E36 (318is) LS1 swap - clutch not fully disengaging

[Richard Franks]

I'm excruciatingly close to being able to take my e36 ls1 swap car to the tuner. I've sorted out all gremlins over the past couple months except for the last one - clutch not disengaging fully. I know others have used the BMW master cylinder with the GM slave cylinder, but I don't seem to be having any luck.

The symptom:
Clutch failing to disengage even when fully depressed. If I start the car in first, clutch in, it wants to move forward a bit and stall out because it's still engaged just a bit. I've put about 40 miles on the car, sometimes it feels better than others. If I get the rev matches closer, it goes in much easier.

My setup:
AMS M0308 master cylinder -> BMW bubble flared line -> bubble flare coupler -> Fragola bubble flare to -3 AN fitting -> -3 AN female to -4 AN line fitting -> -4 AN line -> GM quick disconnect fitting. The clutch, as best as I know, is a Monster level 2 with an F-Body slave. On the other end is a Tick Performance remote bleeder. Below is a picture of the line for better visualization (left side is a crackhead POS I came up with the first time around, right side is what I'm using now)
another view of the jokery.jpg

Troubleshooting steps:

• Replaced the FAG (not sure part number) master cylinder on the car with an AMS M0308 (was also branded FAG, could have been the same), which is listed as compatible for the 318, 325, and m3 e36's on RockAuto. I also tried a Beck/Arnley 072894 but couldn't get it to fit properly on the flared fitting end. Had no better results with a new master cylinder
• Drain all brake fluid through clutch system and replace with new (did this before, and during new master cylinder install)
• Bleed clutch by pushing down on clutch and cracking bleeder
• Bleed clutch by opening bleeder end and using vacuum bleeder
• Depressed clutch and popped back up to attempt to dislodge any hanging bubbles back up into the reservoir

My thoughts:
I think the only differentiating factor between my swap and others, is the line between the master cyl and slave cyl. I don't think length matters, but it could be trimmed down. I'm also wondering if -4AN is too thick for the line, but that's also the size of the crimp fitting on the McLeod 139202 QD fitting I used to make the line.
I've also heard bleeding these things can be impossible, but I'm having trouble sorting out if that's still the issue given that I've drained the system a couple times. There's still a possibility that there's an air bubble trapped in the slave cyl though I guess.
Finally, I've wondered if the remote bleeder is letting air in. Part of it was resting on the header and it burnt off some of the protective sleeve around the line, but no discoloration on the actual stainless steel part.

Would really appreciate hearing if anyone has had this issue, or even if you haven't, what your bleeding procedure was. Grasping at straws at this point - I'm so close to driving this thing!

[BigL350]

I think you might need to shim the slave cylinder if you have an aftermarket clutch. I'm using the BMW master cylinder, a BRAAP modified line, new stock GM slave cylinder, and an LS7 clutch with no problems.


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[doktor b]

i have a monster stage 3 in my swap.
i definitely had to shim the slave to get it into spec for total stack height.
did you check your clutch stack height against the bell/slave depth?

i'm using a Tilton MC, so i'm no help there. but i can tell you 100% my Monster required a shim. OE GM bell, T56, OE GM slave, -3AN hose, TICK remote bleeder.

- - - Updated - - -

this is a heplful post
https://ls1tech.com/forums/manual-tr...need-shim.html

[Richard Franks]

Thanks for the replies, everyone.

did you check your clutch stack height against the bell/slave depth?

I didn't, I bought the ls1 + t56 as a dropout from a '01 Trans Am and took the word of the seller that it ran fine before it got wrecked. That is a good idea to check for though, I hadn't thought of that. I'd hate to have to pull the trans at this point

I think I might try pressure bleeding it. A buddy from work who did a ls1/t56 into a fc RX7 described the same issues, which he solved by pressure bleeding. Failing that, it sounds like I'll be pulling the trans. Would be nice to take a look at everything in there, anyway.

Also - looks like you're just north of me, I'm in north Indianapolis area. Didn't know there were any other lsx e36's around!

[doktor b]

Thanks for the replies, everyone.



