Leaky clutch problem continued

[DanDombrowski]

Ok guys,

Continuing my "highway only soft clutch problem"....

I topped off the fluid (took quite a bit actually, yet the level didnt change much), drove up to gville, same problem. Almost no clutch on the exit ramp, yet perfect by the time I had gone through 3 lights (which in gainesville on a friday night is gear 1, 2, stop, 1, 2, stop, 1, 2, 3....no nevermind stop...you get the idea.

So I got underneath the car today: No brake fluid near the clutch slave, no brake fluid around the master, flex hose is bone dry. So I went to check the connection between the metal hose and the master clutch cylinder, and thats where I ran into problem number 1:

How in the hell do you get to the clutch master cylinder? Is it a 'by feel only' thing, or do I have to remove the brake booster?

Well, I tried to feel my way around there with my hand, which really I didn't expect to do any good since the grommets on the resivoir have been leaking anyway. So in doing that, my arm pushed on the resivoir and the grommet started hemmoraging for lack of a better term. Got a good amount of brake fluid all over the ground, fortunately none on the exterior paint. After cleaning everything up, I went for a drive to check it, and my anti-lock (ABS) light flashed for a bit and then went off.

So at this point I'm kind of stuck in a pickle. On one hand, I don't know if I should fix the grommets first and see if its sucking in air (although I don't know how air that high in the system will hurt the clutch) and then replace the clutch master later (even though I still have no reason to belive its that, its just that I don't see it bieng anything else), or do I just buy everything and do it all at once?

I thought it might be the connection between the clutch master and the metal line, but that brings me back to the same problem-how do I get to that connection? I read brunos page, he says he pulled it a bit and used a wrench. Does he mean he pulled it through the firewall?

Here's the link for those too lazy to look: http://www.bmwe34.net/e34main/mainte..._hydraulic.htm

Ok guys, thanks for all your help. Would like to get this nailed down, or at least get cooler weather (its hot in the volvo with no AC!)

[Bill R.]

the engine compartment? Its inside the car where your feet are at on the pedals... You have to take the lower dash panel off and you can then see the master cylinder up above the clutch pedal.. You look at the boot on it for leakage, if theres no leakage then i wouldn't replace it.

Ok guys,

Continuing my "highway only soft clutch problem"....

I topped off the fluid (took quite a bit actually, yet the level didnt change much), drove up to gville, same problem. Almost no clutch on the exit ramp, yet perfect by the time I had gone through 3 lights (which in gainesville on a friday night is gear 1, 2, stop, 1, 2, stop, 1, 2, 3....no nevermind stop...you get the idea.

So I got underneath the car today: No brake fluid near the clutch slave, no brake fluid around the master, flex hose is bone dry. So I went to check the connection between the metal hose and the master clutch cylinder, and thats where I ran into problem number 1:

How in the hell do you get to the clutch master cylinder? Is it a 'by feel only' thing, or do I have to remove the brake booster?

Well, I tried to feel my way around there with my hand, which really I didn't expect to do any good since the grommets on the resivoir have been leaking anyway. So in doing that, my arm pushed on the resivoir and the grommet started hemmoraging for lack of a better term. Got a good amount of brake fluid all over the ground, fortunately none on the exterior paint. After cleaning everything up, I went for a drive to check it, and my anti-lock (ABS) light flashed for a bit and then went off.

So at this point I'm kind of stuck in a pickle. On one hand, I don't know if I should fix the grommets first and see if its sucking in air (although I don't know how air that high in the system will hurt the clutch) and then replace the clutch master later (even though I still have no reason to belive its that, its just that I don't see it bieng anything else), or do I just buy everything and do it all at once?

I thought it might be the connection between the clutch master and the metal line, but that brings me back to the same problem-how do I get to that connection? I read brunos page, he says he pulled it a bit and used a wrench. Does he mean he pulled it through the firewall?

Here's the link for those too lazy to look: http://www.bmwe34.net/e34main/mainte..._hydraulic.htm

Ok guys, thanks for all your help. Would like to get this nailed down, or at least get cooler weather (its hot in the volvo with no AC!)

[DanDombrowski]

Ok, yeah, I didn't word that very well.

