Bleeding Question??

[BUICKGNX]

Hey Guys,
I just installed a new power master pump motor. I changed the accumulator and switch while i was on a role. Anyways,
The light turned off and the new motor clicks on in less than 20sec. ALL GOOD. One problem is that the pedal feels mushy when i turn the key on, pump fills. It feels soft. There is also like a liquidy watery sound near the pedal. I assume that the brakes need to be bleeded. How do i bleed the brake system on the gn's? Please let me know guys.

Thanks

Mike

 

[trbojo]

start by bleeding the pressure off of the powermaster unit. the key has to be OFF. pump the pedal 15-20 times, until it's good and hard. bleed the system like you would any other car. R/R,L/R,R/F,L/F. one thing i just thought of: if the old unit was bad, you may just be used to a hard pedal. the whooshing sound is pretty much normal.

 

[BUICKGNX]

Hey
Thank you for the reply. So first bleed from the master cylinder. Then bleed from the r rear, L rear, r front, l front. To bleed from the master cylinder, do i just step on pedal, looseen the front line (rear brakes) with a rag around it and watch the fluid spill out. Is there a cleaner way of doing it and will there be alot of mess by doing it the first way.
Please let me know'
Thanks kindly. You have been a great help

Michael

 

[trbojo]

unfortunately, there's no cleaner way to do it. like you said, wrap a rag around the lines while you're bleeding. after you have everything tight, you can spray everything off with your garden hose. brake fluid is water soluable, so it will wash off with just a hose. glad i could help.

 

[dan lephart]

bloody mess!

I use a plastic tube like aquarium air hose and the plastic fittings used to bench bleed a master cylinder on the car to do the master cylinder bleed. Run the hoses back into the reservoir. Cover the master cylinder area with newspaper and a trash bag to protect the engine bay. I attach the same type hose, long enough to run into a jar on the floor, onto the wheel cylinder bleeder and drain the fluid into the jar. Cover the area near the bleeders with plastic wrap or a plastic grocery bag and and some throw away rags and you will have very little mess. Brake fluid strips paint!

 

[BUICKGNX]

THANKS GUYS,
ANY BODY ELSE HAVE ANY INPUT?????

PLEASE RESPOND.....THANKS GENTLEMEN!!

MICHAEL

 

[BUICKGNX]

IS THERE ANY AFFORDABLE BLEEDING KITS TO BUY??

HEY GUYS,
JUST CURIOUS TO SEE IF THERE ARE ANY AFFORDABLE BLEEDING KITS TO BUY? I DONT WANT TO MAKE A MESS IN BLEEDING. DO I HAVE TO BLEED FROM THE MASTER, COMBINATION VALVE AND WHEELS OR CAN I JUST DO IT ALL FROM THE WHEELS WITHOUT MAKING A MESS AT THE MASTER??? WHERE IS THE COMBINATION VALVE LOCATED????IS IT THE SAME AS A PROPORTIONING VALVE. WHAT ARE THE PROCEDURES???

THANKS GUYS

PLEASE RESPOND!!

MIKE

 

[QWK GN]

I picked up a power brake bleeding kit from JEG'S.
It pushes pressureized fluid from the master cylinder through the lines.Its a one man operation and works great.
John O

 

[gofstbuick]

Originally posted by BUICKGNX
HEY GUYS,
JUST CURIOUS TO SEE IF THERE ARE ANY AFFORDABLE BLEEDING KITS TO BUY? I DONT WANT TO MAKE A MESS IN BLEEDING. DO I HAVE TO BLEED FROM THE MASTER, COMBINATION VALVE AND WHEELS OR CAN I JUST DO IT ALL FROM THE WHEELS WITHOUT MAKING A MESS AT THE MASTER??? WHERE IS THE COMBINATION VALVE LOCATED????IS IT THE SAME AS A PROPORTIONING VALVE. WHAT ARE THE PROCEDURES???

THANKS GUYS

PLEASE RESPOND!!

