Hydraulic clutch slipping ?

[Higgins56]

Hi guys !

When making testdrive with my 71 Mach 1 which has brand new American Powertrain delivered hydraulic clutch, I got the feeling that the clutch is slipping .There is 429 engine with Hurst 4 speed + Toploader.

Could it slip all the time, as when driving at a steady speed and pressing hard the gas pedal the response ( acceleration) is somewhat delayed - like rubber band stretching.

The clutch is new standard "three finger" clutch

How can I test a hydraulic clutch if it is working ok ?

 

[tempestairbrush]

There is a good possability it may be slipping if you have too many shim in between the transmission and the throwout bearing. They make a tool to actually get the measurement called a Hydraulic Release Bearing Set-Up Tool, included a link listed below. However when i set up my hydrolic clutch on my race car i was able to get my hand inside the bellhousing and actually feel the throw out bearing to see if it had pressure on the forks when the clutch was released. The bearing should be up against the clutch forks when released, however if you can feel it with your hands you should still be able to still turn the bearing, with the clutch released, this ensures that the clutch has full pressure. If the clutch is released and there is still pressure on the forks, then your clutch will act like the petal is slightly pressed down. The simple fix for it if you can't spin the throwout bearing is remove a shim at a time and retest until you can spin the throw out bearing, but still be able to go into gear easily with the clutch engaged. Too much play add a shim pack, good luck...Rick

heres that tool

http://www.speedwaymotors.com/Hydraulic-Release-Bearing-Set-Up-Tool,3168.html

 

[BigPinoyHunk]

Hi guys !

When making testdrive with my 71 Mach 1 which has brand new American Powertrain delivered hydraulic clutch, I got the feeling that the clutch is slipping .There is 429 engine with Hurst 4 speed + Toploader.

Could it slip all the time, as when driving at a steady speed and pressing hard the gas pedal the response ( acceleration) is somewhat delayed - like rubber band stretching.

The clutch is new standard "three finger" clutch

How can I test a hydraulic clutch if it is working ok ?

whooooo, another aftermarket clutch actuating guy here now. i went thru 3 clutches and alot and tons of adjusting with my cable clutch to get it right. it came to find out, since i am using a OEM pedal and not the aftermarket pedal which is a .15 longer and gives you more throw, it wasn't giving me enough disengagement. therefore, it was requiring me to put a little bit of preload onto the clutch. now since i was preloading clutch, it was at times causing over extension of the finger and it was causing some funky stuff at the track.

i had to step back and do alot of fork throwing measuring, i had found i wasn't getting enough fork movement regardless of anything done. so i actually had to gain throw by removing the rubber bump stop on the pedal to the bracket. that rubber stop is 1/2 thick and provided me with another .15 of throw on the fork which solved all of the issue. after that i was able to release ALL of the preload off of the clutch and have the TB barely touching the finger on the clutch and now its perfect.

i previously had a tiny bit of preload on it and i lost in a ford vs chevy bracket race tourament because of it. the clutch slipped in 3rd gear.

i finally have it right and i won't worry about the clutch adjustment for a while now though.

 

[Higgins56]

Hi guys !

When making testdrive with my 71 Mach 1 which has brand new American Powertrain delivered hydraulic clutch, I got the feeling that the clutch is slipping .There is 429 engine with Hurst 4 speed + Toploader.

Could it slip all the time, as when driving at a steady speed and pressing hard the gas pedal the response ( acceleration) is somewhat delayed - like rubber band stretching.

The clutch is new standard "three finger" clutch

How can I test a hydraulic clutch if it is working ok ?

whooooo, another aftermarket clutch actuating guy here now. i went thru 3 clutches and alot and tons of adjusting with my cable clutch to get it right. it came to find out, since i am using a OEM pedal and not the aftermarket pedal which is a .15 longer and gives you more throw, it wasn't giving me enough disengagement. therefore, it was requiring me to put a little bit of preload onto the clutch. now since i was preloading clutch, it was at times causing over extension of the finger and it was causing some funky stuff at the track.

i had to step back and do alot of fork throwing measuring, i had found i wasn't getting enough fork movement regardless of anything done. so i actually had to gain throw by removing the rubber bump stop on the pedal to the bracket. that rubber stop is 1/2 thick and provided me with another .15 of throw on the fork which solved all of the issue. after that i was able to release ALL of the preload off of the clutch and have the TB barely touching the finger on the clutch and now its perfect.

i previously had a tiny bit of preload on it and i lost in a ford vs chevy bracket race tourament because of it. the clutch slipped in 3rd gear.

i finally have it right and i won't worry about the clutch adjustment for a while now though.

Hi it seems that the clutch ( RAM) is not new...so in case the clutch disc is not able handling power anymore what would you recommend for street use for a 71 Mach 1 with 1.375 " /10 spline shaft gearbox .

The engine gives approximately 450 hp / 650 Nm. I understand that there is achoise of three diameters for the clutch disc 10.5, 11, and 12.

How to choose the right one ?

Mcleod, Centerforce or RAM ? How will it be with the dimensioning of the present hydraulic clutch which is tailor made to the present specs - there are no shims anywhere for adjustment...

In case the present clutch disc is no good - can you advise ?