So, what's the fix for our slave cylinders?


curtis73

Member
Joined
Sep 1, 2018
Messages
73
Reaction score
3
Points
8
Location
Harrisburg, PA
Vehicle Year
1994
Make / Model
Mazda
Engine Size
4.0
Transmission
Manual
When I bought my 94 B4000, the seller produced receipts for new master, slave, and clutch. Upon looking under the hood and under the truck, I noticed the new master. Looking under, I noticed a brand new shiny bleeder, and tell-tale greasy fingerprints all over the transmission and T-case.

It is now almost two years later. I'm trying to remain in denial that the clutch is dragging, but it isn't working. At first, it just showed up as an occasional 1-2 shift difficulty, so I thought it was a pilot bushing. Then it morphed into difficulty getting into first (but no apparent dragging/creeping) which I thought might be a shift fork issue. Now it's a full-on drag. The clutch engages and disengages at logical times, but it obviously dragging. At a stop, push in the clutch, go for first, and it won't go but the truck creeps forward. I have to stop the transmission by clunking it into reverse. Once it stops, it doesn't seem to spin again.

It's pretty obvious that the parts store junk that went in there aren't cutting the mustard. It started giving fits after a few thousand miles, and now after 20k it's just almost undriveable. What is the real fix?
 


Rock Auto 5% Discount Code: 173A8B749AB83C Expires: January 1, 2020

adsm08

Senior Master Grease Monkey
Supporting Member
Ford Technician
TRS 20th Anniversary
Joined
Sep 20, 2009
Messages
32,168
Reaction score
1,472
Points
113
Location
Dillsburg PA
Vehicle Year
1987
Make / Model
Ford
Engine Type
4.0 V6
Engine Size
4.0
Transmission
Manual
2WD / 4WD
4WD
Tire Size
31X10.50X15
The "fix" is using quality parts. Concentric slaves are an issue across the board, not just with Rangers or Fords. My wife used to have an S-10 that had the same setup (probably the same slave) and it would eat them too.

I will say, My Ranger had the EXACT symptoms you listed. I took the trans out, rebuilt it, put it back in with the same clutch hydraulics, did not bleed it, and that particular issue has been resolved.

I know that isn't what you wanted to hear, but it is something to consider.
 

curtis73

Member
Joined
Sep 1, 2018
Messages
73
Reaction score
3
Points
8
Location
Harrisburg, PA
Vehicle Year
1994
Make / Model
Mazda
Engine Size
4.0
Transmission
Manual
I always want to hear the correct answer, so thank you. I might not be want I want to hear, but it wouldn't do me any good to spend 10 minutes on the wrong fix. I'd rather spend a weekend on the right one.

I need to get my other car to pass inspection before I tear into the truck, but that is getting to be a priority. Fortunately it only needs tailpipes.

My other conundrum is a laundry list of little dumb stuff that needs to be done on this truck:
- lifters ticking
- pinhole in the radiator
- gushing valve cover gaskets
- clogged heater core
- driver's side window motor is loose again (my temporary 1/4" lag screw fix needs to be upgraded with a 1/4" bolt fix.)
- stuck injector sucking fuel
- "Clink" sound in the driveline when going from forward torque to reverse torque... which may be related to a low speed vibe that I think is my U-joints.

I'm tempted to buy a complete 4.0 engine/M5OD trans and refurb them both on the bench and take a weekend to swap instead of taking my limited free time and trying to do it in the truck.

So much for a "reliable" low mileage B4000. Grrr.
 

alwaysFlOoReD

Forum Staff Member
Forum Moderator
TRS Banner 2012-2015
TRS 20th Anniversary
Joined
Apr 13, 2009
Messages
9,603
Reaction score
734
Points
113
Location
Red Deer, Canada
Vehicle Year
'91, '94, '80
Make / Model
Ford, GMC
Engine Size
4.0,4.0,350
Transmission
Manual
Clink" sound in the driveline when going from forward torque to reverse torque... which may be related to a low speed vibe that I think is my U-joints
Yes, it's the u-joint.
 

