Presure Bleeding Question

[Dreamer52]

Hi

I just replaced my '89 Targa brake calipers with calipers from PMB. This is the first time I've used my Motive pressure bleeder. I blocked off the return line & checked for leaks and it held 10 lbs fine. I added fluid & pumped to 15 lbs and bled all 4 calipers. Still no pedal. Reading Bentley it says while pressure bleeding you should still have someone pump brakes. I thought with a pressure bleeder you don't need the 2nd person. I checked the calipers and they are dry, no leaks. Any ideas?

Thanks

Carl

[DRACO A5OG]

Make sure the lines are not blocked. Remove line and pump the pedal/

Remember to place a block of wood behind the pedal as not to damage the MC.

You did depress the pedal 2" to keep air from getting back into the MC, yes?

[Dreamer52]

Thanks Draco

Yep, had the pedal depressed while changing everything out. Then the first time I bled the system I forgot to let the pedal out so I let it out & bled the system again. Is there something else I should check?

[DRACO A5OG]

Try the two man bleed first then pressure bleed

[Dreamer52]

Thx, I'll givethat a ty

[yelcab1]

Make sure you have the bleeder valves at the top. I can't tell you how many times that have happened to the best of us.

[Ronnie's.930]

I've never had to do any pedal pumping (ha ha, I said "pumping") before, during, or after pressure bleeding (even after having systems completely apart and every component full of air), but I don't use a pump bottle, rather I hook an air hose to the master res. vent nipple and pressurize it with 15-17 psi from an air compressor. On vehicles that don't have a vent nipple, I then add a hose barb to the res. cap.

[Dreamer52]

Did a manual bleed and pedal firmed up but still spongy. Will try another power bleed tomorrow. And the bleeder valves are on top. Tried to do a clutch bleed, can hook up the tube but can't get a wrench on the bleeder. Anyone know what size the clutch bleeder valve is-same as the other valves?

[rusnak]

Originally Posted by Ronnie's.930

I've never had to do any pedal pumping (ha ha, I said "pumping") before, during, or after pressure bleeding (even after having systems completely apart and every component full of air), but I don't use a pump bottle, rather I hook an air hose to the master res. vent nipple and pressurize it with 15-17 psi from an air compressor. On vehicles that don't have a vent nipple, I then add a hose barb to the res. cap.

Ha, you said "nipple".

When you bleed the calipers, make sure that the bleed hose from the caliper is submerged into old brake fluid. I use an old maynaisse jar with a hole punched in the lid.

The Motive will work most of the time. When you use it, you don't have to pump the pedal. Pedal bleeding will move a LOT MORE fluid than the Motive, and will push all of the air out of the iines really fast. If the Motive fails to get the air out, then go to a two man system. The person in the car pumps the pedal around 10 times or until you get pressure, then hold the pedal down like a panic stop to open the brake proportioning valve. Use a brick under the brake pedal. The person at the caliper opens and then shuts the bleed valve quickly. You'll see a lot of air shoot out of the caliper. After a few times, the air will be out and you'll have a firm pedal. Do this for each caliper.

[Ronnie's.930]

Originally Posted by rusnak

Ha, you said "nipple".

One of the best words in the English (or any other, for that matter) language, for sure!!!

[DRACO A5OG]

Originally Posted by Dreamer52

Did a manual bleed and pedal firmed up but still spongy. Will try another power bleed tomorrow. And the bleeder valves are on top. Tried to do a clutch bleed, can hook up the tube but can't get a wrench on the bleeder. Anyone know what size the clutch bleeder valve is-same as the other valves?

Good now the pressure bleeder should work.

As for the clutch bleeder valve, order one because it is extremely tight and may round off. It is 8MM I think. definitely smaller than the calipers. Oh yeah a real PITA to boot.

[Dreamer52]

So with manual bleeding I was having someone pump brakes then hold, then I open bleeder, pedal goes to floor, then I close valve, then pedal is let go. Sorry for such a simple question-that's how I remember doing it in the past on other cars. Should I shut off the valve before the pedal is fully depressed? I'll put a piece of wood behind the pedal tomorrow if I do the manual. As for the power bleed after I've done a 4 wheels there is still pressure left. I've been turning the top of the Motive unit to relieve pressure then removing excess fluid with a baster. Is that correct?

[azhodge]

buy yourself a cheap wrench from Lowes for the clutch. I forgot the size 7mm??? cut it in halve and use the box end. use the pressure bleeder. you have to find a way to get the hose to stay on the nipple. but even if it keeps falling off the positive pressure will bleed the slave, and the mess is just part of life. I got the nipple hose to stay on using one of those bleed lines with the slip washer that holds the clamp on. run lots of fluid through the slave. one of the worst jobs I can think of for a guy with big hands.

[rusnak]

Originally Posted by Dreamer52

So with manual bleeding I was having someone pump brakes then hold, then I open bleeder, pedal goes to floor, then I close valve, then pedal is let go. Sorry for such a simple question-that's how I remember doing it in the past on other cars.

1. Should I shut off the valve before the pedal is fully depressed?

2. I'll put a piece of wood behind the pedal tomorrow if I do the manual.

As for the power bleed after I've done a 4 wheels there is still pressure left.

3. I've been turning the top of the Motive unit to relieve pressure then removing excess fluid with a baster. Is that correct?

1. Yes
2. Good. You don't want the pedal to go beyond it's normal range of travel.
3. The fluid should be sucked back into the bleeder tank. Really you should not have to use a baster.

[RSTarga]

I don't put fluid in the motive. Just make sure and keep fluid in the reservoir. I only use 10lbs. Motive is the best tool ever!
Pinch breather on the reservoir.
Is the fluid level on the reservoir dropping when you one the bleeder? Only use flare tools on the nipples.

[rusnak]

The Craftsman flare wrench will round off the bleeder. I use my biggest crescent wrench and tighten it down.

[shrtshck]

The slave bleed valve is 7 mm

[porche]

ALWAYS use a 6 point box wrench or deep socket to crack the bleeders open first.
After you've cracked them open you can put the hose on the nipple and use an open end wrench to open and close the bleeder as needed.
Use the 6 point to snug things up when you're done if required and you should never have a problem.

[Dreamer52]

Back home now & just pulled wheels for more bleeding fun. I spun the rears and you can hear a slight rubbing of pads but on front it spins freely & pads aren't touching rotor. You can tell the fronts have made contact before. Is this just a red herring or does it mean something?

[rusnak]

It sounds as thought the front caliper pistons may be retracted too far. That would leave a gap between the pad and rotor, and would cause your pedal to have to travel too far before contact is made. If the pedal is mushy, then you have air. If the pedal just goes too far toward the floor, then you need to push the pistons outward.