Brake bleeding question

[pynacl]

Working on bleeding my standard brakes using a Schwaben power bleeder and RBF600 and seeing some weird results. To set the stage I did these steps:

- siphoned out what was in the brake reservoir
- filled directly with RBF600 (~1L)
- filled the power bleeder with about 1L and pumped to 15psi.

When I crack the bleeder valve on the rear passenger side fluid comes out, but very slowly. Not enough to fill a 1/4" hose (I tested and all 4 corners do this). As a sanity check, I disconnected the bleeder and had a helper push and hold the brake pedal down while I cracked the bleeder and fluid came out much faster for a few seconds and then stopped once it reached the floor (pedal was not lifted until bleeder valve was re-tightened).

Do I need to have some patience? Do I need to bleed the ABS system with INPA? Is the slow fluid flow normal?

[dl.m3]

Pressure bleeders will always pump fluid out slower than the pedal.

When you stomp the brake pedal you're generating several hundred PSIs of hydraulic pressure. Your bleeder generates 15 psi. Just be patient!

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[eacmen]

Pressure bleed is slow. The fluid reservoir cannot hold the same amount of pressure as the system downstream of the master cylinder (1000-2000 psi).

If you have access to a helper the pump the pedal method will yield a better bleed than the pressure bleed.

[pynacl]

Awesome, thanks for the input guys! Assuming since the reservoir never went dry, the slow flow is just normal with 15psi. First time DIY'ing, so always worth double checking when it comes to brakes eh?

[Tbonem3]

Do you have the ability to open abs while bleeding? I would recommend. if not, you can invoke abs while driving, then bleed each corner again, if you have fluid to spare.

I would also bump up the PSI a bit. I use 15-16 and it flows pretty well, but maybe bump it up to 17? IDK, if the flow doesn't go faster, then don't bother.

[Arith2]

Put the bleeder at 2 bar. That's pretty much the intended bleeding pressure. Just don't exceed it as per the repair instructions. To drain the entire system, it will take around 1.5L and about a good 10 minutes depending on flow rate. I don't like siphoning and filling before the pressure bleed because the old fluid always mixes with the new. It's better to just push the old fluid out under pressure. Then there is no mixing. RBF600 is great brake fluid however it will not last as long as OE fluid so just keep that in mind. Bleeding the ABS more often would be a good idea.

[eacmen]

Put the bleeder at 2 bar. That's pretty much the intended bleeding pressure. Just don't exceed it as per the repair instructions. To drain the entire system, it will take around 1.5L and about a good 10 minutes depending on flow rate. I don't like siphoning and filling before the pressure bleed because the old fluid always mixes with the new. It's better to just push the old fluid out under pressure. Then there is no mixing. RBF600 is great brake fluid however it will not last as long as OE fluid so just keep that in mind. Bleeding the ABS more often would be a good idea.

+1 i also bleed at 2 bar

[Estoril]

If using the brake pedal, put a piece of 2x4 under it to keep from flooring it during the down stroke.

[bigjae46]

If you hit the floor, probably won't get any air into the system. If you release the pedal at all with the bleeder valve open, you will get air into the caliper which isn't the end of the world.

If you are activating the ABS, you will need to bleed clean fluid through the pump on all 4 lines. Activate the ABS and then bleed all 4 corners again.

If you are just doing a regular brake bleed for the track every 6 months, just need to bleed out what's in and near the caliper unless you boiled the fluid. I use 1 bottle of Motul for routine brake bleeds

[eacmen]

If you hit the floor, probably won't get any air into the system. If you release the pedal at all with the bleeder valve open, you will get air into the caliper which isn't the end of the world.

If you are activating the ABS, you will need to bleed clean fluid through the pump on all 4 lines. Activate the ABS and then bleed all 4 corners again.

If you are just doing a regular brake bleed for the track every 6 months, just need to bleed out what's in and near the caliper unless you boiled the fluid. I use 1 bottle of Motul for routine brake bleeds

Agreed. In an older master cylinder you want to avoid putting the pedal to the floor as there may be corrosion near the edges of travel that may hurt the seal. If there is suspected air in the master then you have no choice, but if just bleeding the calipers then there is no reason to push the pedal all the way to the floor.

[bigjae46]

Agreed. In an older master cylinder you want to avoid putting the pedal to the floor as there may be corrosion near the edges of travel that may hurt the seal. If there is suspected air in the master then you have no choice, but if just bleeding the calipers then there is no reason to push the pedal all the way to the floor.

Yup.

If I opened the brake fluid system then I do the 2 person method. For maintenance, pressure bleeder.

When I bleed the clutch, always 2 person. There really is no other way unless you can lock the clutch pedal down.


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[M3GA]

I use a 1 man bleeder bottle for all four corners including clutch, easiest bleed process.

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[eacmen]

I use a 1 man bleeder bottle for all four corners including clutch, easiest bleed process.

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I have also used these and they work suprisingly well. But you cant crack the bleeder open too much. Want the smallest opening possible.

Also need to grease around the threads to prevent air from going past the bleeder threads.

[grannyknot]

Speedbleeders, if you are a one man operation. I put them on all my cars.