8 replies to this topic

[mk=john]

Hi
On My Mk1 ooper, I have a pre-verto clutch. There is currently clutch drag, and firstly I want to bleed the system. The hydraulic fluid has been there for about 3 years.
Has this been there for too long? Would it be better to replace the fluid completel?

I have purchased the silicon type hydralic fluid, as it wont damage my paint. i also have the Gunson Ezi-bleed device.

How exactly do I go about removing ALL of the fluid and replacing it with new fluid? is it difficult? I have never dont this before.

Thanks

[Big_Adam]

Clutch is easy to do, not too sure about removing ALL the old fluid the way I did it was to put a pipe on the back of the slave cylinder (its the bit were the spring attached.... well pretty much) then a spanner on the nipple. Open nipple and put the pipe in a jar. Pumped the pedal till fluid stopped coming out then topped with new and sonked that thro a few pumps. Till new clean fluid came out. Topped the res fully pumped some more. Then tighten it back up.

Thats how I did mine and I never had any problems. I probly should have got an assistant to pump it properly to stop any fluid/air working it's way back but I personally never had a problem so far.

[dklawson]

If you decide you want to put the silicone fluid in the system you have to do more than just strain the old fluid out. The common method of handling this is to pump all the old fluid out as mentioned above, then close the bleed nipple and fill the reservoir with isopropyl alcohol. Allow it to sit for a while then pump that fluid through the system by opening the bleed nipple. (Make sure you at least pump the pedal a few times with the alcohol so you get some in the slave cylinder). Do this at least twice. Then make sure your slave cylinder is pushed all the way back in, leave the bleed nipple open, and run low-pressure compressed air through the system to dry it out.

Silicone fluid is sensitive to trapping air bubbles. Clean a long screwdriver and place it in the opening of the reservoir. Pour the fluid on the shaft of the screwdriver slowly so it runs down the shaft into the reservoir. You're trying to avoid making the tiny air bubbles that make bleeding silicone fluid hard. Some people wait over night for any trapped air to escape the fluid before bleeding, I've never gone that far.

The clutch isn't as hard to bleed as the brakes. You shouldn't need EZ-Bleed for this. You need a helper, a length of clear tubing, a clean jar, and a wrench to fit the bleed nipple. With the reservoir full, attach the tubing to the bleed nipple. Put the other end of the tube in the jar. Crack the nipple open 1/4 turn then ask your assistant to slowly push the pedal to the floor and to tell you when the pedal is down. When the pedal is down close the bleed nipple and tell your assistant to release the pedal. When the pedal is back up at the top, crack the nipple open again and repeat the process over and over again until you see no bubbles moving down the clear tubing into the jar. Check the reservoir frequently and top it up so you don't run the risk of running dry.

I would not blame the fluid on your clutch drag. However, normal DOT-3 and DOT-4 fluids really need to be changed every few years anyway because they absorb moisture from the air (DOT-4 a bit slower). Make sure you make the two mechanical adjustments to the clutch. In fact, you may want to make them first before you replace the fluid. You can also loose effective pedal/linkage motion due to: 1) master cylinder clevis wear, 2) Wear of the ball tip (and mating shaft) on the throw-out arm, and 3) Wear of the fulcrum pin of the throw-out arm. So check and adjust all the mechanical bits, don't assume bleeding will fix this.

[mk=john]

Thanks for the replies. I am planning to get new clutch arm, plunger, release bearing, slave cylinder rod and clevises etc tomorrow, basically the whole lot. I will get those at the weekend if bleeding does not correct the problem.

I have a silly question however. I have the ezybleed hydraulic bleeding kit. Do i connect the mai pipe to the master cylinder, and the airline to the spare wheel? Do i still need another jar with a pipe from the bleed nipple?

I have never bled anything before so please excuse this question!!!

[dklawson]

I can't comment on the proper use of EZ-Bleed. However, I gave you the traditional bleed method in my reply.

I hope bleeding the system helps but be mentally prepared for more work.

[mk=john]

Hi
I just bled the clutch today with Ezy- bleed, as I had this anyway. It was dead easy to do and took less than a minute! Anyway, The clutch pedal feels better, and there is sone slight improvement, but I think i still need to go ahead with your process of checking linkages. Can play in linkages really add up?

I've heard through so many people talking about their mini clutch pedal having a very low bite point, that is, close to the floor. Apart from bleeding then, could this be due to work parts?

I have had a good look at my clutch throwout arm, and it looks like the original one from the car. Also, at an earlier date, there was sideways movement of the release bearing. I guess I should change all that eh? I guess that if the throwout arm is the original one, the ball has probably worn quite a lot?

I plan to go to minispares at the weekend to buy the following (I have a pre-verto diaphram clutch):
Throwout arm, plunger, release bearing, slave cylinder rod, clevis pin at both ends of throwout arm, split pins.
Is there anything else I should check or get?

I remember that when I last looked at the clutch, the driving straps were parallel with the flywheel.

John

[Maxmini]

Ezy-bleed kits are great so easy to do the job just make sure you have a air tight system before filling the bottle with brake fliud done the brake system in ten mins .

[dklawson]

Before you invest in parts, inspect what you've got. Start with the clutch master and the pedal. Get under the dash with a flashlight and push the pedal with your hand. Minute amounts of play in the clevis on the master cylinder pushrod can easily result in an additional inch of pedal travel. The clevis pins on the slave cylinder and the throw out arm can also add to this. Over here Mini Mania sells an overpriced clutch kit for the throw-out arm. It has the lever, the rod that goes through the clutch cover, and all the clevis pins. What it lacks is the clevis for the master cylinder. However, a common fix for that over here is to remove the clutch master cylinder and have flat washers with the right size hole (close fit to the pin) welded on the sides to remove the clearance. As an alternative, you could probably go to a breakers and get a complete used master cylinder and use the pushrod from it... assuming you choose one whose clevis isn't badly worn.

I'm glad the EZ-Bleed worked for you.

[mk=john]

Hi Doug
Thanks for the reply. I did what you suggested, and looked at play between the clutch pedal and master cylinder clevis. What I found, is that I was able to lift the pedal up by about 10mm, and the master cylinder clevis did not move at all. It appears that the clevis must have an elongated hole? This was possible with the pedal in it's currect rest position.

Would correcting this solve my problem? I mean, making it so that there is no play in any direction between the pedal and clevis?

Thanks
John