Another Clutch Disengagement Thread -- Bent Clutch Pedal?

**vladimrhtg** · 04-15-2017, 01:08 AM

I wrote a very polite, kickass thread describing my issue and even included some pictures but failed to post it. I think it's now gone forever or at least I don't know how to find it.

Here's the deal, short version:

'99 M3
JB Racing Flywheel, stock other than that
Recently replaced: clutch pivot pin, slave, and fluid to diagnose the clutch disengagement. Pivot pin was a little deformed but not awful, the slave was a little ball of rust, and fluid did have one microscopic bubble that I saw. No dice though, shifted the same.
That left the master--replaced it and it felt good after I bled it properly. Clutch felt like it was at least 95%+ disengaged and that felt like it was enough for me, however it was at the very very bottom of the pedal travel. No clutch stop used ever.
I didn't bench bleed the slave and I don't think my buddy did either, so there's that.

Drove for a few months....fast forward in your mind, a grand total of 2k miles.....

Well, it's three months later, and the shifting feels exactly like it did when it did before I did all that work.
Specifics:
- Seems to get worse as it gets hotter.
- I can still get an 'ok' shift if I really really mash the clutch pedal.

That's about all the relevant information I can think of right now.

I'm nearly convinced it's a master cylinder issue, and here are my reasons why:

The master I pulled out wasn't that old, certainly not OE
I audibly heard some squeaking a few weeks after installation that wasn't a normal e36 clutch pedal squeak. I literally thought, "wow, that sounds exactly what master cylinder seals failing would sound like."
When I look at the pedal box, all held together by that 'support'...it actually looks like my clutch pedal is physically angled to the left, like it's improperly mounted. I was the last one to take it out so I guess that could be my fault but I'm pretty sure I just threw the bushings in there and called it a day. I can post a pic if anyone wants to see.
Has anyone heard of something like that? A bent clutch pedal? I doubt the pedal itself is bent but perhaps the mount, or perhaps it's missing one of the bushings.
I"m wondering because it looks like the clutch pedal is displaced enough to angle the master cylinder piston. Any chance that could affect master cylinder longevity?

The plan: I'm open to recommendations. I'm not dying to put another master cylinder in just for fun. First step will be to give that slave another bleed.........and I suppose I could pull it off and attempt a 'proper' bench bleed underneath the car, since I'd rather do that than mess with the slave.

Let me know if you want more info. Sorry to post yet another 'I can't shift, halp me' thread but I really did read like 15 other clutch threads. No dice. Sorry for all the lists. Sorry for being sorry. Thanks for the help. I'm laughing at how short this 'short' version isn't.

**vladimrhtg** · 04-15-2017, 01:26 PM

Have now read that the bushings can wear out causing the the pedal to lean. Still looking for feedback on whether that can cause master cylinder trouble.

Also....has anyone used the master cylinder rebuild kit? Doesn't save that much $$ but my master cylinder is only months old.

**JDStrickland** · 04-15-2017, 03:05 PM

Yes. the bushings can cause adverse affects to the master cylinder. Also, I replaced the clutch master in my E36, and the new one was defective out of box. I had to make a repair to a new clutch master before I could use it. I don't remember if I cheaped out and bought my clutch master on eBay, I think I probably did.

Having said that, the bushings can make the pedal travel feel very strange with the results of depressing the pedal be all over the ballpark.

The typical action of a failed (leaking) clutch master is that the pedal goes straight to the floor and does not operate the clutch. A clutch master and a brake master both fit into the hydraulic system at the same location, at the pedal. The master cylinder pushes fluid into the hydraulic system as the piston is pushed by your foot. There is an o-ring around the piston to seal it with the body of the cylinder. Fluid leaks past the o-ring and the piston is moved, but since the fluid goes around the o-ring it does not get forced into the hydraulic system. The affected system does not function. The brake system offers no resistance to the movement of your foot, therefore as your foot rests (presses) on the pedal, the leaking fluid allows your foot to slowly fall to the floor. You find that you must release the pedal pressure so the pedal comes up, then you can depress it again to keep the brakes applied. The clutch is a giant spring that you foot is pushing on. When the clutch master fails, the resistance of the spring allows the pedal to fall without doing its job of engaging the clutch. A clutch or brake master are said to be "leaking" when this condition exists, but there can be no visible leak to the outside of the system. The master cylinders push fluid into the hydraulic system which seeks to come out of the opposite end of the plumbing. In the case of the clutch, this is the slave cylinder. In the case of the brakes, it will be the brake calipers or wheel cylinders if the car has drum brakes. The slave, calipers, or wheel cylinders will leak to the outside when they fail. This will present itself as a mess on the ground under the respective cylinder and a loss of brake/clutch fluid. (In your BMW, the clutch and brake fluid is the same fluid. Same reservoir.)

- - - Updated - - -

The force it would take to bend a clutch pedal would surely be an event that you would remember for a long time to come. I'm thinking the event would be one of those times when you go home and change your underwear, and burn the underwear you took off.

**vladimrhtg** · 05-23-2017, 01:58 PM

Originally Posted by JDStrickland

Yes. the bushings can cause adverse affects to the master cylinder. Also, I replaced the clutch master in my E36, and the new one was defective out of box. I had to make a repair to a new clutch master before I could use it. I don't remember if I cheaped out and bought my clutch master on eBay, I think I probably did.

Having said that, the bushings can make the pedal travel feel very strange with the results of depressing the pedal be all over the ballpark.

- - - Updated - - -

The force it would take to bend a clutch pedal would surely be an event that you would remember for a long time to come. I'm thinking the event would be one of those times when you go home and change your underwear, and burn the underwear you took off.

Plot twist: I already have the bronze/brass clutch pedal bushings! Still looked bent, so perhaps the bushings were installed into a worn clutch pedal. I'll edit this post with pictures once it stops raining.

