Clutch pedal sinking to floor - technical people?

[kmb]

Wondering if somebody here could help me. My poor 850 T5 did 500 miles this weekend... and was faultless until I passed the keys to my aging father

Here's the scenario - My father was driving my Volvo 850 yesterday and told me that after 40 motorway miles he pulled up to a roundabout and when he put the clutch pedal down it stayed on the floor and he could not engage any gear.

It was pushed to a verge where he called the AA, during this time he tried to pull the lever up and it came back to the normal position, the AA contracted the job to somebody else who turned up and said something about a sticking plate somewhere maybe and take it easy he should get home OK, he then drove it home 32 miles without any serious problem. He did suggest it was maybe not as easy to select gear but wasn't certain.

It may be a coincidence that I topped the brake fluid up the day before with fresh dot 4, it was nearly on the minimum mark and doesn't appear to be leaking and has stayed at the topped up level, as far as I can see.

My initial thoughts are that I should replace the Clutch Slave Cylinder and have a full brake/Clutch fluid refresh. This looks a relatively inexpensive job.

Reading previous threads, other points to check are:
- Clutch Master Cylinder
- Possible leaking flexi pipe under battery tray

Has anyone had the same problem and is my approach above a good one?

If someone can provide or tell me the best place for a clutch slave cylinder then that would also be great.

Thanks in advance good people of the forum.

[dant5r]

It could also be the seals in the clutch master letting by.

Check if the carpet is wet around the top of the clutch pedal where the mastet connects to the pedal.

[kmb]

Thanks - Absolutely no sign of any leak around the pedal to bulkhead or in the engine bay.

I've just bought a replacement Unipart Slave Cylinder (ref GSY126), £25 delivered new off Ebay, which seemed very reasonable.

Will get a full brake/clutch fluid change when this is fitted and hopefully the problem won't recur!

[craigoodwood]

i sometimes have to stick my foot under my clutch after a casual long journey and after that the biting point is right by the floor for a couple of mins and then back to normal....

[kmb]

I'll let you know if the problem is solved by a new slave cylinder

[Kingsford G]

I'll let you know if the problem is solved by a new slave cylinder

The slave cylinder is in the gearbox bellhousing,if its not leaking is very unlikely to be causing this,brake master cylinder seals is most likely to be the reason as said above.

[kmb]

Thanks Kingsford, is this something that I can replace relatively easily or should I also just change the master cylinder for a new one? I think I've seen the seal kits sold separately.

I'm not sure if there is a leak, nothing I can obviously see, but it looked like the fluid may have dropped a bit since topping up.

Now back in France so won't get a chance to sort out for a month... I'll arrange the MOT at the same time as it will then be within a month of expiry. Hope it passes.

[Kingsford G]

Thanks Kingsford, is this something that I can replace relatively easily or should I also just change the master cylinder for a new one? I think I've seen the seal kits sold separately.

I'm not sure if there is a leak, nothing I can obviously see, but it looked like the fluid may have dropped a bit since topping up.

Now back in France so won't get a chance to sort out for a month... I'll arrange the MOT at the same time as it will then be within a month of expiry. Hope it passes.

The clutch master you should be able to do but the concentric slave is a gearbox out job which is not something you can do Im afraid.Look for any leaks underneath where the gearbox bolted to the engine,a slight drop could be just your pads worn down a bit depends on what u call a slight drop.Sometimes it helps flushing the clutch system but not guaranteed.

[Saaamon]

Some slave cylinders are on the outside and i believe book time is 1-2 hour. A bleed mite get some more life out of it, although worth noting it should really be pressure bled.

[kmb]

The slave cylinder on the 850 looks like this, external:



The garage quoted 1.5h to change and as mentioned it seems to be external on the gearbox housing,as shown below:



I'll try to find out how much changing the master cylinder seals will add to the labour.

[kmb]

I haven't got the car to hand for the next month to see if the clutch slave cylinder is concentric or external... as I've bought an external one (didn't realise the 850 could be concentric), I'm hoping it's that external!

It's a Feb 96 855 (OBDII), does this help define if it's concentric or external? Anyone know?

[Jamest5r]

It will be external

[kmb]

Thanks James - I have also phoned Volvo main dealers (FRF Swansea) in the meantime, with both VIN/Reg, who also confirmed it's external, good news as I've got the correct part on the way.

For added interest and thread info; the Volvo original parts from FRF with their 15% discount, came out:

- Full new master cylinder = £140.67
- External Slave cylinder = £106.60

Final question before I book some garage time, is it a relatively simple job to replace all seals in the existing master cylinder? The main dealer did not list the seal parts separately so I'd also need to source these, if I want to go belt and braces on this fix.

I found lots of useful pictures of the hydraulic line under the battery tray in this thread on converting an auto to manual: http://www.volvohowto.com/how-to-con...70-v70-or-c70/

[Saaamon]

I'd stick a genuine slave cyclinder on it and have a complete fluid change, brakes and clutch. Why is it you want to replace the master cyclinder?

[kmb]

I'd stick a genuine slave cyclinder on it and have a complete fluid change, brakes and clutch. Why is it you want to replace the master cyclinder?

It was only based on comments above, I have already bought the new Unipart Slave which hopefully will be good quality, the car will have a full brake/fluid change when this is fitted.

I was trying to get my head around what happened in simple terms... the foot was pressed and the clutch was not engaged when the pedal stayed on the floor, as no gear could be selected, this led me to believe that the slave cylinder had not extended (for whatever reason) to push and disengage the clutch. Lifting the pedal back up and pressing again did make the clutch work, this made me think slave cylinder had stuck.

Brakes have worked perfectly throughout, well... as good as the standard 280mm front discs can

[Saaamon]

Your brakes and clutch will feel great after a fluid change, seldom is it ever renewed.

[kmb]

Funnily enough, it was the one remaining fluid change that hadn't been done recently, looking through the service history it's been a few years! Just booked it in for the change etc

I'm getting ready to cross everything on the MOT part in a month's time, last time it only had advisory on rear pads/discs which have been done, but I've managed to cover a few miles recently.

[Saaamon]

Always satisfing knowing the car is well serviced and up to date with fluid changes etc. Not sure if you have a project thread going but you always seem to be asking good questions, get the feeling you look after your car well. Do you run it around France when your over there?

[kmb]

Always satisfing knowing the car is well serviced and up to date with fluid changes etc. Not sure if you have a project thread going but you always seem to be asking good questions, get the feeling you look after your car well. Do you run it around France when your over there?

Thanks - I don't really have a project thread, although some details of the car are here:
http://www.vpcuk.org/forums/showthre...=855+pampering

The car had full Volvo service history when I bought it last year, it's a particularly well looked after example for 138k miles, I've tried to go further and ensure it is in top mechanical condition. This forum had been invaluable in helping sort many of the very little technical things like vacuum pipes, BCS, improving and changing things like dodgy wiper switches, sticking boot locks etc

Unlike your mega mileage trips across the continent; I haven't used it for the trip to my place in Lyon France as I generally use my company car 2014 A4 TDi for the haul back and forwards, the free fuel helps!

I recently successfully used the Torque App and ELM327 to identify the leaking vacuum elbow on the left of the inlet manifold, Kingsford G was on hand with the worlds longest pliers to replace, all good stuff and a decent learning experience

[kmb]

Saaamon - You've inspired me to update the thread above, hopefully some of the things I find out will also help others