850 Hydraulic clutch Issue

Post by **manovlov** » 22 Aug 2020, 03:47

Hy buddies,

I've finished to install and fill my hydraulic clutch this morning. The pedal seems to have lot less resistance than usual. The brake pedal seems to works in two time starting from the middle of its run.

I may have plugged the hoses on the tank master cylinder in the wrong way, and of course I didn't take pictures of those before to unplug them.

Pedal master cylinder and clutch slave cylinder are brand new ones and I think I have installed them correctly.

So I have filled out my master cylinder tank, and I'm gonna inverse the two hose.

May someone help me sending couple of pics of his master cylinder hoses, to allow me to understand where I am wrong, or draw me a little diagram that could help me to install hoses properly ?

Is there a hydraulic pump excepting the steering wheel one, to put the clutch lines under pressure ? Do I have to make the engine run to test properly this installation ?

I don't hide you that I'm lost on this issue. I don't try to do mechanic stuff, but restoration, and as a newbie, I make mistakes. I feel uncomfortable in that position because the last time it arrived to me, I was on a French forum and have been shot in flame for my unknowledges of the way to approach mechanical world... It stills hurts.

Thanks to those that will help me.

Manov

Question : I can't install the spring from the clutch pedal. Can someone send me a picture his own clutch pedal ?

Manov

Post by **manovlov** » 23 Aug 2020, 10:11

Hy,

Here's a small video I've done with the pedal. It doesn't come to its normal place and I have to move it with the hand to help it to return toi its place. Does someone have an idea of the reason why ?

I need to find the issue as quick as possible because I must pick up my car for the job tomorrow.

Manov

Post by **volvolugnut** » 23 Aug 2020, 12:35

The clutch system will not have a pump to assist the operation. Only foot pressure on the pedal is used to operate the cylinder at the clutch. The engine does not need to be running for the hydraulic clutch to operate. If the clutch operates at all, then the hose connection should be correct. Did you bleed air from the clutch hydraulic system? There may be an adjustment to set clutch return (up) position.
I do not have a Volvo with hydraulic actuated clutch to answer your specific questions about the hose connections.
volvolugnut

Azik09 · Post by **Azik09** » 23 Aug 2020, 12:42

manovlov wrote: ↑22 Aug 2020, 03:47 Is there a hydraulic pump excepting the steering wheel one, to put the clutch lines under pressure ? Do I have to make the engine run to test properly this installation ?

No for both questions.
Try to bleed it "from below". Take a medical syringe of 20 ccm or greater and a hose which can be fitted to syringe and nipple on the slave cylinder. Then:
Slacken nipple and tight it back slightly
Open fluid reservoire cap.
Connect syringe (filled with fluid) to the nipple, slacken it and push fluid SLOWLY to the cylinder.
Close nipple.
Repeat this until you see fluid raising in reservoire without air bubbles. Remove an excess fluid from reservoir using a syringe. After this your clitch should operate correct, if there is no other defects.

Post by **manovlov** » 24 Aug 2020, 01:13

Azik09 wrote: ↑23 Aug 2020, 12:42
manovlov wrote: ↑22 Aug 2020, 03:47 Is there a hydraulic pump excepting the steering wheel one, to put the clutch lines under pressure ? Do I have to make the engine run to test properly this installation ?
No for both questions.
Try to bleed it "from below". Take a medical syringe of 20 ccm or greater and a hose which can be fitted to syringe and nipple on the slave cylinder. Then:
Slacken nipple and tight it back slightly
Open fluid reservoire cap.
Connect syringe (filled with fluid) to the nipple, slacken it and push fluid SLOWLY to the cylinder.
Close nipple.
Repeat this until you see fluid raising in reservoire without air bubbles. Remove an excess fluid from reservoir using a syringe. After this your clitch should operate correct, if there is no other defects.

Hy,

Thanks for the advice. I've found that which may correspond to your explanation right ?

Thanks again.

Manov

Azik09 · Post by **Azik09** » 24 Aug 2020, 03:56

Exactly. If you have no special bleeding tool as in this video, use a syringe. Order of operations is the same.

Post by **manovlov** » 24 Aug 2020, 09:25

Hy Azik09,

I bought a small bottle the same one the guy uses to. I will tell when I will finish ed to bleed.

manov

Post by **manovlov** » 25 Aug 2020, 04:33

Hy Buddies,

the bleed of the clutch pedal cylinder is a success. I've recovered my clutch brand new. I do sincerely thank Azik09, Volvolugnut,for their precious intervention. I also thank Robert DIY who has followed and supported me during this clutch restoration.

You, Guys, are AmAziNg !

A last question : how can I make longer the "run" of the clutch pedal, because for the moments this run is too short.

Manov.

Post by **manovlov** » 25 Aug 2020, 11:52

Hy buddies,
Against all expectations, the clutch worked for a while this afternoon.The pedal was a bit short, because as soon as the pressure was released with the foot, the gear shifted immediately. Good. A short clutch, I can do with it.
After a few shifts, the clutch went soft again and I broke down, not too far from home. I went to get the necessary to bleed it properly, and after the first bleed, it was better. I got behind the wheel and I activated the pedal, which was back to working at 30% I would say. When I started bleeding again, after a few moments the piston of the receiver on the gearbox started to lose oil through the rubberized part between the fixing ring and the clutch fork.

Failure of the part (original part recommended by volvo for this 850 model), I don't know. After that, towing at home, then tomorrow disassembly, order of a new receiver, arrived at skandix on friday that is to say no car before next wednesday. Not the drama.

But I don't understand what could have happened.
Also, is there someone who drives the same car with a hydraulic clutch and who would have 3 outputs on the master cylinder, who could post pictures, so that I can see if I made a mistake somewhere in the connection of these 3 hoses?

The piston of the receiver has moved back too much: in theory, the air bubbles should have gone up in the master cylinder tank, but there nothing...

Although an apprentice mechanic, I took care to respect the direction of assembly, the tightening, it is only on the master cylinder exits that I would have a doubt. For those who can help me, I refer them to the photos posted above in this post.

Is it possible that such a new part is faulty ? I specify that I'm not equipped with the vida so I reassembled it as I disassembled it.

Type : volvo 850 2.5 L 20 S 170 HP ESSENCE
Brake fluid : FERRODO DOT 4

All your advices will be welcome.

Post by **volvolugnut** » 25 Aug 2020, 12:12

Any rubber part can over time become hard and cracked. It may be that the slave cylinder at the clutch had been on the store shelf for years and went bad. Did the box or package for the slave cylinder look old? Did it have any dates on the package or the part? I would return it for refund of your initial payment.
Sorry this has been troublesome for you to repair.

New thought after reading your comments again: If the reverse pressure bleed forced the slave cylinder too far back, the seal may have reached the end of the cylinder and fluid leaked out the end. Since I do not have direct knowledge of these specific parts, I can't say if that is possible.
volvolugnut