MIKE

Think of the brake reservoirs as two separate units. The larger cavity closest to the passenger side fender well is for power assist (PM) and the two smaller resevoirs (closest to the drivers side fender well) is for brake hydraulics. If you empty the PM reservoir, you can bleed the brake system (with the ignition off) just like a manual brake system. The fluid from the PM side goes all over the place (when you press on the brake pedal), because of the accumulator acting on the power assist system. So empty it and bleed your brake system. You can purchase a master cylinder bleed kit from NAPA. Disconnect the brake lines and connect the master cylinder bleed kit, with the hose dipped into the master cylinder reservoirs (closest to the drivers side) filled with brake fluid. Get into the car and press on the pedal until you don't see any bubbles in the master cylinder. Hook the mastercylinder brake lines up and bleed the lines at the combination valve. Finally bleed the wheel cylinders and calipers. Watch the fluid levels. Or you could even gravity bleed the wheel cylinders and calipers. Again, watch the fluid levels. Once you've completed bleeding the brake side, then add fluid to the PM reservoir. Turn the ignition on and watch the fluid level on the PM reservoir. There are two ports at the bottom of the PM reservoir and the front port is suction. Make sure the front port always stays immersed in brake fluid (once the ignition is on). the PM motor should stop cycling in less than 20 seconds. If it runs for more than 20seconds, turn the ignition off. Then you'll need to bleed the PM side. This is accomplished by loosening the hose beneath the accumulator until fluid flows out (DON'T COMPLETELY REMOVE THE HOSE, ACCUMULATOR OR PRESSURE SWITCH, AS ALL ITEMS ARE UNDER EXTREME PRESSURE-700PSI OR MORE). Then tighten line and turn ignition on again and the motor should stop cycling in less than 20 seconds.

 

[jooset]

I'm trying to learn this system as well. Just put new fron disks/rotors on as well as new rear wheel cylinders. Now, let me get this straight....

Pump pedal 10-15 times with the key not in. Un cover reservoirs. Empty PM side (turkey baster??). Then do the bleeding procedure from each wheel (I like to gravity feed), one at a time (PR, DR, PF, DF). Keep fluid in the driver side reservoir as I go, careful not to let the front port become uncovered with fluid. Once done with the 4 wheels, top off the reservoir, recover, and check things out. What's the correct fill level of the reservoirs by the way? No other pedal pumping other than the initial 10-15??

How does that sound?

Thanks for the help / Matt

 

[gofstbuick]

The PM has to be fully discharged before adjusting the level of the brake fluid on the PM reservior. The braking side of the PM unit can be adjusted at any time. The reason the PM reservoir needs to be discharged (10-15 brake pedal pumps with the ignition off) is that you don't know how much fluid the PM motor, accumulator and line has drawn or accumulated in the system. If you look at the inside of the reservoir, there is a limit line for the PM reservoir, I usually don't exceed 3/4 of that limit, with the sysem fully discharged.

 

[SyHopeful]

I have a swapped vacuum setup and I just did rear brakes today so I need to bleed the system. But there's no bleeder nipples on my car, is that right? On the rears, right about the line fitting there's a little rubber cap covering a hole, do I bleed out those or what?

 

[trbojo]

take the rubber caps off. they cover the bleeder screws. there are also bleeder screws on the calipers!

 

[SyHopeful]

Ahhhh gotcha

Are the bleeder screws recessed? Because the caps are flush with the surface they're in.

I didn't get a great look at 'em, I didn't see what I was expecting to see (Raised bleeder screws) and stopped. I'm such a cautious mofo.

 

[John Larkin]

Yeah they're recessed. Matter of fact lube them up good with some penetrating oil like PB Blaster first. They can be corroded and snapping one means removing the wheel cylinder to repair. If you like, a neat way to do it is get some clear tubing as was mentioned above and slip it over the bleeders. Then dangle the ends into some pop bottles and just let the system bleed via gravity. Keep the master cylinder full. It'll work it's way down the lines slowly but it's effective. You can see bubbles through the tubing. Once they stop you're done.