I realize that the clutch master is at the pedals. The boot has a crack or two, but no fluid on or around it.

What I'm talking about is the connection of the master cylinder to the hydraulic line that goes through the firewall. The bentley says to first disconnect that hose on the engine compartment side of the firewall. Can I completely take the master clutch cyl out from the interior of the car, under the pedals?

I'd like to inspect that fitting between the clutch master and the hose it connects to (the output hose) for leaks, since I don't see where else it could be leaking.

Does anybody think this problem could be caused by a set quantity of air in the lines (not necessarily leaking air, although I don't know how else it would get in) that could be resolved by bleeding, or am I wasting my time with that?

[emw525E34]

The last time I had that light-clutch, it went to zero within 2 miles and I was stuck. The slave was replaced and car was good as new. I got a local Indy to do this.

[Bellicose Right Winger]

Replace the grommets so they can be ruled out as a cause. This will also seal a known leak and help determine if there are other leaks. For example, is the slave cylinder leaking into bell housing and exiting below flywheel where it looks like the engine oil grunge that accumulates there?
You may have to remove SC to be certain it's not leaking.

If the MC outlet connection was leaking, I'd think you would see fluid on the tube that passes thru the firewall.
Yes, the MC is removed from interior of car. Did you remove the aluminum "knee crusher" behind the lower dash panel to give access the pedal assembly?

Did you loosen reservoir cap as suggested by Anthony (M5 in Calgary) to rule out blocked vent possibility? A blocked reservoir vent, combined with leaking grommets "may" create a slight vacuum in the reservoir (like finger on end of a straw) which could starve MC of fluid. It may also draw air into system through any less than perfect seal.

Next time this happens, pump pedal 10-20 times. Clutch should return to normal operation. Your transmission will thank you.

If you have no external leaks and reservoir vent is open, then it's time to change the MC. If the MC is leaking internally, it will push less then the proper volume of fluid on each stroke, because fluid is bypassing the internal plunger seal. This causes clutch to engage close to floor.

Paul Shovestul

Ok, yeah, I didn't word that very well.

I realize that the clutch master is at the pedals. The boot has a crack or two, but no fluid on or around it.

What I'm talking about is the connection of the master cylinder to the hydraulic line that goes through the firewall. The bentley says to first disconnect that hose on the engine compartment side of the firewall. Can I completely take the master clutch cyl out from the interior of the car, under the pedals?

I'd like to inspect that fitting between the clutch master and the hose it connects to (the output hose) for leaks, since I don't see where else it could be leaking.

Does anybody think this problem could be caused by a set quantity of air in the lines (not necessarily leaking air, although I don't know how else it would get in) that could be resolved by bleeding, or am I wasting my time with that?

[Bill R.]

be wet with fluid since thats a pressure side leak. If the clutch master is bypassing internally it will definitely leak at the boot or bellows on the clutch master since its just a single stage master unlike brake masters. It doesn't seem to me that the grommets would have any effect on the clutch master source of fluid since it taps into the reservoir a ways up from the grommets, this would tend to affect the brakes not the clutch... If you did have leaking grommets and the vent in the top of the cap was plugged then the grommets would act as a vent for the fluid going to the clutch master anyway, none of which should have an effect when your on the highway anyway. If you can't see any leakage at all at the master then i would be real tempted to unbolt the slave and see if its been leaking into the bell housing as Paul suggested.. Anytime there is a means for air to get into the system there almost always has to be some visible leakage .

Ok, yeah, I didn't word that very well.

I realize that the clutch master is at the pedals. The boot has a crack or two, but no fluid on or around it.

What I'm talking about is the connection of the master cylinder to the hydraulic line that goes through the firewall. The bentley says to first disconnect that hose on the engine compartment side of the firewall. Can I completely take the master clutch cyl out from the interior of the car, under the pedals?

I'd like to inspect that fitting between the clutch master and the hose it connects to (the output hose) for leaks, since I don't see where else it could be leaking.

Does anybody think this problem could be caused by a set quantity of air in the lines (not necessarily leaking air, although I don't know how else it would get in) that could be resolved by bleeding, or am I wasting my time with that?

