Clutch Problems

[stuart362]

Hey all. New here, so let me know if I’m doing something wrong.

I bought my 91 a while ago, and it had a leaking slave cylinder. I replaced the slave, throw out bearing, clutch plate and pressure plate. Bled the system, and everything was great for a week. After driving it about 200 miles total, something went wrong and now I can’t get it into 1st/Reverse. Tried bleeding it more, with a vacuum pump, checked the master cylinder, and can’t find any issues. There’s no leak, and the clutch pedal feels okay. Any ideas?

91 Ranger, 4x4, 4.0L, 183k.

 

[RonD]

Have someone pump the clutch pedal while you feel the master's hose down to the slave
The hose can get weak and expand under pressure so slave doesn't move as far out as it should

I assume you can easily shift into 1st/Rev with engine OFF

Do not FORCE it into 1st you will break the 1st/2nd roll pin off

 

[stuart362]

The lines all feel good, there’s a small shift on the fitting at the slave cylinder, but looking at the old one it looks like that’s supposed to be there.

Yes, shifts totally fine all gears when not running.

If I start the truck in gear, it doesn’t lurch but I can tell the clutch is engaged. After about 1/2” off the firewall, I can feel the clutch continue to engage the rest of the way.

 

[RonD]

Did you use a SAC(self adjusting clutch) pressure plate?

Makes Ranger clutches work better, well any hydraulic clutchs with internal slave work better with SAC

Its not required, but does make it easier with new clutch disc


Not sure why it worked better and then stopped working well, that part doesn't make sense

How a clutch works
The transmission is always connected to the rear wheels, so the transmission must always spin at rear wheel RPM

The flywheel and pressure plate always spin at engine RPMs
The clutch disc is sandwiched between flywheel and pressure plate, and connected to input shaft of transmission

So when you are stopped, transmission is at 0 RPMs
In Neutral clutch pedal up, clutch disc is at say 750RPM, engine idle

So to put transmission in to 1st(or any) gear, the clutch disc/input shaft MUST slow down to 0 RPMs

If there is ANY rubbing of flywheel or pressure plate on the 10" clutch disc, then the 4" synchro gears will have a very hard time slowing it down to 0 RPMs
And it must slow down to 0 RPMs or it won't go into gear

This rubbing can happen if pressure plate's springs are not pushed in enough, slave not expanding all the way
Which is why air in the system is often the problem

 

[scotts90ranger]

I've said it before and I'll say it again, it's sounds really stupid but works... engine not running or in neutral put the clutch pedal to the floor then slip your foot off the pedal, do that several times, see if it works... these clutches are impossible to gravity bleed or bleed like you would brakes, the master cylinder angle is wrong...

I limped my '91 Explorer along for a couple months with a leaking slave cylinder that way, when the pedal got soft or was hard to shift stopped I'd add more fluid and do that to get going again...

 

[Ramcharger90]

I've said it before and I'll say it again, it's sounds really stupid but works... engine not running or in neutral put the clutch pedal to the floor then slip your foot off the pedal, do that several times, see if it works... these clutches are impossible to gravity bleed or bleed like you would brakes, the master cylinder angle is wrong...

I limped my '91 Explorer along for a couple months with a leaking slave cylinder that way, when the pedal got soft or was hard to shift stopped I'd add more fluid and do that to get going again...

I tried that on my truck. It didnt work so im going T5 I was having the same issue as him we did everything we could think of.

 

[Ramcharger90]

The only thing I can say is bench bleed everything and try again.

You might be able to buy the slave fitting with a 3an fitting. Im using a different trans now but I was able to get these which fit in the master

http://imgur.com/a/HoGZeuw

Call Russell and see if they make something for the slave. And use AN3 line instead of plastic.

 

[scotts90ranger]

The BEST and recommended way to bleed the clutch is to remove the line from the slave, remove the master cylinder, pull the whole assembly out, orient the master horizontal then push on the linkage until it is solid. If it is already solid the air is in the slave cylinder.

 

[ranger_gord]

I was following this link and wondered if you figured out what the problem was with the clutch master slave bleeding etc.

Under the knee bolster, at the brake/clutch assembly they used aluminum to mount the pivot points for both the brake and clutch pedals. They inserted a plastic or similar material bushing. I am not referring to the little clip that holds the clutch pedal to the master clutch rod, but to the right of that, as identified by the red circle in the photo.

The plastic insert wears out, the hole becomes oblong, and changes the pivot point enough that even if you have a new, fully bled master and slave system, the pivot only allows for partial deflection of the clutch rod and doesn’t move the slave (you can measure the deflection at the slave to check this).
Thus, it will grind and “slam” into gear, if you don’t catch it soon enough, it will take out stuff. No amount of bench bleeding or a new clutch assembly will help until you replace it.
If the hole has become oblong, the whole assembly will have to be replaced. If you are handy around a lathe, you may be able to machine an insert out of brass or something more substantial than plastic. If you are lucky and it isn’t oblong, make sure when you replace the insert, to apply a generous amount of grease.
Brent