Help! Bleeding Clutch Issue | SORTED

[moita]

Hi all,

I need some support, as I have tried all method, and to see if someone had the same issue. Before dismantling all by the way, have done brakes are very good, was suppose that clutch was easier (as done before), but being annoying.
I have tried pressure bleed, vacuum bleed, clutch pedal bleed.. and none seem to have a good result.

What happens is if I take foot really off from floor position (quickly) I listen like fast recovery noise (like boot suspension when we force them, like cavitation sound).

The thing is that when I press and take it off quickly and repeat it quickly the slave cylinder keeps moving forward and forward.. so maybe some air is getting in? If tends to rest, the first approach is good, than really hard and the noise when I release.

Note: new Lockheed slave (sounds like not having a clip outside), and rebuild kit on master cylinder

Thank you,

Nuno M.

[Oneball]

Sounds like the master cylinder isn’t fully returning. Is the pedal holding pressure on the master cylinder for some reason?

[moita]

Maybe.. that explains the quick return sound? The slave cylinder does move.

[moita]

I have found out what the problem was.

After swapping all (all was new,) I discover that was the flexible hose (which was as well new) collapsed. Sorted and great pedal feeling now.

[AndyPen]

I have found out what the problem was.

After swapping all (all was new,) I discover that was the flexible hose (which was as well new) collapsed. Sorted and great pedal feeling now.

I had that happen many many years back with a new brake pipe, amazing it can happen and really glad you have sorted it out;-)

[Herbert]

I had the same problem so I changed the hose to Aeroquip. I didn't like the look of the new hose, so I bought a very wide electrical heat shrink hose, put it on and shrunk it. You can't tell its Aeroquip

[moita]

Hi again,

Well, lesson learn, what a internal collapsed tube can do, it was a weird effect, as I had no air in the system.

Herbert, I see, more reliability was a good idea.

[Peter Laidler]

Same thing happened to me during a big bulkhead strip-down about 5 years ago. I had noticed that after I'd removed it, the bottom of the clutch master cylinder had a layer of black greasy stuff. I washed it all out, new seals etc etc. In reassembly with old hose it was hard to press the pedal. Realised that it was a slightly blocked/obstructed hose. Sure enough, it was. Had a new hose handy.

I made a note on the forum and someone said that the cause was the sulphur in the rubber hose breaking down and moving back and forth in action was the cause. That must be correct because someone on the forum said so!

[moita]

Hi Peter,

What I notice was little black dusty things.. and all was working. Pedal was nice but when I took off pedal quickly I heard a "cavitation" sound and I could pump and pressurised the system if like a one way valve was installed. The damn flexible hose was doing that

Now pretty good, lesson learn about that flexible hose, and was new. But maybe to much time on shelf.

I wrote about how it ended/solved as someone could have the same issue

[minibitz]

Collapsed flexi hose is an extremely common occurrence on cars I service.

Normally presents as a stiff pedal or intermittent stiffness if pumping pedal several time in quick succession.

Not sure exactly how many a year I go through but it's a lot!

When replacing slave cylinders I always replace hose as well. Particularly on later injection cars as the labour is mostly in removing the master cylinder and brake booster to gain access to the slave.

[moita]

Exactly that issue! and the pipe was new. I guess to many time in the shelve.

[Exminiman]

Exactly that issue! and the pipe was new. I guess to many time in the shelve.

was it NOS or just new ?

If quality is getting iffy, might be worth going down the Aeroquip route ?

[moita]

Was NOS out appearance and flexibility was nice.. but... Gave some headaches. Until found was the hose.

[Ronnie]

It is usually an assembly problem when the end fitting is inserted into the rubber pipe before crimping, a sliver of rubber is cut from the internal bore of the pipe.

[Peter Laidler]

Another problem I faced with a new hose - on a Saturday afternoon when I was going to use the car on the Sunday, was that the nut securing the hose to the bulkhead bracket wouldn't screw down far enough onto the star washer and bracket to secure the hose!
Not an easy fix as you can't hold the hose in a lathe chuck to skim or clean up the threads with a thread chaser.

Eventually did it - but it shows the importance of where possible, trying things first before final assembly.

Catmint really solved the problem.... Use one of their stainless large dia hose retaining nuts and internal star washer

Can I also suggest that while the clutch hydraulics are apart, you incorporate the simple clutch bleeding modification that's been mentioned on here several times. Turns cltch bleeding from a total chore to something more refined!!!

[moita]

In my case I have space it is a 850 SDL and LHD ! Not difficult to reach the bleeder nipple.