RonD

Well-known member
Joined
Jun 2, 2012
Messages
14,039
Reaction score
743
Points
113
Location
canada
Vehicle Year
1994
Make / Model
Ford
Transmission
Manual
I think you just need to Bleed the clutch system, thats what it reads like to me

The slave is just a cylinder that expands when fluid pressure is applied
It can leak but thats about all it can do when it fails, so if it ain't leaking....................then problem is air in the system or Master is failing

If you had a stuck open injector engine would not run, and if it did start you would have cloud of smoke out the tail pipe.
Check the FPRs(fuel pressure regulators) vacuum hose for gasoline


1994 heater cores are cheap and really easy to change, takes 20min the first time, 10 minutes if you ever do it again
If heater core is clogged up your temp gauge will go up and down randomly after warm up.
If you just don't have heat it could be the cable on the blend door
 
Last edited:

adsm08

Senior Master Grease Monkey
Supporting Member
Ford Technician
TRS 20th Anniversary
Joined
Sep 20, 2009
Messages
32,168
Reaction score
1,472
Points
113
Location
Dillsburg PA
Vehicle Year
1987
Make / Model
Ford
Engine Type
4.0 V6
Engine Size
4.0
Transmission
Manual
2WD / 4WD
4WD
Tire Size
31X10.50X15
The slave is just a cylinder that expands when fluid pressure is applied
It can leak but thats about all it can do when it fails, so if it ain't leaking....................then problem is air in the system or Master is failing
Its rare, but they can leak internally too. Pedal will go to the floor, feel like garbage, and not actuate the clutch. I only know for sure of one that has done it, but that isn't zero.
 

RonD

Well-known member
Joined
Jun 2, 2012
Messages
14,039
Reaction score
743
Points
113
Location
canada
Vehicle Year
1994
Make / Model
Ford
Transmission
Manual
But where would the fluid go???
There is no "internal" in a slave, its like a caliper or wheel cylinder, it just expands or leaks

Not saying it can't happen but I can't picture it in my head on how it could do that?
 

curtis73

Member
Joined
Sep 1, 2018
Messages
73
Reaction score
3
Points
8
Location
Harrisburg, PA
Vehicle Year
1994
Make / Model
Mazda
Engine Size
4.0
Transmission
Manual
A slave can leak internally depending on the design (I haven't looked at a ranger slave). Much like a master, it can just leak past the seals on the piston to the internal chamber behind it.

I don't think that is my situation though. In the 20k or so I've driven it, it has never (and I mean never) let the clutch diaphragm creep. If I hold the clutch to the floor for an entire red light and go to engage it, it always begins engaging at the exact same position. For example, if the pedal moves a total of 10", it always starts engaging at 4", fully engaged at 7". When I push it in, it will disengage at the 4" mark, but pushing it the last 4" to the floor doesn't seem to create any more motion in the slave or diaphragm. So, when I push in the clutch to put it in gear, it doesn't seem to matter if its on the floor, or 2-3" off the floor. Sometimes it goes, sometimes it creeps the truck forward. Almost as if the slave runs out of throw around that 4" mark before it completely disengages the clutch. The real reason I started suspecting the clutch was a few days ago. I was in 1st at a stop light at a very slight incline. The truck remained still without the brake until I yanked it out of first and it drifted back about an inch. It's definitely a dragging clutch, I'm just not sure why. The years of fighting to get it into gear have likely been hell on the synchros, so there may be cause to tear the trans apart as well.
 

curtis73

Member
Joined
Sep 1, 2018
Messages
73
Reaction score
3
Points
8
Location
Harrisburg, PA
Vehicle Year
1994
Make / Model
Mazda
Engine Size
4.0
Transmission
Manual
If you had a stuck open injector engine would not run, and if it did start you would have cloud of smoke out the tail pipe.
Check the FPRs(fuel pressure regulators) vacuum hose for gasoline


1994 heater cores are cheap and really easy to change, takes 20min the first time, 10 minutes if you ever do it again
If heater core is clogged up your temp gauge will go up and down randomly after warm up.
If you just don't have heat it could be the cable on the blend door
There are times when it won't run, particularly when its really hot. Several times this summer I would park it to go into a store and come out and it won't run. Even when it does run at its best, there is always a little misfire. It will barely idle very roughly, then die, and reek of gasoline. My first thought was pump/regulator, but it pumps great... and loses pressure quickly when the problem exists. The real puzzle was the one day... I came out of a restaurant, it wouldn't run, so I pushed the pressure test valve on the fuel rail and got pressurized vapor. Cycling the key got some liquid fuel back to the rail, but it wouldn't maintain pressure and the smell of gas coming out of the air filter was thick. which could also be your FPR suggestion. I'll check that as well. The nice thing about a 94 B4000 is that parts are so ridiculously cheap, I could throw every part at the problem and only spend $50

The heater core is actually sitting in a box ready to go. The previous owner had masked an intake manifold leak with about 6 jars of Barrs leaks. Testing the temperatures on the hoses shows adequate flow, but very little heat difference. My guess is that the heater core is so coated with schmutz that it isn't transferring heat.
 

