Dead Clutch! Need Help.

[mrfatboy]

My clutch went straight to the floor the other day right at a stop sign. Luckily I was in neutral and on a hill and was able to roll off the street.  Of course I forgot my cell phone that day and had to walk to a nearby chruch to use their phone to call AAA!  Yes, after 26 years I finally used their tow service:)

Anyway,  my '69 280sl is back in the garage. There is fluid leaking from the slave cylinder. It seems to becoming from the rubber boot on the slave. The clutch resevoir is empty.  What do I do now. Is there a repair kit? Do I replace the slave cylinder? I have searched on both forums and have not found exactly what I am looking for.

While I was searching for "clutch" I see alot of people talking about bleeding from the Master cylinder. I looked at mine and I don't see the master bleed screw.  Do I have a new master cylinder that does not have the bleed screw anymore?

thanks

[jeffc280sl]

I'd replace the slave cylinder.  Parts cost is about $75.00 and its an easy job.  You will need to bleed the system.

Jeff C.
1970 280SL 4-speed

[ja17]

Hello mrfatboy,

Most likely the slave cylinder seals have been leaking for some time.  You can refill the resevoir and pump the pedal about a hundred times and most likely get it working again. Or follow the bleeding procedures. However you will need to replace the seals in the  slave soon. It is a simple cylinder with one seal on a piston and a rubber boot. It is easy to remove and rebuild.
The difficulty is bleeding it and getting the right parts since there are several versions. Always have the chassis number handy when ordering these parts.  

I strongly suggest ordering the rubber hydraulic hose also. Like old brake hoses they become restricted with age. A new clutch hose usually makes an amazing difference in the responsiveness of the clutch pedal and the ease of operation of th pedal and clutch. Not to mention a system with a restricted hose is even more difficult to bleed.

While you got everything apart consider rebuilding the master cylinder also.  If you use the front brake caliper to back-flush and bleed the system after repairs, you may want to make sure the brake  fluid is also fresh and clean!  So as you see the job can be a simple specific repair or a days worth of other preventative repairs!

I have used a pump oiler with fresh brake fluid in it to back flush and bleed the clutch system. Hook up to the bleeder on the slave cylinder.
Some have suggested dismounting the slave cylinder and and allow the piston to move more then compressing it to force air to the resevoir, this works also.

Not all the master cylinders have a bleeder and it is not much use anyway.

Surprisingly about 100 complete strokes of the pedal will slowly restore and bleed the system in most cases. The system is vertical so air will eventually work its way to the resevoir and out if you exersize the pedal enough. It may slowly begin to respond afer 50 strokes or more.

The slave cylinder must be adjusted to have just a bit of freeplay when the clutch pedal is at top rest. If adjusted too loose the pedal may not return. If adjusted too tight the clutch may not fully engage eventually causing the clutch to wear and slip.

Joe Alexander
Blacklick, Ohio

[mrfatboy]

thanks for the reponses.  I have ordered a new clutch slave cylinder from Miller's for $99. It will come fedex monday.  I will replace and bleed.  I hope the bleeding goes well or I will be back with more questions  

thanks

[mrfatboy]

I have a couple of clutch fluid questions. Probably obvious and dumb but i got to ask so I don't screw it up.

1)Is the same fluid used for the brake and clutch?

2) Should it be DOT 3 or 4?

3) I don't believe I have the synthetic fluid but how do I check to make sure? Do I just flush it to make sure and start from scratch?

thanks in advance

[mrfatboy]

I like to finish off my forum threads with the final outcome so the next person can learn something. so here it goes.

1)  I replaced my clutch slave cylinder. $99 - millers.  it was easy. It had a pinhole leak in the boot.

2) clutch and break fluid are the same (thanks google)    I used DOT 3

3) I took the simple route for bleeding the clutch line and it worked.  I installed the new slave cylinder, got underneath the car and pumped it's lever 50 times. Bubbles came up in resevoir . Then pumped the actual clutch at least 500 times. Works fine.

4) back on the road