Clutch pedal too hard push now, need ideas

I have a custom 1985 diesel jeep (as gas 4 banger in another life), that has a nissan SD-22 power train, diesel engine and 5 speed manual transmission with an MC/SC hydraulic clutch.

Over a decade ago I installed a heavy duty clutch-pressure plate system after rebuilding the transmission. Now I am partly disabled with rheumatoid arthritis and my legs and knees are no longer strong enough to push the clutch pedal more than 2-3 times...But I can operate regular brakes, and new car clutches (tested a ford fiesta last week, and it was easy to operate). I confirmed today that the problem is the HD pressure plate spring and not anything else in the system.

The SC on the transmission is a near exact match area wise to the Jeep, and the jeep MC is a near exact match for the Nissan truck the diesel came from. So the hydraulic pressure at the pressure plate is very close to OEM.

One obvious choice is to try an OEM pressure plate/clutch package.
The other is to make or find a custom vacuum booster operated hydraulic clutch MC assy, or anything that is available in the custom world to make the clutch pedal easy to push. Until I install a weaker factory pressure plate, I will not know if that will be enough so I am working on a custom mod idea now.

I need ideas, links folks!!!! I can not be the first person to have this issue.

I do not want to give up my 34 mpg diesel Cherokee!!! BTW it can be push started, so it is EMP proof LOL.

Thanks!!!!

Man sorry to hear about your RA, that can't be fun. I have no suggestions for you, but I'm curious if you did a write up on the swap. I owned a 98 Euro Spec Diesel XJ for 4 years and absolutely LOVED it. So I'd love to swap in another diesel to my current XJ if the situation presents itself...

What about changing the pedal ratio? Youd have an easier clutch pedal but at the expense of a longer stroke

Vernicious said:

Man sorry to hear about your RA, that can't be fun. I have no suggestions for you, but I'm curious if you did a write up on the swap. I owned a 98 Euro Spec Diesel XJ for 4 years and absolutely LOVED it. So I'd love to swap in another diesel to my current XJ if the situation presents itself...

Click to expand...

Sorry no swap thread on it. There are some odds and ends posts about it here and there. The 4 banger SD-22 is underpowered (about 63 hp) except in concrete flat lands like Houston, LOL. It replaced a 4 banger gaser. The Nissan SD-33, 6 banger, would be a better choice for replacing the six banger gas engine. Al's Nissan diesel web site is a good place to hang out for some good ideas on diesel Nissan engines and hardware.

http://nissandiesel.dyndns.org/viewforum.php?f=16&sid=6bc8d64d388375469a1e74f3f6f3dca2

http://www.naxja.org/forum/showthread.php?t=900819

How about investigating a solenoid operated hydraulic ram. You would be pushing an electrical switch and the hydraulics would do the rest. Actuation speed is adjusted with an in line needle valve.

Just a thought.

Anthropy said:

How about investigating a solenoid operated hydraulic ram. You would be pushing an electrical switch and the hydraulics would do the rest. Actuation speed is adjusted with an in line needle valve.

Just a thought.

Click to expand...

I like the general thought pattern, how exactly do you suggest I set it up?

Pump?

Pump power source, electric?

Pressure plate could return the hydraulic fluid (brake fluid) once the pressure source is off and the pressure is relieved to the fluid reservoir? So we use a three way solenoid valve?

How to foot pedal activate? or are you suggesting a toggle switch (I prefer foot operated).

Why would I need any delay in timing, i.e. the needle valve? Just to smooth it out on engagement?

trippled said:

What about changing the pedal ratio? Youd have an easier clutch pedal but at the expense of a longer stroke

Click to expand...

If you are suggesting increased the torque by extending the moment arm on the pedal shaft, I considered that, but doubt I have enough room to get much bang for my buck. Already looked into that and nearly tried it, but just no room left for it on the 85. Might be able to an inch at most and might create other problems. If I misunderstood "pedal ratio" please explain? Is there a another way to increase pedal ratio?

Anthropy said:

How about investigating a solenoid operated hydraulic ram. You would be pushing an electrical switch and the hydraulics would do the rest. Actuation speed is adjusted with an in line needle valve.

Just a thought.

Click to expand...

I wonder why I could not use a manually actuated 3 way valve? Electric would be cleaner, and have less mounting and alignment and wear issues I guess. Maybe I could use or copy the brake light switch or torque converter switch brake mounted pedal hardware design to add an electric trigger to a clutch pedal assy?

