clutch pedal stuck down (im a diy mechanic get me outa here)

[pablo0874]

no fluid loss leaks or anything the fluid that came out was black like oil and i mean thick llike oil

 

[kbekl]

no fluid loss leaks or anything the fluid that came out was black like oil and i mean thick llike oil

thats possibly your problem it is starting to freeze as said ealier in the thread, try to remove the fluid and put new in it might help

 

[pablo0874]

the black oil looking fluid i took out i put some in freezer and its starting toi thivken up but this does not explaim why the push ros in the master cylinder flows in and out with no resistance could the master be broke now due to the fluid doing this and if so how would i get it all out if i was to replace the master cylinder

 

[kbekl]

it could be that the plunger has too much resistance to return with no pressure in their

 

[briggie]

i know nuffin , but id hazard a guess that the seals on the master cylinder have perished

 

[11redrex]

The fluid is black because it's old and water has got into it, it's the water that's freezing but that would not cause your problem.
You need to get the master cylinder off and check it.
It sounds to me like the return spring has got stuck in the bore, just study the pictures in the manual and it will give you an idea of how it works.
When you take it to bits keep everything very very clean and do not get any dirt, oil or grease in the system.
When you put it back together bled it from the bottom cylinder first, then the top.
If the seals had gone there'd be brake fluid everywhere, inside the cab and down the bulkhead.

 

[Terranosaurus]

ive tried with the engine running no difference clutch is disengaged as was on my drive at the time connected bleed hose to master cylinder pressed pedsl down stayed down but pedal can be lifted by hand and rod just goes in and out of master with no resistance

Engine running or not won't make a jot of difference.

You connected the bleed hose to the master cylinder???? Are you using an easy bleed, pressurised off a tyre or something? You don't pump the pedal when using these you just let the pressure bleed the system when you crack the slave cylinder bleed nipple. Have you checked the slae cylinder for leaks?
When the master cylinder seals go on these trucks, fluid collects in the "bellows" and slowly dribbles down the bulkhead - quite difficult to spot.

 

[tommo]

yes plenty of fluid jusdt no action from the master cylinder the rod just goes in and out no resistance

Hi
Have you opened the bleed valve on the master cylinder first. I had just the same problem when i changed my clutch. You need to bleed the master cylinder first.

 

[ssteve]

black fluid = seals u/s in master cyl, simples

ssteve

 

[ssteve]

The fluid is black because it's old and water has got into it, it's the water that's freezing but that would not cause your problem.
You need to get the master cylinder off and check it.
It sounds to me like the return spring has got stuck in the bore, just study the pictures in the manual and it will give you an idea of how it works.
When you take it to bits keep everything very very clean and do not get any dirt, oil or grease in the system.
When you put it back together bled it from the bottom cylinder first, then the top.
If the seals had gone there'd be brake fluid everywhere, inside the cab and down the bulkhead.

fluid does not go black with water in it

ssteve

 

[11redrex]

that's incorrect, you need to bleed the slave cylinder first Pablo, then the master cylinder
Pump the pedal a few times, open the nipple to let some fluid through, close the nipple, repeat until there's no more air in the fluid.
If you have a long enough clear tube, run it all the way back to the reservoir, and just keep pumping the pedal slowly with the nipple slightly open. That way you won't need to keep topping up the reservoir, and the air bubbles will work their way to the top. Also you can do this by yourself, so you don;t need someone else sitting in the car pressing the pedal for you.

The first thing you need to do is to take the master cylinder off and check it's working properly !

 

[rustic]

there have been reports of seals getting damaged when bleeding by pushing them past the worn ridge in the cylinder, this may have happened to you. Should still be able to get a pedal but not for long, try bleeding em up again to be on the safe side.

If it is the seals damaged that way you'll need a new cylinder.

Seals getting damaged by going past the worn ridge apply to the brakes, and I would have thought not the clutch, as this travels to full limit every time.
So I wouldn't have thought that this operation would have damaged the seals more than they are possibly worn already.

 

[11redrex]

Old brake fluid goes black, seals gone makes it go brown. I've worked on thousands of brake calipers over the years.

 

[ssteve]

but this is not a caliper and its not the brakes !! of course it depends what colour your seals are!!

ssteve

 

[Terranosaurus]

Old brake fluid goes black, seals gone makes it go brown. I've worked on thousands of brake calipers over the years.

Yet you recomend recycling the fluid back into the reservoir - errrr noooooo!!!

 

[kbekl]

Yet you recomend recycling the fluid back into the reservoir - errrr noooooo!!!

think he meant for bleeding new fluid, thats how i read it anyway

 

[pablo0874]

the fluid i got out came out the master cylinder there was only a bleedd pipe full of it one stroke down of the pedal i got and thats when it stayed down,
the rod in the master cylinder can just be pushed in and pulled out without no resistance,
the fluid is black as really used engine oil and has the consistency of like near enough paste like ,its a wonder how it could push anything ,

 

[ssteve]

i refer you to my original post (no 30)

ssteve

 

[pablo0874]

i refer you to my original post (no 30)

ssteve

thanks its just so many posts on here im lookingb this way and that but the water in there seems right someone yesterday said about water being absorbed into the fluid over time it did only start with this cold snap were having just hope its not done no damage to the master cylinder ,
q1 am i right in saying that the master cylinder pushrod should not be able to push in and out with no resistance ?

 

[rustic]

thanks its just so many posts on here im lookingb this way and that but the water in there seems right someone yesterday said about water being absorbed into the fluid over time it did only start with this cold snap were having just hope its not done no damage to the master cylinder ,
q1 am i right in saying that the master cylinder pushrod should not be able to push in and out with no resistance ?

I think I was the first to suggest the water, if there is no fluid in the master cylinder, it will move easily, if there is fluid in there, then either the seals are shot, or the fluid is going somewhere else.
On some models there is an extra pipe that runs to the rear of the vehicle, if so this will have to be purged as well.