Yet another, BMW E-36 LSx conversion... by BRAAPZ

4 minute(s) of a 105 minute read

Engine mount brackets by JTR.

5-6-2010

BREAK THROUGH on the clutch line! 


Short version;
Due to the similar design of the master cylinder hydraulic line connection between GM and BMW, the OE GMLSx clutch line can be made to fit the BMW master cylinder with a small massage, no need to buy fittings, cut the GM clutch line, etc... Only thing needed to buy other than your slave cylinder is a remote bleeder line/kit like the one from TICKshift.com.
I did hammer the tunnel about 3/4" deep trough where the clutch line comes out of the bell-housing to relax the bend on the clutch line, fits nice in the tunnel.

Long version;
Yesterday in finishing up the clutch lines, I was going to go the typical route and cut the GM clutch line, install the -4 fitting, use the -4 to 10mmx1.0mm ISO bubble flare fitting, yadda yadda yadda, but with the GM clutch hose hooked up the trans I noticed its length is absolutely perfect in that it reaches the BMWmaster cylinder. I got to looking at the BMW master cylinder connection a little closer, removed the hard line retaining clip and wiggled the hard line out of the M/C and thought about what it might take to get the GMclutch line to plug into the BMW Master Cylinder. Spent some time measuring up both the GM and BMWmaster cylinder connection bores, then the GM and BMW clutch line fittings, sketched them out in AutoCAD and came to the conclusion it can be done. The BMW M/C bore is smooth at the O-ring diameter for what looks like all the way to the piston so the GM fitting could sit at any depth past the minimum. So I chucked the GM clutch line in the lathe and machined .020" off the diameter of the GM fitting as shown below and added a .040" tall chamfer to allow it to sit deep enough into the M/C to accept the BMW retaining clip and that's it, fits PERFECT! Using the GM O-ring, (BMW O-ring will not fit the GM fitting), it ends up compressing a total of .021” more than it does in the GM M/C, (tighter fit), not so much it causes any issues wit sealing, over squishing, etc. Surprising part is with a little brake fluid on the O-ring it doesn’t feel any tighter when installing it. Installed and removed several times to verify fitment. Best part is the GM clutch line is already the perfect length!


Here are the drawings and pics, enjoy…


BMW Master Cylinder connection detail;

GM LSx Master Cylinder connection detail;

Hybrid LSx line-BMW Master Cylinder;

3D render of the Hybrid connection.

Retaining clip fits perfectly behind the crimped fitting;

Prior to installation;

INSTALLED! Retaining clip holds it firmly, wont go in any deeper or come out and it is already the PERFECT length! SAH-WEEET…