Help me diagnose a persistent clutch hydraulics issue - mechanics?

Hello all.

Persistent issue I'm trying to diagnose before sending it into the workshop.

The issue is cyclic so I'll start with it in the 'working fine' state:

• Clutch fine, all good
• Engine is warm, I stay in one gear for say 3-5 minutes (motorway for instance)
• Clutch now feels like it's got air in it (not saying it necessarily does, just saying it feels like it), as in if I depress it it will not engage the clutch properly until the pedal is much further into its swing. (If I leave it for more than around 5 minutes, it wont even engage the clutch and the pedal will actually sit on the floor and not return.)
• If I put defender in neutral and pump the pedal (pulling by hand if nessesary) the clutch actuation will return over about 5 pumps - i.e. each clutch pedal pump brings the point at which the clutch itself first activates closer and closer to 'normal'
• I can now drive and clutch is magically like you'd expect it out of the shop - rinse and repeat ...

Some more notes:

• I replaced the master cylinder - defender had no issues for about a week, action felt smoother compared to old MC (woohoo!) - then the problem then returned (grrrrr)
• A few times I have purged the working fluid - best method is reverse bleed, of which I see some small bubbles hiccuping out. I try hard to minimise it but I cant be 100% sure they weren't simply introduced in the bleed process (attaching tubes etc.) - keep in mind that when the clutch is in its working state, it really does feel comparable to known working clutch on my mates defender (it actually feels better)
• I see no fluid leaks or loss of level in the reservoir - but I do note, that the fluid gets dark.

It feels like driving with clutch clutching (i.e. pedal up) is introducing air into the line, and then pumping the hydraulics is releasing it again - but that doesn't make much sense to me (why aren't I losing fluid?).

As mentioned, the fluid is getting dark, am I losing clutch fluid to the transmission, and gaining transmission oil ??

Is the spring return on the slave working its way into compression (how?), getting stuck, and the pumping action is releasing it? (actually this doesn't make much sense...)

I don't know enough about this stuff, so my suggestions may make only partial (or zero) sense - keen to learn though...

It's a puma, the slave is internal to the transmission, so I personally cant access it.

Fluid going dark is the rubber breaking down, I would look at the flex hose and the slave cylinder, and if not sure just change them.
Get decent ones TRW etc the rest are just trouble in the long run.
Ive always bled mine downhill.
There is no path for the trans oil to get into the hydraulic system and vice versa.

Good to know regarding the oil cross-contamination - thanks for confirming that.

So ok, flex and/or slave - aside from the bleed valve and various line connections that's all that is left anyway, and it would seem the next step - but what I'd love to understand is how the symptoms I describe can come to be...

Without more info on how it works exactly (other than drawing a very basic hydraulic slave piston), logic would indicate the slave is at fault. Flex hose is just flex hose right? No magic, air introducing/air removing action when fluid flows through it right? It's right by the bleed valve so I've touched it a bit, seems aged, but solid (no bulges). Unless something changes when the engine heats up ??

It'd be great if it were the flex hose, i could do that myself - but again, symptoms seem more complex, indicating the more complex part (slave) may be at fault (?)

Change the slave cylinder. Cheap and easy fix. master and slave cylinders usually follow each other to give up the ghost. My theory is that the seals in both cylinders would be tired and the extra pressure created by a new cylinder will promptly finish off the old seals in the other cylinder. I have had similar symptoms with my series 3 a long time ago. It would start off fine, then in the course of the day the pedal would feel more and more spongy.

In the puma/MT82 the salve is located inside the transmission:



It's the same amount of work as accessing the clutch itself - i.e. if your odometer is high, you may as well swap out the clutch at the same time...

You can see why I'm keen to avoid it if possible!

Yikes! yet another reason for me not to ever want to own a Puma then!

Before you go hauling the gearbox out, it's worth replacing the flexi hose in case it's breaking down internally. There could also be an air leak at one of the unions.

Seems like a good idea.

By suggesting I wait on the gearbox, are you inferring that (aside from the fluid discolouration) that the breaking down flexi hose is causing these clutch symptoms?

Air leak sure at connection sure - but I see no fluid loss, or leaks externally ... It would have to be a pretty selective air leak only letting air in and out, but not fluid, and only in the conditions I've outlined.

I did note there is a breather on the master reservoir, but I swapped that out already.

Wish I knew more about what was going on inside the slave.

Your slave seal/s is breaking down, managing to work a bit, then breaking down a bit and then working a bit and repeat - but not for long and soon you'll have no clutch - sorry. It only needs to lose a tiny bit of fluid - or draw a tiny bit of air to cause your symptoms.
So you have to drop your box to just replace a slave? Really? Which brilliant mind came up with that? Good luck - as said may as well do clutch, bearing etc while you're in there.

ok then, time to bite the bullet! It's going to the mechanics early next week.

What puzzles me is that it is quite deterministic how I can 'reset' it with pumping - in fact, if I pre-emptively pump the clutch every 2mins, I never experience the problem (!)

Of course, I do experience the pain of pumping the clutch every 2mins... But obviously not an issue driving around in the city in traffic.

