Hi
My Eunos has a leaking clutch slave cylinder that needs replacing.
Is this an easy job and can anyone recommend a part they have had good experience with.
Thanks
It is easy if you have a lift or a pit. Less easy if you use axle stands and not to be done if you do not have axle stands.
If your car has a gearbox undertray, the 10mm AF bolts that hold the undertray in place can be rusted in place.
New ones are inexpensive and I would believe the all come from the one plant in the far east.
The first repair I did was a slave cylinder, I did not have axle stands (nor a lift, or pit). For a Mk1, such as a Eunos Roadster, there is no need to remove any engine trays. There are different slave cylinders out there, and that is obvious from the different castings and pistons (some pattern slave cylinders have no or a reduced nipple that engages with the clutch lever, and there are variations in the bleed screw. I can identify at least 6 different factories making these on Alibaba.
Without axle stands, you can reach the slave cylinder fairly easily by turning the wheel. With an axle stand, it makes it obviously a lot easier… If you bench prime the slave cylinder (fill it with brake fluid on the bench), you can gravity bleed the slave cylinder; fit the slave cylinder, loosen the bleed nipple and fit a length of tight fitting tubing, into a jam jar with brake fluid. Top up the master cylinder, and leave it for a bit. Or you you can bleed by pumping the pedal etc.
Succinct instructions:
http://wiki.miata.net/tiki-index.php?page=Replacing%20the%20Slave%20Cylinder
Thanks for the replies.
I will buy one of the Slave cylinders off ebay. Several cheap ones that have sold in big numbers.
Had already found the Miata.net instructions thanks. Just hope I can get the bolts and fluid union undone as probably been on there for quite a few years.
The slave cylinders last about 50k miles, pattern or OE.
When replacing the slave cylinder I would recommend that you attach the hydraulic pipe to the cylinder before bolting the cylinder to the car. This will avoid cross threading the union nut if the pipe is misaligned.
The job went very well. Hardest part was loosening the fluid union which required a snapon 10mm brake spanner to apply the required torque.
New part was easy to fit but we seem to have a problem with bleeding the air out of the system.
Two hours of bleeding to the point that brake fluid was being recirculated and air bubbles still coming out.
Can anyone see where we are going wrong?
Using fluid sealed bleed so no possibility of air getting sucking in.
Engine not running just using clutch pedal - open bleed/pedal down and close bleed pedal back up.
We got quite an efficient system going in the end but after maybe 30 fills at 25 pedal up and downs had to give up.
Put some ptfe tape around the bleed nipple to form a seal on the threads before fully tightening down, or you could use a dab of silicone sealant.
And a trick i always use, get a length of 6mm bore flexible transparent tube, fit one end on the nipple and feed the opposite end into the fluid reservoir making a closed air tight circuit.
Pump away to your hearts content, no need to down, tighten, up, tighten, down, tighten etc, etc.
I think you are on to something safetymatch. The new slave bleed nipple threads may be allowing air to be sucked in and straight out through the bleed.
Will try a bit of PTFE tomorrow and report back.
When I replaced my Mk1 slave, master and changed the clutch line for a hel stainless flexible, I had an absolute nightmare bleeding the system afterwards.
I could not get it to bleed in the conventional manner ( top to bottom ), but in the end I used a hand oil pump ( the one I use for the outdrive oil for my boat ) and pumped the fluid up from the slave to the master, therefore excluding all air. This method worked perfectly first time.
Here is a link to the pump I used
The only hiccup in using this type of pump is that the threaded part which fits on to the outdrive oil bottle is some unusual US fitting, so you would probably have to buy a liter of outdrive oil, use the oil for something else and keep the bottle for future use.
This system also works well when refilling diffs and gearboxes as we have previously discussed on here.
The pump and oil are available from most marine chandlers or from online outfits such as marine parts direct
https://marineparts.ie/engine-systems/oils-lubricants-and-protection/gear-oils/gear-oil-pump/
Its probably around a £25 investment, but worth every penny if you do your own mechanics.
Good luck
Richard
I am hoping that we have finally resolved this but what a struggle.
MX5 Clutch Slave Cylinder is the one I bought.
Looked good quality and easy to install. The bottom mount bolt was hand threaded in a few pitches before the fluid union was threaded in by hand to make sure no cross threading. A little bit of leverage was required to get the top bolt mount holes to align but unit fitted in about 10 minutes.
After problems with air continually being bled out we changed strategy. Slow use of clutch pedal and bleed only opened when pedal being depressed. This immediately stopped the air bubbles proving that air bypassing the bleed valve threads. Tightened it all up and depressed the pedal 10 times. Result was a weep of fluid from the threaded part of the valve, nothing from bleed port. This valve works with a taper bedding in to a cup. We had to seal the reservoir cap with layered clingfilm and remove the bleed valve - messy job! Wound on some PTFE tape and refitted. This sealed the thread and appears to have worked.
What appears to be the original Mazda part has a ball bearing that seals the bleed.
Perhaps we were unlucky and this was a duff part? At least three hours wasted and that assumes the PTFE tape has permanently resolved the issue.
UPDATE
We contacted MX5 Heaven and Jeff replied very quickly and courteously. Sold hundreds and ours is the first one with a problem. Will be sending a replacement spare out.
Hopefully we had the worst luck possible and that is the end of it.