Easy Clutch Pedal

Easy Clutch Pedal

Easy Clutch Pedal

jmb
03 July 2009
06:08 PM
Was out with my bride today for her weekly driving lesson.  She is having trouble with the stiffness of the clutch.  Is there some kind of booster or something that makes the clutch petal pressure less hard to operate?  Her left leg is just not strong enough to comfortably back up and such.  And if so are is there any down side, and what is the cost?
Thanks in advance.
JB
Ray H
03 July 2009
10:29 PM
Some of the folks have replaced their clutch with an Easy-Pedal.  I've heard it takes less pressure to operate although I've never had the pleasure of trying one for a comparison.  Compared to cars and light trucks, a clutch in these HDTs take a lot more pressure to operate.  My wife won't even try as her knees give her a problem.  I'm sure some of the folks that have made the switch will chime in shortly with a lot more info.
Ray
Jack Mayer
04 July 2009
10:29 AM
The clutches vary widely (one might say wildly) in the depression pressure required - even within the Easy Clutches.  I have pressed standard clutches that were very easy.  I have pressed "easy" clutches that ranged from "car -like" easy, to no different than my clutch - which is pretty stiff.  No one has been able to tell my why the difference.  Every truck mechanic I have asked has said this is "normal" and with no logical explanation as to why the range in a "properly" maintained system
Jeff- C IL
04 July 2009
11:54 AM
Jack:
What you said got me thinking.  Obviously, a clutch with newer (and stiffer) springs is going to push harder than a well used one.  The other thing that may play into this is that as the clutch wears the finger angle is going to change slightly in the throwout bearing.  Is it possible that a slight change here could result in a significant difference in force needed to move it?  I've noticed that sometimes a clutch needs a lot of force at the top, then moves easier as you continue to depress it.  (If we could figure this out you might be able to predict when to adjust the clutch!!)  Other than that, I couldn't begin to think why two similar trucks with lubricated linkages and throwout bearings would be different.

I would be interested in anybody's answer on this issue as well, as I have a big ole farm tractor with a 10 speed Fuller and Manual clutch that REALLY needs a booster.  I've even thought of making some sort of hydraulic ram arrangement.  Question: Are there any HDT that use hydraulic clutches?  Lots of small cars and ag. combines use a hydraulic master/slave just like a brake to operate the clutch and it sure is a lot easier!

Phil D
04 July 2009
12:50 PM
Many trucks have hydraulic clutches, Jeff.  In fact, there's a recent thread here about Rif's AutoShift problem, which the repair shop has diagnosed as leaking master and slave cylinders.

Volvo had the best solution to difficult clutches years ago -- the air-assisted clutch -- but somewhere along the line the industry has left them behind.  Dave Mattson's (Toyhauler) early 90's WIA has an air-assisted clutch, and clutching his truck is no more difficult than is a pickup truck.

marvmarcy
04 July 2009
01:33 PM
I had the clutch replaced when the tranny was replaced several years ago. I was told it made sense to go with the Easy Pedal so I did.  I couldn't tell any difference.  My wife can depress the clutch but it isn't nearly as light as a pickup clutch.  It only really matters when I have to keep it depressed for awhile - heavy traffic, backing, etc.
Marv
Scrap
04 July 2009
02:32 PM
It the truck has an Autoshift it was built with a Solo clutch - which already is an easy pedal.  There are only a couple of non-easy pedals out there.  They are aftermarket and you have to work pretty hard to get one. They aren't mainstream.

A truck can't really be compared with a pickup in force.  The truck has a 15.5" dual plate clutch with up to 3000lbs of plate pressure.  A pickup (stock) has a 13.25" single plate organic with what, 1200lbs of pressure?  Aside from some medium duties, the truck is a pull type and doesn't have fingers.  It has 7 or 8 angle springs that do the releasing.  The release yoke can wear, but on a rod type it just changes your pedal freeplay.  Solo clutches are required to use a roller finger that negates that anyway.  I suspect 80% of the variability is coming from the hydraulics and/or a combination of hydraulics and different plate loads at the different torque ratings.  Besides, Jeff, if you remember a combine with a clutch in it you are old .

Phil, every KW except the T2 has the option to add air boosters.  There are two air cylinders that do the pushing and the pulling of the rods.  It isn't available on AutoShifts though.  It is a big hairball of wirebraid hoses, cylinders, and brackets that won't fit around the x-y shifters.  It does, however, reduce pedal effort by almost half while still maintaining the regular freeplay and feel of a rod type clutch.  I've driven some of the DAF's and K260's with the air assisted hydraulic and they were pretty cool.  Pretty nice for the highway and in town but not enough 'feel' for work in the dirt and gooey spots.  I'll admit, though, I'm a disaster with hydraulic clutches.  Losing the freeplay and the engagement feel throws me all off.

Anyways, I know little about hydraulic clutch actuators, but the ISM in the original truck in question should have a pretty light load clutch so I'm suspecting the hydraulics.

Phil D
04 July 2009
03:07 PM
Because they're never mentioned, I had no idea that they were still available anywhere.  I've got to say that the clutch in Dave's WhiteGMC . . . errrrrr . . . Volvo was really remarkable.  It felt just like a traditional clutch, certainly not as light as the clutch in a little s***box econocar, but no heavier than you'd find in a 3/4 or one ton truck.  Between the air-assisted clutch and the synchronized Volvo transmission, only having to deal with the Roadranger-like complexity of a range selector and splitter in addition to the customary "H" pattern shifting serves as a reminder of just how large a vehicle you're actually driving.
MacDaddy
05 July 2009
11:26 PM
Take a look under the truck and find where the clutch release cylinder is located.  If it's side mounted you do not have options.  If it mounts under the transmission, there is an air over hydraulic cylinder that can replace the oil only cylinder and provide the power assist you are looking for.

The under the transmission installation replaced the side mounted cylinder sometime around 1998 but I'm not feeling confident on the dates.....