Rather than just do a whitewash replace I'd really like to know what it is - but yeah, the work involved in the iterations of testing amounts to too much time and $$

I'm not familiar with that slave and some design idiot may have made it way more complex than it need be................... but basically a hydraulic clutch - as you know - is just two syringes connected by a pipe, push one in - other has to go out - in theory. What can happen, and I've seen this, is the "lip" on the seal wears and can distort then starts doing all sorts of unpredictable things like letting fluid past one way but not the other or drawing air in but not letting fluid out. Your pedal lifting probably momentarily re-flexes the seal and temporarily fixes the problem. I had a very heavy clutch in a truck and once only it let fluid past the seal, strip slave, clean and replace [same seal] never happened again............................. good luck

Had similar issues with my series and that was down to perished flex you hose as advised. That's where I would start if you have already replaced master cylinder.

Thanks for all the tips and experience - looks like it's time to get in there.

I'm guessing with mechanics closed over the summer break they'll have a waiting list so I may as well do the flex hose myself while I'm waiting. Hopefully a part is available local, otherwise it's a weeks wait. My personal prediction is the flex isn't at fault, but it isn't a huge sunk cost to replace so - yes, mind made up on that.

I can always cancel slave/clutch/bearing replacement booking (for a later date) if the flex was at fault. Fingers crossed.

As for the slave I'm certainly not doing that myself, who knows how many new problems I'll introduce myself in getting that far inside - not to mention I only have a used driveway for working space.



Hopefully I can find a mechanic that isn't (outwardly at least) against me peering over his/her shoulder at every step.

Looking at the parts I see some more points of possible failure:



16 is the flex hose
21 is a 'damper' (suspicious??)
18 and 19 are both listed as 'adaptors' - although 19 is the bleed valve also

Should I also replace these other elements? What does the 'damper' do... Usually I'd expect a damper to be in essence a dashpot, i.e. something that resists attempts at fast fluid flows (a fluid resistor ?).

I didnt realise it was a puma, I assumed it was old hence the hose suggestion, I doubt on such a new motor that its at fault, but got to be worth a try as a lot cheaper than the slave!

I also have the same problem with my 2010 puma clutch, changed master cylinder worked fine for about 2 hours. Ended up being towed to garage.
Did you replace the hose and did it work ?

So Land Rover managed to "develop" the hydraulic clutch from THE most basic of fluid dynamics into this level of complication? Alas, if it's all inside the bellhousing replace the lot [and be grateful you're not half way across the Sahara] GOOD LUCK

PS. Possibly the "damper" lightens the clutch action? Which begs the question would you prefer a heavy clutch that actually works?

its never the flexi hose its master cylinder or concentric (slave cylinder)usually both that need changing

Good day to all.

So, I've searched the web and this Landyzone forum and found this thread to be the closest to my clutch issue. It's just that the AgentMulder that posted the thread did not give the final resolve for his problem.

First, let me tell you about my clutch issue. I've got a 2007 Freelander 2 2.2 Td4 SE with 260k Km on it.

I had a slave cylinder issue about 20k Km (2 years) ago, when the clutch pedal went to the floor and when I pulled it back it just went straight down to the floor. I looked under the engine and saw the brake fluid pouring out between the gearbox bell housing and the engine. I then looked at the service manual and found that the slave cylinder is combined in the thrust bearing. This immediately showed me that it was going to be a big job dropping the gearbox. So, I did the responsible thing and changed the dual mass flywheel, clutch plate, pressure plate and the thrust bearing, which is also the slave cylinder, all at the same time. This was a solve for the first clutch problem.

Now, I'm experiencing more or less the same issue. About a month back the clutch pedal started going soft and after a few days also went to the floor and as I pull it back up, it would just go down again. First this I thought is the slave again and looked under the engine for leaks. No leaks and the brake fluid level did not drop. Then it could not be the slave cylinder again as it is only replaced about 2 years ago.

So, I then replaced the master cylinder, which was another big job that I did not expect. Bleeded the entire clutch system after replacing the master cylinder and the clutch was working fairly good, but still some air in the system. I drove with it couple of days and kept bleeding the system and it just kept being a bit soft, thinking there must still be air in the system. So, a week ago I bleed the clutch system with the bottle method with a bit of brake fluid in and a pipe inside and connected to the bleeding nipple. I did this untill I saw all the air coming out of the system and only clean brake fluid coming out the pipe.

The clutch was perfect. I was so happy that the issue was solved. Yeah right, only for 200 Km, then it started going soft again. It happened gradually. When I drive in town it's perfect, but when I drive on the freeway over 30 km then the pedal goes soft and stay on the floor. Then I pull it back up, pump it a few times and it's fine again, until I drive on the freeway again, then the clutch goes soft again. I can't see any leaks anywhere. I can't think that the slave is busy going again just after around 20k Km. Can it be? I'm not looking forward to dropping the gearbox again. It's not an easy job and to pay the agents an arm and a leg just to replace the slave is rediculous.

My only thought is to drop the gearbox and replace the slave again as I can't see any other solution.