seems to get worse as it warms up when driving in the city. feels like the clutch pedal wants to stay in the down position and is having hard time coming back up. when shifting gears, i have to push or pump the pedal all the way to the floor for it to respond.

only happens when warm

 

There could be air in the lines or your master/slave cylinder are getting tired. Or your bracket might have broken from the pressure that the pedal puts on it.

I recently replaced mine with ones from wabfab, and it didn't take that long..maybe an hour or two. It was a night and day difference..bled the nasty black fluid and was good to go.

 

X2

You probably have a leak in your slave cylindar and it's letting air in. Just put a new one on and bleed the entire system. Then you should be good to go...

 

Also, look up above the pedals and check if the master cylinder is leaking where the rod connects to the clutch pedal. Mine was leaking pretty bad there.

 

Mine started this way and I could not diagnose it...but eventually after searching on here I replaced the clutch master cylinder and slave and re-bled and good to go.

 

Mine was mush as well, and I would have a hard time shifting it. Turns out I was tracking gross black fluid all.over from the leak at the master cylinder. New master cylinder and its perfect.

 

thanks for the info !

 

the clutch fluid is dark and nasty. so it won't make a difference if I flush it and refill with clean fluid?

 

Yes it makes it so much better to have clean brake fluid in there so yes it makes a difference!!!

 

i used a vacum cylinder tool to suck the fluid from the reservoir. didnt make a difference, in fact it got worse. i think i need to drain/bleed the fluid from the bottom?

also how hard is it to replace the master cylinder? and how do you bleed the system once the master cylinder is replaced?

thanks

 

You bench bleed the master, then install the master, then crack the bleeder on the slave, then you bleed it.

 

to bench bleed: add fluid to the reservoir and manually pump the master cylinder?

install master: removing and installing the master seems easy from the outside. what about the inside? is there a large pin in between the pedal assembly and master cylinder that needs to be removed/installed?

i know the fluid comes out from the bleeder. whats the procedure to properly bleed it? same as the brake system? push clutch pedal, bleed, tighten bleeder valve, let go clutch, repeat same process until no bubbles or air are present? then at the end slow push clutch pedal, allow a bit of fluid to come out from the bleeder and tight bleeder valve before clutch pedal reaches bottom?

 

truck is now undriveable. this has to get done today for sure.

 

On the outside there are just two nuts to take off, along with the line. From the inside, it might be best to remove the driver seat so you have some room..or if your really flexible just go to it . Take the bottom part of the dash off, along the tube that goes to your heater vent/nut warmer. There is a pin on the clutch pedal that holds the rod in that goes to the master cylinder.

Take out the pin, two bolts, and the fluid line and your set. It took me and a buddy about an hour to replace the master and slave.

You had the right idea about bleeding it. Do it the same way you would brakes. Use the buddy from above instructions (or wife/girlfriend..just keep telling them they look sexy with a wrench in their hand ).

 

LOL
Sorry...but I insist on the wrench in my hand, thank you vary much.
Put them in the cab taking orders from the guy with the wrench.
Also, make sure you put that rubber cap back on...it will be so much easier the next time (20 years or so).

 

thanks guys.

i just got back from flushing the entire clutch master and slave cylinder fluid. got all the nasty stuff out and it made no difference at the end. bleed all the air out of the system and it still dragging air back in. looks like I will be replacing both master cylinder and slave cylinder. the slave cylinder looks old anyway and I can feel too much play in it.

will get back with results.

thanks for the info

by the way I had an uncle help with the pedal. my wife is at work ;p

 

Good call on using your uncle. I had my wife "help" me bleed the clutch. I put her in the cab, crawled under and told her to push the clutch to the floor. We went thru several rounds, I never got any fluid coming out the bleeder. I kept crawling out to check the master, see the what heck was going on....and of course she was pressing the brake.

 

Most of the time I use my girl as my tool lady lol. She always tries to help out in some way. Yesterday she tore apart half of a motor for her car with me. She is getting pretty good at tagging and bagging bolts .

Sinful, its always a good idea if your replacing one to replace the other. They seem to go out at the same time. If you replaced one then it might make the other go bad because of the pressure difference. The slave isn't that expensive, and it takes just a few minutes to change out.

Let us know what you come up with.

 

Both of my 88's have slowly leaked into the cab for many years now. I have the kits to rebuild them in the glove boxes. Someday .....

 

update:

replaced master cylinder only and everything is working perfect now. I couldn't find the slave cylinder in stock at our local parts store so we had to take a chance.

believe it or not it cost me like 12 bucks for the master cylinder including a 1/4 of motorcraft brake fluid at our local parts store here in Mexico state of Nayarit. Can't get better than this !