Bleeding the clutch..

Post Sat Oct 27, 2012 5:05 pm

Did a search but nothing came up on the first 8 pages..

Had the slave cylinder fail on my 325i touring.

So have replaced both master and slave cylinder today. I also put a Goodridge braided hose on.

After a little research I decided to bleed the system from the slave up in order to chase the air in its natural direction; up.

I attached a tube to a old styled oil pump then filled the tube with the clutch fluid so that no air was in it, then pushed it over the bleed screw on the slave, loosened it and pumped the fluid through until it came up at the other end in the reservoir.

I then tightened the bleed screw, got someone to pump the clutch several times and hold it down, opened the bleed screw to check, let a little fluid with no trace of air, tightened it off.

The clutch still felt a little spongey so I refilled the tube with fluid, attached it to the bleed screw and repeated the process...

Its still doesn't feel right, I pulled it into 2nd gear to see if there was enough travel in it but now its stuck in 2nd.

Its was also in gear the whole time whilst I worked on the car today, if that makes any difference.

Any advise on the bleeding would be great or if I've missed something, or do I just repeat this until its feels right??

Post Sat Oct 27, 2012 5:19 pm

Actually having just got it the car the clutch on the pedal feels okay (i think) but I still can't pull it out of 1st... it was vise versa.. I had it in 2nd gear whilst doing the work then put it into 1st after bleeding it... now its stuck in 1st

Post Sat Oct 27, 2012 5:19 pm

I've always introduced new fluid into the master cylinder and bled from the slave. Seems odd to be filling from the slave, but I kinda see your logic!

Also, I wouldn't pump the pedal several times. With open ended pipe over open bleed screw, get assistant to slowly push pedal to floor, tighten bleed screw, slowly raise pedal fully. Repeat until no bubbles come out.

Post Sat Oct 27, 2012 5:22 pm

It should come out of gear even without the clutch down.

Try rocking the car backwards and forwards while moving the gear stick.

Ben

Post Sat Oct 27, 2012 6:57 pm

i had to fill my resiviour up 2/3 times before it felt right, i didnt use any hose just undone the nipple with my mate pumping the clutch

Post Sat Oct 27, 2012 6:59 pm

As Alex said. This is what i did on my old touring.

Post Sat Oct 27, 2012 9:31 pm

greg124 wrote:I've always introduced new fluid into the master cylinder and bled from the slave. Seems odd to be filling from the slave, but I kinda see your logic!

This is what a watched

Got it sorted... I think. Ben you were right, I had it jacked up and I guess it was sitting on the gear. Took it off the axel stands, rocked it a bit; nothing, put the clutch down and let it roll back a bit and it came out of gear easily.. Thanks for that and thanks to everyone else for your comments.

It did get stuck in first again when I pulled up in a car park an hour ago or so. Alex I might just keep bleeding it though like you said. Otherwise I guess it might be gear linkage wear? I'll do some more research..

Post Sat Oct 27, 2012 10:11 pm

Glad to here you got one problem sorted.
Started to watch that on youtube, but the yank was just so bloody boring...
You might need to bleed 2 or 3 times to get all the air out, specially when you're filling new components for the first time.

Post Sat Oct 27, 2012 11:21 pm

Clutch fluid tends to get full of microscopic bubbles when filling and bleeding from empty.
Bleed it the best you can, then leave it for 24 hours, by when the minute bubbles will have joined together into a few larger bubbles, which can be bled out in the conventional way.
The 'reverse bleed' technique can be used if you get a really awkward one, and is usually performed by connecting a piece of tube from the front left brake calliper to the clutch slave, then using the brake pedal to pump the fluid through.

Post Sun Oct 28, 2012 9:43 am

^Cheers for this. Shall have another go at it today or tomorrow..

Post Sun Oct 28, 2012 7:03 pm

greg124 wrote:Glad to here you got one problem sorted.
Started to watch that on youtube, but the yank was just so bloody boring...
You might need to bleed 2 or 3 times to get all the air out, specially when you're filling new components for the first time.

Cheers..

American's Auto DIY vids are always a tad dull.. but then again what other home made DIY vids are..

Post Sun Oct 28, 2012 8:16 pm

Sometimes letting them sit for 10 minutes can transform them completely. Trying to let them gravity bleed through first can help as well, but you can struggle with a completely empty system.

I did mine the other week and it was a right pig. Got there in the end though. Letting it sit, and let it drip through itself did more wonders than having someone sat in pumping.

When you do have someone pumping, make sure to really emphasize the go slow and gently bit.

Post Mon Oct 29, 2012 10:33 am

The way I do these is to have the slave cylinder connected to the hydraulic line but unbolted from the box and hanging down. I made a clamp to hold the pushrod in whilst bleeding it. They can be a right bastard.