'96 Clutch issue.

[jvt321]

I have been reading many posts on this issue, I "think" I know the problem, but I'd like to hear from more experienced people. Thank you!

Well, had issues that pointed to air in the clutch line. Hard to shift, and I read that one issue I had, "will shift if I turn it off" was related to an air bubble in either the master cylinder because of the angle it sits on the firewall, and the loop that is in the line for this model.
Reservoir was only down about 3/4 inch. Dirty.
A friend and I took out the line and master cylinder and bench bled it.
Moved it all angles, lightly tapping to remove air bubble. Numerous positions until no more bubbles and hydraulic was firm.
Put it back in and...the same. Maybe a little worse even.
So, I read on another post that the slave cylinder doesn't go "bad" really, it just leaks.
I looked at the reservoir this morning (only drove 2 blocks down an alley in 1st) and doesn't seem to have lost any.
Is it possible we actually did not get all the air out? And that's the problem?
Or, maybe there is a tiny leak in the slave cyl that allows air to come in?
Thanks for your help!

 

[RonD]

Welcome to TRS

Yes, the hydraulic clutch system in Rangers has always had air issues if reservoir was ran dry or on installation of new clutch

If this is a new clutch installation then there can be a couple of things
You should always use a SAC(self adjusting clutch) pressure plate, makes things much easier(you can't reuse these without resetting them)
If you use a regular pressure plate then it will be harder to shift for a month or so until new disc wears down a bit

Yes, not much to a Slave, just a cylinder that expands when fluid is pumped in, if air was coming IN then fluid would be coming OUT, there is much more pressure to force fluid OUT that there would be air pressure to force air IN

Is there any noise associated with clutch pedal down or up?
There is a Throw out bearing and Pilot bearing, that come into use in both up or down positions
You don't mention a noise

Hose from master to slave
Because the tolerance is so tight on the slave movement to fully release clutch disc any small difference matters ALOT
An older hydraulic hose can get a weak spot so the hose EXPANDS when pedal is pushed down, so slave doesn't get ALL the fluid to expand fully
You can run your hand along the hose while some one pumps the pedal to feel if its expanding at a weak spot

Check valve in Master
Take cap off reservoir and remove rubber "air cup", if its still there(cup is there to minimize air brake fluid contact, not part of the clutch system)
Watch the fluid in reservoir when someone pushes down on the clutch pedal, it should NOT move at all
When pedal is up fluid in reservoir can run down into system to replace any fluid that may be leaking out, when pedal is first pushed the reservoir opening should be sealed off to NO FLUID will be pushed back up into the reservoir
Reservoir should never have any pressure inside, its just a gravity feed to keep system topped up, same a master brake cylinder reservoir

You can "gravity bleed" the clutch system, just have cap off reservoir and open bleeder on slave, should get out any residual air and then a trickle of fluid as reservoir feeds it via gravity.
This means reservoir valve is open, as it should be, and can replace any lost fluid from a leak.



The transmission gears move at rear wheel speed, no disconnect for that
The clutch disconnects Engine from transmission
Engine idles at say 700rpms
When stopped transmission is a 0rpms
So to put transmission into ANY gear, the clutch disc must be at 0rpms to match transmission
The clutch disc is sandwiched between flywheel and pressure plate, which ALWAYS spin at engine rpms
The slave is expanded out to pull pressure plate back so clutch disc can slow down to 0rpms
If there is any "rubbing" of the disc on flywheel or pressure plate then clutch disc can't easily slow down to 0rpms
So if slave(system) has any air in it then slave doesn't expand fully so there is "rubbing"
So hard to get disc down to 0rpms

When moving it can be easier to change a gear, but still noticeably harder to shift than it should be, because now you are "rpm matching", engine rpms and gear/rear wheel rpms match
Those that are old enough will remember the pre-synchromesh transmissions that you had to double clutch and rpm match to shift to any gear while moving, lol

 

[jvt321]

Sub-issue. Thank you After your post and reading others, it seems clear to be the slave cylinder. All the symptoms plus at times I can hear that Throw out bearing spin.
I began to get estimates. It was working and I was driving very little, store and back, etc. Today the pedal just stopped solid hard in place. Felt like the quick connect disconnected. Got under, sure enough it did. Reconnected it. Tugged on it. Felt secure. Got in put the clutch pedal (engine off), pedal worked. Next push. Pedal was hard. Got underneath, disconnected again. Clicked it back in, really tugged on it, couldn't pull it out, it felt securely connected. Got pushed the pedal about 3 times (engine off) and quick connect disconnected again.
I really want to keep it connected to at least drive it to a shop and not pay for a tow.
Any ideas?
Thanks!

 

[RonD]

Pedal should not move at all when slave is disconnected, not even a little, if it does check for play in the pedal bushing at the top of the pedal, that could be why clutch is acting up, you don't have full travel on the Master because clutch pedal is shifting position

You do need to open the bleeder to push the quick connect on all the way, don't worry that doesn't let air in
As soon as its connected fluid should start dripping out of bleeder

 

[jvt321]

Yeah, it doesn't move at all when the slave is disconnected. Like it shouldn't.
I read another post where they had the same issue with quick connector.
It felt like it connected and was secure, but didn't fully connect until they opened the bleeder screw first.
Thanks.

 

[86isuzu]

Pedal should not move at all when slave is disconnected, not even a little, if it does check for play in the pedal bushing at the top of the pedal, that could be why clutch is acting up, you don't have full travel on the Master because clutch pedal is shifting position

You do need to open the bleeder to push the quick connect on all the way, don't worry that doesn't let air in
As soon as its connected fluid should start dripping out of bleeder

Threadjack.

My pedal goes to the floor with the line disconnected. Not a loose bushing. An issue with my master perhaps?

 

[RonD]

Threadjack.

My pedal goes to the floor with the line disconnected. Not a loose bushing. An issue with my master perhaps?

Yes, master is bad
The quick connected fitting at the Slave end of the masters line seals tight when removed from slave, so fluid doesn't run out of master
So if that line is disconnected at the slave end then master can not push any fluid out, so won't move at all

If you can push pedal down the fluid is moving so, running out the end of that line, failed quick connect or its being push UP into the reservoir
Can't imagine the piston seals would fail that bad but its possible

In any case new master would be the way to proceed

 

[86isuzu]

Yes, master is bad
The quick connected fitting at the Slave end of the masters line seals tight when removed from slave, so fluid doesn't run out of master
So if that line is disconnected at the slave end then master can not push any fluid out, so won't move at all

If you can push pedal down the fluid is moving so, running out the end of that line, failed quick connect or its being push UP into the reservoir
Can't imagine the piston seals would fail that bad but its possible

In any case new master would be the way to proceed

Awesome. Thanks RonD. A new master and slave is in my near future.