Clutch issue, what to check first?

[Mark92131]

The clutch on my Cabriolet has been acting up on the last few outings and I am looking for some direction based on the symptoms.  It is a 245 OD Getrag 5 speed from a 320i.  It was installed with a new clutch, pressure plate, and throw-out bearing for a 228mm flywheel and a new clutch master cylinder, slave and IE longer clutch line for the 5 speed conversion.  The fluid is topped up and no leaks have been detected.  For the most part the car has been shifting correctly since the install, but lately I have been experiencing an alarming condition.

 

When I am on any kind of incline, slipping the clutch is very difficult.  As I start to let the clutch out and it starts to engage, I press the clutch in and it continues to engage lurching the car forward even with the clutch pedal on the floor.  To avoid hitting the car in front of me I have had to slam on the brake and kill the motor.  When this symptom is happening, I can't get the car out of 1st to neutral even with the clutch pedal fully on the floor.  This symptom seems to be related to the slow operation of the clutch, because it shifts OK between gears with quick shifts on a flat surface.  I am thinking that either the master or the slave is slowly losing fluid pressure and the clutch begins to engage even with the clutch pedal fully depressed, or there is air in the system that is causing this problem.

 

My first thought is to bleed the system and see if it helps, but I am more inclined to think I have either a bad master or slave cylinder.  Has anyone had this problem and what was the cause?

 

Thanks,

 

 

Mark92131

[HBChris]

I would try bleeding first, I had this same issue with a new and now only 1 1/2 year old parts on my 2800.  It was the slave cylinder, but, on the early round slaves you can peel the boot back where I found fluid.  Don't think that's the case with the 245 slave.  Crazy that they can go bad so quickly.

[Son of Marty]

I think you have a pretty good idea on what is likely happening as HBChris said try bleeding first and if thats not it it's got to be a internal leak on one of the cylinders.  

[Hans]

The bleed screw should point down.

[Preyupy]

If you are not loosing fluid from the reservoir you most likely have a master cylinder that is starting to fail.  When the slave cylinder fails you usually have brake fluid dripping from the bell housing and the level in the reservoir keeps dropping.  Are you able to pump it up once you have stalled the engine? 

[Mark92131]

18 hours ago, Preyupy said:

Are you able to pump it up once you have stalled the engine?

 

Yes, once the engine is stalled, I can take it out of gear, start the engine and time it correctly to get it into first and let out the clutch before it tries to do it on its own.  Not a lot of fun on a hill with cars behind you because you need a clear path to launch.

 

I will try bleeding the clutch this weekend and will probably order a new clutch master as a first step in the process of correcting the cause of this issue.

 

Thanks,

 

 

Mark92131

[TobyB]

If you're not losing fluid, it's a leaking master...

 

gay- roon- teed!

 

t

 

[Rob Zaeos]

@Mark92131 did you ever find the solution to this. Having the exact same issue.

Thanks

[John76]

Rob,

An easy way to tell if the master is leaking is to check the "puddle" box for brake fluid. Stick a long cotton swab between the slits in the carpet for the clutch and brake pedals and probe the bottom. If it's wet ... it's the master. No sign of fluid ... it's the slave. 

[Mark92131]

10 hours ago, Rob Zaeos said:

did you ever find the solution to this. Having the exact same issue.

Thanks

 

Replaced the master and slave and this resolved the issue.  

 

Mark92131

[Rob Zaeos]

9 hours ago, John76 said:

Rob,

An easy way to tell if the master is leaking is to check the "puddle" box for brake fluid. Stick a long cotton swab between the slits in the carpet for the clutch and brake pedals and probe the bottom. If it's wet ... it's the master. No sign of fluid ... it's the slave. 

Thanks, Its a long store but here is everything that has been done, New master, slave, clutch, TO bearing, Pivot, Pilot bearing, shifter plate and seals. I suspect the issue is with the 228mm flywheel. The mechanic used a 320i TOB instead of the 323i TOB. I'm assuming this is just short enough that if the slave isn't fully extended then it drags.

 

My other thought is the slave isn't completely bled (even though i've done it several times with various methods i.e. gravity, reverse, vacuum) The thing i notice is when i crack the bleeder valve fluid comes out through the threads as well as the hose attached which leads me to believe that air is getting in through the threads. My next plan is to remove the slave and hold it up above the master with the nipple at the highest point and bleed that way. This will be the last attempt before returning it to the mechanic to try to install the 323i TOB. (unless someone thinks i could just extend the slave push rod and accomplish a fix)

 

I've been able to recreate the issue consistently. It only happens when i partially let out the clutch and then try to press it back in. The clutch drags and i can't take the trans out of gear. I then have to shut off the car to take it out of gear.

[Son of Marty]

2 hours ago, Rob Zaeos said:

My other thought is the slave isn't completely bled

If it's a 5 speed is the clutch slave bleeder pointed down? And it does sound like you might have the 215mm throw out bearing (the shorter of the two) installed.

[Rob Zaeos]

6 minutes ago, Son of Marty said:

If it's a 5 speed is the clutch slave bleeder pointed down? And it does sound like you might have the 215mm throw out bearing (the shorter of the two) installed.

Yep, nipple pointed down when installed and bled. It has the shorter bearing from teh 320i, but the mechanic has used this particular combination successfully before and to me it makes sense this would cause these symptoms but i just want to eliminate all possibilities before pulling the trans again.