I'm trying to help my son (again) with his 88 F-150. Straight six, 4x4 with a 5 speed.

On his way home last night, the clutch pedal went to the floor on the 1st to 2nd shift and stayed there. His phone description tells me the pedal is just flapping in breeze and the clutch is engaged.

Of course, I told him to start looking at the Z bar and linkage... But now I see it's a hydraulic clutch. Honestly, that surprised me... but I haven't had a truck with more than two pedals in a long time...

So.... Where should we start looking??

 

Hi,
There is a good chance the slave cylinder went, or

The hydralic line from the Master Cylinder to the Slave cylinder blew?

My money is on the Slave Cylinder! (don't ask why I say that!)

The bad news is you have to pull the tranny on the Mazda 5 speeds to get to the slave cylinder!

 

Well do you see fluid leaking anywhere? The clutch hydraulics use brake fluid so just look around. If it's coming out of the bellhousing then yeah probably your slave cylinder is junk.

 

He didn't see any hydraulic fluid.

I probably should add that we're digging out from the snow storm... 2 feet plus of the white stuff and the truck is outdoors (of course), so it could have dumped all the fluid and he might not have seen it.

 

It is possible the plastic sleeve that holds the master cylinder rod to the clutch arm broke, and the clutch pedal is just swinging. Check under the dash above the gas pedal. Mine did that in traffic one day with me just a few feet from the stopped car in front of me.

 

This makes the most sense to me so far. He tells me that there was no warning, everything was good and then it was bad.

 

Hi,
I would put that at the bottom of the list!

Just sayin!

99% sure, when the party is over, you got a bad Slave Cylinder OR bad Master Cylinder!

Just sayin!

 

As it looks like you'll likely be replacing the slave or master cylinder, I would strongly recommend replacing the clutch line at the same time while you have the tranny off. I did my slave, and days later the same issue happened to me, but it was the clutch line. Tranny comes off again....

 

Actually, the craptastic plastic bushing between the pedal arm and the pushrod is at the TOP of the list. I've had brand new ones pop off. Options -
- If the pushrod eyelet is in good shape, you can get some 1/2"OD x 7/16"ID brass tubing, cut off a small bit and use it as a replacement bushing. Then assemble, and put a 7/16" drill stop collar on the end of the "stub" on the arm, to hold it in place. Running both my '95s that way with zero issues.
- If the original bushing wore to the point of metal-on-metal contact, the eyelet may be ovalized ("egged" out), which would create a lot of slop with the above fix. Better option would be to cut off the eyelet and install a Heim joint (search any of the truck forums for "heim joint clutch fix").

 

Of course it is... It's an easy thing to check... and it doesn't involve crawling under the truck. LOL.

I couldn't get over to his house to help today. He's working tonight, so we won't get to look at this until tomorrow.

 

Hi,
Well...anything is possible?

Never had a problem with that little plastic bushing???

Slave Cylinders and Master Cylinders???

Oh yea!

 

I had a chance to take a quick look at it today.

It's not the linkage, and there doesn't seem to be any external leakage at the master cylinder. The reservoir was almost dry. No fluid on the ground or what I could see without climbing under the truck. The snow was coming down sideways about this time and I'm too old for that crap.

So.... I think it's the slave. He's going to fill the reservoir just for laughs and see what happens, but I'm not expecting anything.

I think we're gonna farm this repair out. He's in the middle of moving and I'm really not up for lifting transmissions in and out anymore. I have a couple good shops I can use.

 

The M5OD is a pretty light transmission, but if you don't have a place to work on it out of the weather, then I hear where you're coming from. There's also an inspection port covered by a rubber plug that you can use to see what's happening inside. If the reservoir was dry, then all that fluid had to go somewhere. You may get a brake fluid shower if you rubber than inspection cover off.

 

Had the mis-fortune of losing my clutch at a red lite, I first checked the cylinder level, which was real low. Walked to a convenience store and got some brake fluid and topped it off. Sitting through four traffic signal sequences, I managed to 'bleed' system enough to get on my way. That fluid level gets checked regular now.

 

Yea, he doesn't have anywhere he can do it and he's got so many irons in the fire, he doesn't have the time anyway.

I thought about bringing it to my place.. The concrete would still be cold, but the rest of the garage would be warm. But.. doing that type of work has gotten pretty tough for me. Past injuries haunt me and getting older sure doesn't help. I still do a lot of work on my own stuff, but I've learned to set some limits. If he had the time, we'd do it... He'd do the grunt work and I'd hand him the tools and hold the light.