850 Hydraulic clutch Issue

[volvolugnut]

So, if I understand, a pin (where?) fell out of the master cylinder while you were in the main intersection during lunch time? Is that correct?

We can fix it, really.

volvolugnut

[manovlov]

Sorry Buddies, a moment of lost... So.

So, if I understand, a pin (where?) fell out of the master cylinder while you were in the main intersection during lunch time? Is that correct?

We can fix it, really.

volvolugnut

At first, thanks to the rescue team ...

@volvolugnut :
This pin:

slave cylinder 1.jpeg (76.9 KiB) Viewed 796 times

I succeed in repairing the clutch, it works for approximately 25/30 pedale pressures, and the pedal stays in the bottom of the "foot switch". The pin is in extension, the clutch is "open", it means that you can't change any gear, the slave cylinder is full of DOT. And you are bombed with tones of insultes, even someones I didn't know they were existing...

I will re install the slave cylinder tomorrow, and plug its bleeder to a brake caliper one, and use the brake pedal to push the dot in the circuit.

I come back to my question :
that's how I have plugged the hoses with my Volvo dealer advice :

Reservoir Master cylinder.png (103.47 KiB) Viewed 796 times

Do the 2 and 3 be Interverted ?

Any idea ? I must go further on my car.It's about to become crazy.

Manov

[Chuck W]

Did the slave cylinder pop loose from it's location again? Was the c-clip still in place? It's not really possible for the slave piston/pin to push itself that far out when things are properly retained.

There is no pressure in that reservoir, so it shouldn't really matter where you attach it to the clutch master cylinder.

The only other possibility is there MAY be an issue with the clutch fork inside the transmission. Maybe it's out of place, or worn or something, which is allowing the slave cylinder to push farther than it's supposed to and forcing the piston out.

You need a friend to push on the clutch pedal for you while you watch things under the hood to see what might be happening.

[manovlov]

Exactly what I was thinking of. It's 2:06 in the morning here. I think about this thing since 4 hours. Yes, the fork... The last time I had this issue, when I depresses the pistionafo the slave cylinder, she looked as she was completely free. Is there a way she should stay in place ? What 's the option ? May I correct this issue without put down the gearbox ?

The clutch worked perfectly from September 19 till august this year, until the seal of the clutch pedal failed.... It's a track to explore.

I will see it tomorrow.

If someone has a very precise board on how this fork should be placed, I take.

Thanks to have brought me on this track.

Could it be the 6 and 6a the issue ? If yes, does it mean I can fix it gearbox on place ?

Manov - Clutch.png (526.29 KiB) Viewed 775 times

Manov

I've found this, which looks like my issue. Excepted that all parts are OEM and brand new.
https://volvoforums.com/forum/volvo-850 ... ork-24526/

[Chuck W]

The problem in the link you posted is that the poster didn't install the clutch itself correctly. You don't have any problems or odd noises in your clutch actuation until it just fails. The fork pivot ball bushing (6a in the diagram) could cause issues if it's worn, but you'd also have problems with the clutch engaging/releasing, as you wouldn't have full travel. The fork will have some free movement in it, as it isn't held down by any fasteners. It just holds the throw-out bearing around the transmission input shaft and rests on the pivot ball.

On your car, when things fail, is the slave cylinder still securely attached in the transmission? If not, the problem is that the slave cylinder is being pushed out of its mount. If it is, then the problem is probably with the clutch fork, or its pivot and bushing, which unfortunately requires the transmission to be removed.

[manovlov]

Ok. This could be the problem.

[manovlov]

Ok. I've controlled everything, re assembled the slave cylinder, the clips etc.... Then I get started to push the fork to full the Dot circuit. Then, I've controlled the reservoir level, and, to finish, I started to pump in the car with the pedal. 5 time and again same problem. I think it has to matter with the fork. It moves to the front, to the back, but also up and down, too much to me. There no other choice than get the gearbox down.

[abscate]

You will be the MVS expert on transmission removal , Manov.

I think you say.. “ to something , everything bad is good” in French

We say..every cloud has a silvery lining.

Trivia,,,in Swedish it’s every cloud has a gold lining. No wonder Volvo parts are expemsive!

[Chuck W]

So, the clutch slave cylinder is still properly fixed in its mounting place on the trans when things fail? (You haven't really answered that question yet).

Do you have someone watching the slave/fork actuation when it fails? (To see if the clutch fork actually moves to the side, allowing the issue)

What is the mileage on the car? Does the clutch work perfectly until it fails? Or does it act like you're not getting enough clutch engagement/release?

A transmission drop in one of these isn't too difficult, but not something you're going to want to attempt without the proper equipment.

[manovlov]

So, the clutch slave cylinder is still properly fixed in its mounting place on the trans when things fail? (You haven't really answered that question yet).

Yes, it's stay on its place and the clips is ok

Do you have someone watching the slave/fork actuation when it fails? (To see if the clutch fork actually moves to the side, allowing the issue)

No, no-one to help me. But I don't know if the clutch should move this way. I suppose I may always have air in the circuit, that the reason why to me, the fork move on the side.

What is the mileage on the car?

155 000 kilometers - 96 400 miles.

Does the clutch work perfectly until it fails?

Yes, everything was fine before this issue.

Or does it act like you're not getting enough clutch engagement/release?

No, everything works then after a certain numbers of pedal pressures, it failes.