Clutch Master Cylinder Pushrod: reasons for snapping in half

[usualdeviant]

That happened to me today. I want to say I have been daily driving my 87 325i since I put an "OEM" CMC on it 2 or 3 years ago. Then while driving it, the end of the pushrod snapped off, right where the rod meets the ring. I was able to drive it back home without the clutch by starting it in first gear and then power-shifting it and then shutting the engine off at stops. But damn. Everything around it looks fine. Just a bad part? I don't think a clutch stop would have helped, would it?

[LowR3V'in]

picture of carnage pls

[usualdeviant]

I'll make it happen.

[usualdeviant]

[richardb]

try my DIY for replacement, hope it helps

https://youtu.be/_7j8wTiBDo0

[TobyB]

Looks like it might have bound on the pivot.
It can't take the twisting.
Try some grease next time...

t

[usualdeviant]

That was a great video. Made me feel good about how I managed to disconnect and reconnect the hard line at the master. Also reminded me about the plastic fitting. Damn, gotta get that too. Grease doesn't sound like a bad idea, definitely going to include that this time. Thanks guys!

[usualdeviant]

So Toby, I think it was absolutely binding on the pivot. If I remember correctly, I way-overtorqued the hardware when I installed it. Surprising it lasted as long as it did. What can I say? I learn things the hard way!

Oh and I have no idea how I was able to get a wrench on the flare nut at the master last time. Maybe disconnected a fuel hose or something. This time I used a flare nut crow's foot on a 6 inch-ish wobble and a relatively small ratchet.

[usualdeviant]

Richard, it looks like you have the bolt and nut reversed from the diagram here. http://www.realoem.com/bmw/enUS/show...diagId=21_0004

I wonder if it matters. Also it looks like I installed the pushrod to the left of the pedal hole (it lined up nice there) and yours is on the right. Unfortunately the diagram does not say which way it goes.

[bmwman91]

Man, I can tell that OP doesn't skip leg day at the gym!

Seriously though, that is odd. It sounds like you have a good guess though. Also I think that yours is installed on the proper side. Plunger attaches on the left of the pedal (not my pic, but it is a clear image):

https://www.r3vlimited.com/board/showthread.php?p=2120713&p=2120713

[e30davie]

The nut used to hold the pivot is a self locking nut. it should be installed loosy goosy to allow the pivot to swivel easily. If you tightened it - there is your problem:)

[usualdeviant]

Yeah I'd say that's why it broke I didn't even realize it was supposed to be 15 ft. lbs. instead of 45 or whatever I had it at.

[LowR3V'in]

i remember mine just being a pin with a clip not a bolt.

[gunsnbacon]

Your pedal box has a huge crack in it where the master cylinder mounts. Weld it back and reinforce it before you master cylinder swap.

[usualdeviant]

Maybe yours, not mine. Unless you see a crack that I don't...