Series One 4.2 Clutch Bleed...again!

[andrewh]

Chaps, I thought I had bled the slave cylinder successfully on my 4.2 Series One but after standing idle for a few months, its got air in it again. I recall reading that there are several different slave cylinders and therein lies some of the problems with bleeding, needing different techniques? Since air tends to get gravitate upwards having the bleed nipple on the bottom of the cylinder perhaps is causing the problem, I also wonder whether if I remove the cotter pin and push the cylinder back in and block it there whether that may make bleeding more of a success. I cannot see any leaks anywhere. All ideas much appreciated as I am getting too old to mess around underneath it for any longer than I need. Thanks as always chaps.

[cactusman]

Don't want to sound pessimistic but if it had no air in it a few months ago and it does now there is a leak somewhere...air can only get in if fluid somehow leaks out. It is a bit of a pain to bleed but once done that should be it. I would check the whole system carefully for leaks at unions and the master and slave cylinders before bleeding again. If there is a leak you would be wasting your time without fixing it....

[mgcjag]

Hi Andrew......what ive done in the past is bleed as usual but also pull the pushrod fully in, no need to disconnect the pin....the extra bit you push in usually results in more bubbles being expelled.......you need 2 to bleed.....open valve, push pedal down...pull pushrod in the extra bit....close valve...release pedal......repeat.. Steve

[288gto]

Hi Andrew,

I know you like originality but I fitted this remote bleed from Fosseway.
It takes the bleed from the top rather than the bottom.



Failing that some form of pressure or vacuum bleed to purge the air out.
I might be wrong but suspect it is air still in the system. I would be interested to know how air is being drawn into the system without showing up as some sort of leak?

Hope you get to the bottom of it.

Simon

[andrewh]

thanks Chaps. And of course, if it its gone soft again, then there is air getting in. From somewhere. I had thought that there would be some tell tale leak . I guess not, it must be sucking air in somewhere rather than leaking fluid out. Anyway, I am interested in the easibleed from Fosseway and will call Simon tomorrow. Its not rocket science, I suspect a leak on one of the new pipes. tomorrow I will have another go!

[andrewh]

Sorted! I thought I had bled it correctly last time, although with the bleed nipple on the bottom its the devils own job. The Fosseway easy bleed kit looks a serious contender for next time, principally because it allow the bleed nipple to be on the top but accessible via the extended bleed nipple which I understand incorporates a non return valve. I have not bought one or have any affiliation with the company, but it looks a good solution to a couple of problems.

Anyway, back to my problem, it appeared that the pushrod had too much clearance, so what appeared to be air was in fact free play in the pedal. I spent some time talking with SNG about different pushrods, cylinders etc and came to the conclusion that the cylinders are all the same now, regardless of length ( SNG certainly could not tell me one was hydrostatic and one was not) but you need to ensure that you have 1/16th inch free play or else your pedal will be taken up with free movement. Another problem solved..a few more to sort! thanks for the input chaps

[Durango2k]

I have been exactly there a month ago.

Same with SNG, I finally welded up the rod with a thick 9 inch nail shortened to fit. And fitted the spring. Perfect now !

Freaky that I also made my own bleeding kit. Entry is now lengthened pipe and comes from below, exit to the top as SHOULD BE, MR. HEYNES, and I made an angled retainer, fitted to the final inlet manifold stud, and set a brake pipe coupling plus a bleed nipple there. Now, I can stand on the RH side and bleed my clutch in 5 minutes with a 50 cm clear hose.

Btw, the Citroen SM has Front inboard brakes, and to easen your life, the fitted remote bleeder from new. Being a hydraulic pressurized system, you open them, connect hoses to oil bin, start engine, sit inside, hit brake mushroom 5 times, shut of engine, close nipples, remove hoses, job done. No dirty fingers !

Carsten

[Hugo]

...... I would be interested to know how air is being drawn into the system without showing up as some sort of leak .....

Haha yes! - my Bristol does this - if left standing it draws air in by the offside rear wheel cylinder. One pump of the pedal and you get the air out & away you go. This seems to defy the laws of physics, since the whole system is supposed to be pressurised to a couple of PSI (the Bristol I'm talking about). Also I knew a girl who had the exact same problem on her Renault Espace - the pedal would gradually go soft - one pump at the o/s front caliper & it would be back to normal. No fluid leaks from either vehicle. Probably no help at all to you, except to say that yes, this can and does happen, for reasons that I can't explain.