Help me diagnose my brake/clutch bleeding issues!

[BenM]

So I have a track event coming up this Friday in New Hampshire and went to flush my brake fluid yesterday and have had nothing but problems!

I used a pressure bleeder to flush the 1yr. old ATE Super Blue out (through the RR Line first, then LR, RF, LF) and then replaced the Front Driver's side Brake line hose (the old one was questionable). I then added ATE Typ 200 fluid and bled the system. I accidentally pumped the brakes twice after the pressure bleeder cap was removed before I put the reservoir cap on, and I'm not sure if I introduced air into the system.

I rebleed and get no air coming out of the lines so I thought all was well. Get into the car and the brake pedal has pressure, but sinks to the floor. Clutch pedal has a little pressure, but the engagement point is so finite that it makes driving a chore.

After that I spent hours rebleeding the system at all lines, including the Clutch slave. I even tried to manually bleed it with my dad which didn't work either. I get constant fluid out of all the lines, but both of the damn pedals feel like crap! I know that a sinking pedal usually means Master Cylinder, but the fact that both the brake pedal and clutch pedal can't seem to maintain pressure makes me think there is air trapped somewhere in the system. Here are my thoughts on what the possible problems are:

- Air trapped in the ABS Pump (ABS needs to be cycled and then bled)
- Air trapped in the Master Cylinder (Master Cylinder needs to the bled)
- Master Cylinder seal(s) are torn (would account for brake pedal sinking)

Car is a 1991 318i with an M50TU, E21 booster, E32 750 25mm MC, E36 M3 Front Brakes and E36 M3 Rear Brakes (318ti rotors with 10mm spacers).

I'll be working on it tonight, but any help/advice/guidance would be great!

[hwy84]

Your process doesn't make sense to me -

You said you first flushed out the super blue (what did you flush it out with?)

Then you replaced a line (so you definitely introduced a ton of air)

Then you bled with Typ200 (but what was in there before?)

You say you pumped the pedal after you pulled th pressure bleeder off - was there fluid in the reservoir? If there was no fluid in the res, regardless of whether or not you pumped the brake pedal, you have a ton of air.

So...

Look up the right way to bleed brakes. Maybe you did it right, but your description sounds very suspiciously like you added air in to the system a million different ways.

You want to fill the reservoir, pump (or pressure bleed) only until the res gets down a little, but is still ABOVE the clutch line hole, then refill to the top and bleed some more.

If you have air in the system, it sounds to me like it is in the line you replaced, and in the brake master (since you likely let the res run dry), and in the top of the clutch line (same deal). Getting rid of that much air, that high in the system is going to take a fair amount of brake fluid. Like - at least a full bottle of Typ200. If I was you, I'd go get a cheap big ass bottle of regular old DOT4, bleed like a sumbitch, and then switch over to Type 200 only after I was sure there was no air in there.

If you are pushing your pedal all the way to the floor, you ARE damaging your master cylinder seals. If you wreck 'em, you'll have a pedal that feels firm and normal, but sinks after you build pressure. If this is the case - you need a new master.

Read up on the process, take your time, flush a TON of fluid through, and hopefully you are just all full of air.

[BenM]

Your process doesn't make sense to me -

You said you first flushed out the super blue (what did you flush it out with?)

Then you replaced a line (so you definitely introduced a ton of air)

Then you bled with Typ200 (but what was in there before?)

You say you pumped the pedal after you pulled th pressure bleeder off - was there fluid in the reservoir? If there was no fluid in the res, regardless of whether or not you pumped the brake pedal, you have a ton of air.

So...

Look up the right way to bleed brakes. Maybe you did it right, but your description sounds very suspiciously like you added air in to the system a million different ways.

You want to fill the reservoir, pump (or pressure bleed) only until the res gets down a little, but is still ABOVE the clutch line hole, then refill to the top and bleed some more.

If you have air in the system, it sounds to me like it is in the line you replaced, and in the brake master (since you likely let the res run dry), and in the top of the clutch line (same deal). Getting rid of that much air, that high in the system is going to take a fair amount of brake fluid. Like - at least a full bottle of Typ200. If I was you, I'd go get a cheap big ass bottle of regular old DOT4, bleed like a sumbitch, and then switch over to Type 200 only after I was sure there was no air in there.

If you are pushing your pedal all the way to the floor, you ARE damaging your master cylinder seals. If you wreck 'em, you'll have a pedal that feels firm and normal, but sinks after you build pressure. If this is the case - you need a new master.

Read up on the process, take your time, flush a TON of fluid through, and hopefully you are just all full of air.

I guess I just used air from the pressure bleeder when I flushed the super blue out of it. I've done it successfully before, but sounds like that is a big no no and feels like my brake master cylinder has shit the bed from what you describe. When I pumped the brakes, the lines and reservoir were full of Typ 200.

I'm going to first try and bleed it right at the master cylinder, then cycling the abs, and then bleed to see if that helps.

Guess my main question is would a bad brake master cylinder also be the cause for a poor clutch engagement point along with spongy brakes?

[hwy84]

I guess I just used air from the pressure bleeder when I flushed the super blue out of it.

Guess my main question is would a bad brake master cylinder also be the cause for a poor clutch engagement point along with spongy brakes?

If you pumped all the super blue out of the system with just air, you will have some serious bleeding to do to remove the air from the system. You haven't broken anything, but you will have a lot of bubbles of air trapped in there. Bleed and bleed and bleed.

A bad brake master cylinder will have no affect on clutch engagement. The only shared component between brakes and clutch is the fluid reservoir.

[BenM]

If you pumped all the super blue out of the system with just air, you will have some serious bleeding to do to remove the air from the system. You haven't broken anything, but you will have a lot of bubbles of air trapped in there. Bleed and bleed and bleed.

A bad brake master cylinder will have no affect on clutch engagement. The only shared component between brakes and clutch is the fluid reservoir.

Ok that's some reassurance then lol. I will take your advice and flush the system with some cheap DOT4 for the time being and then add the Typ 200 in to displace the cheap stuff.

Thank you for the input!

[BenM]

I just wanted to say I fixed the issue about 12hrs. before my track day last Thursday night.

Ended up replacing the Master Cylinder and wasting 2 more pints of ATE Typ200 until finally having an epiphany. When I stuck the M3 rear calipers on I actually put them on backwards (Left Rear on Right Rear and Right Rear on Left Rear) so the E30 brake lines would fit, but consequentially putting the bleeder screws below the lines leaving them useless and unable to be properly bled.

Put the Ti rear calipers back on, bled them very little and immediately had a nice properly stiff pedal!