I had a guy tell me it was probably the slave cylinder...? The clutch slowly went out over a period of one day...help!!!

If it's the slave cylinder, you'll be losing fluid. Check that first.

I've had a number of master cylinders fail over the years, but I have yet to lose a slave cylinder before it was replaced as part of a clutch job.

Check your fluid level. Low fluid starves the clutch before the brakes.

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1977 300d 70k--sold 08
1985 300TD 185k+
1984 307d 126k--sold 8/03
1985 409d 65k--sold 06
1984 300SD 315k--daughter's car
1979 300SD 122k--sold 2/11
1999 Fuso FG Expedition Camper
1993 GMC Sierra 6.5 TD 4x4
1982 Bluebird Wanderlodge CAT 3208--Sold 2/13

yeah, and specifically it is the rear section of the brake master cyl res that supplies the clutch.

also you can lose the clutch master and not have any leaks. it can be an internal leak like a brake master cyl.

if it is the clutch master you will be able to pump up the clutch and get action. but if you sit at a light with the clutch depressed it will slowly engage and the car starts to take off.

tom w

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[SIGPIC] Diesel loving autocrossing grandpa Architect. 08 Dodge 3/4 ton with Cummins & six speed; I have had about 35 benzes. I have a 39 Studebaker Coupe Express pickup in which I have had installed a 617 turbo and a five speed manual.[SIGPIC]

..I also have a 427 Cobra replica with an aluminum chassis.

fluid was low in the rear of the brake resovoir. can the master cylinder can go bad without any leaks?... Or because the brake resovoir is low the slave is leaking fluid.

Remove the lower panel and feel the clutch master cylinder. It is probably wet with brake fluid. The undersurface of the floor mat will probably be wet as well.

Kevin
1979 240D manual
1984 190D manual

Even if the reservoir level goes below the clutch bleed port, if there are no leaks in the clutch hydraulics it will still work and continue to work. You most likely have a leak.

I find it quite fascinating that someone could diagnose this problem as the slave cylinder without having seen the car or gotten further information. Quite impressive.

Before I effected repairs based on this long distance diagnosis, I would investigate for myself. Begin by seeing if there is any brake fluid on or under the drivers side floor mat. If so, the problem is most likely the master cylinder. If not, the slave cylinder should be checked next. Pull it out of it's mount and see if any fluid has made it past the piston.

Also, when checking the master cylinder, ensure that the hose has not slipped off the top.

Is the clutch operated mechanically through linkage or is there a cable involved? Probably no cable since nobody mentioned it, but that's my two cents on the matter

I've had a clutch literally explode on me once (the rivets holding the clutch springs broke). Still drivable though, sans clutch.

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-justin

1987 300TD, 1987 300TD
2008 R32, 2000 Passat Wagon

Justin, these clutches are hydraulic with master and slave cylinder configuration. No cable means no adjusting like my old VW, but also means another system to maintain. Don't get me wrong, I think it is better but man is it a pain to get under the dash and replace.

Kevin

1979 240D manual
1984 190D manual

You could still have a cable that operates a slave cylinder.

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-justin

1987 300TD, 1987 300TD
2008 R32, 2000 Passat Wagon

There are NO cables. There is a master cylinder above the clutch pedal that is fed by a hose that leads to the brake master cylinder reservoir. The line out of the clutch m/c leads to the slave cylinder that is mounted on the bell housing portion of the transmission. No cable or mechanical linkage saving for the clutch pedal arm and the throwout arm in the bell housing.

Thanks Larry, that answered my curiosity.

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-justin

1987 300TD, 1987 300TD
2008 R32, 2000 Passat Wagon

There could be a hole in the hydraulic line. That is how mine failed. New line was $125 from the dealer.

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1979 240D- 316K miles - VGT Turbo, Intercooler, Stick Shift, Many Other Mods - Daily Driver

1982 300SD - 232K miles - Wife's Daily Driver

1986 560SL - Wife's red speed machine

I replaced my master cylinder and bled the system, I thought I had fixed the problem, three weeks later same problem (the system was leaking down). so I replaced the slave. the old slaves piston was real sloppy, seemed worn out. for sure the slave was the problem.