I didn't, I bought the ls1 + t56 as a dropout from a '01 Trans Am and took the word of the seller that it ran fine before it got wrecked. That is a good idea to check for though, I hadn't thought of that. I'd hate to have to pull the trans at this point

I think I might try pressure bleeding it. A buddy from work who did a ls1/t56 into a fc RX7 described the same issues, which he solved by pressure bleeding. Failing that, it sounds like I'll be pulling the trans. Would be nice to take a look at everything in there, anyway.

Also - looks like you're just north of me, I'm in north Indianapolis area. Didn't know there were any other lsx e36's around!

i just changed my clutch MC last weekend from a Tilton 75 series to a 78 series. so i just went through the bleeding thing. it's not the most fun...but it's not terrible with the remote bleeder. i have a Motive power bleeder if you need to borrow one.
i'd heard there was another one in town, but no confirmed sightings. lol.
i live and work in Noblesville. but i also have job2 out at Park 100. (where i'm at currently)
if you need a hand, i can swing by in my (super limited) free time and see if i can help.

also, if you end up pulling the trans...
leave the bell and clutch on the engine. you can take your measurements with them on the engine and then manually collapse the slave and take that measurement with the gearbox on the ground/bench. it's worse than not pulling the trans...but not as bad as taking it all out.

[richzx]

I had the same issue once and it was the throw out bearing sticking on the spline because I never put quite enough lubricant on the new bearing.

[Richard Franks]

I pressure bled the crap out of the clutch, even tried pressure bleeding with a vacuum bleeder on the remote bleeder end. Still nothing - clutch grabs immediately off the ground. It feels like it builds pressure late in the clutch throw, with more resistance at the bottom. There's no mid point where the pedal feel changes like other manual cars I've had. Drove it about 10 miles but then could not get the thing in gear for the lift of me.

I bought the Tick 3 pack of clutch shims, and will measure it all out once I get the trans out. Will also check for a sticking throw out bearing and other symptoms. Looking under the car, it doesn't seem nearly as bad as I originally thought it would be.

Huge thanks to doktor b for the knowledge and letting me borrow the pressure bleeder. I'll update in detail when I'm done since it seems like there's a few threads asking this question, but not many come back to post the solution.

[Richard Franks]

Alright, a month later, I've made some progress.

Gonna be verbose here in case anyone else has this problem in the future and finds this thread.

I pulled the trans, measured the distance from the face of the bell housing to the face of the pressure plate, then the distance from the face of the trans to the face of the compressed throwout bearing. I got a distance of just barely under 0, so it wasn't a shim like I'd hoped.

I got another slave cylinder from O'Reilly which measured at .10" shorter than the other, so I put the .088" Tick shim in there behind it. Reinstalled it all and crushed the bleed line between the trans and bell housing when I did which was GREAT. Got a new bleed line, connected the trans and bell housing again, bolted everything back up and got to bleeding.

It took me 3 hours to get it bled to the point where it would build pressure. Vacuum bleeding, bleeding with the bleed screw, bleeding without the bleed screw, etc etc. I don't know what the heck I was doing wrong. I think at one point I built too much vacuum on with the vacuum bleeder and pulled air past the slave cylinder seals. After that I just went with cracking the bleed screw and allowing fluid to flow out of that while I hammered the clutch pedal.

After doing that for awhile it built pressure, but not enough to disengage the clutch. I did some more bleed screw bleeding and capped it off again, built pressure, and finally got it to disengage. It still disengages right off the floor, but it can actually be slid into gear now rather than having to ram the hell out of it. I'll bleed it a little more next time I get a chance to work on it and should be good to go.

I don't know which part fixed it - the new slave cylinder, a better bleed line that wasn't a little roughed up, or the bleeding method, but I think I'm in the clear now.

[TipsyMcStagger]

Alright, a month later, I've made some progress...



...I don't know which part fixed it - the new slave cylinder, a better bleed line that wasn't a little roughed up, or the bleeding method, but I think I'm in the clear now.

Glad to hear you got it squared away. Thanks for the follow-up.

Tipsy