Clutch hydraulics advice / experiences

[Blackie 510]

Hi all,

I couldn't see a clutch / gearbox section so hope this is the right place.

Car is an E36 with Getrag

My car has been sitting for close to a year as I was doing an engine swap. Once the engine was back in I refitted the clutch slave into the gearbox and tried the clutch pedal. The pedal was rock hard. I checked the clutch slave and all looked good, so tried again. Eventually their was a bang and the pedal broke loose going right to the floor. I removed the slave and found it had blown apart and shot brake fluid everywhere.

Fast forward and I now have a different clutch and new slave cylinder. I've been trying to bleed the slave like I would on any car but it doesn't appear to be working. I get someone to hold down the pedal, release the fluid, close the bleeder, return pedal to normal, pump again and repeat. The pedal is very easy to press and doesn't feel like it's connected to/operating anything mechanical i.e. the clutch. When under the car the clutch slave hose moves but I can't hear any sign of the fork moving. My next step is to remove the slave while someone presses the pedal and observe if it's moving.

I'm starting to think the hard pedal was actually the master cylinder and the blown slave just the result of the sudden pressure surge when it broke free. Does anyone have any thoughts on any of the above or experience with this issue?

Cheers

[Eagle 1662]

If you are sure there is no air in the system then its likely the master.

Ive always had to remove the slave, rotate it with the bleeder is facing upwards then push in the rod while the bleed screw is open to get out the trapped air. A lot easier with pressure bleeder. 

 

[Blackie 510]

51 minutes ago, Eagle said:

If you are sure there is no air in the system then its likely the master.

Ive always had to remove the slave, rotate it with the bleeder is facing upwards then push in the rod while the bleed screw is open to get out the trapped air. A lot easier with pressure bleeder. 

 

Thanks, will give that method a try, although it sounds difficult to achieve under the car - like needing 3 pairs of hands!

[B.M.W Ltd 950]

1 hour ago, Eagle said:

 A lot easier with pressure bleeder. 

 

A vacuum bleeder is much safer and you won't run the risk of the work area or other cars being sprayed with brake fluid and it can be done by one person

Edited September 2, 2019 by B.M.W Ltd

[Eagle 1662]

2 hours ago, Blackie said:

Thanks, will give that method a try, although it sounds difficult to achieve under the car - like needing 3 pairs of hands!

I believe the proper BMW tool is a metal plate which you bolt the slave onto and wind in the bolts compressing the rod. You can do it yourself with a one man bleeder system and pushing the rod by hand or against the bellhousing etc depending on how strong you are. Helps to have some keep watch the fluid level though. 

1 hour ago, B.M.W Ltd said:

A vacuum bleeder is much safer and you won't run the risk of the work area or other cars being sprayed with brake fluid and it can be done by one person

Are you are talking about too much pressure pushing the cylinder out the bore? I suppose you could always reverse bleed with a decent syringe

[B.M.W Ltd 950]

12 minutes ago, Eagle said:

 

Are you are talking about too much pressure pushing the cylinder out the bore? I suppose you could always reverse bleed with a decent syringe

No.. some of the screw on type pressure bleeders that fit on the reservoir caps

[Eagle 1662]

Oh right. Never had any trouble with my motive one but i only use it for pressurizing the reservoir so don't actual fill it up. 

[Blackie 510]

Okay bleeded again by pushing the push rod in by hand with the bleeder on top. No difference. Clutch master next.

[Blackie 510]

So, still fighting this.

New clutch master and slave - both quality parts.

Can't get a pedal that feels like it is doing anything mechanical. Have tried pedal bleeding, inverted slave bleeding and reverse bleeding.

Starting to wonder if the 318 clutch I fitted somehow requires more leverage than the clutch slave can supply?

So frustrating.

[Secniv 182]

On 1/26/2020 at 4:38 PM, Blackie said:

So, still fighting this.

New clutch master and slave - both quality parts.

Can't get a pedal that feels like it is doing anything mechanical. Have tried pedal bleeding, inverted slave bleeding and reverse bleeding.

Starting to wonder if the 318 clutch I fitted somehow requires more leverage than the clutch slave can supply?

So frustrating.

Did you figure this out? 

Ive followed this process and looks like I’ve got all the air out but pedal doesn’t spring back.