 

[V6UnderPressure]

Originally posted by gofstbuick
Think of the brake reservoirs as two separate units. The larger cavity closest to the passenger side fender well is for power assist (PM) and the two smaller resevoirs (closest to the drivers side fender well) is for brake hydraulics. If you empty the PM reservoir, you can bleed the brake system (with the ignition off) just like a manual brake system. The fluid from the PM side goes all over the place (when you press on the brake pedal), because of the accumulator acting on the power assist system. So empty it and bleed your brake system. You can purchase a master cylinder bleed kit from NAPA. Disconnect the brake lines and connect the master cylinder bleed kit, with the hose dipped into the master cylinder reservoirs (closest to the drivers side) filled with brake fluid. Get into the car and press on the pedal until you don't see any bubbles in the master cylinder. Hook the mastercylinder brake lines up and bleed the lines at the combination valve. Finally bleed the wheel cylinders and calipers. Watch the fluid levels. Or you could even gravity bleed the wheel cylinders and calipers. Again, watch the fluid levels. Once you've completed bleeding the brake side, then add fluid to the PM reservoir. Turn the ignition on and watch the fluid level on the PM reservoir. There are two ports at the bottom of the PM reservoir and the front port is suction. Make sure the front port always stays immersed in brake fluid (once the ignition is on). the PM motor should stop cycling in less than 20 seconds. If it runs for more than 20seconds, turn the ignition off. Then you'll need to bleed the PM side. This is accomplished by loosening the hose beneath the accumulator until fluid flows out (DON'T COMPLETELY REMOVE THE HOSE, ACCUMULATOR OR PRESSURE SWITCH, AS ALL ITEMS ARE UNDER EXTREME PRESSURE-700PSI OR MORE). Then tighten line and turn ignition on again and the motor should stop cycling in less than 20 seconds.

ok, all that brake line disconnecting seems confusing. You cant just suck out the fluid on the pm side, then just bleed the brakes one by one rear to front? do the brakes HAVE to be disconnected at the combination valve/master cylinder? Sorry to rise this thread from the dead again guys.

Scott

 

[gofstbuick]

Originally posted by Scott4DMny
ok, all that brake line disconnecting seems confusing. You cant just suck out the fluid on the pm side, then just bleed the brakes one by one rear to front? do the brakes HAVE to be disconnected at the combination valve/master cylinder? Sorry to rise this thread from the dead again guys.

Scott

Lets sort out the lines issue first. From front of master cylinder to rear, the front brake line supplies hydraulic pressure to the rear brakes, the middle line supplies pressure the the front brakes and the rear line (with the hose going over the top of the master cylinder body) is the feed line (to the accumulator) for the power master assist (I think, but would have to look at a diagram). If you have rebuilt the master cylinder, you'll have to bench bleed it, before bleeding the bleeding the brakes. NAPA sell a bench bleed kit, that will allow you to hook plastic fittings and hose to the front and middle port of the master cylinder (MC). You can even do it with the MC attached to the vehicle. Hook up th bleed kit and pump the pedal (ignition off) until there are no more bubbles in the fluid, then hook the brake lines up). The next step is to get the air out of the combination (proportioning) valve. Loosen the other end of the MC lines going to the combo valve and press on the pedal until only fluid comes out of the line (may need assistance) and close the line with the pedal on the floor. Then bleed at the wheel cylinders and calipers. Finally add fluid to the PM reservoir and follow the instructions above. If you need additional explanation, email me and we can discuss through email or I can even shoot you a phone number so we can talk.

 

[gofstbuick]

Scott,
sent you PM

 

[Sal Lubrano]

Is there anyway to bleed the PM without the bench bleeder kit? I just changed my pm and don't have the kit. Does the proportion valve have to be bled as well or is it accomplished as the wheel are done?
Sal

 

[acoen]

Yeah they're recessed. Matter of fact lube them up good with some penetrating oil like PB Blaster first. They can be corroded and snapping one means removing the wheel cylinder to repair. If you like, a neat way to do it is get some clear tubing as was mentioned above and slip it over the bleeders. Then dangle the ends into some pop bottles and just let the system bleed via gravity. Keep the master cylinder full. It'll work it's way down the lines slowly but it's effective. You can see bubbles through the tubing. Once they stop you're done.

I noticed the same thing, so that is why people are gravity bleeding their rear brakes. Can you loosen the bleed valve with a socket wrench? How long does it take to gravity bleed. Can you do all corners at one time?