Shifting after the clutch install

Originally Posted by bigjae1976

any updates???

not yet - I should have something to post about in a week or so

i would try bleeding like mentioned in the video that was posted on this thread, push fluid in from the slave
you in the hartford area, could probally stop by and give you a hand if your close

Originally Posted by bmc911

i would try bleeding like mentioned in the video that was posted on this thread, push fluid in from the slave

Originally Posted by cyberkaa

Starts at 3:10.

Maybe this^ works well if you unplug/replace the slave cylinder, but I'd wonder what's getting pushed back up into the hydraulic system with this method.

Also note that, on a 330, there's what looks like a bubble baffle (crazystraw metal tubing) mounted right below the slave cylinder- it's pretty unlikely any bubbles would get past even the first 2 turns of that and up into the hydraulic hose- so any air that does get in is usually gonna be trapped fairly close to the bleed screw. The slave cylinder in the video doesn't have a baffle.

Originally Posted by McSpeed

Maybe this^ works well if you unplug/replace the slave cylinder, but I'd wonder what's getting pushed back up into the hydraulic system with this method.

Also note that, on a 330, there's what looks like a bubble baffle (crazystraw metal tubing) mounted right below the slave cylinder- it's pretty unlikely any bubbles would get past even the first 2 turns of that and up in the hydraulic hose- so any air that does get in is usually gonna be trapped fairly close to the bleed screw. The slave cylinder in the video doesn't have a baffle.

The exit will be the master cylinder low pressure hose, which would be detached from the brake reservoir. If you were bleeding the other way, the equivalent question would be, "what's getting pushed down into the hydraulic system?" The answer is the same in both directions.

The looped metal tubing is present on other models as well. If you're expecting those bubbles to remain there when fluid is pumped up through the system, they would remain there when fluid is pushed down through the system as well. Again, doesn't make sense to point that out when talking about only one direction.

Originally Posted by cyberkaa

The exit will be the master cylinder low pressure hose, which would be detached from the brake reservoir. If you were bleeding the other way, the equivalent question would be, "what's getting pushed down into the hydraulic system?" The answer is the same in both directions.

Doesn't junk tend to find its way into the brake fluid near the pistons, rather than the reservoir, over time?

Originally Posted by cyberkaa

The looped metal tubing is present on other models as well. If you're expecting those bubbles to remain there when fluid is pumped up through the system, they would remain there when fluid is pushed down through the system as well. Again, doesn't make sense to point that out when talking about only one direction.

I'm just saying that air, if it's going to come in, is going to come in through the piston end and [if my bubble baffle theory is correct] hang out pretty close to the bleeder valve, so you might as well bleed the normal direction since the air will have to travel way less distance [plus I'd think it's cleaner per above].

Also, from what I've seen in my hose, the bubbles have no problem moving when a pressure bleeder is involved


Update: turns out the shiftng issue wasn't related to the slave cylinder...details forthcoming

Originally Posted by McSpeed

Doesn't junk tend to find its way into the brake fluid near the pistons, rather than the reservoir, over time?



I'm just saying that air, if it's going to come in, is going to come in through the piston end and [if my bubble baffle theory is correct] hang out pretty close to the bleeder valve, so you might as well bleed the normal direction since the air will have to travel way less distance [plus I'd think it's cleaner per above].

Also, from what I've seen in my hose, the bubbles have no problem moving when a pressure bleeder is involved


Update: turns out the shiftng issue wasn't related to the slave cylinder...details forthcoming

The difference being...? The "junk" will find its way out of the system either way when it's bled.

Bleeding upwards is similar to pressure bleeding downwards, but with the pressure applied in the other direction. Just as you said, the bubbles have no problem moving when pressure is involved.

I'm not saying that one method is superior to the other in all instances; there are times when I'd switch between the two. E.g., when bleeding the original slave cylinder after a clutch job (assuming it wasn't detached), I'd bleed the system downwards because any air that entered the system would most likely have entered from the sealing sleeve and accumulated in the slave cylinder. It would save time. I'd prefer bleeding a dry or hard-to-bleed system upwards, though.

Originally Posted by cyberkaa

The difference being...?

If you push fluid in from the bottom you're pushing the most contaminated fluid/debris up into the reservoir, no? That's all I'm saying might be a reason I'd choose the usual direction.

I agree though, that if you unplug the slave cylinder entirely or replace it, there'll be a LOT of air in there, so the upward method is possibly better there.

Originally Posted by McSpeed

If you push fluid in from the bottom you're pushing the most contaminated fluid/debris up into the reservoir, no? That's all I'm saying might be a reason I'd choose the usual direction.

I agree though, that if you unplug the slave cylinder entirely or replace it, there'll be a LOT of air in there, so the upward method is possibly better there.

You'd disconnect the low pressure hose from the reservoir. If you're not willing to do that, then don't try it, haha.