[DanDombrowski]

Man Paul and Bill, you're freakin johnny on the spot with these replies. Many thanks to you guys for the professional help.

The problem I saw with replacing just the grommets is the logistics- pay 2nd day air shipping for 2 little rubber things when they could be included in free shipping with the MC (from BMA) or just waste my time driving out to the dealer to get parts?....well, thats my problem, not yours.

I thought about the slave clutch cyl leaking internally. I suppose that if it were leaking in air and fluid out, after a few pumps it would pump the air out at the end and be good? This makes sense to me. Now, what other consequences might leaking hydraulic fluid into the bellhousing might I have? A glazed clutch? Because I *thought* I felt the clutch judder a little this morning, and thats new, but it might have just been in my head.

Yeah, I cracked the resivoir cap a little on my drive home, no difference. I removed the plastic trim that holds the gong and the air vent, I didn't know about removing any aluminum knee crusher. I can see most of the master cylinder and the hose that connects to the top, but not the hose that connects to the outlet side of the MC, it looks like it sticks out through the firewall.

Alright guys, I'm putting an order into BMA as soon as they wake up (its 5:30 am where they are) and I'll see what the costs are, I'll prob buy the slave as preventative maintenance, replace the grommets, and bleed the system. I'm spending way too much time on this, I'm taking up your time, and I'll still end up spending less than taking it to a shop, so I might as well get it done with. Later all, and thanks again!

[Bill R.]

bell housing won't make its way to the clutch disc

Man Paul and Bill, you're freakin johnny on the spot with these replies. Many thanks to you guys for the professional help.

The problem I saw with replacing just the grommets is the logistics- pay 2nd day air shipping for 2 little rubber things when they could be included in free shipping with the MC (from BMA) or just waste my time driving out to the dealer to get parts?....well, thats my problem, not yours.

I thought about the slave clutch cyl leaking internally. I suppose that if it were leaking in air and fluid out, after a few pumps it would pump the air out at the end and be good? This makes sense to me. Now, what other consequences might leaking hydraulic fluid into the bellhousing might I have? A glazed clutch? Because I *thought* I felt the clutch judder a little this morning, and thats new, but it might have just been in my head.

Yeah, I cracked the resivoir cap a little on my drive home, no difference. I removed the plastic trim that holds the gong and the air vent, I didn't know about removing any aluminum knee crusher. I can see most of the master cylinder and the hose that connects to the top, but not the hose that connects to the outlet side of the MC, it looks like it sticks out through the firewall.

Alright guys, I'm putting an order into BMA as soon as they wake up (its 5:30 am where they are) and I'll see what the costs are, I'll prob buy the slave as preventative maintenance, replace the grommets, and bleed the system. I'm spending way too much time on this, I'm taking up your time, and I'll still end up spending less than taking it to a shop, so I might as well get it done with. Later all, and thanks again!

[Bellicose Right Winger]

Master clutch cylinders can leak internally without leaking at the boot/bellows. The following link shows why.

http://www.gordon-glasgow.org/Images/45.gif

The master cylinder piston (10) has two seals (11) and (13). (11) is the primary seal which holds pressure required to operate the slave cylinder. (13) is the seal that prevents leakage towards the clutch rod boot/bellows (23).
Internal leakage can bypasses seal (11) and return to MC reservoir, without any traces of an external leak.

Paul Shovestul

......If the clutch master is bypassing internally it will definitely leak at the boot or bellows on the clutch master since its just a single stage master unlike brake masters.

[Bill R.]

clutch masters that i've replaced i haven't yet seen one that bypasses internally without evidence of a leak at the boot... but i suppose after 30 years there's always a first time.

Master clutch cylinders can leak internally without leaking at the boot/bellows. The following link shows why.

http://www.gordon-glasgow.org/Images/45.gif

The master cylinder piston (10) has two seals (11) and (13). (11) is the primary seal which holds pressure required to operate the slave cylinder. (13) is the seal that prevents leakage towards the clutch rod boot/bellows (23).
Internal leakage can bypasses seal (11) and return to MC reservoir, without any traces of an external leak.

Paul Shovestul