Clutch slave cylinder replacement

[The Veg]

Assuming no unexpected headaches, would I be correct to assume that this would be a fairly quick and easy job?

[john.p.clegg]

The most difficult part is getting the snap-ring/circlip off...

John

[mbell]

I found it pretty straight forward with nothing too tricky. The only real problem is bleeding, the bleed nipple isn't at the high point of the slave cylinder so hard to get the air out.

There are many many threads on here with suggestions on the magic solution to get the system to bleed. I'd predict you will read many and try many before you get it fully bleed.

[The Veg]

Thanks guys; you've given some useful information. I searched and read some old posts about bleeding and circlips and I'm pretty sure that I've got my head around it all and feel prepared. It's not the toughness of the job that worried me, it's the fact that the car is new to me so I haven't been under it yet, or even taken possession of it yet- it gets trucked Saturday morning from the seller's house to a friend's house where there is a four-post lift that I can use, and once the job is complete I can drive the car home. So I don't want to find myself unprepared and wind up having the car stuck at my friend's house for a variety of reasons. But I feel confident now and am looking forward to getting it done.

[webbslinger]

On my car, the hardest part is that the exhaust has to come off to get at the slave and to be able to pull it forward and out. The circlip will probably pop off your pliers a couple of times and it's tight with the wrenches on the port screws but it's straightforward. Nice to have the lift and if someone helps you it will go even easier. I'd taken slaves on and off a number of times and never had a problem bleeding until several months ago when I mistakenly adjusted the clearance on the clutch arm without making sure the plunger was pushed all the way in first. There was a post about that that I finally read. If you have to take the exhaust off you should probably have some new gaskets at hand. I think it would be worth it to put in a remote bleed line at the same time you replace the slave. It will make a simple job of it this time, and next time. Read all the posts, there probably isn't anthing that can go wrong that one of us hasn't written about.

[Robbie693]

I did this last week so it's fresh in my mind.

First off disconnect the inlet, if you have a Spyder chassis there is room for less than a flat of a turn with a spanner so lots of small swings and spanner turning are required, very tedious. Unless you remove the exhaust... The slave can rotate a bit so if the inlet and bleed screw are very tight you will need something to wedge against the spring boss to hold it in place. Removing the bleed screw first allows a bit more room to swing a spanner.

If you have the correct snap ring/ 'C' clip then snap ring pliers help a bit but I found I still had to do some persuasion with small screwdrivers to get it out of the groove. I have the straight type pliers but in hindsight the angled ones would probably be better.

This time around I found it difficult to get the inlet back in to the new slave perfectly square to avoid cross-threading, the exhaust is in the way preventing two fingers on one hand to reach the flats to turn them while pushing the inlet in the hole. Much profanity ensued.

Re-attach snap ring, same deal as above.

Get some fluid in and do a first bleed before adjusting the pushrod. The manual states that the adjustment should be done 'after the pedal has returned to the full length of it's travel'.

I used an easybleed initially to push the fluid through as I was on my own but I find this never works completely so I resorted to the only method that works every time and that is to wedge the pedal down for a few days and let the system self bleed. Not ideal if you want to drive straight away though.

I think part of the reason people have varying amounts of difficulty with the bleeding depends on just how much the solid pipe kinks and bends on the run from the bell housing to the slave inlet - mine bends all over the place and looks like a great place for air pockets to sit...

Good luck

Robbie

[Grizzly]

The job is easy enough but the last one i did was seized into the bell housing and was a bit of a pain to get out without damaging anything. I had to heat the loop up that secures it with some bottles to get the cylinder out (didn't want to smack anything cast with a hammer)

Don't forget to reset the clutch rod length (mine was too tight when the new slave was fitted and was slightly operating the clutch which i imagine wouldn't do the Thrust bearing any good)

Also have a good look at the return spring, my +2's spring was very weak when i removed it and again if that's bad it doesn't do your Thrust bearing much good.

As you might be able to tell i had to replace my Thrust bearing and thats a job i wouldn't wish on anyone.


One last thing, if you have the Nylon clutch hose check it carefully for nicks etc, mine had been rubbing and was giving me a similar fault as a faulty Slave cylinder so i got rid and fitted a Braided line which made a huge difference.

[Robbie693]

Don't forget to reset the clutch rod length (mine was too tight when the new slave was fitted and was slightly operating the clutch which i imagine wouldn't do the Thrust bearing any good)

That's something I forgot to mention - I had to back off the adjuster to even get the slave into the bell housing, it didn't seat all the way in with the push rod at the same length as it was with the old slave even though the piston on the new slave was all the way back. Maybe the piston was a bit longer on the new one, I didn't bother to find out.

Robbie

[elanner]

Strangely enough I never had a problem with bleeding the clutch, a couple of pumps and it was done. Go figure.

However, I did write a note in here last year about the hassle of the slave cylinder circlip. I didn't have the right tool so ended up using a regular circlip with eyes that could be opened by normal circlip pliers. This seems to be common practice.

Several months later I stumbled across the right tool in a small hardware store. They had just the one, so I grabbed it. It made fitting the right clip quite straightforward, if you ignore the convenient placement of the exhaust pipe.

Nick

[TroonSprint]

I filled the clutch system from the bottom up with an Eezibleed and very low pressure from a tyre, less than 5 psi. Let the fluid rise from the bleed nipple until the master cylinder reservoir is half full, then dive underneath and shut off the nipple. On both my Elan and my MGB I had an operating clutch right away. Air likes to go upwards, don't you know!

Mike

[Chancer]

That is brilliant lateral thinking, I would have never thought of using an easibleed backwards but it makes absolute sense!

[The Veg]

I went ahead and ordered the eyed circlips and a 90-degree plier. The merchant I ordered from (McMaster Carr) did have the lockring plier like Nick posted pictures of, but I did not order it since I have no idea whether this car has that type of ring or not. I should be good to go for whatever, as I've got plenty of tools to manipulate (or even destroy, if need be) the old ring.

One more question: what tubing inside diameter fits the nipple nice and snugly?

[TroonSprint]

That is brilliant lateral thinking, I would have never thought of using an easibleed backwards but it makes absolute sense!

Thanks Chancer. I wish I could claim credit for the idea, but I read it somewhere. Great idea though.

Mike

[Boomer100E]

Maybe it?s all been said before, but I thought that I?d add my two penn?orth on the ?wedge the pedal down for days? school of clutch bleeding. My thinking is that with the pedal permanently held down, the main clutch spring imposes a constant pressure in the hydraulic system. Over time, this pressure would lead to some ?blow-by? at the rubber seals. In the slave cylinder, some fluids may escape, but with air having the lower viscosity it will be expelled preferentially. Note that unless the car is significantly off horizontal, this process gets around the problem of the bleed screw not being at the highest point in the slave cylinder, as the air will simply escape past the rubber seal at the uppermost part of the cylinder bore.
If there should also be some blow-by in the master cylinder, this flow will encourage any trapped air in the solid and/or flexible pipework to migrate slowly upward to the highest point (the u-bend by the master cylinder). Days later, when the clutch pedal is finally released, the master cylinder will take a big gulp of fluid, drawing any bubble the final few centimetres back into the cylinder and expelling it out through the reservoir cap.
So much for the theory, now out to the garage to put it to the test?!
Cheers, Doug
1967 S3? Elan DHC in BRG (45/6311)

[Robbie693]

Good luck Doug.

My interpretation was simply that, with the pedal down, the valve in the master cylinder is open allowing any air in the system to bubble up into the reservoir. After I had released the pedal the fluid level had dropped a bit which I assume was because the air had gone. I haven't seen any leaks. Yet!

Robbie