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Is a clutch slave cylinder hard to fix?

5K views 6 replies 7 participants last post by  Magnetoz 
#1 ·
Here's a response I got to my massive craigslist "diesel wanted" postings:

"I have a 1974 Mercedes Diesel 240D with a manual transmission that I want to sell. The car does run but currently does not drive as the slave cylinder for the clutch has just kicked the bucket or is clogged really bad.The previous owner was a fool and never bled out the brake system. I bleed the system when I got the car. It ran perfectly fine for several months. Then I left on a trip to Canada for a month and when I come back I pressed the clutch to start the car and the pedal became stuck. I have tried to bleed the clutch system out but there is either a bad clog or the slave cylinder has crapped out. So the clutch pedal is stuck to the floor. As for that thought the engine was recently rebuilt, the brakes are good,clutch is great and tires have 65% tread left. The exterior is straight with faded creme paint. The interior is brown with very comfortable peugeot seats.I also recently replaced the glow plugs and all the drive belts. If you are interested in the vehicle I can take some pictures and we can discuss it further."

At $600 it's a steal, but the car is a couple hundred miles away so I would need to repair it on the spot or hire a mechanic. Since my mechanical skill level is about a 2 out of 10 and I have very little money, would this be a wise trip to make? It sounds really simple, but so do a lot of complicated repairs.
 
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#2 ·
Those hydraulic clutches can be a royal pain in the butt, but not a major mechanical issue. My experience is if you don't drive the car for a while, the slave cylinder will leak. If you drive them frequently, they work.

To get it up and running again, it will most likely only require new fluid and bleeding to get the air out. There is a bleeder on the slave cylinder which, when open, should allow air out and gravity to fill the cylinder with fluid with the pedal up. In same cases, for whatever reason, you may need to reverse bleed the system by pumping fluid into the slave bleeder and back up the system to get the air out. Even a little air will cause the pedal to go to the floor. Everything is fairly easy to get to if you don't mind crawling under the car. The clutch master cylinder might be under the dash on that model.

Worse case is you may need to replace the slave cylinder with new, put a new hose on (as they can plug up), and in extreme cases, replace the clutch master cylinder. If the owner has did it before, maybe he could help you out.
 
#3 ·
how good are you at driving? If the clutch is good like the seller says then just put the car in gear and start it in gear and off you go. You will then have to shift without clutching that's where your skill comes in. I driven cars for 100 of miles with a bad slave cylinder because once you get on highway you good to go. If he is not that far from interstate it may be easy way to get it back to your garage. Has anyone ever driven one of these without a clutch pedal?
 
#4 ·
An "old school" Mercedes

mechanic, and personal friend, always bled the air from the hydraulic system on the slave cyl. from below; he worked on "commission" and told me this is the fastest method. He used an ordinary trigger-pump style "oiler" filled with brake fluid and a length of windshield washer hose to link the oiler and the bleed nipple.

Now, if the lip seal in the slave cylinder is shot, you may be able to locate a NOS rebuild kit, or take the seal to an general/import car parts store and see if they can match up a seal from a wheel cylinder for a car equipped with drum brakes.

Good luck,

JR
 
#6 ·
The car probably needs a new clutch hose, the one between the chassis mounted pipe and the slave cyl. Pretty easy fix. Like brake hoses, they do need to be replaced. Get a new slave cyl as well.
 
#7 · (Edited)
I just changed the slave on mine two weeks ago. Its really quite simple. I didn't even lift the car off the ground. Picked one up at autozone. Only two bolts hold it to the bell housing. Loosen the hydraulic line and replace. It will mostly bleed itself. Get as much air out as you can, then just pump the pedal and it will pump the rest of the air out through the reservoir. The entire system is easy to see. If the slave is bad you'll see brake fluid dripping from the bell housing. The hose is half metal, half rubber and should be simple to spot any leaks. The master is inside the car under the pedal. I have a brand new master that I didn't use. Let me know and i can send it your way cheap.

Before i replaced the slave, it would hold enough pressure to get the car going and i could just drive it around with out the clutch pedal. Not to difficult, but get the occasional grind. I'd just top off the res and pump till i got pressure and take off.
 
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