I knew somebody on here must have some ideas. Keep em coming folks, I need some help here please!!!!

Howe makes master cylinders for hot rods and race cars. I put one on my 85 XJ back in the day. You can get various cylinder sizes. You can get a smaller diameter and it will make it easier. You will have to keep it adjusted, but their master cylinders actually run less than most stock aftermarket units and have stainless sleeves and you can get rebuild kits. If it hasn't gotten lost, there should be a build thread about this around here somewhere.

I am going to ask a different question. Why not go with an automatic. I wheeled a stick for years, I converted over to an auto about 10 years ago and have never regretted it. It works very well offroad.

Howe makes master cylinders for hot rods and race cars. I put one on my 85 XJ back in the day. You can get various cylinder sizes. You can get a smaller diameter and it will make it easier. You will have to keep it adjusted, but their master cylinders actually run less than most stock aftermarket units and have stainless sleeves and you can get rebuild kits.

I am going to ask a different question. Why not go with an automatic. I wheeled a stick for years, I converted over to an auto about 10 years ago and have never regretted it. It works very well offroad.

old_man said:

Howe makes master cylinders for hot rods and race cars. I put one on my 85 XJ back in the day. You can get various cylinder sizes. You can get a smaller diameter and it will make it easier. You will have to keep it adjusted, but their master cylinders actually run less than most stock aftermarket units and have stainless sleeves and you can get rebuild kits. If it hasn't gotten lost, there should be a build thread about this around here somewhere.

I am going to ask a different question. Why not go with an automatic. I wheeled a stick for years, I converted over to an auto about 10 years ago and have never regretted it. It works very well offroad.

Click to expand...

It is a 5 speed nissan transmission on the back of a Nissan diesel. I spent three months in the 100 F shop on my weekends and $2000 in parts on the tranny. I am too old and too tired to mess with it again when it works perfectly. I have had enough headaches with Auto transmissions for 40 years.... They do not like me or my kids it seems. I can operate a brand new ford fiesta manual clutch all day long. Tested my friends on my leg/foot last week. So I need a smaller piston on the MC, thanks, that was one clue I was looking for confirmation on.

I might be OK with an OEM pressure plate (pay some friends to swap it for me as my health will not allow me to heavy lifting or nut busting), but I am thinking ahead on the hydraulics. Thanks for the ideas!!

Can you define adjusted??? "You will have to keep it adjusted"

X2 with old man. I had a similar situation, I installed a 302 Ford into my MJ with a bw t5. Of course it moves over 300 to the rears so I wanted a clutch that would hang onto it, well it was ungodly stiff and frankly, it sucked. I swapped out the master to a wilwood of a smaller diameter. (bolted in) works great now.

Anyway, there is math to do. It's called Pascal's law, it will help.

Ecomike said:

It is a 5 speed nissan transmission on the back of a Nissan diesel. I spent three months in the 100 F shop on my weekends and $2000 in parts on the tranny. I am too old and too tired to mess with it again when it works perfectly. I have had enough headaches with Auto transmissions for 40 years.... They do not like me or my kids it seems. I can operate a brand new ford fiesta manual clutch all day long. Tested my friends on my leg/foot last week. So I need a smaller piston on the MC, thanks, that was one clue I was looking for confirmation on.

I might be OK with an OEM pressure plate (pay some friends to swap it for me as my health will not allow me to heavy lifting or nut busting), but I am thinking ahead on the hydraulics. Thanks for the ideas!!

Can you define adjusted??? "You will have to keep it adjusted"

Click to expand...

If you find my original build thread on this, you will see that I made the brake linkage adjustable. Since a smaller diameter bore will yield a shorter throw on the slave, you will need to get it adjusted so what throw you have is in the right range.

Well I am taking the first step. Just received a new OEM clutch kit Saturday. Let's see what the OEM pressure plate feels like first, then on to the other options, if needed.

Good news here, got the OEM pressure plate, T-Bearing and clutch installed and the foot pressure at the pedal needed to operate the clutch dropped about 50%. I can actually use it for a short trip now good days when my legs and knees are doing OK
(fighting severe Rheumatoid arthritis now!!!1)

The heavy duty PP may have helped finish off the old MC and cracked firewall I repaired 4 years ago.

Now on the hint for another 50% drop in pressure If can pull it off using some hydraulic design changes suggested here.