Originally Posted by McSpeed

Update: turns out the shiftng issue wasn't related to the slave cylinder...details forthcoming

I'm not surprised. Looking forward to hearing all the details....

Here's my experience:
I installed an aftermarket pressure plate and clutch from a well known BMW tuner. The drivers complained that the car would grind in every gear. So, I decided to put back in the stock pressure plate and clutch. The problem went away. Reinstalled the aftermarket system, problem came back. Put back in the stock system, problem went away.

I decided to take my spare motor and transmission and bolt them together with the stock system. Then I made a jig to measure the amount of travel that it took to get the clutch to release. I measured the amount of distance that the slave cylinder would need to travel to release the clutch. I then replaced the system with a aftermarket unit and repeated the experiment. I found out that it took an increased distance to release the clutch.

With that, I did a bit of research and found out how far the slave cylinder will travel. Then I cut apart the aftermarket unit and a Sachs Motorsport unit. At that point, I found the error in the aftermarket unit.

Many times, people will blame some sort of bleeding problem after a clutch replacement. Thing is, I have been replacing clutch assemblies for about 30 years and have never had a bleeding issue. This is because you don't have to break open a line in the clutch system when you replace a clutch. Think about it, do you need to bleed a system after a brake pad change?

Amazing work pinpointing that!^

Originally Posted by mrshelley

Many times, people will blame some sort of bleeding problem after a clutch replacement. Thing is, I have been replacing clutch assemblies for about 30 years and have never had a bleeding issue. This is because you don't have to break open a line in the clutch system when you replace a clutch. Think about it, do you need to bleed a system after a brake pad change?

mrshelley, my issue was ultimately nothing to do with hydraulics, but in TIS it mentioned being careful to slowly extract the slave cylinder from the bell housing once it's unbolted- because if the piston shoots out too fast, air can be sucked in. When I first took it off, I thought I had let it all the way out slowly, so I let it go and then it went a little farther pretty quick and made a buzzy squeak-like noise- was that the noise of a some air getting sucked in?

UUC = problems, we refuse to install any UUC clutches. Didn't read the whole thread but people with clutch issues. 9/10 it's UUC.

Originally Posted by TxZHP04

I'm not surprised. Looking forward to hearing all the details....

For the record, here's the long overdue followup for my UUC Performance Organic Clutch fiasco: it ended up being a pressure plate travel issue just like mrshelley says.

Originally Posted by mrshelley

I measured the amount of distance that the slave cylinder would need to travel to release the clutch. I then replaced the system with a aftermarket unit and repeated the experiment. I found out that it took an increased distance to release the clutch.

With that, I did a bit of research and found out how far the slave cylinder will travel. Then I cut apart the aftermarket unit and a Sachs Motorsport unit. At that point, I found the error in the aftermarket unit.

Once I heard about that^ and the experience of another extremely competent forum member with the exact same setup, I suspected that the UUC design was flawed. I then installed the stiff-pedalled Sachs Race Engineering Performance Organic Setup from TC Kline and guess what happened?: perfect clutch operation. I got a refund for the UUC unit and the SRE has been great ever since. I honestly do not even notice the Sachs' pedal weight anymore (thanks to my now massive left quadricep ). The engagement & feel of the Sachs is great and I highly recommend it. Plus, when you install it- it works!

So in conclusion:

I know of at least 3 identical nightmare cases over a time span of about 4 years, all involving:

• the UUC clutch
• the six speed trans
• and brand new stock dual mass flywheels

I'd have thought that the design would have been corrected after mrshelley's experience, but years later, I found the same thing out the hard way. Dang.

Thus I would categorically avoid the UUC Performance Organic clutch setup if:

• you have an M54B30 w/ the 6 speed trans
• and you want to run the OEM dual mass flywheel

Sounds like the same problem I had with ClutchMasters.

Originally Posted by TxZHP04

Sounds like the same problem I had with ClutchMasters.

I hear that the aftermarket vendors take the Sachs Race Engineering pressure plate and re-jigger it to reduce pedal stiffness. In doing so they lose some range of motion and voila!: clutch nightmare for our cars.

Good to know. Thanks for sharing.

Luckily, I have the UUC flywheel so I do not have any parts issues...just installer issues.

The same thing happens with a 5 speed. We smoked the syncros in one about 4 years ago. The only real difference between the setups is the splines on the disk and the pilot bearing location (6 speed is in the flywheel and 5 is in the crank).

Originally Posted by mrshelley

The same thing happens with a 5 speed. We smoked the syncros in one about 4 years ago. The only real difference between the setups is the splines on the disk and the pilot bearing location (6 speed is in the flywheel and 5 is in the crank).

Bummer - smoked the synchros while it was up in the air?!
or was the clutch drag subtle enough that the synchros could overcome it to force a shift?