How to soften the clutch pedal?

[Maui-sprint]

Restarting this thread with a different title.

The force needed to push my clutch in is significant. So much so, I stressed the firewall to the point of cracking at the Clutch Master Cylinder mounting bolt. My truck was original Automatic which I converted over to MT using all new parts about 12 months ago (approx 12k miles). Im surprised it failed so quickly since the firewall has never had a clutch MC mounted to it and I used all new parts specific for my year and engine size. The fact that a crack developed in the firewall so soon tells me the forces are higher-than-normal. What can I do to get a softer clutch pedal? Ive already accepted the fact that I will probably need to replace MC, Slave, and clutch (which are all new). Looking for recommendations on what parts have worked for others.

 

[bobbywalter]

pivot point.


its common though for those cracks.

 

[Maui-sprint]

I still plan to repair this by either welding or bolting a brace on the backside to strengthen. The trick would be to do it so it doesn't reduce the pedal throw.

The other issue Im having is the tranny is difficult to shift. Its like the clutch isn't releasing properly. I'm actually on my second MC and clutch line since the conversion 12 months ago. Tranny was shifting perfect the first 6 months then pedal started hanging up at floor when released. I figured it was MC so I replaced it along with the line. Have had that damn thing out so many times Ive become pretty good at bleeding the system. Ive got plenty of pedal. Shifts fine when engine off but when running it doesn't want to go into ANY gear unless I force it. Im thinking its the cheap ass slave cylinder I installed. So if I'm going to take the whole thing apart, AGAIN, then Im making sure I put in quality parts that won't stress the MC pivot point any more.

Would like to know what has worked for the TRS guys resulting in a forgiving pedal.

Also, is there a way to test if clutch is releasing properly (ie: jacking up rear axle and putting into gear)?

 

[bobbywalter]

are the dowels in good shape? any odd wear on the pilot?

might need to clock the trans around a bit.

though the pressure plate and slave would be more suspect then the master for me since the typical air issues were not present

 

[Maui-sprint]

Dowels were tight when installed 12 months ago
Flywheel and Pilot bearing is new (12 months old)
Slave, throwout bearing, pressure plate, disc (12 months old)
MC is brand new
Clutch line is brand new (FORD OEM F1TZ-7A512-A)

I bench-bled the MC+line. Installed it and have a rock-hard pedal when slave quick connect is disconnected.
Bled the slave using a custom bleeder consisting of an old slave connector+clear tube+squeeze bottle to make sure no air was going into it. This tool allows you to pump the fluid through the slave. Ran a quart of fluid through the slave before reconnecting the clutch line, then gravity-bled an additional 2 reservoirs' just to make sure.

I beefed up the crack with a rigid brace on the backside so I stopped any flex in the firewall.

Right now, I get a nice firm pedal but still having trouble getting into gear when running. Trans shifts smoothly when not truck not running.
When its in gear running, it grabs almost instantly when pedal comes off floor about an inch.

Heres another thing: When I bleed the slave using my custom bleeder, I get no bubbles in the clear outlet tube when Im squeezing (forcing) fluid through the slave. However, when I stop squeezing, and allow gravity to take over, bubbles re-appear.

The above symptoms would indicate air in the hydraulics but I had it performing perfectly for a year with a fraction of the bleeding effort. At this point I suspect either the slave cylinder went bad after beating on it hard for a year or I still have some air in the Ford OEM clutch line (which has a section of rubber hose in it). Ive never seen a line like this before so it makes me wonder if ford discontinued them....

 

[SenorNoob]

That's definitely weird. I've never seen a line like that. Both of the ones I have are just nylon or whatever the whole way.

 

[Maui-sprint]

I have never seen this before either and if you think about it, it may be my issue. The rubber hose section of this line probably adds volume to the system compared to the 100% nylon lines or even the aftermarket braided steel lines. The reason I went for an OEM line is because the cheap after market one I installed previous to this blew out of the slave connection while driving to work one morning. Cost me a tow home.

Im going to pick up another aftermarket clutch line and try that before dropping my tranny. Any recommendations on brand/part# to look for? Are the stainless steel braided types better than the nylon lines?

 

[Mechrick]

Mine has excess pedal effort as well. I plan to find a master with a smaller piston, I know they are out there. The pedal on my '94 F150 was super light by comparison.

I used an3 to Ford clutch/slave adapters and an3 line. Worked great.

 

[19Walt93]

I've seen worn discs and defective pressure plates both cause the symptoms you're describing. In both Rangers and F trucks that vintage we saw cracks around the clutch master, especially if the owner ignored the hard pedal for a while. Ford used to offer a bolt in firewall brace but the stiff clutch still needed to be fixed.

