Brake Bleed Question

[duperdog]

Family is out of town this weekend so looking to tackle a few projects on the M3 uninterrupted. I am putting in SS Brake lines and plan to bleed the brakes and clutch after with a pressure bleeder, but was curious about the last few steps following Madrussian's DIY. The last 2 steps call for "old school" bleeding by having someone pumping the brake pedal while opening the bleed valve once more for each corner. Since I won't have anyone around, is this step just extra precaution or really necessary? I can always wait for the final steps for when everyone returns and do the old "ok, now press and hold..." which is always a fun time, but was hoping to knock it all out by myself. When doing my other vehicles, I use the pressure bleeder only and have not had any issues with air,

Thanks for your advice.

[bmwfnatic]

I work alone on my cars most of the time and have never had any issues with using the pressure bleeder instead of the 2 man method.

[Cubieman]

Pressure bleeder is fine, just a heads up that clutch slave cylinder can be a bitch to fully bleed sometimes.

I bled the slave cylinder the same way I bled the brakes, some do remove it and use a U bolt of something similar to depress the plunger while bleeding it out and/or tap on it with the bleeder upright to release more air.

[duperdog]

Ok, thanks for the responses! I didn't have any issues with the clutch slave cylinder in the past, but good to know.

[heinzboehmer]

Ok, thanks for the responses! I didn't have any issues with the clutch slave cylinder in the past, but good to know.

It only really becomes an issue if you let air into it.

In case that happens to you (or anyone else), this is the best way to bleed it IMO: https://www.youtube.com/watch?v=xl5WQCgUjDc

[Tbonem3]

Clutch is self bleeding. Make sure to buy pressure bleeder meant for euro cars, or get the euro attachment. Make sure the oring is centered, and the cap screws on evenly. I find I have to go over 10psi to really get good movement.

[Tbonem3]

You can just pump the clutch if there's a little air. For installation, the U bolt trick is nice to start out with almost no air.

[heinzboehmer]

You can just pump the clutch if there's a little air. For installation, the U bolt trick is nice to start out with almost no air.

When I fully drained and refilled my system, I was unable to get all the air out of the slave cylinder initially. Tried with both the pressure bleeder and just by pumping the clutch. Technique linked above is what ended up getting the air out.

For most regular situations, the clutch should self bleed, but if you get air into the slave cylinder, you might need to do the reverse bleed thing.

[eacmen]

I haven't had good luck with the pressure bleeders getting all the air out but they are still useful part of the process. This is my new process which is probably too pedantic for some folks but works for me:

1. Engine off, pump brakes to get vacuum out of booster.
2. Measure pedal distance slop before pedal starts to engage. Write it down
3. Perform brake work.
4. Pressure bleed each caliper.
5. Measure slop and compare, if same or close then you're done. If not proceed.
6. Hook up bleed bottle with one way valve in it ($10 at HF or amazon)
7. Top up MC. Hook up one way bleeder bottle, crack the bleeder, and pump the pedal a few times. Close bleeder. Repeat for each caliper.
8. Generally at this step I'm good to go. If not i'll drive it on a slipper surface and get ABS to engage and repeat the whole process again.

The price went up on the one I use:

Allstar Performance ALL11017 Bleeder Bottle with Magnet and Check Valve , White https://a.co/d/esEvNTq


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[bigjae46]

The old school method is better but you'll be fine with a pressure or vacuum bleeder. I would use the two man if you have a lot of air in the system. Same applies to the clutch, the only difference is you keep the clutch pedal to the floor which opens the master. Otherwise you'll never get the air out. Should bleed in a 15-20 seconds at most.

[cobra]

I installed Speed Bleeders and can do a brake bleed super quick with no helper. It's just a little check valve in the bleeder valve.

[Casa de Mesa]

If you're doing the old skool method for bleeding hydraulic clutches in general, I have found that pumping the clutch pedal 3x times before opening the bleeder seems to help.

[Estoril]

If you're doing the old skool method for bleeding hydraulic clutches in general, I have found that pumping the clutch pedal 3x times before opening the bleeder seems to help.

If you use the pedal method, place a piece of 2X4 under the pedal so it doesn't travel all the way to the floor.

[Casa de Mesa]

For what purpose? To prevent blowing debris into the line?

[eacmen]

If the MC is new there is no reason not to push the pedal to the floor. If the MC has alot of miles in it and the brake fluid change interval is not known the MC could have developed rust and corrosion in the unused part of the bore and damage the seal at full pedal travel.


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