Problems bleeding clutch !

[sparky2]

Hi All, yesterday changed the brake fluid OK on my 2009 Scout,it says then it's best to bleed the clutch which was going OK but now it won't get any pressure and the pedal stays down and there's no fluid coming out, brake reservoir has been topped up but now there's nothing. Any clues ?  I'm thinking main clutch cylinder seals.  Cheers Stuart

[J.R.]

Did you bleed it or not?

 

If so then that is obviously where your problem came from, you don't need to ask for clues.

 

How did you bleed it?

[sparky2]

Hi J, Clutch was working fine beforehand, we're due to go to France a week on Tue leaving home next Fri with our caravan so checking the car over decided to change the brake fluid,did that yesterday OK, so this morning bled the clutch with the wife, open valve pedal down shut valve pedal up etc, only trouble is the pedal was staying down and not returning so she hooked her foot behind it and flipped it up, fluid was coming out dirty so kept going until the fluid stopped even though I was topping up the reservoir and never went below half way, now there's nothing coming out of the bleed valve.So I'm thinking the clutch master cylinder needs new seals. Cheers Stuart

[Guest]

@sparky2

 

It will be fine, they are notorious for going bad when bleeding manually and leaving you with a pedal that flip flops the full travel without actually doing anything.

 

You need a pressure bleeding kit like a Gunson Eezibleed.

 

Alternatively in a pinch you could improvise something similar to do the job:

 

1. fill the fluid reservoir to the top.

2 form a seal over the top using a plastic bag/cling film etc. scrunched up.

3. using a length of hose/turkey basting syringe/whatever, integrate it into the seal you fashioned so that you can add positive pressure to the reservoir.

4. open the clutch slave cylinder bleed nipple and blow/pump to force the fluid through. You shouldn't need much pressure if the nipple is fully open.

5. once you have bled a small amount, close the nipple and test for correct pedal operation.

6. repeat as required.

 

Even an inflated condom/balloon over the reservoir would do to pressurise it!

 

Be mindful of running the fluid low, the clutch feed is higher in the reservoir than the brake's

Edited 20 August, 2022 by MicMac

[J.R.]

That is not the way to bleed the clutch nor is a pressure bleeder necessary, the system is designed for gravity bleeding.

 

You simply attach a bleed hose and leave it vertical for bleeding or loop it down into a jar to purge the fluid.

 

You open the knurled thumbturn bleed valve and if bleeding just wait for the air bubbles to rise, they will be sat in the air chamber just under the bleed knob, if purging the fluid just wait until the fluid runs clear while topping up the master cylinder, the take off port is above the bottom so you cant run it dry and affect the brakes but you could put air in the clutch if you let it drop too far.

 

Never hook up the pedal if it remains down especially with the bleed valve closed, it can detach the plastic master cylinder pushrod from the piston, when using the correct procedure you will never be in the situation of having the pedal on the floor.

 

I understand why you bled it using the time honoured procedure, I did the same myself and gave myself a whole world of problems, after 2, maybe 3 master cylinder changes (I broke the pushrod once) and ending up losing the clutch and having to bleed it every 5 miles in stop start traffic conditions I learned a lot about the clutch hydraulics and how to bleed them blind at the side of the road in minutes.

 

I suggest you start again with a patient gravity bleed to just get the air out (no assistant needed) as the fluid has already been purged.

Edited 20 August, 2022 by J.R.

[sparky2]

I've taken off the master cylinder and ran some brake fluid through it and there were black bits coming out so I've bought a new cylinder,it's now fitted and I've just tried pressuring it with a gunsons bleed kit (20psi), it blew out into a jar with fluid in and blew bubbles and fluid, pedal goes straight to floor, I'm now going to try taking the reservoir down to below the clutch outlet remove that pipe and inject clean brake fluid until no bubbles come out of the slave cylinder bleed valve with the pedal up.

 

[J.R.]

You are your the author of your own destiny.

Edited 21 August, 2022 by J.R.

[StevesTruck]

Literally just brim the reservoir, sit the cap on top to keep the grime out, open the bleed nipple on the clutch and let it gravity bleed, preferably into a bit of clear pipe so you can watch it. Then go for lunch while it sorts itself out. 

 

I'm very much not a fan of the eezi pressure bleeders. I prefer a vac bleeder, either one that goes on the compressor or a handpump. If a gravity bleed won't do it, that's going to be the next course of action. 

 

Once you've got fluid there, and the pedal returning - I'd bleed it in the normal manner that I bleed clutches:

 

Press the clutch down and release it about 10 times, hold it down on the last one. 

Stick a bit of pipe on the bleed nipple, run it into a pot with some brake fluid it.

Release the bleed nipple (pedal still down)

With the pipe still running into the pot of fluid - Pump the clutch about another 10 times. Hold it down on the last one and close the bleed nipple. 

 

Not everyone's going to be a fan, but that's just what works for me. 

[Guest]

You could rig up a squirty bottle trigger/push pump to the bleed nipple to act as a vacuum bleeder.

Edited 21 August, 2022 by MicMac

[sparky2]

I've used a syringe and pushed the fluid through until no bubbles are in the clear tube into a bottle of fluid at the bleed end all with the pedal up, then I've reattached the inlet pipe onto the reservoir and topped up the reservoir and put the cap on, not tried the pedal as I'm going to leave it standing overnight and see what it's like Tomm lunch.