Yesterday, my clutch pedal went straight to the floor with no resistance. Master cylinder failure. I suppose I shouldn't be surprised, but....

I'll be replacing a few of the things in that area....master cylinder, pedal, spring bracket...and will report back!
Of course there will be a proper bleed after this, but once that all happens, I won't be too sure where else to go if shifting still isn't consistent. I'll add a power bleeder to that list too since I have a feeling that I'll need it.

Further edit:
IMG_20170523_143953.jpg IMG_20170523_144006.jpg

Check out the wear from that pin! I mean...I've pressed the clutch pedal pretty hard, but I think I have to blame the previous owners for that one. Curious to know what the adhesive is that's splattered around the top. Also curious to know why the ground off the tab on the passenger's side of the pedal near that pin.
This is the only wear I can find on the pedal....perhaps that's enough to make the master cylinder piston sit unevenly? Still not sure why the pedal looked to be off to one side. If it still looks off after a new pedal then I'll know we have serious issues!

--edit--
Dug up some old photos from when I first looked at it:
IMG_20170410_225453.jpg IMG_20170410_225448.jpg
I think lens refraction is working against us, but there she blows. Misalignment can be seen in the brackets that sit inside the spring. Not sure how that can be while the pedal looks mostly straight, but there it is.
Parts on the way: Master cylinder, pedal, brackets, pedal return spring (this car hasn't had one in a while), power bleeder. Wish me luck! Second time can't be as bad. Any thoughts appreciated.

**FiberFast** · 05-23-2017, 04:47 PM

I am having similar issues. I reverse bled the system and it worked perfectly for 3hours before the trouble started again. Try a reverse bleed (pump fluid into the slave up to the res) if it works well at first and then gets worse you have a failing master cylinder. I am going to replace mine this weekend, last time I went to replace it I discovered there are two different types of master cylinder. In my case I believe the leak to be at the gromet and plastic angled pipe leading to the resivoir.

**vladimrhtg** · 05-24-2017, 04:06 PM

Originally Posted by FiberFast

I am having similar issues. I reverse bled the system and it worked perfectly for 3hours before the trouble started again. Try a reverse bleed (pump fluid into the slave up to the res) if it works well at first and then gets worse you have a failing master cylinder. I am going to replace mine this weekend, last time I went to replace it I discovered there are two different types of master cylinder. In my case I believe the leak to be at the gromet and plastic angled pipe leading to the resivoir.

I bought a master cylinder this time with a lifetime warranty so it's only going to get better from here!
Interesting that you're having comparable issues....stock clutch & flywheel setup?

**FiberFast** · 05-24-2017, 06:58 PM

Originally Posted by vladimrhtg

I bought a master cylinder this time with a lifetime warranty so it's only going to get better from here!
Interesting that you're having comparable issues....stock clutch & flywheel setup?

I have a newish 325is Luk dual mass flywheel with a newish sachs disc and pressure plate on an M52. I have custom brass tip 1/8" longer on a new slave cylinder, a brass pivot pin, a new clutch fork, a new sachs throw out bearing, Stainless clutch line. I went to replace the master cylinder and discovered my car has the older style compression fitting without the cdv. I took the guts out of the new 20mm duralast unit and installed them in the old 19mm master cylinder housing. I had the problem before and after the master cylinder "Rebuild" and I believe it to be leaking at the grommet to the reservoir. I reverse bled the system and it worked perfectly for about three hours before the problems returned. I am thinking I just need to replace the damned thing completely this time and get a new plastic pipe as well.
If it persists I am going to make a friggin hand pump with a valve on it and plum it into the slave bleed port.
"Oh you wanna race? Hang on let me pump up my clutch pressure real quick."

**vladimrhtg** · 05-25-2017, 11:47 PM

Originally Posted by FiberFast

"Oh you wanna race? Hang on let me pump up my clutch pressure real quick."

HAHAHA That's exactly what I've been doing for the last few months! And rest assured that I always make sure to get the drop in first gear, since I know I have zero chance of getting a clean or fast shift into second. 0-60 times are probably a few seconds higher these days.

Originally Posted by FiberFast

I have a newish 325is Luk dual mass flywheel with a newish sachs disc and pressure plate on an M52. I have custom brass tip 1/8" longer on a new slave cylinder, a brass pivot pin, a new clutch fork, a new sachs throw out bearing, Stainless clutch line. I went to replace the master cylinder and discovered my car has the older style compression fitting without the cdv. I took the guts out of the new 20mm duralast unit and installed them in the old 19mm master cylinder housing. I had the problem before and after the master cylinder "Rebuild" and I believe it to be leaking at the grommet to the reservoir. I reverse bled the system and it worked perfectly for about three hours before the problems returned. I am thinking I just need to replace the damned thing completely this time and get a new plastic pipe as well.
If it persists I am going to make a friggin hand pump with a valve on it and plum it into the slave bleed port.

Interesting that you're not using stock setup. At this point I'm considering anything that could be causing problems for me.
I'm a little jealous of your brass pivot pin. I bought one for my e36 when I had the transmission out but ended up with an e30 pin instead, so I just threw a plastic one in and called it a day. The one I pulled out was a little deformed but it honestly wasn't awful. Sounds bad, but I'm somehow encouraged to hear that you're having comparable problems even with the pivot pin, since I've regretted not having one in since I've had issues.

I'm going to make a power bleed system with an external reservoir. Find a place in the engine bay for an electric pump (I have no cruise control, maybe that would work), and then run some sort of release or valve right on the slave like you wrote. Sure would be more convenient than getting under the car every day.

If it's leaking at the connection to the reservoir....does that give it an opportunity for air to get into the system? I checked my connection to reservoir but it looks good.