engine and drivetrain Clutch Pedal -- Randomly, No Resistance?!

[S-L]

Hello, more noob questions.

I've been driving my '02 as a daily for well over 4 months with absolutely not a single hiccup (other than a fuel leak, due to it being my fault). But, I think I've stumbled upon my first problem.

I was driving and noticed that the pedal randomly had nearly no pressure when pressing down; therefore, it'd pretty much just go straight down into the car wall with no resistance. That resistance comes and goes throughout my drives, but definitely frustrating when it doesn't allow me to switch to first on a stoplight because its either grinding or just won't (I'm guessing because the transmission "thinks" the pedal isn't down). I'm not sure really what the case here, but I'm gonna need some help.

Not to mention a random fuel leak that just started yesterday, but I think I got that handled.

Appreciate all the help in advance, and would be glad to answer any questions to diagnose or fix what is wrong with my transmission.

Thanks.

['76mintgrün'02]

Has the fluid in the brake/clutch reservoir dropped to the level of the clutch outlet?

This would imply a leak.

Both the slave an master leaked on my car and I replaced them.

Unfortunately the new master is leaking again.

Mine made little puddles.

Is yours leaking?

[OriginalOwner]

+1 Mint.

 

My first thought is the rubber cup(s) inside the clutch master cylinder are dirty and you're getting occasional fluid bypass.  Or it could be the clutch slave cylinder with that problem.  Or of course, both.

   You mention "transmission" but I don't believe that is the problem ..... it is a hydraulics problem.

 

The Easy Fix:  make sure your master cylinder is at the proper "fill" level.  The "easy" part is maybe that is the entire problem:  low fluid level and nothing is leaking.

 

The Medium Ugly Problem:  you've got a hydraulic fluid leak somewhere and you're losing brake fluid.  A leak could be from clutch master cylinder, clutch slave cylinder, brake master cylinder, brake cylinders at each wheel ..... look everywhere for a leak.

 

The Really Ugly Problem:  something to do with the brake booster leaking ??  This problem I know nothing about, so do some "search" here at the FAQ.

 

Cheers,

 

Carl

Edited June 24, 2015 by OriginalOwner

[Arizona02]

Faulty clutch master  or air in the fluid line, same low pedal can happen to brake pedal and really wakes you up.

Edited June 25, 2015 by Arizona02

[peterschop]

All good information given. The clutch hose is closest to the top of the brake fluid reservoir so a leak anywhere in the brake or clutch system will cause the clutch pedal to not get fluid first. If low, top it off.  If the fluid continues to go down, check for leaks. 

 

Take care of that fuel leak first!

[TobyB]

It's the master, as O-O posits.  They wear out- the cup's not making a positive seal to the bore, and as it uses pressure to make its

seal, when it leaks, it simply doesn't work.  And at the beginning of the end, they can work intermittently.  It might work more reliably

if you 'stomp' the clutch rather than 'creep' it, as that stands a better chance of spreading the seal to, well, seal...

 

If I'm right, you have enough fluid and haven't lost any.

 

It's an easy fix- buy a FAG or ATE replacement, swap it, add some fluid, pump it a bunch, and it'll come back.  You might need to open

the bleeder at the slave once, just to get everything primed.

 

A 'two banana' job in 2002 ownership.

 

If you're the kind of person who likes do touch things once, you can swap the slave and the rubber line at this

point too, and as long as you change your brake fluid every 2 years, you shouldn't have another clutch hydraulic problem

for another 100,000 miles.

 

hth

 

t

Edited June 25, 2015 by TobyB

[OriginalOwner]

LOL, TobyB has my '74tii figured out, and he's never met my '74tii.

      In 40 years (and 240,000 miles) I removed & rebuilt the clutch master cylinder 1 time.  In those same 40 years (and same 240,000 miles) I removed & rebuilt the clutch slave cylinder 1 time. 

 

They don't last forever, but it sure seems like it.

 

Cheers,

 

Carl

[S-L]

It's the master, as O-O posits. They wear out- the cup's not making a positive seal to the bore, and as it uses pressure to make its

seal, when it leaks, it simply doesn't work. And at the beginning of the end, they can work intermittently. It might work more reliably

if you 'stomp' the clutch rather than 'creep' it, as that stands a better chance of spreading the seal to, well, seal...

If I'm right, you have enough fluid and haven't lost any.

It's an easy fix- buy a FAG or ATE replacement, swap it, add some fluid, pump it a bunch, and it'll come back. You might need to open

the bleeder at the slave once, just to get everything primed.

A 'two banana' job in 2002 ownership.

