flywheel/slave cylinder shims

[rocketcouch]

so ive been reading a lot about some of the drawbacks to the aftermarket parts for the flywheels and slave cylinders for the m50r1 transmissions. the fitment isnt as perfect as the stock parts and most people seem to be able to tell a negative difference in shifting and clutch engagement with them. with my explorer i found that to get enough depression of the clutch to get it to fully release the pressure plate i had to remove the bump stop at the bottom of the pedal assembly.

this is after i replaced almost everything
-upper pedal bushings
-clutch
-slave/master
-hydraulic line
-flywheel
-bled multiple times

i did read on other cars that some had to use flywheel shims or slave cylinder shims to get the right clearence/preload between the slave cylinder and the fingers on the clutch. i found that ATP makes flywheel shims for the rangers but they specify up to the 3.0v6 not the 4.0. what i dont know is what the spec should be because i wouldnt want to just throw a 0.040 shim in there for no reason.

any info on this or help would be great.

 

[rb142]

Flywheel shims are to make up for material machined off the flywheel to resurface it. The size shim you need is the amount cut off. Shims shouldn't be needed with replacement parts if they are correctly made. I'm not sure how you would measure the clearance if you did have a spec.

 

[AndyDrew]

any info on this or help would be great.

Did you ever get any good information? I am struggling with my clutch in my 1995 XLT. I too wonder about shims for the flywheel. My flywheel was resurfaced with the last clutch, but I don't know how much they took off.

Andy

 

[rb142]

ATP does make shims for both the six bolt and 8 bolt crank configurations. Don't remember the thicknesses. Rock auto has them. 0.040" would be a really large amount removed to just resurface a flywheel. But the parts stores doing that work often don't have a clue anyway.

That said, if you put a 0.040" (1mm) shim in there, I can't see that causing any problems as the slave moves a lot farther than that before it does anything. If you had the flywheel resurfaced, throwing a shim in is probably worth doing.

But before all that, be sure you really have the system bled out fully. It doesn't take much air in there for it to not release all the way.

 

[AndyDrew]

I have bled this system 3 different ways, at least a dozen times over the past 4 years... so yes, I have bled the air.

I have removed the whole hydraulic system and bench bled.

I have gravity bled in the vehicle (Haynes manual method)

I have pumped and bled in the vehicle (Similar to bleeding brakes)

I have also measured the throw of the release bearing and after bleeding it is within specifications. But I also feel like 0.5 mm is all it takes for the clutch to not fully release, which is very difficult to measure.

Next stop... shims or a new flywheel, they are rather inexpensive from RockAuto.com

Thanks,

 

[fast_dave]

I have bled this system 3 different ways, at least a dozen times over the past 4 years... so yes, I have bled the air.

I have removed the whole hydraulic system and bench bled.

I have gravity bled in the vehicle (Haynes manual method)

I have pumped and bled in the vehicle (Similar to bleeding brakes)

I have also measured the throw of the release bearing and after bleeding it is within specifications. But I also feel like 0.5 mm is all it takes for the clutch to not fully release, which is very difficult to measure.

Next stop... shims or a new flywheel, they are rather inexpensive from RockAuto.com

Thanks,

I Flush/Bleed my Slave Cylinder on a yearly basis (or when I hear some "chatter" when taking off from a dead stop).

I use a Harbor Freight Vacuum Bleeder and Valvoline Synthetic Brake Fluid DOT 3/4.

After bleeding/flushing, the "chatter" stops, and the fluid in the brake bleeder has black bits in it from rubber contamination.

Your Mileage May Vary

P.S. With regards to the Clutch Master Cylinder - there is a VERY SMALL rubber "o" ring that is installed between the clutch master cylinder and the hydraulic line that goes into the Clutch Master Cylinder. The line then leads it's way down to the to the Clutch Slave Cylinder, which is inside of the transmission bell housing. Sometimes this very small "o" ring is overlooked when replacing the clutch master cylinder - just throwing that out there

 

[rocketcouch]

i ended up changing the plastic pivot bushings on the pedal assembly and pulled the rubber stopper at the bottom of the mount that the clutch pedal hits and its helped. im sure that right now im just compensating for bad synchros seeing i got like 220k on the thing.

the best way i found to bleed the system was to get a small syringe to bleed with through the master cylinder and run a hose form the bleeder screw going over the top of the tranny to the passenger side to make sure no air back feeds. anytime i tried using that vaccum bleeder it never works for me. always sucked air passed the threads of the bleeder screw.

you may just have air trapped in the master cylinder still

 

[fast_dave]

anytime i tried using that vaccum bleeder it never works for me. always sucked air passed the threads of the bleeder screw.

Here's a great tip passed on to me by an old timer - on those rare occasions you have to crack any type of bleeder nipple more than 1/4 of a turn, before you start bleeding, first dab a lil' grease 360 degrees around the base of the nipple, where it meets the cylinder. The grease will prevent air slipping past the nipple threads.