Clutch and transmission fun

[Elutheros]

A couple weeks ago the 1/2 shift fork in my M5ODR2 failed and I loss those gears at a very inopportune moment on a steep uphill 90 degree turn. A quick shift to 3rd and smoking the clutch got her over the top and home. I diagnosed it, bought new shift forks and installed them and then it would stick in second gear, so I gave up, yanked the trans and took it to a shop where they replaced the shift forks again and told me it was all good.

Meanwhile, I did all the stuff one ought to do when you're in there: pilot bearing, rear main seal, new clutch/pressure plate, flywheel refinish, slave cylinder, and throwout bearing. After 6 or 7 hours of transmission/transfer case wrestling I got it all back together last Friday. Bled the slave cylinder, cranked her up only to find the clutch would not disengage to allow any gear selection. Bled it again and again. No go. Removed the master cylinder and bled it (yes, I know the proper procedure and have done it successfully before). No air bubbles were observed in the bleeding process. Still no clutch release. The master cylinder is a used JY piece that I installed when I did the V8 swap. The only thing I can figure is that the master cylinder is bad and won't supply enough travel to disengage the clutch. I ordered a new one and I sure hope it works. I'm not looking forward to hours on the concrete pulling the transfer case and transmission one more time.

 

[Elutheros]

I'm still whining like a lost puppy. Bought a new master cylinder and bled it twice. No leaks anywhere. Ran half a bottle of brake fluid through the slave after I connected the master. Clutch pedal feels and acts just like it did with the old master cylinder. It will not disengage the clutch to get into any gear.

At this point I have to assume the slave is defective unless someone gives me a better idea. I'm really not looking forward to all this practice removing and installing the transfer case and transmission

 

[Curious Hound]

Can you have someone else operate the clutch while you watch the slave cylinder through the inspection hole? Maybe the hydraulic parts are fine but something else got mixed up during re-assembly.

Sent from my SM-G920V using Tapatalk

 

[bobbywalter]

correct pp?

 

[Elutheros]

Next steps: 1. as suggested have someone operate the clutch while I check through the access hole for movement. 2. make sure no wires from the O2 sensors got caught between the trans and the block. 3. do the diagnosis of clutch master shaft movement and slave movement.

I checked all the part numbers and compared parts taken out to parts installed during the process so I'm sure the right parts are in there.

 

[Elutheros]

I kept working on it and had someone push the clutch pedal while I took video of the movement(can't get your head up in there on a 4x4) The slave does move, but not enough. Next I checked the travel on the master cylinder pushrod. It is about 1/4 inch before I get resistance. I took the master cylinder out again and bench bled it. I couldn't move the pushrod in at all once I completed the bleed. Reinstalled master cylinder, connected QD to transmission, bled 4 ounces of brake fluid through slave cylinder and checked the pushrod again--still 1/4 inch travel before any resistance. Clutch still won't disengage. I have to conclude that the slave cylinder is the problem Looks like I get to do it all over again--practice makes perfect

 

[Jbrown1238]

Try removing the clutch master cylinder from the fire wall and tipping it upside down. Tap on the side with a wrench and let it sit over night upside down to remove any trapped air.

 

[Elutheros]

There is an end to all this madness of clutch master and slave bleeding

I'm only posting this so others who encounter this won't give up on bench bleeding the sucker and may be able to find a solution for their particular issue.

Took it all apart, checked every part number to be correct, put it all back together with a new slave cylinder and of course it didn't change anything. Bench bled the master again, followed by reinstall, bled slave and still didn't work. I've concluded that the quick connector must be leaking air into the system since my bench bleeding always resulted in an 1/8 inch or less of shaft movement on the master, but as soon as I connected to the slave and bled it the shaft had more play. I pulled out my 25 year old MityVac pump and vacuum bled the slave a couple times and still got the same result.

Sooooo,I removed the master again, replaced the hydraulic line to the slave with the Dorman part, bench bled it again, reinstalled, bled the slave and it now goes into 1st and reverse with just a little extra effort. I left it sit overnight and hopefully it will continue to work Friday when I get back to it.