E36 large clutch pedal dead zone

[Bahaa425]

Hello all,

so something strange has occurred with my 93 e36. It has had a manual swap performed at a local shop and when I got it back the clutch pedal sat a good 3-4+ inches higher than the brake and gas pedal. Fine because the engagement was fine. Now though, after a few months of driving. The pedal has a huge dead spot. Those 3-4+ inches before the brake pedal plane is completely dead with zero resistance. Once the clutch pedal reaches the brake pedal plane, it gets resistance and feels like a normal clutch. It engages fine at that point. What is strange is that the pedal will return to its high position even with the dead zone.

I am am looking for ideas of what to look for to see what could be causing this.

Here is a video
https://www.youtube.com/watch?v=lAZNtKgZUYE

Thanks all

[bmwdirtracer]

Well, the clutch pedal doesn't match the brake pedal, so you've got a parts mismatch at the pedals, to start. It would also seem that the brake pedal is too far down, because how are you ever going to heel-and-toe, if the brake pedal's two inches past the gas pedal as soon as you apply the brakes?

Now, all that said, there is also a possible discrepancy in anything mismatched in the hydraulic system. As I recall, there are two different length slave cylinder throws on E36's....

Let's see: a 94 325is used a slave with a 20,64 mm throw; part number ending 045, combined with a master cyl. part number ending 830.
A '97 M3 used a slave with a throw of 22.20mm, part number ending 829, combined with a master ending in 924.

We've already got incorrect pedals; maybe someone put in a new part for the wrong car, which caused a mismatch in pedal heights and hydraulics, too?

And then, there's WEAR. Most of the time, clutch engagement height gets higher, as the clutch wears, but sometimes, the engagement height gets lower. Have you been driving hard? Did you have a brand new clutch kit and flywheel?

[shadowpuck]

chris - i was thinking the same thing when i saw it was a swap car. there's a lot of variables we don't know yet. it's very easy to mix/match parts and end up with a hodgepodge....

[bmwdirtracer]

Yup, note that the clutch pedal arm is a later, hollow type, and the brake pedal arm is an early solid steel part. You and I both know that any single mismatch can cause the system to work incorrectly.

[Bahaa425]

Well, the clutch pedal doesn't match the brake pedal, so you've got a parts mismatch at the pedals, to start. It would also seem that the brake pedal is too far down, because how are you ever going to heel-and-toe, if the brake pedal's two inches past the gas pedal as soon as you apply the brakes?

Now, all that said, there is also a possible discrepancy in anything mismatched in the hydraulic system. As I recall, there are two different length slave cylinder throws on E36's....

Let's see: a 94 325is used a slave with a 20,64 mm throw; part number ending 045, combined with a master cyl. part number ending 830.
A '97 M3 used a slave with a throw of 22.20mm, part number ending 829, combined with a master ending in 924.

We've already got incorrect pedals; maybe someone put in a new part for the wrong car, which caused a mismatch in pedal heights and hydraulics, too?

And then, there's WEAR. Most of the time, clutch engagement height gets higher, as the clutch wears, but sometimes, the engagement height gets lower. Have you been driving hard? Did you have a brand new clutch kit and flywheel?

These aregood points. I do not know which parts exactly we’re used from which years. I will need to get underneath and check out the part numbers. I had a shop do it, it is possible they got the bolder model m3 parts instead of the 93/4 325is.

i do not drive the car, my gf does to get to school and back. She is a great driver, German in fact so she’s very nice on the clutch. The clutch wasnt new I don’t believe, I plan to do a transmission swap soon so this was just to make t daily able.

What is strange is is that it worked previously with no dead zone as seen in the video

[bmwdirtracer]

It's generally known as "free play", and generally runs 1 or 1.5 inches with a new clutch. In older cars and trucks, it was adjustable. Probably time to replace the clutch kit; you can always use that as an excuse to replace the worn overheated dual mass flywheel with a lighter solid one!

[Bahaa425]

It's generally known as "free play", and generally runs 1 or 1.5 inches with a new clutch. In older cars and trucks, it was adjustable. Probably time to replace the clutch kit; you can always use that as an excuse to replace the worn overheated dual mass flywheel with a lighter solid one!

I noticed in the first post you said that the pedals were also different, I know they bought a manual swap pedal kit, so shouldn't the pedals have been the same? i will spend time today to get under the car and look at the slave/master to see what parts i have, it would make sense that if the miss matched slave/master is causing some weird feel but i never understood why the clutch sits so high in comparison to the brake.

Its also strange that previously the clutch pedal engaged at the very top of the pedal travel. and only after a few months the free play came in for the first few inches of travel. Is that a sign of something going? or is it due to the mismatched hydraulics? The clutch feels fine and engages fine on the plane of the brake, its just weird/concerning that it just started happening with the excessive free play.

[bmwdirtracer]

"Kit" is a relative term. "THEY" bought it and installed it, YOU didn't.

Look carefully at the pictures. See how the brake pedal arm is one piece of solid steel? See how the clutch pedal arm is a hollow "C" section (the empty part is at the rear). Older cars used hefty solid steel; newer cars....like my M5...use the hollow C-section parts.

The clutch pedal usually sits at about 1/2" to 1" above the brake pedal, at rest. Someone screwed up, sorry. Likely the wrong clutch master cylinder vs. clutch pedal arm.

Swaps are not as straightforward as people like to pretend. At some point, you're very likely to use parts from two different cars, and that's where the problem arrives. Research is king.

The clutch pedal should never have engaged at the very top of the travel. In general, it should begin to engage at just before half way up. However, as mentioned, this figure varies a bit, as the clutch wears.

[asuliman1993]

Hello . I’m new on here. Was wondering if you checked your clutch return spring . Maybe worn spring or broken center rod .

[Bahaa425]

Hey thanks for the help, I should've updated this awhile ago. It turns out my clutch slave was going out. It ended up going out on me a few weeks later, fixed that and its all good now.