 

[Maui-sprint]

Agreed but I know my clutch is not worn yet. My goal of this thread was to get a brand/part# of a clutch kit with a forgiving pressure plate. I converted from AT to MT 12 months ago using brand new parts and my pedal has been stiff from the get go (as you can see from the cracks in the firewall). Still waiting for some feedback on a clutch recommendation. In the meantime, I will be adding a brace so the crack doesn't propagate any further.

As far as my dragging clutch problem, I believe the cause is the OEM clutch line I recently installed. My guess is that this line added additional volume to the hydraulic system resulting in a reduced throw of the slave cylinder which is causing my clutch to drag and make it difficult for me to switch gears. I've only used the "stock" nylon types which work good but have a lot of bends in them and I would think are susceptible to heat off the exhaust pipe. I'm leaning toward using an an3 type as suggested by Mechrick. These I think would be easier to bleed as well. Again, any recommendations on which brand to buy/not buy would be appreciated. If I don't hear back I figure I will go with this one:

 

[Maui-sprint]

Mine has excess pedal effort as well. I plan to find a master with a smaller piston, I know they are out there. The pedal on my '94 F150 was super light by comparison.

I used an3 to Ford clutch/slave adapters and an3 line. Worked great.

Curious why you used adaptors when there are products available (see last post) to do the job? Adaptors just add another spot for something to fail. As far as the MC with smaller piston, wouldnt that reduce the overall slave cylinder throw along with the foot pressure?

 

[bobbywalter]

Agreed but I know my clutch is not worn yet. My goal of this thread was to get a brand/part# of a clutch kit with a forgiving pressure plate. I converted from AT to MT 12 months ago using brand new parts and my pedal has been stiff from the get go (as you can see from the cracks in the firewall). Still waiting for some feedback on a clutch recommendation. In the meantime, I will be adding a brace so the crack doesn't propagate any further.

As far as my dragging clutch problem, I believe the cause is the OEM clutch line I recently installed. My guess is that this line added additional volume to the hydraulic system resulting in a reduced throw of the slave cylinder which is causing my clutch to drag and make it difficult for me to switch gears. I've only used the "stock" nylon types which work good but have a lot of bends in them and I would think are susceptible to heat off the exhaust pipe. I'm leaning toward using an an3 type as suggested by Mechrick. These I think would be easier to bleed as well. Again, any recommendations on which brand to buy/not buy would be appreciated. If I don't hear back I figure I will go with this one:

View attachment 113799

what myself and Walt were referring too is not simply clutch wear. the two things moving down line from the master are the two things that can bind.

if the pressure plate is defective it will side load the release bearing and bind on its stroke as well....and side load the clutch disk... say the fingers from 9 oclock to 12 oclock are 75 pounds and the rest are 30 pounds....just numbers for a visualization..... the problem from the beginning is the stiff clutch and gears not being happy...this is causing clutch hub bind as well draggin on the input shaft. the clutch hub itself may have a centric issue....


. this can be bad fluid in the trans which the syncros dont like as well.


brand new out of the box. centerforce has kicked my ass many times.

 

[alwaysFlOoReD]

I don't see how extra volume in the clutch line would affect movement in the slave. The master pushes a certain amount of volume per stroke. The slave moves a certain amount for that same volume. The volume of the line has nothing to do with either, it just transfers the volume from one place to the other.

Using a smaller diameter master will move less volume making it seem easier to press the pedal down, but the slave will move less as well.

 

[Maui-sprint]

what myself and Walt were referring too is not simply clutch wear. the two things moving down line from the master are the two things that can bind.

if the pressure plate is defective it will side load the release bearing and bind on its stroke as well....and side load the clutch disk... say the fingers from 9 oclock to 12 oclock are 75 pounds and the rest are 30 pounds....just numbers for a visualization..... the problem from the beginning is the stiff clutch and gears not being happy...this is causing clutch hub bind as well draggin on the input shaft. the clutch hub itself may have a centric issue....


. this can be bad fluid in the trans which the syncros dont like as well.


brand new out of the box. centerforce has kicked my ass many times.

Got it. Besides the clutch kit being defective, is there anything I may have done wrong in the install which could cause it to side-load? What clutch would you recommend to give me that nice stock feeling?

 

[Maui-sprint]

I don't see how extra volume in the clutch line would affect movement in the slave. The master pushes a certain amount of volume per stroke. The slave moves a certain amount for that same volume. The volume of the line has nothing to do with either, it just transfers the volume from one place to the other.

Using a smaller diameter master will move less volume making it seem easier to press the pedal down, but the slave will move less as well.

I have to agree with you on this given a perfectly rigid line. But the OEM part I have currently installed has a flexible rubber section in it. Not sure why Ford did that, maybe to give a more springy feel to the pedal? I think at this point I'm going to change out the line regardless to see if it changes or not before I drop the tranny again. argh