I have a 91 f-150 with a 302 and a 5-speed,,,,i started it up today,(mind you it was ok till today), and the clutch pedal stuck in,,,now the clutch is stuck in the disengaged position, so now i cant drive it....I took the cap off of the master cylinder and noticed it was empty,,,but there is nothing under the truck,,,so i dont know if its leaking or not,,,so i put fluid in it and tried to pump the pedal the best i could by pulling it back up and pushing it down, but still have nothing,,,and the fluid that i put in it didnt go down either....what do i do?????


thanks, Sean

 

You've got to have a leak somewhere if the clutch master cylinder was empty. You need to locate it or you will continue to have the same problem. My thought is that maybe your slave cylinder is leaking. I am going to assume you have the concentric (internal) slave cylinder. This leak will probably show up at the lowest part of the front of the bellhousing. If it looks like this is the problem you will have to pull the tranny to fix it. Also check the hydraulic line and the bleeder screw to make sure the problem isn't there.
Here is a link to an article found in the articles/specs button on the gray bar at the top of this page on how to bleed your hydraulic clutch.
https://www.ford-trucks.com/article/...tch_Setup.html

If the MC got so low that you got air in it you may have to bench bleed it to get it all out. You did take the rubber diapragm out of the master cylinder before adding fluid?

 

Sean, I have the exact same problem with my truck. One thing to mention is you CAN actually drive with a leak...you just have to push down really REALLY hard . If you put your finger inside the bellhousing like gustang said, feel around in there. If there's a dirty type of oily crap. It's most likely the slave cylinder, meaning you'll have to do what gustang said.

 

yes i took the diaphram out of the mc first

 

i am pretty sure the guy i got the truck from said that he put a slave in it along with the clutch kit,,,,but i dont know if he bled it or if he did but forgot to keep adding fluid when he did,,,as i said in my question post,,,there is nothing leaking from under the truck,,,unless its just not coming out on to the ground....there is nothing under it.....that is why i am lost,,,no spots, and the clutch kit is new and i do believe the slave is too....

 

sean, here's the thing though. You won't see the fluid on the ground if it's a leaky slave cylinder. It will probably only leak when you apply pressure to it (pumping the clutch petal), which will most likely only happen when your on the road. Plus, if it's only a small leak, it will build up inside the bellhousing instead of leaking out. We're talking about a very small ammount of fluid here.

 

but my master cylinder was empty,,,,and i cant tell if its gonna leak under pressure because the pedal got stuck in,,,it wont come back up so i cant pump it to build it up..

 

Its most likely a slave cylinder issue, which you have to remove the transmission to get to it. I doubt you have a ZF 5 speed, some of those are outside mounted, the t-18s i belive.

Get a vacume bleeder if you are by yourself, or have a friend pump the petal for you like you would do your brakes on the car, and get down there and bleed the cylinder, there is a bleeder valve on there.
use a piece of hoze so you dont squirt fluid all over.

Once you get it bled, it should get you around for a bit, and always check your fluid.
you will most likely have to get it fixed.

 

The master cylinder has bypassed, most probably due to loss of fluid through the slave cylinder. See if the bell housing is wet at the bottom edge. I just went through this last year. DO NOT take that to a Ford Disservice Department. $1443 for the package deal, and they didn't bother to replace one more $15 seal (rear main on the engine) while they had the tranny out, despite me telling them to. About the only thing they didn't do was throw me on the floor before raping me. Well, can you guess what I did last weekend? See my gallery for a good idea. If he replaced the slave, you may be OK. But, like I said, check the bell housing for any brake fluid residue. Also check the line from the master to the slave where it connects at the slave, and see if there's any evidence where it has leaked in the past. Sometimes folks ain't too careful when they hook that line back up, and nick the o-ring on that coupling.

I have no idea what replacing a master cylinder is like on one of these, but can say it looks pretty simple. The only reason I took mine to a Ford Disservice Center was because I didn't have the time to work on it. It can't be much worse than installing a brake master cylinder on a VW. For the most part, it will bleed itself by gravity when you open the bleeder on the slave. Just be careful and don't let the waste fluid go in the bell housing on the clutch. Just to be sure, pull the rubber plug on the bell housing right behind the connection to the slave cylinder. Look in there and see if anything looks wet. Wet inside the bell is bad.

As others said, we're talking a small amount of fluid, unless it failed like mine, a total failure of the slave. Then, I poured fluid in and could watch it drip from the bell with one press of the clutch. The master cylinder bypassed two days after the slave started leaking badly. If you have the M5OD, there's actually a gap between the backplate and the bell where the ooey gooey will run out. Nothing stays in the bell. The M5OD bell is actually vented (several big holes in it) to aid cooling the clutch after use. The rubber seals in the master cylinder have probably turned backward from going into a dry bore if the clutch was used with no fluid in the reservoir. The seals are certainly damaged now, as indicated if the pedal doesn't return by itself, and will not heal themselves. You're looking at a master cylinder replacement, minimum, but be prepared to find a dead slave too.

Now, if you find yourself pulling the tranny, do yourself a favor, and go ahead and replace the rear main oil seal on the engine, ESPECIALLY if the engine has high mileage on it. It is a piece of cake to do once you have the tranny out, and might save you pulling the tranny again within the next year. See my gallery for a step-by-step on replacing the rear main seal. The same procedure can be used for replacing the slave cylinder if it's necessary. I even listed the tools I used. I didn't notice if you said 4x4, but I have the 4x2 with the M5OD. It ain't rocket science, but there is some pretty serious wrench pulling to do. Obviously, if you have a 4x4, you've got the transfer case and front drive-shaft to remove, too.

 

well,,,,i think i may have figured it out,,,,try this one on for size....
there is a hugh freakin mouse nest inside the transmission....and low and behold it is right in the front where the clutch and everything is.....and when i say there is a mouse nest in there,,,it is every freakin where......so, no matter what i am pulling the tranny,,whether i want to or not....i know its not gonna work with all that **** in there....

 

well,,,,i think i may have figured it out,,,,try this one on for size....
there is a hugh freakin mouse nest inside the transmission....and low and behold it is right in the front where the clutch and everything is.....and when i say there is a mouse nest in there,,,it is every freakin where......so, no matter what i am pulling the tranny,,whether i want to or not....i know its not gonna work with all that **** in there....

 

I was attempting to bleed my slave on my M5R2 in my 51 ford and I unscrewed the bleed valve too far and it dropped into the transmission housing. I can't find it.....Do I have to drop the tranny to find it or is there anyone with a trick to find it? I am feeling very vulnerable to jokes so please be kind to me.....