Review: RJM AFP Clutch Pedal System

Originally Posted by Ryan @ RJM

Also TBatt made a good point about setting the AFP to zero for doing a full bleed. This is needed to push the highest volume of fluid thru the system and to ensure the MC goes full stroke to get all the air out of it. There is one exception here though - you only need to do this if you have air in the system you need to get out. Such as when you've had the system opened up to replace something. If just doing a simple clutch fluid flush for maintenance with one person pumping the pedal and another opening/closing the bleed screw then you don't need to adjust AFP first since there shouldn't be any trapped air you need out.
That note Is mostly just for guys or shops who installed the pedal along with a new clutch, CSC, clutch line or MC at the same time which is quite common.

Originally Posted by Ryan @ RJM

Good evening, this is a classic case of the master cylinder not fully returning and causing fluid to be trapped on the high pressure side of the master cylinder. When the car sits overnight the fluid in the line contracts causing the squishy pedal feel until the car warms up causing the fluid to expand again and feel normal. There is a tiny fluid port inside the MC that allows fluid to flow between the reservoir and the high side of the system which is only open when the master cylinder is 100% up and closes upon the slightest amount of MC travel down the piston bore. The port staying closed causes the feel you're describing.

Two main causes for this are:
1) the upper cruise control switch adjusted too tight holding the pedal down slightly. This keeps the port closed all the time leading to changing pedal feel from cold to hot.
2.) if the two side tension bolts that take up side-side play in the pedal are adjusted too tight the pivot bearings will have extra drag and the pedal may not fully return to the top under it's own power 100% of the time. This can cause the feeling you describe to happen either randomly or all the time depending on how tight the bearings are.

To check for this is easy. Go under the dash and press the pedal down by hand then release the pedal very very slowly. Then note where it stops on its own. Did it go all the way to the top and hit the upper switch firmly? If so likely the switch is set too tight. If it stopped short of pressing the switch and you can pull it up more by hand after it stopped then the bearings are too tight. In this case loosen the two side tension bolts evenly a 1/4 turn each and retest. Do this until the pedal comes fully up when releasing slowly.

That should take care of it.

Also TBatt made a good point about setting the AFP to zero for doing a full bleed. This is needed to push the highest volume of fluid thru the system and to ensure the MC goes full stroke to get all the air out of it. There is one exception here though - you only need to do this if you have air in the system you need to get out. Such as when you've had the system opened up to replace something. If just doing a simple clutch fluid flush for maintenance with one person pumping the pedal and another opening/closing the bleed screw then you don't need to adjust AFP first since there shouldn't be any trapped air you need out.
That note Is mostly just for guys or shops who installed the pedal along with a new clutch, CSC, clutch line or MC at the same time which is quite common.

Originally Posted by darkphantom

So I've had the RJM Clutch pedal on my car ever since I bought it, but today it wouldn't crank!

Kept saying push in clutch, which I did several times, but no go! I had to pump the clutch a few times for it to finally detect it.

Any idea if the RJM Clutch pedal is affecting it? Someone said to check the clutch return spring.

Originally Posted by kmsb3001

i just install the RJM on my 370z TT .
i had one problem now. with high RPM and full boost above 6500rpm i can not shift hard or fast it seems like something lock between the gears . the only way
to shift is to remove full my foot from the accelerator and full clutch press rpm goes down thin i can shift happens with all gears .

any help or idea .

Originally Posted by Ryan @ RJM

Hi Kmsb3001, sounds like not enough disengagement stroke for your clutch setup at high RPM's. What clutch setup are you running?
I would recommend increasing the clutch rod setting a bit to raise the friction point a little at a time and test if that allows shifting under the same conditions. If not I would try reducing the AFP setting a bit as well to see if that makes the difference. The clutch isn't fully disengaging and causing some drag which is magnified at high RPM causing the gear lock outs.


Let me know how it goes.

Ryan@RJM

Originally Posted by kmsb3001

Ryan,

The car has CSC kit and Spec twin clutch .we already adjust but still same problem.

Originally Posted by s2krazyyy

Do any of you experience a a lot of play/loose clutch on a cold start? I usually experience a lot of play with the clutch on a cold start and then when the car warms up it goes back to the normal stiffness and has a full travel. Hopefully its not my csc going out, I also checked the fluid levels and it looks all good. I have my rev3 set at recommended setting of 75 afp.

Originally Posted by wsarver

See post 150