surfaces.

[Classic Heartbeat]

I bench bleed the master cylinder right on the truck. You can purchase a kit to do so, or like me I just bent a couple of brake lines to do it. Just mount the lines to the master cylinder itself and carefully bend them around into their prospective reservoirs. Fill the reservoirs 3/4 full of fluid, (making sure the ends of the lines are submerged in the fluid) and pump until you do not see air bubbles either coming out of the lines or valve assembly in the bottom of the master cylinder.
Once this is done, you can reconnect the lines from the master cylinder to the proportioning valve, and then on to the rest of the system.
You can gravity bleed the system like some here like to do, starting by opening the bleeder valve farthest from the master cylinder. Unless you have mounted your master cylinder in a custom place, the furthest bleeder is the right rear one, then left rear, then right front, and finally left front.
I personally like the pump the brakes and reliece bleeder method.
Witch the order of bleeding is the same, just instead of counting on gravity to bleed you are forcing the fluid through.
The combination valve is another name for the proportioning valve.
Also with SS brake lines you will need to tighten them extra tight because the flairs are harder and do not seat as easily to the wheel cylinders. WES

[Rack Man]

awesome info as usual from you guys.....thanks a bunch!

Great info. WES.....thats why I buy from you!!

[Classic Heartbeat]

Glad that I was able to help you. WES

[Rack Man]

Ok..One more quick question on this...How much brake fluid (approx) will I need for the entire system..?