[hdrewh]

Trying to use my Motive pressure bleeder for the first time, not sure what I'm doing wrong but pressure just doesn't seem to be making it to through the lines.

I replaced rear rotors and pads so figure while I'm in there, let me bleed and at least partially flush the system.

Put a liter of fluid in, pumped it up to 20psi (I know most DIYs say 10-15 but factory service manual says 29psi max), I crack the bleed nipple on the rear passenger side, fluid comes out but just barely. Same for rear driver.

Maybe relevant - how important is it to have the car level when doing this? Both rears are up on jacks, front is on the ground. I know I'm working against gravity but with the pressure from the Motive should it matter?

No leaks or any other red flags 'far as I can tell.

Not sure what else to try at this point.
Any advice appreciated.

[montr]

My experience with the Motive pressure bleeder, it will come out slowly.

Did you use the regular DOT-4 brake fluid or the DOT-4 LV? The LV is for "Low-Viscosity". It should come out faster.

[juld0zer]

The rears will bleed slower, even at 2 bar you can bleed both fronts in the time it takes to bleed one rear. Nothing wrong, unless it is very slow like drip drip slow with a half turn?

[hdrewh]

Not even dripping, some fluid comes out but then starts to back up in the tube. Even without the Motive, with a helper stepping on the brake pedal, same thing. I'm clearly missing something stupid/obvious.

[GRUESOM3]

Did you take out the old fluid from the brake fluid tank and top it off with new fluid before starting procedure you might be throwing air into the system.

I always have whole car level , pump to about 20psi and make sure you crack the bleeders open good and usually do a cycle of 2x on each corner at least.

Make sure the motive is in the locked position when you build up pressure and be sure all connections are tight.

Watch motive pressure so it doesn't drop too much

Start with furthest from master cylinder and end with closest, works every time.

[BB_cuda]

Not sure how important this is but i made sure the tube going from bleeder to the master cylinder (MC) cap was full of fluid. There was one bubble i couldn't get out but it somehow stayed stationary as i moved fluid into MC. The rears both bubbled for me early on but i think the connection of the tubes on the back end to the bleed nipples (in my case at least) allows air into the bleeder tube stream. As i messed with the tube connection to the nipple, the air bubbles would disappear and reappear. I got immediate flow on both rear circuits though.

I will get a taste of this again very soon as i had to open the brake lines to lower the rear subframe for sub frame bushings and M3 sway bar switch. I must say, it was weird how the fluid is warmer than room temperature when it leaked after cracking open the connections. I suspect the warm temp is because system is under pressure. I devised 2 plugs to keep upstream leak to a minimum. I bought 2 screws (M10x1.0 pitch) and cut them real short with dremel. I got thin brass washers from Oreilly to serve as crush washers. I used a matching nut on the screws to clean up the threads after using dremel. The trick is to have the nuts screwed all the way up and cut on the screw just a hair down from the nut. Then, clear threads with the nuts. I cranked in the screws with washers on up stream side and they held the fluid pretty well. Maybe a stray drop once every 2 days. The warm fluid thing was still going on when I removed the plugs and reconnected the downstream lines (after sub frame bolted back up on chassis).
Good luck on getting rear nipples to flow.

[juld0zer]

Streams of bubbles while using a pressure bleeder is normal and can be a false alarm. Usually it is caused by air being drawn in through the threads of the bleeder nipple as the constant stream of fluid is passing, being drawn down via gravity especially if you use a long bleed hose. You dont have to prime the pressure bleeder hose. Think of it as an automatic reservoir replenisher. It just pushes out what is inside the reservoir using air or fluid but whatever air was in the hose is never more than the capacity of the reservoir. As long as your reservoir is not completely empty.

No need for any complicates plugs. Borrow a 5th jack stand and erect it against the seat and brake pedal until the pedal is level with the accelerator pedal. Crack a rear bleeder to relieve the pressure, then do your work. With the pedal held down it closes the feed port in the master. You will lose very little fluid and it also cuts down your bleed time.

[BB_cuda]

Juld0zer, thanks for those helpful tips. I saw (Bentley manual) the business about rigging pedal to be held down but didn't have the tool shown in book. I should have found something else (like a scissor jack) to do what you say. I agree with your false alarm bubbles seen in bleeder hose statement. I tried to express same thought above. Almost ready to bleed my rear circuits. Diff going back up in sub frame after diff bushing installation.

OP, did you get rear bleeds flowing yet?

[The Nightman]

First time hearing about keeping the brake pedal down for a pressure bleed. Do you have any more details? I'm willing to try anything that'll make this process faster

[juld0zer]

No need for a scissor jack or the workshop tool. Use a jack stand or if you don't have one spare then get a big piece of wood or a log, slide your seat forward and use the wood to hold the pedal down.

Freedomfries - holding pedal down is solely for preventing (minimising) loss of brake fluid and eliminating risk of an empty fluid reservoir while you have a brake line disconnected.

It really isn't a long process. With the car up on 4 stands, it should take less than 40mins for most people. With all 4 wheels off it is even faster. Pump the thing up to 30psi if you like. But as i said above, even with no rust or dirt in the bleeders, the rears take twice as long as the fronts

[BB_cuda]

I used the power bleeder to get rear brake circuits back in order today. I did notice when i would first start each rear wheel that the initial flow was quite slow. It would then pick up after about a minute. I ran a fair amount of fluid though the system but it was already clean. I had just changed the fluid in October 2016.

[mweisdorfer]

Originally Posted by hdrewh

Trying to use my Motive pressure bleeder for the first time, not sure what I'm doing wrong but pressure just doesn't seem to be making it to through the lines.

I replaced rear rotors and pads so figure while I'm in there, let me bleed and at least partially flush the system.

Put a liter of fluid in, pumped it up to 20psi (I know most DIYs say 10-15 but factory service manual says 29psi max), I crack the bleed nipple on the rear passenger side, fluid comes out but just barely. Same for rear driver.

Maybe relevant - how important is it to have the car level when doing this? Both rears are up on jacks, front is on the ground. I know I'm working against gravity but with the pressure from the Motive should it matter?

No leaks or any other red flags 'far as I can tell.

Not sure what else to try at this point.
Any advice appreciated.

What is the condition of the bleed screws? It's been my experience that they don't last long in the rust belt part of the country.

Even if you are in a non rust belt state, they only last so long anyway. I'd say after 100k replace them. Rust belt state, replace them every 2-3 years.