lost clutch pedal 1987 2.5DT
 

1987 2.5DT with auto swapped out to an '84 190E manual 5-speed. Used all manual parts from the 190E including clutch pedal and associated slave cylinder at transmission.

Lost clutch pedal but fluid in brake resevoir is steady - any suggestions on how to trouble shoot to determine whether the pump attached to the pedal isn't creating pressure or the slave at the tranny is the culprit? Is it better to rebuild or replace? Should both units be replaced?

Thanks!

Did you drive it ok for a period of time before you ' lost ' it ?

Did you ever get it bled so it would operate? If not, you need to do that. Reverse bleed by connecting a hose from the nearest brake caliper bleeder to the bleeder on the slave cylinder, and pump the brakes until no more bubbles come up on the brake fluid reservoir.

You may need to use zip ties on the hoses at the bleeders to keep the pressure from popping the hose off.

If you had it working and then it quite, you need to inspect for leaks. Brake fluid is very bitter, touch any wet areas around both the master and slave cylinders, then touch that finger to your tongue; you will easily taste the bitterness of the brake fluid.

First thing I'd do is pull the carpet down between the pedals and feel around for the clutch master cylinder hard line and make sure brake fluid is not running down it, then see if anything is leaking out on the ground under the bell housing, indicating a leaking clutch slave. My cars are W123s but I think the systems are smellier.

If you have to bleed your system, this is a very easy way, just plug in the hose loosen the bleeder, pump brake fluid, close bleeder, done . Much simpler than using the brake slave. One guy used a syringe from a country vet to pump the brake fluid.

System has worked properly for a couple years. I'm not down any noticeable amount in the brake resevoir and don't see any drips under the car. Father in law had a stroke the day after it happened so I haven't had time yet to jack it up and look closely underneath as of yet.

Mainly was wondering if there are rebuild kits for the 2 cylinders (at pedal and at tranny) or if total replacements are the way to go? On Peachparts the Slave Cylinder $41 and Master Cylinder $53 are reasonable but the internal rubber for both should be under $10 each if available.

Is it a good idea to refresh one end without doing the other?

Also, I recall some type of unusual bleed procedure? Can anyone direct me to that DIY thread? Is it as simple as Max stated?

Go with both new ones... you have plenty of other things to deal with... and you did not state the cost of only the seals.. only assumed their cost ... and availability...
You could easily get them apart and the seals ready only to find the bores too messed up to fix....

Bleeding the clutch is kind of unusual as it must be bled from the bottom up and the
"book' has you connect a hose from the brake caliper to the clutch slave and pump the brakes like crazy. the bleed nipples are different sizes, thats a pain to deal with. The whole procedure is a pain but doable if you like. Heres a post on using the squirt can.

http://www.peachparts.com/shopforum/diesel-discussion/319093-note-clutch-bleeding.html

If you need to replace either of the cylinders just do both, as there's a good chance the other will go out soon and then you have to deal with it all over again

Thats what they say, but its not like "once your in there, might as well do both" Its two different jobs and I've always wanted to get back on the road after that painful master cylinder job or not so bad slave cylinder. I only replace them when they go south. One thing that could be done after replacing one or both of those cylinders is flush the entire hydraulic system using the pressure bleeder like in "bleeding the brakes and then do the clutch last. That will flush the entire system and things last longer. I think MB recommends the brake fluid is flushed every couple years or so, not that I follow that to the letter:o

One should never pump the brakes furiously..

Look at the master and pull the boot back. See if it's wet and nasty in there. If not, replace the slave.

If the master is leaking replace it, the slave, and the rubber lines in between.

My rule of thumb. Idk.

The only reason I say it is because I replaced one and the other blew out before I could leave the driveway haha, fortunately. No problems since replacing though, but now I get to change them on the w115 this weekend hopefully

lost clutch pedal
 

You put a nice new master behind and old squishy slave? It's just like wheel cylinders. When they are on there way out you can visually see it leaking under the boot. It's not a guessing game.

I think it just depends on the situation. For example, my benz is going well. Motor is solid, and I'm on top of the problems. I had replaced master and slave but not the lines. The feed line is collapsing internally and not letting the pedal rise back up.

I went all out. New lines. New calipers and new brake lines. Etc.

My truck is knocking for the lower end. It needs: rear breaks, front brakes, output seals, diff cover leaking, front drag link shot, and a front u-joint.

I bought a $12 u-joint. Don't want to pogo stick it. The rest, meh.