2.3L ('83-'97) Clutch Bleeding Issues After Transmission Swap

[Paul18181818]

I have posted here about this swap before and have narrowed my issues down to the clutch hydraulics. To recap, I swapped my 1993 2.3 2wd ranger from an a4ld automatic to a m5od-r1 manual transmission. At this point, I have dropped the transmission 3 times trying to narrow down the issues. I have installed a brand new master cylinder, line, slave, clutch, pressure plate, pilot bearing and rear main seal. The master cylinder was pre-bled when I bought it and I have both gravity bled and pump bled the system multiple times. Still, I get a spongy pedal after a couple seconds. What are some other techniques I can try to get the air out? I'm beyond frustrated at this point and will likely try bench bleeding the master cylinder again this weekend. Any help is appreciated!

 

[Rowdy Fitzgerald]

Pull the master cylinder, stretch it out straight while keeping the reservoir up. Start tapping it with a tool from the bottom, up. Then pump the master cylinder to try to get the air to back feed, up into the reservoir.

 

[Bgunner]

 

[Paul18181818]

So today I pulled the master cylinder and bench bled it as instructed. It felt good and has less than a 1/16 in of play when disconnected from the slave. I reconnected and I still have the same problem. I also rented a vacuum bleeder, no luck there either. Still the same problem, the clutch feels great when the engine is off but as soon as I turn the engine on and try to go in gear, the clutch gets mushy and I can’t get it in gear. Any ideas?

 

[Rowdy Fitzgerald]

There is no reason for it to change when the engine is running. It’s not vacuum boosted like brakes. There’s air trapped somewhere.

 

[Paul18181818]

It doesn't make sense to me either, but that's the only way I can describe it. The clutch pedal only softens up if the engine is running. With the engine off, I can press it as many times as I want and it won't go soft. With the engine on, the clutch softens up after the first pump or two. It feels like air in the line, but I have tried every method of bleeding at this point. Is it possible the new slave unit was defective?

 

[Rowdy Fitzgerald]

It is possible. Have you tried putting the front tires on ramps or jack stands. Then bleeding it?
Are you pumping the clutch 10 times, holding the pedal to the floor, while bleeding it? You must hold the pedal down, open the bleeder valve until all the pressure is relieved and then close the valve before the pedal is released. Otherwise it will suck air back into it.

 

[Bgunner]

New means not tested now a days. They used to test parts before boxing but they no longer do that so more defective parts leave the manufacture.

 

[Paul18181818]

I will try lifting the front of the truck next time I bleed it but something seems wrong. I may have to pull the transmission again to inspect or replace the slave.

 

[alwaysFlOoReD]

Take a look at the firewall and make sure it's not cracked and/or flexing by the pedals. Another possibility I've also had is the ear or both ears on the master are cracked/broken. Both situations act like air in the lines.

 

[Paul18181818]

So today I disconnected the master from the slave. The clutch pedal has no movement at all when I press on it, so I think the master is fine. Then, I took my old clutch line and used it to pressure bleed the slave separately using my vacuum bleeder. Then I reconnected the two and before turning the truck on, had my friend press the pedal down while I checked the travel through the transmission port. I saw good travel and could see the pressure plate raising slightly indicating to me that it should be releasing just fine. But again I have the same problem: The clutch feels great when the truck is off, and if I start the truck with the clutch down in first gear I can move it in and out of gear just fine. However, if I put it in neutral and release the clutch, I immediately feel slop in the clutch pedal and I am unable to get it back in gear. It doesn’t make sense to me because it shouldn’t matter if the truck is running or not, yet here I am. I’m considering dropping the transmission for what will be the 5th time and putting a new slave in but i’m hesitant because the slave I put in there was new and I can’t see any fluid leaking from it. Any help is appreciated.

 

[Bgunner]

Internal parts could be bad on the so called new slave cylinder preventing full movement. This issue reads as the slave is not fully disengaging the clutch. Just because the pressure plate moves a little does not mean that the clutch disk is fully disengaged leading to not being able to put it in first while the engine is spinning, trans input shaft is spinning due to not being fully dis engaged.

 

[gw33gp]

I know you said you replaced the pilot bearing but that is one thing that can make a difference between the engine running or not. If it is binding some way or the transmission input shaft is contacting the flywheel rotation in some way. I know that would not make the clutch pedal soft but it would make it difficult to get it in gear.

It is very doubtful that you have installed the clutch disc backward but that is another thing that can make a difference between the engine running of not. I don't know if it would cause a soft pedal.

What brand components did you use? I am chasing a problem somewhat related to yours without the issue of the engine running. My clutch engages with the pedal to close to the floor. It does disengage and I can get it into gear and shift with no problem. I just have to make sure I step on the pedal all the way to the floor. I can bleed the slave and get a little air out. It improves a little for a while but eventually gets worse again.

When I did the initial slave bleed, I got a lot of white grease like stuff come out with the brake fluid. Sometimes, with the next few bleeds I have gotten a little more out. I don't know if that is related to my problem, but it is not right.

Normally, I use LUK components and I did again this time. I did make one exception, I used a Sachs slave because it has a rubber bellows that I felt would protect it from dirt. I do a lot of off-road trips and that seemed important. That may have been a mistake.

 

[89Twincharge]

Was the input shaft clean of all rust and debris and lightly lubed? Had a situation like this customer did own clutch and it was doing same thing. When I pulled trans input shaft was caked with clutch fluid and disk material and was binding up before it moved all the way in/out when it started the the vibration/movement shook it free and no clutch! If not then faulty slave! Good luck!

 

[Paul18181818]

I have the transmission out currently and I can’t see anything wrong with the slave. It’s not leaking or anything and looks exactly the same as the replacement. The input shaft wasn’t too dirty, but I greased it up anyway just in case. Is there any compatibility issue with the parts I have? I think the transmission is from a 94, flywheel is from a 95, clutch kit is for a 95 without the self adjust, and it’s going in a 93 ranger. I’m starting to think I might just need to put some shims behind the slave cylinder to push it out a bit more.