[StevesTruck]

I'd probably leave it open with a bit of pipe as a funnel if I were going down that route. 

[J.R.]

Did you fit a new seal to the rigid pipe that goes into the master cylinder?

 

Did you fit it to the pipe and not into the cylinder?

 

Did you push it on to the pipe until it clicked?

 

If not then shine a torch behind the cylinder into the space between the heat insulation and the bulkhead, if the joint is leaking, which will make bleeding impossible, the fluid runs down there unseen and can pool unseen on the undertray, or simply puddle on the drive unseen under the car.

 

Don't ask me how I know - I told you I was an expert!

[J.R.]

4 hours ago, sparky2 said:

I'm now going to try taking the reservoir down to below the clutch outlet remove that pipe and inject clean brake fluid until no bubbles come out of the slave cylinder bleed valve with the pedal up.

As you are determined not to use the correct gravity procedure if this hasn't worked then next time you should do it the opposite way around, you are trying to push air downwards when it wants to go upwards, the bleed valve is for bleeding any air in the slave cylinder below it (assuming a concentric cylinder) any air bubbles in the pipework above will rise up to the reservoir naturally unless you have created an airlock with your bleeding attempts, in which case you need to start again, if you are determined to use a syringe use it from the bottom pushing the fluid and air to the top, better still use a Mytyvac from the top.

Edited 21 August, 2022 by J.R.

[sparky2]

 found how the garage does it.

Edited 22 August, 2022 by sparky2

[sparky2]

Just been out to try it again and there's no resistance on the pedal, topped up the reservoir to the brim, didn't Use any new seals as it was weekend,yes to taking off the rubber inserts and fitting them to the pipe,carnt see any leaks,there's a round thing in the pipework at the back of the bulkhead ?,   I've got a dentist app so I will try again in a couple of hours.thanks for people's help 

 

Edited 22 August, 2022 by sparky2

[J.R.]

I have several of those round things, wherever the pipe takes a 90° bend, I never did work out what their function was but in my case it was a red herring.

 

What slave cylinder does your car have, is it an internal concentric release bearing one or the external one with a pushrod to the clutch release bearing lever?

 

You should have a flexible pipe to the bleed block, if you clamp that and very gently depress the clutch you will be able to tell if the air is upstream or downstream, if downstream the pedal will be rock hard, do not push any more as you will have no doubt noticed that the master cylinder pushrod is plastic.

 

Once again don't ask me how I know

[sparky2]

Hi JR, it looks like it's inside the bell housing so I presume concentric,I will try clamping the rubber pipe but there is absolutely no resistance on the pedal and I pumped it up and down 20 times !  Is there anything inside the main cylinder that gives problems ? I will show a pic of the main outlet pipe after removal as I don't know if the seal was still on it ? Although I would have thought it would pee out fluid if it wasn't there.

 

[sparky2]

[sparky2]

Hurray found it, I had the car up on axle stands for bleeding the brakes and it was slightly nose down, enough to form an air lock in the master cylinder as the fluid outlet is underneath on the end, I read on here that they raised the front of the car, and it worked ! I bled it with the gunsons easybleed fed off an old bike innertube and followed the Skoda instructions.Thanks for all the suggestions, Happy bunny.

[Breezy_Pete]

Nice one, cheers for sharing that fix!

[J.R.]

Excellent news and thanks for the additional knowledge!

 

Enjoy your caravan holiday in France, looks like I will be going in the other direction at that time.

[simonds3135]

On 20/08/2022 at 22:29, J.R. said:

That is not the way to bleed the clutch nor is a pressure bleeder necessary, the system is designed for gravity bleeding.

 

You simply attach a bleed hose and leave it vertical for bleeding or loop it down into a jar to purge the fluid.

 

You open the knurled thumbturn bleed valve and if bleeding just wait for the air bubbles to rise, they will be sat in the air chamber just under the bleed knob, if purging the fluid just wait until the fluid runs clear while topping up the master cylinder, the take off port is above the bottom so you cant run it dry and affect the brakes but you could put air in the clutch if you let it drop too far.

 

Never hook up the pedal if it remains down especially with the bleed valve closed, it can detach the plastic master cylinder pushrod from the piston, when using the correct procedure you will never be in the situation of having the pedal on the floor.

 

I understand why you bled it using the time honoured procedure, I did the same myself and gave myself a whole world of problems, after 2, maybe 3 master cylinder changes (I broke the pushrod once) and ending up losing the clutch and having to bleed it every 5 miles in stop start traffic conditions I learned a lot about the clutch hydraulics and how to bleed them blind at the side of the road in minutes.

 

I suggest you start again with a patient gravity bleed to just get the air out (no assistant needed) as the fluid has already been purged.

 

Hi J.R, apologies for reviving an old thread but I need to bleed my clutch so was reading various posts on here and just wondered where you came across this information that a pressure bleeder is not necessary and the system is designed to be 'gravity bled'? I downloaded the Skoda workshop manuals and they say to use a pressure bleeder? 🤔

Edited 19 October, 2023 by simonds3135
Can't type properly

[J.R.]

With the evidence and experience of my own eyes and hands :

 

On 20/08/2022 at 23:29, J.R. said:

after 2, maybe 3 master cylinder changes (I broke the pushrod once) and ending up losing the clutch and having to bleed it every 5 miles in stop start traffic conditions I learned a lot about the clutch hydraulics and how to bleed them blind at the side of the road in minutes.