RonD

Well-known member
Joined
Jun 2, 2012
Messages
14,039
Reaction score
743
Points
113
Location
canada
Vehicle Year
1994
Make / Model
Ford
Transmission
Manual
You most likely have a SAC(self adjusting clutch) which means the pressure plate moves closer to the flywheel as the clutch disc wears down, this keeps the clutch pedal's engage/disengage in the same place through out the life of the clutch disc
 

RonD

Well-known member
Joined
Jun 2, 2012
Messages
14,039
Reaction score
743
Points
113
Location
canada
Vehicle Year
1994
Make / Model
Ford
Transmission
Manual
3rd party heater cores can have a pass thru at the top, so enough coolant flows thru at the top of the core to keep hose warm and there is enough flow so temp gauge stays steady
But no flow in the bottom of core so little or no cab heat
Yes, any "stop leak" can clog heater core

In Rangers the heater core is the water pump/thermostat by pass, so must always have some flow or temp gauge will go up and down, not overheat, just up and down
 

curtis73

Member
Joined
Sep 1, 2018
Messages
73
Reaction score
3
Points
8
Location
Harrisburg, PA
Vehicle Year
1994
Make / Model
Mazda
Engine Size
4.0
Transmission
Manual
You most likely have a SAC(self adjusting clutch) which means the pressure plate moves closer to the flywheel as the clutch disc wears down, this keeps the clutch pedal's engage/disengage in the same place through out the life of the clutch disc
Yup. One of the problems with Ranger clutches (from research here) is that as the clutch wears and the slave piston moves further out in the bore, it runs out of throw before the clutch material wears fully. I was curious if there was some aftermarket (or factory upgrade) that has the throw it needs and fixes that engineering "flaw."
 

RonD

Well-known member
Joined
Jun 2, 2012
Messages
14,039
Reaction score
743
Points
113
Location
canada
Vehicle Year
1994
Make / Model
Ford
Transmission
Manual
That doesn't happen, with or without SAC

The pressure plate's fingers/springs are always the same distance from slave and in contact with the throwout bearing
That never changes
Inside, the pressure plate can move in and out to engage and disengage pressure on the clutch disc against the flywheel
SAC pressure plate just stays closer to clutch disc as it wears down

Non-SAC with new clutch disc is hard to disengage, pedal is down at the floor
Then as clutch disc wears down the disengage move up from the floor farther and farther until clutch starts to slip with foot off the pedal

With SAC clutch pedal disengage stays in the same place, well.......with a brand new clutch pedal can need to be down to the floor for a month or so, lol.


Your symptom reads like there is air in the system somewhere, top of master maybe
Could be the Masters hose is expanding a bit under pressure, this reduces pressure at the slave so it doesn't expand fully
 

gw33gp

Well-known member
U.S. Military - Veteran
TRS Banner 2010-2011
Joined
Aug 7, 2007
Messages
1,073
Reaction score
34
Points
48
Location
Costa Mesa, CA
Vehicle Year
2002
Make / Model
Ford
Engine Type
4.0 V6
Engine Size
4.0 SOHC
Transmission
Manual
2WD / 4WD
4WD
Tire Size
33"
I didn't see a pilot bearing in the list of new parts. A bad pilot bearing can give you the same symptoms you described. I had one fail so bad that it would try to make my Ranger go forward at a stop with it in gear and the clutch in. I had done a complete quality clutch job just a few years before but the pilot bearing apparently was not quality. What was happening is the needles in the bearing where so worn that they could get partially sideways and clamp down on the part of the transmission input shaft they ride on. So, the clutch could be disengaged but the pilot bearing was still trying to turn the input shaft. I installed a new quality pilot bearing and have not had any problem with in over 100K miles.

The Ranger/Mazda slave cylinder can't hold very much brake fluid externally when it leaks. You should see evidence of leakage if it is leaking. The master cylinder can leak internally without any evidence of showing externally. It basically can leak back up into the reservoir. I had to have one replaced under the original warranty because of that. The problem it was a come and go type of thing. I would take it in to the dealer and they could find nothing wrong with it. I waited until it gave the problem and drove it right into the dealer. They finally found the problem.
 

RonD

Well-known member
Joined
Jun 2, 2012
Messages
14,039
Reaction score
743
Points
113
Location
canada
Vehicle Year
1994
Make / Model
Ford
Transmission
Manual


Top