If you're the kind of person who likes do touch things once, you can swap the slave and the rubber line at this

point too, and as long as you change your brake fluid every 2 years, you shouldn't have another clutch hydraulic problem

for another 100,000 miles.

hth

t

All great information, except one thing. I've noticed stomping in fact is the worst way to get into gear...instead "creeping in" is more effective. Not sure, weather that indicates another problem or not.

FYI, I was stuck in downtown for 30min in my parking spot, because it was just stubborn and wouldn't switch into any gear.

Sent from my SM-N910V using Tapatalk

[OriginalOwner]

"stomping" or "creeping in" are not indicative of any other problem.

 

I'm still of the opinion the clutch master and/or slave cylinder innards are going bad.  Most likely the master.

 

Cheers,

 

Carl

[PaulTWinterton]

Slavik,  What is the fluid level in the reservoir?  First clue to check as stated above.

[TobyB]

Yeah, +4 on fluid level. 

 

Either way, replacement is the effacement for displacement.

 

(sorry- haven't been drinking)

 

t

[S-L]

Slavik,  What is the fluid level in the reservoir?  First clue to check as stated above.

 

aaaannnnnnddd, it's EMPTY. (Well, I guess that has something to do with the problem then?)

---

Alright, as for the rest of you. I'm a still a young dude who's learning cars & mechanics. Please once again, excuse my "amature-ness".

 

But here's some decent photos that I snapped earlier in the day. Looks like there's a leak, not exactly sure where it's coming from (although I could take a closer look).

From what a friend who knows classics, according to the pictures, suggested a clutch master cylinder replacement.

Found one a the following link: http://www.partsgeek.com/catalog/1971/bmw/2002/clutch/clutch_master_cylinder.html

 

If that's all that needs to be replaced, I'm a happy man. I'm a young college student, so replacing everything 'just to be safe' isn't really an option for me -although, that's all of course in the plans-, but taking it by step by step and working up the priority list due to financial reasons. So, I really need to narrow this down if possible.

 

I was suggested to look around the forums with people more familiar to german cars & specifically 2002's. So here I am.

 

Apologize about he late replies, but I hope I can get some good suggestions from the information and new pictures I provided.

 

Thanks.

 

Here go the photos...

If any more pictures are needed, I'd gladly be able to shoot em up on here. Just let me know!

Edited July 6, 2015 by Slavik

[OriginalOwner]

empty ..... whew, that'll do it .......

 

and those 2nd & 3rd pictures of the slave cylinder ... in the foreground, that threaded rod thingie .... I'm thinking there's supposed to be a Nut on that !!!!!!   Is that the pitman arm coming off the steering gearbox ??????

 

 

 

Cheers,

 

Carl

Edited July 3, 2015 by OriginalOwner

[S-L]

empty ..... whew, that'll do it .......

 

and those 2nd & 3rd pictures of the slave cylinder ... in the foreground, that threaded rod thingie .... I'm thinking there's supposed to be a Nut on that !!!!!!   Is that the pitman arm coming off the steering gearbox ??????

 

 

 

Cheers,

 

Carl

So. Add fluid? That's it?

 

About the "rod thingie". Honestly, not sure. Been running like that ever since day 1. Hmmm....

 

Pitman arm? Nah, I don't think so...aren't those usually much thinner?

[PaulTWinterton]

Not sure (from the pictures) about the  threaded rod/bolt/coupling, BUT GET IT CHECKED IMMEDIATELY BY A TIRE/ALIGNMENT SHOP.  They will charge you minimally to inspect and put a nut on there if necessary.

 

Fluid level

 

If the reservoir is COMPLETELY empty, you must bleed your brakes as well.  Read up.

 

If the reservoir has some in the bottom you are lucky.  Top up the reservoir with DOT4 brake fluid and loosen the nipple on the clutch slave.  When it starts to drip, let the air escape before tightening the nipple again.  The best way to do the job is with a length of clear plastic tubing on the nipple.  When you crack the connection, fluid and air will escape until all the air is out of the system and the fluid is clear in the tubing.  No need to pump the clutch pedal.

 

In the long term what you have to consider is the reason there is no fluid in the reservoir.

 

1.    The master brake cylinder is possibly leaking on the ground, onto your frame rails (very bad) and/or into the brake booster. 

 

2.   Your master clutch cylinder may be leaking into your pedal box.  Strip back the carpet under the pedals, remove the rubber cover and inspect the inside of the box.  If there is a puddle of fluid, it's time to replace the clutch mc.

 

3.   Previous owner never checked level and minor leaks have drained the system.  If that's the case I'd learn all about the system and replace fluid with clean new DOT4.  Check and bleed all 4 brakes to get the old (crappy) fluid out of the system.

 

I must say your slave cylinder looks good and dry. Likely replaced recently and not a problem.

Edited July 3, 2015 by PaulTWinterton